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Commit | Line | Data |
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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. | |
6922c0c7 HD |
9 | * Copyright (C) 2002-2011 Hugh Dickins. |
10 | * Copyright (C) 2011 Google Inc. | |
0edd73b3 | 11 | * Copyright (C) 2002-2005 VERITAS Software Corporation. |
1da177e4 LT |
12 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
13 | * | |
14 | * Extended attribute support for tmpfs: | |
15 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
16 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
17 | * | |
853ac43a MM |
18 | * tiny-shmem: |
19 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
20 | * | |
1da177e4 LT |
21 | * This file is released under the GPL. |
22 | */ | |
23 | ||
853ac43a MM |
24 | #include <linux/fs.h> |
25 | #include <linux/init.h> | |
26 | #include <linux/vfs.h> | |
27 | #include <linux/mount.h> | |
caefba17 | 28 | #include <linux/pagemap.h> |
853ac43a MM |
29 | #include <linux/file.h> |
30 | #include <linux/mm.h> | |
b95f1b31 | 31 | #include <linux/export.h> |
853ac43a MM |
32 | #include <linux/swap.h> |
33 | ||
34 | static struct vfsmount *shm_mnt; | |
35 | ||
36 | #ifdef CONFIG_SHMEM | |
1da177e4 LT |
37 | /* |
38 | * This virtual memory filesystem is heavily based on the ramfs. It | |
39 | * extends ramfs by the ability to use swap and honor resource limits | |
40 | * which makes it a completely usable filesystem. | |
41 | */ | |
42 | ||
39f0247d | 43 | #include <linux/xattr.h> |
a5694255 | 44 | #include <linux/exportfs.h> |
1c7c474c | 45 | #include <linux/posix_acl.h> |
39f0247d | 46 | #include <linux/generic_acl.h> |
1da177e4 | 47 | #include <linux/mman.h> |
1da177e4 LT |
48 | #include <linux/string.h> |
49 | #include <linux/slab.h> | |
50 | #include <linux/backing-dev.h> | |
51 | #include <linux/shmem_fs.h> | |
1da177e4 | 52 | #include <linux/writeback.h> |
1da177e4 | 53 | #include <linux/blkdev.h> |
bda97eab | 54 | #include <linux/pagevec.h> |
41ffe5d5 | 55 | #include <linux/percpu_counter.h> |
708e3508 | 56 | #include <linux/splice.h> |
1da177e4 LT |
57 | #include <linux/security.h> |
58 | #include <linux/swapops.h> | |
59 | #include <linux/mempolicy.h> | |
60 | #include <linux/namei.h> | |
b00dc3ad | 61 | #include <linux/ctype.h> |
304dbdb7 | 62 | #include <linux/migrate.h> |
c1f60a5a | 63 | #include <linux/highmem.h> |
680d794b | 64 | #include <linux/seq_file.h> |
92562927 | 65 | #include <linux/magic.h> |
304dbdb7 | 66 | |
1da177e4 | 67 | #include <asm/uaccess.h> |
1da177e4 LT |
68 | #include <asm/pgtable.h> |
69 | ||
caefba17 | 70 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
1da177e4 LT |
71 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
72 | ||
1da177e4 LT |
73 | /* Pretend that each entry is of this size in directory's i_size */ |
74 | #define BOGO_DIRENT_SIZE 20 | |
75 | ||
69f07ec9 HD |
76 | /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ |
77 | #define SHORT_SYMLINK_LEN 128 | |
78 | ||
b09e0fa4 EP |
79 | struct shmem_xattr { |
80 | struct list_head list; /* anchored by shmem_inode_info->xattr_list */ | |
81 | char *name; /* xattr name */ | |
82 | size_t size; | |
83 | char value[0]; | |
84 | }; | |
85 | ||
285b2c4f | 86 | /* Flag allocation requirements to shmem_getpage */ |
1da177e4 | 87 | enum sgp_type { |
1da177e4 LT |
88 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
89 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 90 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
91 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
92 | }; | |
93 | ||
b76db735 | 94 | #ifdef CONFIG_TMPFS |
680d794b AM |
95 | static unsigned long shmem_default_max_blocks(void) |
96 | { | |
97 | return totalram_pages / 2; | |
98 | } | |
99 | ||
100 | static unsigned long shmem_default_max_inodes(void) | |
101 | { | |
102 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
103 | } | |
b76db735 | 104 | #endif |
680d794b | 105 | |
68da9f05 HD |
106 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
107 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); | |
108 | ||
109 | static inline int shmem_getpage(struct inode *inode, pgoff_t index, | |
110 | struct page **pagep, enum sgp_type sgp, int *fault_type) | |
111 | { | |
112 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
113 | mapping_gfp_mask(inode->i_mapping), fault_type); | |
114 | } | |
1da177e4 | 115 | |
1da177e4 LT |
116 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
117 | { | |
118 | return sb->s_fs_info; | |
119 | } | |
120 | ||
121 | /* | |
122 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
123 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
124 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
125 | * consistent with the pre-accounting of private mappings ... | |
126 | */ | |
127 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
128 | { | |
0b0a0806 HD |
129 | return (flags & VM_NORESERVE) ? |
130 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
131 | } |
132 | ||
133 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
134 | { | |
0b0a0806 | 135 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
136 | vm_unacct_memory(VM_ACCT(size)); |
137 | } | |
138 | ||
139 | /* | |
140 | * ... whereas tmpfs objects are accounted incrementally as | |
141 | * pages are allocated, in order to allow huge sparse files. | |
142 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
143 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
144 | */ | |
145 | static inline int shmem_acct_block(unsigned long flags) | |
146 | { | |
0b0a0806 HD |
147 | return (flags & VM_NORESERVE) ? |
148 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
149 | } |
150 | ||
151 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
152 | { | |
0b0a0806 | 153 | if (flags & VM_NORESERVE) |
1da177e4 LT |
154 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
155 | } | |
156 | ||
759b9775 | 157 | static const struct super_operations shmem_ops; |
f5e54d6e | 158 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 159 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
160 | static const struct inode_operations shmem_inode_operations; |
161 | static const struct inode_operations shmem_dir_inode_operations; | |
162 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 163 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 164 | |
6c231b7b | 165 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 166 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 167 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
168 | }; |
169 | ||
170 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 171 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 | 172 | |
5b04c689 PE |
173 | static int shmem_reserve_inode(struct super_block *sb) |
174 | { | |
175 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
176 | if (sbinfo->max_inodes) { | |
177 | spin_lock(&sbinfo->stat_lock); | |
178 | if (!sbinfo->free_inodes) { | |
179 | spin_unlock(&sbinfo->stat_lock); | |
180 | return -ENOSPC; | |
181 | } | |
182 | sbinfo->free_inodes--; | |
183 | spin_unlock(&sbinfo->stat_lock); | |
184 | } | |
185 | return 0; | |
186 | } | |
187 | ||
188 | static void shmem_free_inode(struct super_block *sb) | |
189 | { | |
190 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
191 | if (sbinfo->max_inodes) { | |
192 | spin_lock(&sbinfo->stat_lock); | |
193 | sbinfo->free_inodes++; | |
194 | spin_unlock(&sbinfo->stat_lock); | |
195 | } | |
196 | } | |
197 | ||
46711810 | 198 | /** |
41ffe5d5 | 199 | * shmem_recalc_inode - recalculate the block usage of an inode |
1da177e4 LT |
200 | * @inode: inode to recalc |
201 | * | |
202 | * We have to calculate the free blocks since the mm can drop | |
203 | * undirtied hole pages behind our back. | |
204 | * | |
205 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
206 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
207 | * | |
208 | * It has to be called with the spinlock held. | |
209 | */ | |
210 | static void shmem_recalc_inode(struct inode *inode) | |
211 | { | |
212 | struct shmem_inode_info *info = SHMEM_I(inode); | |
213 | long freed; | |
214 | ||
215 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
216 | if (freed > 0) { | |
54af6042 HD |
217 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
218 | if (sbinfo->max_blocks) | |
219 | percpu_counter_add(&sbinfo->used_blocks, -freed); | |
1da177e4 | 220 | info->alloced -= freed; |
54af6042 | 221 | inode->i_blocks -= freed * BLOCKS_PER_PAGE; |
1da177e4 | 222 | shmem_unacct_blocks(info->flags, freed); |
1da177e4 LT |
223 | } |
224 | } | |
225 | ||
7a5d0fbb HD |
226 | /* |
227 | * Replace item expected in radix tree by a new item, while holding tree lock. | |
228 | */ | |
229 | static int shmem_radix_tree_replace(struct address_space *mapping, | |
230 | pgoff_t index, void *expected, void *replacement) | |
231 | { | |
232 | void **pslot; | |
233 | void *item = NULL; | |
234 | ||
235 | VM_BUG_ON(!expected); | |
236 | pslot = radix_tree_lookup_slot(&mapping->page_tree, index); | |
237 | if (pslot) | |
238 | item = radix_tree_deref_slot_protected(pslot, | |
239 | &mapping->tree_lock); | |
240 | if (item != expected) | |
241 | return -ENOENT; | |
242 | if (replacement) | |
243 | radix_tree_replace_slot(pslot, replacement); | |
244 | else | |
245 | radix_tree_delete(&mapping->page_tree, index); | |
246 | return 0; | |
247 | } | |
248 | ||
46f65ec1 HD |
249 | /* |
250 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
251 | */ | |
252 | static int shmem_add_to_page_cache(struct page *page, | |
253 | struct address_space *mapping, | |
254 | pgoff_t index, gfp_t gfp, void *expected) | |
255 | { | |
aa3b1895 | 256 | int error = 0; |
46f65ec1 HD |
257 | |
258 | VM_BUG_ON(!PageLocked(page)); | |
259 | VM_BUG_ON(!PageSwapBacked(page)); | |
260 | ||
46f65ec1 HD |
261 | if (!expected) |
262 | error = radix_tree_preload(gfp & GFP_RECLAIM_MASK); | |
263 | if (!error) { | |
264 | page_cache_get(page); | |
265 | page->mapping = mapping; | |
266 | page->index = index; | |
267 | ||
268 | spin_lock_irq(&mapping->tree_lock); | |
269 | if (!expected) | |
270 | error = radix_tree_insert(&mapping->page_tree, | |
271 | index, page); | |
272 | else | |
273 | error = shmem_radix_tree_replace(mapping, index, | |
274 | expected, page); | |
275 | if (!error) { | |
276 | mapping->nrpages++; | |
277 | __inc_zone_page_state(page, NR_FILE_PAGES); | |
278 | __inc_zone_page_state(page, NR_SHMEM); | |
279 | spin_unlock_irq(&mapping->tree_lock); | |
280 | } else { | |
281 | page->mapping = NULL; | |
282 | spin_unlock_irq(&mapping->tree_lock); | |
283 | page_cache_release(page); | |
284 | } | |
285 | if (!expected) | |
286 | radix_tree_preload_end(); | |
287 | } | |
288 | if (error) | |
289 | mem_cgroup_uncharge_cache_page(page); | |
46f65ec1 HD |
290 | return error; |
291 | } | |
292 | ||
6922c0c7 HD |
293 | /* |
294 | * Like delete_from_page_cache, but substitutes swap for page. | |
295 | */ | |
296 | static void shmem_delete_from_page_cache(struct page *page, void *radswap) | |
297 | { | |
298 | struct address_space *mapping = page->mapping; | |
299 | int error; | |
300 | ||
301 | spin_lock_irq(&mapping->tree_lock); | |
302 | error = shmem_radix_tree_replace(mapping, page->index, page, radswap); | |
303 | page->mapping = NULL; | |
304 | mapping->nrpages--; | |
305 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
306 | __dec_zone_page_state(page, NR_SHMEM); | |
307 | spin_unlock_irq(&mapping->tree_lock); | |
308 | page_cache_release(page); | |
309 | BUG_ON(error); | |
310 | } | |
311 | ||
7a5d0fbb HD |
312 | /* |
313 | * Like find_get_pages, but collecting swap entries as well as pages. | |
314 | */ | |
315 | static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping, | |
316 | pgoff_t start, unsigned int nr_pages, | |
317 | struct page **pages, pgoff_t *indices) | |
318 | { | |
319 | unsigned int i; | |
320 | unsigned int ret; | |
321 | unsigned int nr_found; | |
322 | ||
323 | rcu_read_lock(); | |
324 | restart: | |
325 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, | |
326 | (void ***)pages, indices, start, nr_pages); | |
327 | ret = 0; | |
328 | for (i = 0; i < nr_found; i++) { | |
329 | struct page *page; | |
330 | repeat: | |
331 | page = radix_tree_deref_slot((void **)pages[i]); | |
332 | if (unlikely(!page)) | |
333 | continue; | |
334 | if (radix_tree_exception(page)) { | |
8079b1c8 HD |
335 | if (radix_tree_deref_retry(page)) |
336 | goto restart; | |
337 | /* | |
338 | * Otherwise, we must be storing a swap entry | |
339 | * here as an exceptional entry: so return it | |
340 | * without attempting to raise page count. | |
341 | */ | |
342 | goto export; | |
7a5d0fbb HD |
343 | } |
344 | if (!page_cache_get_speculative(page)) | |
345 | goto repeat; | |
346 | ||
347 | /* Has the page moved? */ | |
348 | if (unlikely(page != *((void **)pages[i]))) { | |
349 | page_cache_release(page); | |
350 | goto repeat; | |
351 | } | |
352 | export: | |
353 | indices[ret] = indices[i]; | |
354 | pages[ret] = page; | |
355 | ret++; | |
356 | } | |
357 | if (unlikely(!ret && nr_found)) | |
358 | goto restart; | |
359 | rcu_read_unlock(); | |
360 | return ret; | |
361 | } | |
362 | ||
363 | /* | |
364 | * Remove swap entry from radix tree, free the swap and its page cache. | |
365 | */ | |
366 | static int shmem_free_swap(struct address_space *mapping, | |
367 | pgoff_t index, void *radswap) | |
368 | { | |
369 | int error; | |
370 | ||
371 | spin_lock_irq(&mapping->tree_lock); | |
372 | error = shmem_radix_tree_replace(mapping, index, radswap, NULL); | |
373 | spin_unlock_irq(&mapping->tree_lock); | |
374 | if (!error) | |
375 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
376 | return error; | |
377 | } | |
378 | ||
379 | /* | |
380 | * Pagevec may contain swap entries, so shuffle up pages before releasing. | |
381 | */ | |
24513264 | 382 | static void shmem_deswap_pagevec(struct pagevec *pvec) |
7a5d0fbb HD |
383 | { |
384 | int i, j; | |
385 | ||
386 | for (i = 0, j = 0; i < pagevec_count(pvec); i++) { | |
387 | struct page *page = pvec->pages[i]; | |
388 | if (!radix_tree_exceptional_entry(page)) | |
389 | pvec->pages[j++] = page; | |
390 | } | |
391 | pvec->nr = j; | |
24513264 HD |
392 | } |
393 | ||
394 | /* | |
395 | * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. | |
396 | */ | |
397 | void shmem_unlock_mapping(struct address_space *mapping) | |
398 | { | |
399 | struct pagevec pvec; | |
400 | pgoff_t indices[PAGEVEC_SIZE]; | |
401 | pgoff_t index = 0; | |
402 | ||
403 | pagevec_init(&pvec, 0); | |
404 | /* | |
405 | * Minor point, but we might as well stop if someone else SHM_LOCKs it. | |
406 | */ | |
407 | while (!mapping_unevictable(mapping)) { | |
408 | /* | |
409 | * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it | |
410 | * has finished, if it hits a row of PAGEVEC_SIZE swap entries. | |
411 | */ | |
412 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, | |
413 | PAGEVEC_SIZE, pvec.pages, indices); | |
414 | if (!pvec.nr) | |
415 | break; | |
416 | index = indices[pvec.nr - 1] + 1; | |
417 | shmem_deswap_pagevec(&pvec); | |
418 | check_move_unevictable_pages(pvec.pages, pvec.nr); | |
419 | pagevec_release(&pvec); | |
420 | cond_resched(); | |
421 | } | |
7a5d0fbb HD |
422 | } |
423 | ||
424 | /* | |
425 | * Remove range of pages and swap entries from radix tree, and free them. | |
426 | */ | |
285b2c4f | 427 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
1da177e4 | 428 | { |
285b2c4f | 429 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 430 | struct shmem_inode_info *info = SHMEM_I(inode); |
285b2c4f | 431 | pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
bda97eab | 432 | unsigned partial = lstart & (PAGE_CACHE_SIZE - 1); |
285b2c4f | 433 | pgoff_t end = (lend >> PAGE_CACHE_SHIFT); |
bda97eab | 434 | struct pagevec pvec; |
7a5d0fbb HD |
435 | pgoff_t indices[PAGEVEC_SIZE]; |
436 | long nr_swaps_freed = 0; | |
285b2c4f | 437 | pgoff_t index; |
bda97eab HD |
438 | int i; |
439 | ||
440 | BUG_ON((lend & (PAGE_CACHE_SIZE - 1)) != (PAGE_CACHE_SIZE - 1)); | |
441 | ||
442 | pagevec_init(&pvec, 0); | |
443 | index = start; | |
7a5d0fbb HD |
444 | while (index <= end) { |
445 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, | |
446 | min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, | |
447 | pvec.pages, indices); | |
448 | if (!pvec.nr) | |
449 | break; | |
bda97eab HD |
450 | mem_cgroup_uncharge_start(); |
451 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
452 | struct page *page = pvec.pages[i]; | |
453 | ||
7a5d0fbb | 454 | index = indices[i]; |
bda97eab HD |
455 | if (index > end) |
456 | break; | |
457 | ||
7a5d0fbb HD |
458 | if (radix_tree_exceptional_entry(page)) { |
459 | nr_swaps_freed += !shmem_free_swap(mapping, | |
460 | index, page); | |
bda97eab | 461 | continue; |
7a5d0fbb HD |
462 | } |
463 | ||
464 | if (!trylock_page(page)) | |
bda97eab | 465 | continue; |
7a5d0fbb HD |
466 | if (page->mapping == mapping) { |
467 | VM_BUG_ON(PageWriteback(page)); | |
468 | truncate_inode_page(mapping, page); | |
bda97eab | 469 | } |
bda97eab HD |
470 | unlock_page(page); |
471 | } | |
24513264 HD |
472 | shmem_deswap_pagevec(&pvec); |
473 | pagevec_release(&pvec); | |
bda97eab HD |
474 | mem_cgroup_uncharge_end(); |
475 | cond_resched(); | |
476 | index++; | |
477 | } | |
1da177e4 | 478 | |
bda97eab HD |
479 | if (partial) { |
480 | struct page *page = NULL; | |
481 | shmem_getpage(inode, start - 1, &page, SGP_READ, NULL); | |
482 | if (page) { | |
483 | zero_user_segment(page, partial, PAGE_CACHE_SIZE); | |
484 | set_page_dirty(page); | |
485 | unlock_page(page); | |
486 | page_cache_release(page); | |
487 | } | |
488 | } | |
489 | ||
490 | index = start; | |
491 | for ( ; ; ) { | |
492 | cond_resched(); | |
7a5d0fbb HD |
493 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, |
494 | min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, | |
495 | pvec.pages, indices); | |
496 | if (!pvec.nr) { | |
bda97eab HD |
497 | if (index == start) |
498 | break; | |
499 | index = start; | |
500 | continue; | |
501 | } | |
7a5d0fbb | 502 | if (index == start && indices[0] > end) { |
24513264 HD |
503 | shmem_deswap_pagevec(&pvec); |
504 | pagevec_release(&pvec); | |
bda97eab HD |
505 | break; |
506 | } | |
507 | mem_cgroup_uncharge_start(); | |
508 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
509 | struct page *page = pvec.pages[i]; | |
510 | ||
7a5d0fbb | 511 | index = indices[i]; |
bda97eab HD |
512 | if (index > end) |
513 | break; | |
514 | ||
7a5d0fbb HD |
515 | if (radix_tree_exceptional_entry(page)) { |
516 | nr_swaps_freed += !shmem_free_swap(mapping, | |
517 | index, page); | |
518 | continue; | |
519 | } | |
520 | ||
bda97eab | 521 | lock_page(page); |
7a5d0fbb HD |
522 | if (page->mapping == mapping) { |
523 | VM_BUG_ON(PageWriteback(page)); | |
524 | truncate_inode_page(mapping, page); | |
525 | } | |
bda97eab HD |
526 | unlock_page(page); |
527 | } | |
24513264 HD |
528 | shmem_deswap_pagevec(&pvec); |
529 | pagevec_release(&pvec); | |
bda97eab HD |
530 | mem_cgroup_uncharge_end(); |
531 | index++; | |
532 | } | |
94c1e62d | 533 | |
1da177e4 | 534 | spin_lock(&info->lock); |
7a5d0fbb | 535 | info->swapped -= nr_swaps_freed; |
1da177e4 LT |
536 | shmem_recalc_inode(inode); |
537 | spin_unlock(&info->lock); | |
538 | ||
285b2c4f | 539 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1da177e4 | 540 | } |
94c1e62d | 541 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 542 | |
94c1e62d | 543 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 LT |
544 | { |
545 | struct inode *inode = dentry->d_inode; | |
1da177e4 LT |
546 | int error; |
547 | ||
db78b877 CH |
548 | error = inode_change_ok(inode, attr); |
549 | if (error) | |
550 | return error; | |
551 | ||
94c1e62d HD |
552 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
553 | loff_t oldsize = inode->i_size; | |
554 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 555 | |
94c1e62d HD |
556 | if (newsize != oldsize) { |
557 | i_size_write(inode, newsize); | |
558 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
559 | } | |
560 | if (newsize < oldsize) { | |
561 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
562 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
563 | shmem_truncate_range(inode, newsize, (loff_t)-1); | |
564 | /* unmap again to remove racily COWed private pages */ | |
565 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
566 | } | |
1da177e4 LT |
567 | } |
568 | ||
db78b877 | 569 | setattr_copy(inode, attr); |
39f0247d | 570 | #ifdef CONFIG_TMPFS_POSIX_ACL |
db78b877 | 571 | if (attr->ia_valid & ATTR_MODE) |
1c7c474c | 572 | error = generic_acl_chmod(inode); |
39f0247d | 573 | #endif |
1da177e4 LT |
574 | return error; |
575 | } | |
576 | ||
1f895f75 | 577 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 578 | { |
1da177e4 | 579 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 580 | struct shmem_xattr *xattr, *nxattr; |
1da177e4 | 581 | |
3889e6e7 | 582 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
583 | shmem_unacct_size(info->flags, inode->i_size); |
584 | inode->i_size = 0; | |
3889e6e7 | 585 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 586 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 587 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 588 | list_del_init(&info->swaplist); |
cb5f7b9a | 589 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 | 590 | } |
69f07ec9 HD |
591 | } else |
592 | kfree(info->symlink); | |
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 | 614 | radswap = swp_to_radix_entry(swap); |
e504f3fd | 615 | index = radix_tree_locate_item(&mapping->page_tree, radswap); |
46f65ec1 | 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. | |
778dd893 HD |
669 | */ |
670 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
671 | if (error) | |
672 | goto out; | |
46f65ec1 | 673 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
1da177e4 | 674 | |
cb5f7b9a | 675 | mutex_lock(&shmem_swaplist_mutex); |
41ffe5d5 HD |
676 | list_for_each_safe(this, next, &shmem_swaplist) { |
677 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
285b2c4f | 678 | if (info->swapped) |
41ffe5d5 | 679 | found = shmem_unuse_inode(info, swap, page); |
6922c0c7 HD |
680 | else |
681 | list_del_init(&info->swaplist); | |
cb5f7b9a | 682 | cond_resched(); |
2e0e26c7 | 683 | if (found) |
778dd893 | 684 | break; |
1da177e4 | 685 | } |
cb5f7b9a | 686 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 | 687 | |
778dd893 HD |
688 | if (!found) |
689 | mem_cgroup_uncharge_cache_page(page); | |
690 | if (found < 0) | |
691 | error = found; | |
692 | out: | |
aaa46865 HD |
693 | unlock_page(page); |
694 | page_cache_release(page); | |
778dd893 | 695 | return error; |
1da177e4 LT |
696 | } |
697 | ||
698 | /* | |
699 | * Move the page from the page cache to the swap cache. | |
700 | */ | |
701 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
702 | { | |
703 | struct shmem_inode_info *info; | |
1da177e4 | 704 | struct address_space *mapping; |
1da177e4 | 705 | struct inode *inode; |
6922c0c7 HD |
706 | swp_entry_t swap; |
707 | pgoff_t index; | |
1da177e4 LT |
708 | |
709 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
710 | mapping = page->mapping; |
711 | index = page->index; | |
712 | inode = mapping->host; | |
713 | info = SHMEM_I(inode); | |
714 | if (info->flags & VM_LOCKED) | |
715 | goto redirty; | |
d9fe526a | 716 | if (!total_swap_pages) |
1da177e4 LT |
717 | goto redirty; |
718 | ||
d9fe526a HD |
719 | /* |
720 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
721 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
48f170fb | 722 | * might use ->writepage of its underlying filesystem, in which case |
d9fe526a | 723 | * tmpfs should write out to swap only in response to memory pressure, |
48f170fb | 724 | * and not for the writeback threads or sync. |
d9fe526a | 725 | */ |
48f170fb HD |
726 | if (!wbc->for_reclaim) { |
727 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
728 | goto redirty; | |
729 | } | |
730 | swap = get_swap_page(); | |
731 | if (!swap.val) | |
732 | goto redirty; | |
d9fe526a | 733 | |
b1dea800 HD |
734 | /* |
735 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
6922c0c7 HD |
736 | * if it's not already there. Do it now before the page is |
737 | * moved to swap cache, when its pagelock no longer protects | |
b1dea800 | 738 | * the inode from eviction. But don't unlock the mutex until |
6922c0c7 HD |
739 | * we've incremented swapped, because shmem_unuse_inode() will |
740 | * prune a !swapped inode from the swaplist under this mutex. | |
b1dea800 | 741 | */ |
48f170fb HD |
742 | mutex_lock(&shmem_swaplist_mutex); |
743 | if (list_empty(&info->swaplist)) | |
744 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 745 | |
48f170fb | 746 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
aaa46865 | 747 | swap_shmem_alloc(swap); |
6922c0c7 HD |
748 | shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); |
749 | ||
750 | spin_lock(&info->lock); | |
751 | info->swapped++; | |
752 | shmem_recalc_inode(inode); | |
826267cf | 753 | spin_unlock(&info->lock); |
6922c0c7 HD |
754 | |
755 | mutex_unlock(&shmem_swaplist_mutex); | |
d9fe526a | 756 | BUG_ON(page_mapped(page)); |
9fab5619 | 757 | swap_writepage(page, wbc); |
1da177e4 LT |
758 | return 0; |
759 | } | |
760 | ||
6922c0c7 | 761 | mutex_unlock(&shmem_swaplist_mutex); |
cb4b86ba | 762 | swapcache_free(swap, NULL); |
1da177e4 LT |
763 | redirty: |
764 | set_page_dirty(page); | |
d9fe526a HD |
765 | if (wbc->for_reclaim) |
766 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
767 | unlock_page(page); | |
768 | return 0; | |
1da177e4 LT |
769 | } |
770 | ||
771 | #ifdef CONFIG_NUMA | |
680d794b | 772 | #ifdef CONFIG_TMPFS |
71fe804b | 773 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 774 | { |
095f1fc4 | 775 | char buffer[64]; |
680d794b | 776 | |
71fe804b | 777 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 778 | return; /* show nothing */ |
680d794b | 779 | |
71fe804b | 780 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
781 | |
782 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 783 | } |
71fe804b LS |
784 | |
785 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
786 | { | |
787 | struct mempolicy *mpol = NULL; | |
788 | if (sbinfo->mpol) { | |
789 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
790 | mpol = sbinfo->mpol; | |
791 | mpol_get(mpol); | |
792 | spin_unlock(&sbinfo->stat_lock); | |
793 | } | |
794 | return mpol; | |
795 | } | |
680d794b AM |
796 | #endif /* CONFIG_TMPFS */ |
797 | ||
41ffe5d5 HD |
798 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
799 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 800 | { |
52cd3b07 | 801 | struct mempolicy mpol, *spol; |
1da177e4 LT |
802 | struct vm_area_struct pvma; |
803 | ||
52cd3b07 | 804 | spol = mpol_cond_copy(&mpol, |
41ffe5d5 | 805 | mpol_shared_policy_lookup(&info->policy, index)); |
52cd3b07 | 806 | |
1da177e4 | 807 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 808 | pvma.vm_start = 0; |
41ffe5d5 | 809 | pvma.vm_pgoff = index; |
c4cc6d07 | 810 | pvma.vm_ops = NULL; |
52cd3b07 | 811 | pvma.vm_policy = spol; |
41ffe5d5 | 812 | return swapin_readahead(swap, gfp, &pvma, 0); |
1da177e4 LT |
813 | } |
814 | ||
02098fea | 815 | static struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 816 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 LT |
817 | { |
818 | struct vm_area_struct pvma; | |
1da177e4 | 819 | |
c4cc6d07 HD |
820 | /* Create a pseudo vma that just contains the policy */ |
821 | pvma.vm_start = 0; | |
41ffe5d5 | 822 | pvma.vm_pgoff = index; |
c4cc6d07 | 823 | pvma.vm_ops = NULL; |
41ffe5d5 | 824 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
52cd3b07 LS |
825 | |
826 | /* | |
827 | * alloc_page_vma() will drop the shared policy reference | |
828 | */ | |
829 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 830 | } |
680d794b AM |
831 | #else /* !CONFIG_NUMA */ |
832 | #ifdef CONFIG_TMPFS | |
41ffe5d5 | 833 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b AM |
834 | { |
835 | } | |
836 | #endif /* CONFIG_TMPFS */ | |
837 | ||
41ffe5d5 HD |
838 | static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
839 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 840 | { |
41ffe5d5 | 841 | return swapin_readahead(swap, gfp, NULL, 0); |
1da177e4 LT |
842 | } |
843 | ||
02098fea | 844 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 845 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 846 | { |
e84e2e13 | 847 | return alloc_page(gfp); |
1da177e4 | 848 | } |
680d794b | 849 | #endif /* CONFIG_NUMA */ |
1da177e4 | 850 | |
71fe804b LS |
851 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
852 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
853 | { | |
854 | return NULL; | |
855 | } | |
856 | #endif | |
857 | ||
1da177e4 | 858 | /* |
68da9f05 | 859 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
860 | * |
861 | * If we allocate a new one we do not mark it dirty. That's up to the | |
862 | * vm. If we swap it in we mark it dirty since we also free the swap | |
863 | * entry since a page cannot live in both the swap and page cache | |
864 | */ | |
41ffe5d5 | 865 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
68da9f05 | 866 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) |
1da177e4 LT |
867 | { |
868 | struct address_space *mapping = inode->i_mapping; | |
54af6042 | 869 | struct shmem_inode_info *info; |
1da177e4 | 870 | struct shmem_sb_info *sbinfo; |
27ab7006 | 871 | struct page *page; |
1da177e4 LT |
872 | swp_entry_t swap; |
873 | int error; | |
54af6042 | 874 | int once = 0; |
1da177e4 | 875 | |
41ffe5d5 | 876 | if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
1da177e4 | 877 | return -EFBIG; |
1da177e4 | 878 | repeat: |
54af6042 | 879 | swap.val = 0; |
41ffe5d5 | 880 | page = find_lock_page(mapping, index); |
54af6042 HD |
881 | if (radix_tree_exceptional_entry(page)) { |
882 | swap = radix_to_swp_entry(page); | |
883 | page = NULL; | |
884 | } | |
885 | ||
886 | if (sgp != SGP_WRITE && | |
887 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
888 | error = -EINVAL; | |
889 | goto failed; | |
890 | } | |
891 | ||
892 | if (page || (sgp == SGP_READ && !swap.val)) { | |
b409f9fc | 893 | /* |
27ab7006 HD |
894 | * Once we can get the page lock, it must be uptodate: |
895 | * if there were an error in reading back from swap, | |
896 | * the page would not be inserted into the filecache. | |
b409f9fc | 897 | */ |
54af6042 HD |
898 | BUG_ON(page && !PageUptodate(page)); |
899 | *pagep = page; | |
900 | return 0; | |
27ab7006 HD |
901 | } |
902 | ||
903 | /* | |
54af6042 HD |
904 | * Fast cache lookup did not find it: |
905 | * bring it back from swap or allocate. | |
27ab7006 | 906 | */ |
54af6042 HD |
907 | info = SHMEM_I(inode); |
908 | sbinfo = SHMEM_SB(inode->i_sb); | |
1da177e4 | 909 | |
1da177e4 LT |
910 | if (swap.val) { |
911 | /* Look it up and read it in.. */ | |
27ab7006 HD |
912 | page = lookup_swap_cache(swap); |
913 | if (!page) { | |
1da177e4 | 914 | /* here we actually do the io */ |
68da9f05 HD |
915 | if (fault_type) |
916 | *fault_type |= VM_FAULT_MAJOR; | |
41ffe5d5 | 917 | page = shmem_swapin(swap, gfp, info, index); |
27ab7006 | 918 | if (!page) { |
54af6042 HD |
919 | error = -ENOMEM; |
920 | goto failed; | |
1da177e4 | 921 | } |
1da177e4 LT |
922 | } |
923 | ||
924 | /* We have to do this with page locked to prevent races */ | |
54af6042 | 925 | lock_page(page); |
27ab7006 | 926 | if (!PageUptodate(page)) { |
1da177e4 | 927 | error = -EIO; |
54af6042 | 928 | goto failed; |
1da177e4 | 929 | } |
54af6042 HD |
930 | wait_on_page_writeback(page); |
931 | ||
932 | /* Someone may have already done it for us */ | |
933 | if (page->mapping) { | |
934 | if (page->mapping == mapping && | |
935 | page->index == index) | |
936 | goto done; | |
937 | error = -EEXIST; | |
938 | goto failed; | |
1da177e4 | 939 | } |
27ab7006 | 940 | |
aa3b1895 HD |
941 | error = mem_cgroup_cache_charge(page, current->mm, |
942 | gfp & GFP_RECLAIM_MASK); | |
943 | if (!error) | |
944 | error = shmem_add_to_page_cache(page, mapping, index, | |
945 | gfp, swp_to_radix_entry(swap)); | |
54af6042 HD |
946 | if (error) |
947 | goto failed; | |
948 | ||
949 | spin_lock(&info->lock); | |
285b2c4f | 950 | info->swapped--; |
54af6042 | 951 | shmem_recalc_inode(inode); |
27ab7006 | 952 | spin_unlock(&info->lock); |
54af6042 HD |
953 | |
954 | delete_from_swap_cache(page); | |
27ab7006 HD |
955 | set_page_dirty(page); |
956 | swap_free(swap); | |
957 | ||
54af6042 HD |
958 | } else { |
959 | if (shmem_acct_block(info->flags)) { | |
960 | error = -ENOSPC; | |
961 | goto failed; | |
1da177e4 | 962 | } |
0edd73b3 | 963 | if (sbinfo->max_blocks) { |
fc5da22a | 964 | if (percpu_counter_compare(&sbinfo->used_blocks, |
54af6042 HD |
965 | sbinfo->max_blocks) >= 0) { |
966 | error = -ENOSPC; | |
967 | goto unacct; | |
968 | } | |
7e496299 | 969 | percpu_counter_inc(&sbinfo->used_blocks); |
54af6042 | 970 | } |
1da177e4 | 971 | |
54af6042 HD |
972 | page = shmem_alloc_page(gfp, info, index); |
973 | if (!page) { | |
974 | error = -ENOMEM; | |
975 | goto decused; | |
1da177e4 LT |
976 | } |
977 | ||
54af6042 HD |
978 | SetPageSwapBacked(page); |
979 | __set_page_locked(page); | |
aa3b1895 HD |
980 | error = mem_cgroup_cache_charge(page, current->mm, |
981 | gfp & GFP_RECLAIM_MASK); | |
982 | if (!error) | |
983 | error = shmem_add_to_page_cache(page, mapping, index, | |
984 | gfp, NULL); | |
54af6042 HD |
985 | if (error) |
986 | goto decused; | |
987 | lru_cache_add_anon(page); | |
988 | ||
989 | spin_lock(&info->lock); | |
1da177e4 | 990 | info->alloced++; |
54af6042 HD |
991 | inode->i_blocks += BLOCKS_PER_PAGE; |
992 | shmem_recalc_inode(inode); | |
1da177e4 | 993 | spin_unlock(&info->lock); |
54af6042 | 994 | |
27ab7006 HD |
995 | clear_highpage(page); |
996 | flush_dcache_page(page); | |
997 | SetPageUptodate(page); | |
a0ee5ec5 | 998 | if (sgp == SGP_DIRTY) |
27ab7006 | 999 | set_page_dirty(page); |
1da177e4 LT |
1000 | } |
1001 | done: | |
54af6042 HD |
1002 | /* Perhaps the file has been truncated since we checked */ |
1003 | if (sgp != SGP_WRITE && | |
1004 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
1005 | error = -EINVAL; | |
1006 | goto trunc; | |
e83c32e8 | 1007 | } |
54af6042 HD |
1008 | *pagep = page; |
1009 | return 0; | |
1da177e4 | 1010 | |
59a16ead | 1011 | /* |
54af6042 | 1012 | * Error recovery. |
59a16ead | 1013 | */ |
54af6042 HD |
1014 | trunc: |
1015 | ClearPageDirty(page); | |
1016 | delete_from_page_cache(page); | |
1017 | spin_lock(&info->lock); | |
1018 | info->alloced--; | |
1019 | inode->i_blocks -= BLOCKS_PER_PAGE; | |
59a16ead | 1020 | spin_unlock(&info->lock); |
54af6042 HD |
1021 | decused: |
1022 | if (sbinfo->max_blocks) | |
1023 | percpu_counter_add(&sbinfo->used_blocks, -1); | |
1024 | unacct: | |
1025 | shmem_unacct_blocks(info->flags, 1); | |
1026 | failed: | |
1027 | if (swap.val && error != -EINVAL) { | |
1028 | struct page *test = find_get_page(mapping, index); | |
1029 | if (test && !radix_tree_exceptional_entry(test)) | |
1030 | page_cache_release(test); | |
1031 | /* Have another try if the entry has changed */ | |
1032 | if (test != swp_to_radix_entry(swap)) | |
1033 | error = -EEXIST; | |
1034 | } | |
27ab7006 | 1035 | if (page) { |
54af6042 | 1036 | unlock_page(page); |
27ab7006 | 1037 | page_cache_release(page); |
54af6042 HD |
1038 | } |
1039 | if (error == -ENOSPC && !once++) { | |
1040 | info = SHMEM_I(inode); | |
1041 | spin_lock(&info->lock); | |
1042 | shmem_recalc_inode(inode); | |
1043 | spin_unlock(&info->lock); | |
27ab7006 | 1044 | goto repeat; |
ff36b801 | 1045 | } |
54af6042 HD |
1046 | if (error == -EEXIST) |
1047 | goto repeat; | |
1048 | return error; | |
1da177e4 LT |
1049 | } |
1050 | ||
d0217ac0 | 1051 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1052 | { |
d3ac7f89 | 1053 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1054 | int error; |
68da9f05 | 1055 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 1056 | |
27d54b39 | 1057 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1058 | if (error) |
1059 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 1060 | |
456f998e YH |
1061 | if (ret & VM_FAULT_MAJOR) { |
1062 | count_vm_event(PGMAJFAULT); | |
1063 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
1064 | } | |
68da9f05 | 1065 | return ret; |
1da177e4 LT |
1066 | } |
1067 | ||
1da177e4 | 1068 | #ifdef CONFIG_NUMA |
41ffe5d5 | 1069 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
1da177e4 | 1070 | { |
41ffe5d5 HD |
1071 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1072 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); | |
1da177e4 LT |
1073 | } |
1074 | ||
d8dc74f2 AB |
1075 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1076 | unsigned long addr) | |
1da177e4 | 1077 | { |
41ffe5d5 HD |
1078 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1079 | pgoff_t index; | |
1da177e4 | 1080 | |
41ffe5d5 HD |
1081 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
1082 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
1da177e4 LT |
1083 | } |
1084 | #endif | |
1085 | ||
1086 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1087 | { | |
d3ac7f89 | 1088 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1089 | struct shmem_inode_info *info = SHMEM_I(inode); |
1090 | int retval = -ENOMEM; | |
1091 | ||
1092 | spin_lock(&info->lock); | |
1093 | if (lock && !(info->flags & VM_LOCKED)) { | |
1094 | if (!user_shm_lock(inode->i_size, user)) | |
1095 | goto out_nomem; | |
1096 | info->flags |= VM_LOCKED; | |
89e004ea | 1097 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1098 | } |
1099 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1100 | user_shm_unlock(inode->i_size, user); | |
1101 | info->flags &= ~VM_LOCKED; | |
89e004ea | 1102 | mapping_clear_unevictable(file->f_mapping); |
1da177e4 LT |
1103 | } |
1104 | retval = 0; | |
89e004ea | 1105 | |
1da177e4 LT |
1106 | out_nomem: |
1107 | spin_unlock(&info->lock); | |
1108 | return retval; | |
1109 | } | |
1110 | ||
9b83a6a8 | 1111 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1112 | { |
1113 | file_accessed(file); | |
1114 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1115 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1116 | return 0; |
1117 | } | |
1118 | ||
454abafe | 1119 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
09208d15 | 1120 | umode_t mode, dev_t dev, unsigned long flags) |
1da177e4 LT |
1121 | { |
1122 | struct inode *inode; | |
1123 | struct shmem_inode_info *info; | |
1124 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1125 | ||
5b04c689 PE |
1126 | if (shmem_reserve_inode(sb)) |
1127 | return NULL; | |
1da177e4 LT |
1128 | |
1129 | inode = new_inode(sb); | |
1130 | if (inode) { | |
85fe4025 | 1131 | inode->i_ino = get_next_ino(); |
454abafe | 1132 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1133 | inode->i_blocks = 0; |
1da177e4 LT |
1134 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1135 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1136 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1137 | info = SHMEM_I(inode); |
1138 | memset(info, 0, (char *)inode - (char *)info); | |
1139 | spin_lock_init(&info->lock); | |
0b0a0806 | 1140 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1141 | INIT_LIST_HEAD(&info->swaplist); |
b09e0fa4 | 1142 | INIT_LIST_HEAD(&info->xattr_list); |
72c04902 | 1143 | cache_no_acl(inode); |
1da177e4 LT |
1144 | |
1145 | switch (mode & S_IFMT) { | |
1146 | default: | |
39f0247d | 1147 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1148 | init_special_inode(inode, mode, dev); |
1149 | break; | |
1150 | case S_IFREG: | |
14fcc23f | 1151 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1152 | inode->i_op = &shmem_inode_operations; |
1153 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1154 | mpol_shared_policy_init(&info->policy, |
1155 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1156 | break; |
1157 | case S_IFDIR: | |
d8c76e6f | 1158 | inc_nlink(inode); |
1da177e4 LT |
1159 | /* Some things misbehave if size == 0 on a directory */ |
1160 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1161 | inode->i_op = &shmem_dir_inode_operations; | |
1162 | inode->i_fop = &simple_dir_operations; | |
1163 | break; | |
1164 | case S_IFLNK: | |
1165 | /* | |
1166 | * Must not load anything in the rbtree, | |
1167 | * mpol_free_shared_policy will not be called. | |
1168 | */ | |
71fe804b | 1169 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1170 | break; |
1171 | } | |
5b04c689 PE |
1172 | } else |
1173 | shmem_free_inode(sb); | |
1da177e4 LT |
1174 | return inode; |
1175 | } | |
1176 | ||
1177 | #ifdef CONFIG_TMPFS | |
92e1d5be | 1178 | static const struct inode_operations shmem_symlink_inode_operations; |
69f07ec9 | 1179 | static const struct inode_operations shmem_short_symlink_operations; |
1da177e4 | 1180 | |
1da177e4 | 1181 | static int |
800d15a5 NP |
1182 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1183 | loff_t pos, unsigned len, unsigned flags, | |
1184 | struct page **pagep, void **fsdata) | |
1da177e4 | 1185 | { |
800d15a5 NP |
1186 | struct inode *inode = mapping->host; |
1187 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
800d15a5 NP |
1188 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
1189 | } | |
1190 | ||
1191 | static int | |
1192 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1193 | loff_t pos, unsigned len, unsigned copied, | |
1194 | struct page *page, void *fsdata) | |
1195 | { | |
1196 | struct inode *inode = mapping->host; | |
1197 | ||
d3602444 HD |
1198 | if (pos + copied > inode->i_size) |
1199 | i_size_write(inode, pos + copied); | |
1200 | ||
800d15a5 | 1201 | set_page_dirty(page); |
6746aff7 | 1202 | unlock_page(page); |
800d15a5 NP |
1203 | page_cache_release(page); |
1204 | ||
800d15a5 | 1205 | return copied; |
1da177e4 LT |
1206 | } |
1207 | ||
1da177e4 LT |
1208 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1209 | { | |
d3ac7f89 | 1210 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 | 1211 | struct address_space *mapping = inode->i_mapping; |
41ffe5d5 HD |
1212 | pgoff_t index; |
1213 | unsigned long offset; | |
a0ee5ec5 HD |
1214 | enum sgp_type sgp = SGP_READ; |
1215 | ||
1216 | /* | |
1217 | * Might this read be for a stacking filesystem? Then when reading | |
1218 | * holes of a sparse file, we actually need to allocate those pages, | |
1219 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1220 | */ | |
1221 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1222 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1223 | |
1224 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1225 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1226 | ||
1227 | for (;;) { | |
1228 | struct page *page = NULL; | |
41ffe5d5 HD |
1229 | pgoff_t end_index; |
1230 | unsigned long nr, ret; | |
1da177e4 LT |
1231 | loff_t i_size = i_size_read(inode); |
1232 | ||
1233 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1234 | if (index > end_index) | |
1235 | break; | |
1236 | if (index == end_index) { | |
1237 | nr = i_size & ~PAGE_CACHE_MASK; | |
1238 | if (nr <= offset) | |
1239 | break; | |
1240 | } | |
1241 | ||
a0ee5ec5 | 1242 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1243 | if (desc->error) { |
1244 | if (desc->error == -EINVAL) | |
1245 | desc->error = 0; | |
1246 | break; | |
1247 | } | |
d3602444 HD |
1248 | if (page) |
1249 | unlock_page(page); | |
1da177e4 LT |
1250 | |
1251 | /* | |
1252 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1253 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1254 | */ |
1255 | nr = PAGE_CACHE_SIZE; | |
1256 | i_size = i_size_read(inode); | |
1257 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1258 | if (index == end_index) { | |
1259 | nr = i_size & ~PAGE_CACHE_MASK; | |
1260 | if (nr <= offset) { | |
1261 | if (page) | |
1262 | page_cache_release(page); | |
1263 | break; | |
1264 | } | |
1265 | } | |
1266 | nr -= offset; | |
1267 | ||
1268 | if (page) { | |
1269 | /* | |
1270 | * If users can be writing to this page using arbitrary | |
1271 | * virtual addresses, take care about potential aliasing | |
1272 | * before reading the page on the kernel side. | |
1273 | */ | |
1274 | if (mapping_writably_mapped(mapping)) | |
1275 | flush_dcache_page(page); | |
1276 | /* | |
1277 | * Mark the page accessed if we read the beginning. | |
1278 | */ | |
1279 | if (!offset) | |
1280 | mark_page_accessed(page); | |
b5810039 | 1281 | } else { |
1da177e4 | 1282 | page = ZERO_PAGE(0); |
b5810039 NP |
1283 | page_cache_get(page); |
1284 | } | |
1da177e4 LT |
1285 | |
1286 | /* | |
1287 | * Ok, we have the page, and it's up-to-date, so | |
1288 | * now we can copy it to user space... | |
1289 | * | |
1290 | * The actor routine returns how many bytes were actually used.. | |
1291 | * NOTE! This may not be the same as how much of a user buffer | |
1292 | * we filled up (we may be padding etc), so we can only update | |
1293 | * "pos" here (the actor routine has to update the user buffer | |
1294 | * pointers and the remaining count). | |
1295 | */ | |
1296 | ret = actor(desc, page, offset, nr); | |
1297 | offset += ret; | |
1298 | index += offset >> PAGE_CACHE_SHIFT; | |
1299 | offset &= ~PAGE_CACHE_MASK; | |
1300 | ||
1301 | page_cache_release(page); | |
1302 | if (ret != nr || !desc->count) | |
1303 | break; | |
1304 | ||
1305 | cond_resched(); | |
1306 | } | |
1307 | ||
1308 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1309 | file_accessed(filp); | |
1310 | } | |
1311 | ||
bcd78e49 HD |
1312 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1313 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1314 | { | |
1315 | struct file *filp = iocb->ki_filp; | |
1316 | ssize_t retval; | |
1317 | unsigned long seg; | |
1318 | size_t count; | |
1319 | loff_t *ppos = &iocb->ki_pos; | |
1320 | ||
1321 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1322 | if (retval) | |
1323 | return retval; | |
1324 | ||
1325 | for (seg = 0; seg < nr_segs; seg++) { | |
1326 | read_descriptor_t desc; | |
1327 | ||
1328 | desc.written = 0; | |
1329 | desc.arg.buf = iov[seg].iov_base; | |
1330 | desc.count = iov[seg].iov_len; | |
1331 | if (desc.count == 0) | |
1332 | continue; | |
1333 | desc.error = 0; | |
1334 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1335 | retval += desc.written; | |
1336 | if (desc.error) { | |
1337 | retval = retval ?: desc.error; | |
1338 | break; | |
1339 | } | |
1340 | if (desc.count > 0) | |
1341 | break; | |
1342 | } | |
1343 | return retval; | |
1da177e4 LT |
1344 | } |
1345 | ||
708e3508 HD |
1346 | static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
1347 | struct pipe_inode_info *pipe, size_t len, | |
1348 | unsigned int flags) | |
1349 | { | |
1350 | struct address_space *mapping = in->f_mapping; | |
71f0e07a | 1351 | struct inode *inode = mapping->host; |
708e3508 HD |
1352 | unsigned int loff, nr_pages, req_pages; |
1353 | struct page *pages[PIPE_DEF_BUFFERS]; | |
1354 | struct partial_page partial[PIPE_DEF_BUFFERS]; | |
1355 | struct page *page; | |
1356 | pgoff_t index, end_index; | |
1357 | loff_t isize, left; | |
1358 | int error, page_nr; | |
1359 | struct splice_pipe_desc spd = { | |
1360 | .pages = pages, | |
1361 | .partial = partial, | |
1362 | .flags = flags, | |
1363 | .ops = &page_cache_pipe_buf_ops, | |
1364 | .spd_release = spd_release_page, | |
1365 | }; | |
1366 | ||
71f0e07a | 1367 | isize = i_size_read(inode); |
708e3508 HD |
1368 | if (unlikely(*ppos >= isize)) |
1369 | return 0; | |
1370 | ||
1371 | left = isize - *ppos; | |
1372 | if (unlikely(left < len)) | |
1373 | len = left; | |
1374 | ||
1375 | if (splice_grow_spd(pipe, &spd)) | |
1376 | return -ENOMEM; | |
1377 | ||
1378 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1379 | loff = *ppos & ~PAGE_CACHE_MASK; | |
1380 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1381 | nr_pages = min(req_pages, pipe->buffers); | |
1382 | ||
708e3508 HD |
1383 | spd.nr_pages = find_get_pages_contig(mapping, index, |
1384 | nr_pages, spd.pages); | |
1385 | index += spd.nr_pages; | |
708e3508 | 1386 | error = 0; |
708e3508 | 1387 | |
71f0e07a | 1388 | while (spd.nr_pages < nr_pages) { |
71f0e07a HD |
1389 | error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
1390 | if (error) | |
1391 | break; | |
1392 | unlock_page(page); | |
708e3508 HD |
1393 | spd.pages[spd.nr_pages++] = page; |
1394 | index++; | |
1395 | } | |
1396 | ||
708e3508 HD |
1397 | index = *ppos >> PAGE_CACHE_SHIFT; |
1398 | nr_pages = spd.nr_pages; | |
1399 | spd.nr_pages = 0; | |
71f0e07a | 1400 | |
708e3508 HD |
1401 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
1402 | unsigned int this_len; | |
1403 | ||
1404 | if (!len) | |
1405 | break; | |
1406 | ||
708e3508 HD |
1407 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
1408 | page = spd.pages[page_nr]; | |
1409 | ||
71f0e07a | 1410 | if (!PageUptodate(page) || page->mapping != mapping) { |
71f0e07a HD |
1411 | error = shmem_getpage(inode, index, &page, |
1412 | SGP_CACHE, NULL); | |
1413 | if (error) | |
708e3508 | 1414 | break; |
71f0e07a HD |
1415 | unlock_page(page); |
1416 | page_cache_release(spd.pages[page_nr]); | |
1417 | spd.pages[page_nr] = page; | |
708e3508 | 1418 | } |
71f0e07a HD |
1419 | |
1420 | isize = i_size_read(inode); | |
708e3508 HD |
1421 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
1422 | if (unlikely(!isize || index > end_index)) | |
1423 | break; | |
1424 | ||
708e3508 HD |
1425 | if (end_index == index) { |
1426 | unsigned int plen; | |
1427 | ||
708e3508 HD |
1428 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
1429 | if (plen <= loff) | |
1430 | break; | |
1431 | ||
708e3508 HD |
1432 | this_len = min(this_len, plen - loff); |
1433 | len = this_len; | |
1434 | } | |
1435 | ||
1436 | spd.partial[page_nr].offset = loff; | |
1437 | spd.partial[page_nr].len = this_len; | |
1438 | len -= this_len; | |
1439 | loff = 0; | |
1440 | spd.nr_pages++; | |
1441 | index++; | |
1442 | } | |
1443 | ||
708e3508 HD |
1444 | while (page_nr < nr_pages) |
1445 | page_cache_release(spd.pages[page_nr++]); | |
708e3508 HD |
1446 | |
1447 | if (spd.nr_pages) | |
1448 | error = splice_to_pipe(pipe, &spd); | |
1449 | ||
1450 | splice_shrink_spd(pipe, &spd); | |
1451 | ||
1452 | if (error > 0) { | |
1453 | *ppos += error; | |
1454 | file_accessed(in); | |
1455 | } | |
1456 | return error; | |
1457 | } | |
1458 | ||
726c3342 | 1459 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1460 | { |
726c3342 | 1461 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1462 | |
1463 | buf->f_type = TMPFS_MAGIC; | |
1464 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1465 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1466 | if (sbinfo->max_blocks) { |
1da177e4 | 1467 | buf->f_blocks = sbinfo->max_blocks; |
41ffe5d5 HD |
1468 | buf->f_bavail = |
1469 | buf->f_bfree = sbinfo->max_blocks - | |
1470 | percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1471 | } |
1472 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1473 | buf->f_files = sbinfo->max_inodes; |
1474 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1475 | } |
1476 | /* else leave those fields 0 like simple_statfs */ | |
1477 | return 0; | |
1478 | } | |
1479 | ||
1480 | /* | |
1481 | * File creation. Allocate an inode, and we're done.. | |
1482 | */ | |
1483 | static int | |
1a67aafb | 1484 | shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 | 1485 | { |
0b0a0806 | 1486 | struct inode *inode; |
1da177e4 LT |
1487 | int error = -ENOSPC; |
1488 | ||
454abafe | 1489 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1490 | if (inode) { |
2a7dba39 | 1491 | error = security_inode_init_security(inode, dir, |
9d8f13ba | 1492 | &dentry->d_name, |
2a7dba39 | 1493 | NULL, NULL); |
570bc1c2 SS |
1494 | if (error) { |
1495 | if (error != -EOPNOTSUPP) { | |
1496 | iput(inode); | |
1497 | return error; | |
1498 | } | |
39f0247d | 1499 | } |
1c7c474c CH |
1500 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1501 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1502 | if (error) { |
1503 | iput(inode); | |
1504 | return error; | |
570bc1c2 | 1505 | } |
718deb6b AV |
1506 | #else |
1507 | error = 0; | |
1c7c474c | 1508 | #endif |
1da177e4 LT |
1509 | dir->i_size += BOGO_DIRENT_SIZE; |
1510 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1511 | d_instantiate(dentry, inode); | |
1512 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1513 | } |
1514 | return error; | |
1515 | } | |
1516 | ||
18bb1db3 | 1517 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
1518 | { |
1519 | int error; | |
1520 | ||
1521 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1522 | return error; | |
d8c76e6f | 1523 | inc_nlink(dir); |
1da177e4 LT |
1524 | return 0; |
1525 | } | |
1526 | ||
4acdaf27 | 1527 | static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
1da177e4 LT |
1528 | struct nameidata *nd) |
1529 | { | |
1530 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1531 | } | |
1532 | ||
1533 | /* | |
1534 | * Link a file.. | |
1535 | */ | |
1536 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1537 | { | |
1538 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1539 | int ret; |
1da177e4 LT |
1540 | |
1541 | /* | |
1542 | * No ordinary (disk based) filesystem counts links as inodes; | |
1543 | * but each new link needs a new dentry, pinning lowmem, and | |
1544 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1545 | */ | |
5b04c689 PE |
1546 | ret = shmem_reserve_inode(inode->i_sb); |
1547 | if (ret) | |
1548 | goto out; | |
1da177e4 LT |
1549 | |
1550 | dir->i_size += BOGO_DIRENT_SIZE; | |
1551 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1552 | inc_nlink(inode); |
7de9c6ee | 1553 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1554 | dget(dentry); /* Extra pinning count for the created dentry */ |
1555 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1556 | out: |
1557 | return ret; | |
1da177e4 LT |
1558 | } |
1559 | ||
1560 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1561 | { | |
1562 | struct inode *inode = dentry->d_inode; | |
1563 | ||
5b04c689 PE |
1564 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1565 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1566 | |
1567 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1568 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1569 | drop_nlink(inode); |
1da177e4 LT |
1570 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1571 | return 0; | |
1572 | } | |
1573 | ||
1574 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1575 | { | |
1576 | if (!simple_empty(dentry)) | |
1577 | return -ENOTEMPTY; | |
1578 | ||
9a53c3a7 DH |
1579 | drop_nlink(dentry->d_inode); |
1580 | drop_nlink(dir); | |
1da177e4 LT |
1581 | return shmem_unlink(dir, dentry); |
1582 | } | |
1583 | ||
1584 | /* | |
1585 | * The VFS layer already does all the dentry stuff for rename, | |
1586 | * we just have to decrement the usage count for the target if | |
1587 | * it exists so that the VFS layer correctly free's it when it | |
1588 | * gets overwritten. | |
1589 | */ | |
1590 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1591 | { | |
1592 | struct inode *inode = old_dentry->d_inode; | |
1593 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1594 | ||
1595 | if (!simple_empty(new_dentry)) | |
1596 | return -ENOTEMPTY; | |
1597 | ||
1598 | if (new_dentry->d_inode) { | |
1599 | (void) shmem_unlink(new_dir, new_dentry); | |
1600 | if (they_are_dirs) | |
9a53c3a7 | 1601 | drop_nlink(old_dir); |
1da177e4 | 1602 | } else if (they_are_dirs) { |
9a53c3a7 | 1603 | drop_nlink(old_dir); |
d8c76e6f | 1604 | inc_nlink(new_dir); |
1da177e4 LT |
1605 | } |
1606 | ||
1607 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1608 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1609 | old_dir->i_ctime = old_dir->i_mtime = | |
1610 | new_dir->i_ctime = new_dir->i_mtime = | |
1611 | inode->i_ctime = CURRENT_TIME; | |
1612 | return 0; | |
1613 | } | |
1614 | ||
1615 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1616 | { | |
1617 | int error; | |
1618 | int len; | |
1619 | struct inode *inode; | |
9276aad6 | 1620 | struct page *page; |
1da177e4 LT |
1621 | char *kaddr; |
1622 | struct shmem_inode_info *info; | |
1623 | ||
1624 | len = strlen(symname) + 1; | |
1625 | if (len > PAGE_CACHE_SIZE) | |
1626 | return -ENAMETOOLONG; | |
1627 | ||
454abafe | 1628 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
1629 | if (!inode) |
1630 | return -ENOSPC; | |
1631 | ||
9d8f13ba | 1632 | error = security_inode_init_security(inode, dir, &dentry->d_name, |
2a7dba39 | 1633 | NULL, NULL); |
570bc1c2 SS |
1634 | if (error) { |
1635 | if (error != -EOPNOTSUPP) { | |
1636 | iput(inode); | |
1637 | return error; | |
1638 | } | |
1639 | error = 0; | |
1640 | } | |
1641 | ||
1da177e4 LT |
1642 | info = SHMEM_I(inode); |
1643 | inode->i_size = len-1; | |
69f07ec9 HD |
1644 | if (len <= SHORT_SYMLINK_LEN) { |
1645 | info->symlink = kmemdup(symname, len, GFP_KERNEL); | |
1646 | if (!info->symlink) { | |
1647 | iput(inode); | |
1648 | return -ENOMEM; | |
1649 | } | |
1650 | inode->i_op = &shmem_short_symlink_operations; | |
1da177e4 LT |
1651 | } else { |
1652 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1653 | if (error) { | |
1654 | iput(inode); | |
1655 | return error; | |
1656 | } | |
14fcc23f | 1657 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1658 | inode->i_op = &shmem_symlink_inode_operations; |
1659 | kaddr = kmap_atomic(page, KM_USER0); | |
1660 | memcpy(kaddr, symname, len); | |
1661 | kunmap_atomic(kaddr, KM_USER0); | |
1662 | set_page_dirty(page); | |
6746aff7 | 1663 | unlock_page(page); |
1da177e4 LT |
1664 | page_cache_release(page); |
1665 | } | |
1da177e4 LT |
1666 | dir->i_size += BOGO_DIRENT_SIZE; |
1667 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1668 | d_instantiate(dentry, inode); | |
1669 | dget(dentry); | |
1670 | return 0; | |
1671 | } | |
1672 | ||
69f07ec9 | 1673 | static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 1674 | { |
69f07ec9 | 1675 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->symlink); |
cc314eef | 1676 | return NULL; |
1da177e4 LT |
1677 | } |
1678 | ||
cc314eef | 1679 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1680 | { |
1681 | struct page *page = NULL; | |
41ffe5d5 HD |
1682 | int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
1683 | nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); | |
d3602444 HD |
1684 | if (page) |
1685 | unlock_page(page); | |
cc314eef | 1686 | return page; |
1da177e4 LT |
1687 | } |
1688 | ||
cc314eef | 1689 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1690 | { |
1691 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1692 | struct page *page = cookie; |
1da177e4 LT |
1693 | kunmap(page); |
1694 | mark_page_accessed(page); | |
1695 | page_cache_release(page); | |
1da177e4 LT |
1696 | } |
1697 | } | |
1698 | ||
b09e0fa4 | 1699 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 1700 | /* |
b09e0fa4 EP |
1701 | * Superblocks without xattr inode operations may get some security.* xattr |
1702 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
1703 | * like ACLs, we also need to implement the security.* handlers at |
1704 | * filesystem level, though. | |
1705 | */ | |
1706 | ||
b09e0fa4 EP |
1707 | static int shmem_xattr_get(struct dentry *dentry, const char *name, |
1708 | void *buffer, size_t size) | |
39f0247d | 1709 | { |
b09e0fa4 EP |
1710 | struct shmem_inode_info *info; |
1711 | struct shmem_xattr *xattr; | |
1712 | int ret = -ENODATA; | |
39f0247d | 1713 | |
b09e0fa4 EP |
1714 | info = SHMEM_I(dentry->d_inode); |
1715 | ||
1716 | spin_lock(&info->lock); | |
1717 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1718 | if (strcmp(name, xattr->name)) | |
1719 | continue; | |
1720 | ||
1721 | ret = xattr->size; | |
1722 | if (buffer) { | |
1723 | if (size < xattr->size) | |
1724 | ret = -ERANGE; | |
1725 | else | |
1726 | memcpy(buffer, xattr->value, xattr->size); | |
1727 | } | |
1728 | break; | |
1729 | } | |
1730 | spin_unlock(&info->lock); | |
1731 | return ret; | |
39f0247d AG |
1732 | } |
1733 | ||
b09e0fa4 EP |
1734 | static int shmem_xattr_set(struct dentry *dentry, const char *name, |
1735 | const void *value, size_t size, int flags) | |
39f0247d | 1736 | { |
b09e0fa4 EP |
1737 | struct inode *inode = dentry->d_inode; |
1738 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1739 | struct shmem_xattr *xattr; | |
1740 | struct shmem_xattr *new_xattr = NULL; | |
1741 | size_t len; | |
1742 | int err = 0; | |
1743 | ||
1744 | /* value == NULL means remove */ | |
1745 | if (value) { | |
1746 | /* wrap around? */ | |
1747 | len = sizeof(*new_xattr) + size; | |
1748 | if (len <= sizeof(*new_xattr)) | |
1749 | return -ENOMEM; | |
1750 | ||
1751 | new_xattr = kmalloc(len, GFP_KERNEL); | |
1752 | if (!new_xattr) | |
1753 | return -ENOMEM; | |
1754 | ||
1755 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
1756 | if (!new_xattr->name) { | |
1757 | kfree(new_xattr); | |
1758 | return -ENOMEM; | |
1759 | } | |
1760 | ||
1761 | new_xattr->size = size; | |
1762 | memcpy(new_xattr->value, value, size); | |
1763 | } | |
1764 | ||
1765 | spin_lock(&info->lock); | |
1766 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1767 | if (!strcmp(name, xattr->name)) { | |
1768 | if (flags & XATTR_CREATE) { | |
1769 | xattr = new_xattr; | |
1770 | err = -EEXIST; | |
1771 | } else if (new_xattr) { | |
1772 | list_replace(&xattr->list, &new_xattr->list); | |
1773 | } else { | |
1774 | list_del(&xattr->list); | |
1775 | } | |
1776 | goto out; | |
1777 | } | |
1778 | } | |
1779 | if (flags & XATTR_REPLACE) { | |
1780 | xattr = new_xattr; | |
1781 | err = -ENODATA; | |
1782 | } else { | |
1783 | list_add(&new_xattr->list, &info->xattr_list); | |
1784 | xattr = NULL; | |
1785 | } | |
1786 | out: | |
1787 | spin_unlock(&info->lock); | |
1788 | if (xattr) | |
1789 | kfree(xattr->name); | |
1790 | kfree(xattr); | |
1791 | return err; | |
39f0247d AG |
1792 | } |
1793 | ||
bb435453 | 1794 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 1795 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1c7c474c CH |
1796 | &generic_acl_access_handler, |
1797 | &generic_acl_default_handler, | |
b09e0fa4 | 1798 | #endif |
39f0247d AG |
1799 | NULL |
1800 | }; | |
b09e0fa4 EP |
1801 | |
1802 | static int shmem_xattr_validate(const char *name) | |
1803 | { | |
1804 | struct { const char *prefix; size_t len; } arr[] = { | |
1805 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
1806 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
1807 | }; | |
1808 | int i; | |
1809 | ||
1810 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
1811 | size_t preflen = arr[i].len; | |
1812 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
1813 | if (!name[preflen]) | |
1814 | return -EINVAL; | |
1815 | return 0; | |
1816 | } | |
1817 | } | |
1818 | return -EOPNOTSUPP; | |
1819 | } | |
1820 | ||
1821 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
1822 | void *buffer, size_t size) | |
1823 | { | |
1824 | int err; | |
1825 | ||
1826 | /* | |
1827 | * If this is a request for a synthetic attribute in the system.* | |
1828 | * namespace use the generic infrastructure to resolve a handler | |
1829 | * for it via sb->s_xattr. | |
1830 | */ | |
1831 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1832 | return generic_getxattr(dentry, name, buffer, size); | |
1833 | ||
1834 | err = shmem_xattr_validate(name); | |
1835 | if (err) | |
1836 | return err; | |
1837 | ||
1838 | return shmem_xattr_get(dentry, name, buffer, size); | |
1839 | } | |
1840 | ||
1841 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
1842 | const void *value, size_t size, int flags) | |
1843 | { | |
1844 | int err; | |
1845 | ||
1846 | /* | |
1847 | * If this is a request for a synthetic attribute in the system.* | |
1848 | * namespace use the generic infrastructure to resolve a handler | |
1849 | * for it via sb->s_xattr. | |
1850 | */ | |
1851 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1852 | return generic_setxattr(dentry, name, value, size, flags); | |
1853 | ||
1854 | err = shmem_xattr_validate(name); | |
1855 | if (err) | |
1856 | return err; | |
1857 | ||
1858 | if (size == 0) | |
1859 | value = ""; /* empty EA, do not remove */ | |
1860 | ||
1861 | return shmem_xattr_set(dentry, name, value, size, flags); | |
1862 | ||
1863 | } | |
1864 | ||
1865 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
1866 | { | |
1867 | int err; | |
1868 | ||
1869 | /* | |
1870 | * If this is a request for a synthetic attribute in the system.* | |
1871 | * namespace use the generic infrastructure to resolve a handler | |
1872 | * for it via sb->s_xattr. | |
1873 | */ | |
1874 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1875 | return generic_removexattr(dentry, name); | |
1876 | ||
1877 | err = shmem_xattr_validate(name); | |
1878 | if (err) | |
1879 | return err; | |
1880 | ||
1881 | return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE); | |
1882 | } | |
1883 | ||
1884 | static bool xattr_is_trusted(const char *name) | |
1885 | { | |
1886 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
1887 | } | |
1888 | ||
1889 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
1890 | { | |
1891 | bool trusted = capable(CAP_SYS_ADMIN); | |
1892 | struct shmem_xattr *xattr; | |
1893 | struct shmem_inode_info *info; | |
1894 | size_t used = 0; | |
1895 | ||
1896 | info = SHMEM_I(dentry->d_inode); | |
1897 | ||
1898 | spin_lock(&info->lock); | |
1899 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1900 | size_t len; | |
1901 | ||
1902 | /* skip "trusted." attributes for unprivileged callers */ | |
1903 | if (!trusted && xattr_is_trusted(xattr->name)) | |
1904 | continue; | |
1905 | ||
1906 | len = strlen(xattr->name) + 1; | |
1907 | used += len; | |
1908 | if (buffer) { | |
1909 | if (size < used) { | |
1910 | used = -ERANGE; | |
1911 | break; | |
1912 | } | |
1913 | memcpy(buffer, xattr->name, len); | |
1914 | buffer += len; | |
1915 | } | |
1916 | } | |
1917 | spin_unlock(&info->lock); | |
1918 | ||
1919 | return used; | |
1920 | } | |
1921 | #endif /* CONFIG_TMPFS_XATTR */ | |
1922 | ||
69f07ec9 | 1923 | static const struct inode_operations shmem_short_symlink_operations = { |
b09e0fa4 | 1924 | .readlink = generic_readlink, |
69f07ec9 | 1925 | .follow_link = shmem_follow_short_symlink, |
b09e0fa4 EP |
1926 | #ifdef CONFIG_TMPFS_XATTR |
1927 | .setxattr = shmem_setxattr, | |
1928 | .getxattr = shmem_getxattr, | |
1929 | .listxattr = shmem_listxattr, | |
1930 | .removexattr = shmem_removexattr, | |
1931 | #endif | |
1932 | }; | |
1933 | ||
1934 | static const struct inode_operations shmem_symlink_inode_operations = { | |
1935 | .readlink = generic_readlink, | |
1936 | .follow_link = shmem_follow_link, | |
1937 | .put_link = shmem_put_link, | |
1938 | #ifdef CONFIG_TMPFS_XATTR | |
1939 | .setxattr = shmem_setxattr, | |
1940 | .getxattr = shmem_getxattr, | |
1941 | .listxattr = shmem_listxattr, | |
1942 | .removexattr = shmem_removexattr, | |
39f0247d | 1943 | #endif |
b09e0fa4 | 1944 | }; |
39f0247d | 1945 | |
91828a40 DG |
1946 | static struct dentry *shmem_get_parent(struct dentry *child) |
1947 | { | |
1948 | return ERR_PTR(-ESTALE); | |
1949 | } | |
1950 | ||
1951 | static int shmem_match(struct inode *ino, void *vfh) | |
1952 | { | |
1953 | __u32 *fh = vfh; | |
1954 | __u64 inum = fh[2]; | |
1955 | inum = (inum << 32) | fh[1]; | |
1956 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1957 | } | |
1958 | ||
480b116c CH |
1959 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
1960 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 1961 | { |
91828a40 | 1962 | struct inode *inode; |
480b116c CH |
1963 | struct dentry *dentry = NULL; |
1964 | u64 inum = fid->raw[2]; | |
1965 | inum = (inum << 32) | fid->raw[1]; | |
1966 | ||
1967 | if (fh_len < 3) | |
1968 | return NULL; | |
91828a40 | 1969 | |
480b116c CH |
1970 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
1971 | shmem_match, fid->raw); | |
91828a40 | 1972 | if (inode) { |
480b116c | 1973 | dentry = d_find_alias(inode); |
91828a40 DG |
1974 | iput(inode); |
1975 | } | |
1976 | ||
480b116c | 1977 | return dentry; |
91828a40 DG |
1978 | } |
1979 | ||
1980 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
1981 | int connectable) | |
1982 | { | |
1983 | struct inode *inode = dentry->d_inode; | |
1984 | ||
5fe0c237 AK |
1985 | if (*len < 3) { |
1986 | *len = 3; | |
91828a40 | 1987 | return 255; |
5fe0c237 | 1988 | } |
91828a40 | 1989 | |
1d3382cb | 1990 | if (inode_unhashed(inode)) { |
91828a40 DG |
1991 | /* Unfortunately insert_inode_hash is not idempotent, |
1992 | * so as we hash inodes here rather than at creation | |
1993 | * time, we need a lock to ensure we only try | |
1994 | * to do it once | |
1995 | */ | |
1996 | static DEFINE_SPINLOCK(lock); | |
1997 | spin_lock(&lock); | |
1d3382cb | 1998 | if (inode_unhashed(inode)) |
91828a40 DG |
1999 | __insert_inode_hash(inode, |
2000 | inode->i_ino + inode->i_generation); | |
2001 | spin_unlock(&lock); | |
2002 | } | |
2003 | ||
2004 | fh[0] = inode->i_generation; | |
2005 | fh[1] = inode->i_ino; | |
2006 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2007 | ||
2008 | *len = 3; | |
2009 | return 1; | |
2010 | } | |
2011 | ||
39655164 | 2012 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2013 | .get_parent = shmem_get_parent, |
91828a40 | 2014 | .encode_fh = shmem_encode_fh, |
480b116c | 2015 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2016 | }; |
2017 | ||
680d794b AM |
2018 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2019 | bool remount) | |
1da177e4 LT |
2020 | { |
2021 | char *this_char, *value, *rest; | |
2022 | ||
b00dc3ad HD |
2023 | while (options != NULL) { |
2024 | this_char = options; | |
2025 | for (;;) { | |
2026 | /* | |
2027 | * NUL-terminate this option: unfortunately, | |
2028 | * mount options form a comma-separated list, | |
2029 | * but mpol's nodelist may also contain commas. | |
2030 | */ | |
2031 | options = strchr(options, ','); | |
2032 | if (options == NULL) | |
2033 | break; | |
2034 | options++; | |
2035 | if (!isdigit(*options)) { | |
2036 | options[-1] = '\0'; | |
2037 | break; | |
2038 | } | |
2039 | } | |
1da177e4 LT |
2040 | if (!*this_char) |
2041 | continue; | |
2042 | if ((value = strchr(this_char,'=')) != NULL) { | |
2043 | *value++ = 0; | |
2044 | } else { | |
2045 | printk(KERN_ERR | |
2046 | "tmpfs: No value for mount option '%s'\n", | |
2047 | this_char); | |
2048 | return 1; | |
2049 | } | |
2050 | ||
2051 | if (!strcmp(this_char,"size")) { | |
2052 | unsigned long long size; | |
2053 | size = memparse(value,&rest); | |
2054 | if (*rest == '%') { | |
2055 | size <<= PAGE_SHIFT; | |
2056 | size *= totalram_pages; | |
2057 | do_div(size, 100); | |
2058 | rest++; | |
2059 | } | |
2060 | if (*rest) | |
2061 | goto bad_val; | |
680d794b AM |
2062 | sbinfo->max_blocks = |
2063 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2064 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2065 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2066 | if (*rest) |
2067 | goto bad_val; | |
2068 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2069 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2070 | if (*rest) |
2071 | goto bad_val; | |
2072 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2073 | if (remount) |
1da177e4 | 2074 | continue; |
680d794b | 2075 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2076 | if (*rest) |
2077 | goto bad_val; | |
2078 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2079 | if (remount) |
1da177e4 | 2080 | continue; |
680d794b | 2081 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2082 | if (*rest) |
2083 | goto bad_val; | |
2084 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2085 | if (remount) |
1da177e4 | 2086 | continue; |
680d794b | 2087 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2088 | if (*rest) |
2089 | goto bad_val; | |
7339ff83 | 2090 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2091 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2092 | goto bad_val; |
1da177e4 LT |
2093 | } else { |
2094 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2095 | this_char); | |
2096 | return 1; | |
2097 | } | |
2098 | } | |
2099 | return 0; | |
2100 | ||
2101 | bad_val: | |
2102 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2103 | value, this_char); | |
2104 | return 1; | |
2105 | ||
2106 | } | |
2107 | ||
2108 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2109 | { | |
2110 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2111 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2112 | unsigned long inodes; |
2113 | int error = -EINVAL; | |
2114 | ||
680d794b | 2115 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2116 | return error; |
1da177e4 | 2117 | |
0edd73b3 | 2118 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2119 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2120 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2121 | goto out; |
680d794b | 2122 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2123 | goto out; |
2124 | /* | |
54af6042 | 2125 | * Those tests disallow limited->unlimited while any are in use; |
0edd73b3 HD |
2126 | * but we must separately disallow unlimited->limited, because |
2127 | * in that case we have no record of how much is already in use. | |
2128 | */ | |
680d794b | 2129 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2130 | goto out; |
680d794b | 2131 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2132 | goto out; |
2133 | ||
2134 | error = 0; | |
680d794b | 2135 | sbinfo->max_blocks = config.max_blocks; |
680d794b AM |
2136 | sbinfo->max_inodes = config.max_inodes; |
2137 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2138 | |
2139 | mpol_put(sbinfo->mpol); | |
2140 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2141 | out: |
2142 | spin_unlock(&sbinfo->stat_lock); | |
2143 | return error; | |
1da177e4 | 2144 | } |
680d794b | 2145 | |
34c80b1d | 2146 | static int shmem_show_options(struct seq_file *seq, struct dentry *root) |
680d794b | 2147 | { |
34c80b1d | 2148 | struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); |
680d794b AM |
2149 | |
2150 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2151 | seq_printf(seq, ",size=%luk", | |
2152 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2153 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2154 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2155 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
09208d15 | 2156 | seq_printf(seq, ",mode=%03ho", sbinfo->mode); |
680d794b AM |
2157 | if (sbinfo->uid != 0) |
2158 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2159 | if (sbinfo->gid != 0) | |
2160 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 2161 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b AM |
2162 | return 0; |
2163 | } | |
2164 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2165 | |
2166 | static void shmem_put_super(struct super_block *sb) | |
2167 | { | |
602586a8 HD |
2168 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2169 | ||
2170 | percpu_counter_destroy(&sbinfo->used_blocks); | |
2171 | kfree(sbinfo); | |
1da177e4 LT |
2172 | sb->s_fs_info = NULL; |
2173 | } | |
2174 | ||
2b2af54a | 2175 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2176 | { |
2177 | struct inode *inode; | |
0edd73b3 | 2178 | struct shmem_sb_info *sbinfo; |
680d794b AM |
2179 | int err = -ENOMEM; |
2180 | ||
2181 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2182 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b AM |
2183 | L1_CACHE_BYTES), GFP_KERNEL); |
2184 | if (!sbinfo) | |
2185 | return -ENOMEM; | |
2186 | ||
680d794b | 2187 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2188 | sbinfo->uid = current_fsuid(); |
2189 | sbinfo->gid = current_fsgid(); | |
680d794b | 2190 | sb->s_fs_info = sbinfo; |
1da177e4 | 2191 | |
0edd73b3 | 2192 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2193 | /* |
2194 | * Per default we only allow half of the physical ram per | |
2195 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2196 | * but the internal instance is left unlimited. | |
2197 | */ | |
2198 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b AM |
2199 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2200 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2201 | if (shmem_parse_options(data, sbinfo, false)) { | |
2202 | err = -EINVAL; | |
2203 | goto failed; | |
2204 | } | |
1da177e4 | 2205 | } |
91828a40 | 2206 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2207 | #else |
2208 | sb->s_flags |= MS_NOUSER; | |
2209 | #endif | |
2210 | ||
0edd73b3 | 2211 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2212 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2213 | goto failed; | |
680d794b | 2214 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2215 | |
285b2c4f | 2216 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 LT |
2217 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2218 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2219 | sb->s_magic = TMPFS_MAGIC; | |
2220 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2221 | sb->s_time_gran = 1; |
b09e0fa4 | 2222 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2223 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2224 | #endif |
2225 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2226 | sb->s_flags |= MS_POSIXACL; |
2227 | #endif | |
0edd73b3 | 2228 | |
454abafe | 2229 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2230 | if (!inode) |
2231 | goto failed; | |
680d794b AM |
2232 | inode->i_uid = sbinfo->uid; |
2233 | inode->i_gid = sbinfo->gid; | |
318ceed0 AV |
2234 | sb->s_root = d_make_root(inode); |
2235 | if (!sb->s_root) | |
48fde701 | 2236 | goto failed; |
1da177e4 LT |
2237 | return 0; |
2238 | ||
1da177e4 LT |
2239 | failed: |
2240 | shmem_put_super(sb); | |
2241 | return err; | |
2242 | } | |
2243 | ||
fcc234f8 | 2244 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2245 | |
2246 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2247 | { | |
41ffe5d5 HD |
2248 | struct shmem_inode_info *info; |
2249 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
2250 | if (!info) | |
1da177e4 | 2251 | return NULL; |
41ffe5d5 | 2252 | return &info->vfs_inode; |
1da177e4 LT |
2253 | } |
2254 | ||
41ffe5d5 | 2255 | static void shmem_destroy_callback(struct rcu_head *head) |
fa0d7e3d NP |
2256 | { |
2257 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
fa0d7e3d NP |
2258 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2259 | } | |
2260 | ||
1da177e4 LT |
2261 | static void shmem_destroy_inode(struct inode *inode) |
2262 | { | |
09208d15 | 2263 | if (S_ISREG(inode->i_mode)) |
1da177e4 | 2264 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
41ffe5d5 | 2265 | call_rcu(&inode->i_rcu, shmem_destroy_callback); |
1da177e4 LT |
2266 | } |
2267 | ||
41ffe5d5 | 2268 | static void shmem_init_inode(void *foo) |
1da177e4 | 2269 | { |
41ffe5d5 HD |
2270 | struct shmem_inode_info *info = foo; |
2271 | inode_init_once(&info->vfs_inode); | |
1da177e4 LT |
2272 | } |
2273 | ||
41ffe5d5 | 2274 | static int shmem_init_inodecache(void) |
1da177e4 LT |
2275 | { |
2276 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2277 | sizeof(struct shmem_inode_info), | |
41ffe5d5 | 2278 | 0, SLAB_PANIC, shmem_init_inode); |
1da177e4 LT |
2279 | return 0; |
2280 | } | |
2281 | ||
41ffe5d5 | 2282 | static void shmem_destroy_inodecache(void) |
1da177e4 | 2283 | { |
1a1d92c1 | 2284 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2285 | } |
2286 | ||
f5e54d6e | 2287 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2288 | .writepage = shmem_writepage, |
76719325 | 2289 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2290 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
2291 | .write_begin = shmem_write_begin, |
2292 | .write_end = shmem_write_end, | |
1da177e4 | 2293 | #endif |
304dbdb7 | 2294 | .migratepage = migrate_page, |
aa261f54 | 2295 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2296 | }; |
2297 | ||
15ad7cdc | 2298 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2299 | .mmap = shmem_mmap, |
2300 | #ifdef CONFIG_TMPFS | |
2301 | .llseek = generic_file_llseek, | |
bcd78e49 | 2302 | .read = do_sync_read, |
5402b976 | 2303 | .write = do_sync_write, |
bcd78e49 | 2304 | .aio_read = shmem_file_aio_read, |
5402b976 | 2305 | .aio_write = generic_file_aio_write, |
1b061d92 | 2306 | .fsync = noop_fsync, |
708e3508 | 2307 | .splice_read = shmem_file_splice_read, |
ae976416 | 2308 | .splice_write = generic_file_splice_write, |
1da177e4 LT |
2309 | #endif |
2310 | }; | |
2311 | ||
92e1d5be | 2312 | static const struct inode_operations shmem_inode_operations = { |
94c1e62d | 2313 | .setattr = shmem_setattr, |
f6b3ec23 | 2314 | .truncate_range = shmem_truncate_range, |
b09e0fa4 EP |
2315 | #ifdef CONFIG_TMPFS_XATTR |
2316 | .setxattr = shmem_setxattr, | |
2317 | .getxattr = shmem_getxattr, | |
2318 | .listxattr = shmem_listxattr, | |
2319 | .removexattr = shmem_removexattr, | |
2320 | #endif | |
1da177e4 LT |
2321 | }; |
2322 | ||
92e1d5be | 2323 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2324 | #ifdef CONFIG_TMPFS |
2325 | .create = shmem_create, | |
2326 | .lookup = simple_lookup, | |
2327 | .link = shmem_link, | |
2328 | .unlink = shmem_unlink, | |
2329 | .symlink = shmem_symlink, | |
2330 | .mkdir = shmem_mkdir, | |
2331 | .rmdir = shmem_rmdir, | |
2332 | .mknod = shmem_mknod, | |
2333 | .rename = shmem_rename, | |
1da177e4 | 2334 | #endif |
b09e0fa4 EP |
2335 | #ifdef CONFIG_TMPFS_XATTR |
2336 | .setxattr = shmem_setxattr, | |
2337 | .getxattr = shmem_getxattr, | |
2338 | .listxattr = shmem_listxattr, | |
2339 | .removexattr = shmem_removexattr, | |
2340 | #endif | |
39f0247d | 2341 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2342 | .setattr = shmem_setattr, |
39f0247d AG |
2343 | #endif |
2344 | }; | |
2345 | ||
92e1d5be | 2346 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2347 | #ifdef CONFIG_TMPFS_XATTR |
2348 | .setxattr = shmem_setxattr, | |
2349 | .getxattr = shmem_getxattr, | |
2350 | .listxattr = shmem_listxattr, | |
2351 | .removexattr = shmem_removexattr, | |
2352 | #endif | |
39f0247d | 2353 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2354 | .setattr = shmem_setattr, |
39f0247d | 2355 | #endif |
1da177e4 LT |
2356 | }; |
2357 | ||
759b9775 | 2358 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2359 | .alloc_inode = shmem_alloc_inode, |
2360 | .destroy_inode = shmem_destroy_inode, | |
2361 | #ifdef CONFIG_TMPFS | |
2362 | .statfs = shmem_statfs, | |
2363 | .remount_fs = shmem_remount_fs, | |
680d794b | 2364 | .show_options = shmem_show_options, |
1da177e4 | 2365 | #endif |
1f895f75 | 2366 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2367 | .drop_inode = generic_delete_inode, |
2368 | .put_super = shmem_put_super, | |
2369 | }; | |
2370 | ||
f0f37e2f | 2371 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2372 | .fault = shmem_fault, |
1da177e4 LT |
2373 | #ifdef CONFIG_NUMA |
2374 | .set_policy = shmem_set_policy, | |
2375 | .get_policy = shmem_get_policy, | |
2376 | #endif | |
2377 | }; | |
2378 | ||
3c26ff6e AV |
2379 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2380 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2381 | { |
3c26ff6e | 2382 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2383 | } |
2384 | ||
41ffe5d5 | 2385 | static struct file_system_type shmem_fs_type = { |
1da177e4 LT |
2386 | .owner = THIS_MODULE, |
2387 | .name = "tmpfs", | |
3c26ff6e | 2388 | .mount = shmem_mount, |
1da177e4 LT |
2389 | .kill_sb = kill_litter_super, |
2390 | }; | |
1da177e4 | 2391 | |
41ffe5d5 | 2392 | int __init shmem_init(void) |
1da177e4 LT |
2393 | { |
2394 | int error; | |
2395 | ||
e0bf68dd PZ |
2396 | error = bdi_init(&shmem_backing_dev_info); |
2397 | if (error) | |
2398 | goto out4; | |
2399 | ||
41ffe5d5 | 2400 | error = shmem_init_inodecache(); |
1da177e4 LT |
2401 | if (error) |
2402 | goto out3; | |
2403 | ||
41ffe5d5 | 2404 | error = register_filesystem(&shmem_fs_type); |
1da177e4 LT |
2405 | if (error) { |
2406 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2407 | goto out2; | |
2408 | } | |
95dc112a | 2409 | |
41ffe5d5 HD |
2410 | shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER, |
2411 | shmem_fs_type.name, NULL); | |
1da177e4 LT |
2412 | if (IS_ERR(shm_mnt)) { |
2413 | error = PTR_ERR(shm_mnt); | |
2414 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2415 | goto out1; | |
2416 | } | |
2417 | return 0; | |
2418 | ||
2419 | out1: | |
41ffe5d5 | 2420 | unregister_filesystem(&shmem_fs_type); |
1da177e4 | 2421 | out2: |
41ffe5d5 | 2422 | shmem_destroy_inodecache(); |
1da177e4 | 2423 | out3: |
e0bf68dd PZ |
2424 | bdi_destroy(&shmem_backing_dev_info); |
2425 | out4: | |
1da177e4 LT |
2426 | shm_mnt = ERR_PTR(error); |
2427 | return error; | |
2428 | } | |
853ac43a MM |
2429 | |
2430 | #else /* !CONFIG_SHMEM */ | |
2431 | ||
2432 | /* | |
2433 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2434 | * | |
2435 | * This is intended for small system where the benefits of the full | |
2436 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2437 | * their complexity. On systems without swap this code should be | |
2438 | * effectively equivalent, but much lighter weight. | |
2439 | */ | |
2440 | ||
2441 | #include <linux/ramfs.h> | |
2442 | ||
41ffe5d5 | 2443 | static struct file_system_type shmem_fs_type = { |
853ac43a | 2444 | .name = "tmpfs", |
3c26ff6e | 2445 | .mount = ramfs_mount, |
853ac43a MM |
2446 | .kill_sb = kill_litter_super, |
2447 | }; | |
2448 | ||
41ffe5d5 | 2449 | int __init shmem_init(void) |
853ac43a | 2450 | { |
41ffe5d5 | 2451 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
853ac43a | 2452 | |
41ffe5d5 | 2453 | shm_mnt = kern_mount(&shmem_fs_type); |
853ac43a MM |
2454 | BUG_ON(IS_ERR(shm_mnt)); |
2455 | ||
2456 | return 0; | |
2457 | } | |
2458 | ||
41ffe5d5 | 2459 | int shmem_unuse(swp_entry_t swap, struct page *page) |
853ac43a MM |
2460 | { |
2461 | return 0; | |
2462 | } | |
2463 | ||
3f96b79a HD |
2464 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2465 | { | |
2466 | return 0; | |
2467 | } | |
2468 | ||
24513264 HD |
2469 | void shmem_unlock_mapping(struct address_space *mapping) |
2470 | { | |
2471 | } | |
2472 | ||
41ffe5d5 | 2473 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
94c1e62d | 2474 | { |
41ffe5d5 | 2475 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
94c1e62d HD |
2476 | } |
2477 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
2478 | ||
0b0a0806 HD |
2479 | #define shmem_vm_ops generic_file_vm_ops |
2480 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2481 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2482 | #define shmem_acct_size(flags, size) 0 |
2483 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
2484 | |
2485 | #endif /* CONFIG_SHMEM */ | |
2486 | ||
2487 | /* common code */ | |
1da177e4 | 2488 | |
46711810 | 2489 | /** |
1da177e4 | 2490 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2491 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2492 | * @size: size to be set for the file | |
0b0a0806 | 2493 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2494 | */ |
168f5ac6 | 2495 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2496 | { |
2497 | int error; | |
2498 | struct file *file; | |
2499 | struct inode *inode; | |
2c48b9c4 AV |
2500 | struct path path; |
2501 | struct dentry *root; | |
1da177e4 LT |
2502 | struct qstr this; |
2503 | ||
2504 | if (IS_ERR(shm_mnt)) | |
2505 | return (void *)shm_mnt; | |
2506 | ||
285b2c4f | 2507 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
2508 | return ERR_PTR(-EINVAL); |
2509 | ||
2510 | if (shmem_acct_size(flags, size)) | |
2511 | return ERR_PTR(-ENOMEM); | |
2512 | ||
2513 | error = -ENOMEM; | |
2514 | this.name = name; | |
2515 | this.len = strlen(name); | |
2516 | this.hash = 0; /* will go */ | |
2517 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2518 | path.dentry = d_alloc(root, &this); |
2519 | if (!path.dentry) | |
1da177e4 | 2520 | goto put_memory; |
2c48b9c4 | 2521 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2522 | |
1da177e4 | 2523 | error = -ENOSPC; |
454abafe | 2524 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2525 | if (!inode) |
4b42af81 | 2526 | goto put_dentry; |
1da177e4 | 2527 | |
2c48b9c4 | 2528 | d_instantiate(path.dentry, inode); |
1da177e4 | 2529 | inode->i_size = size; |
6d6b77f1 | 2530 | clear_nlink(inode); /* It is unlinked */ |
853ac43a MM |
2531 | #ifndef CONFIG_MMU |
2532 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2533 | if (error) | |
4b42af81 | 2534 | goto put_dentry; |
853ac43a | 2535 | #endif |
4b42af81 AV |
2536 | |
2537 | error = -ENFILE; | |
2c48b9c4 | 2538 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2539 | &shmem_file_operations); |
2540 | if (!file) | |
2541 | goto put_dentry; | |
2542 | ||
1da177e4 LT |
2543 | return file; |
2544 | ||
1da177e4 | 2545 | put_dentry: |
2c48b9c4 | 2546 | path_put(&path); |
1da177e4 LT |
2547 | put_memory: |
2548 | shmem_unacct_size(flags, size); | |
2549 | return ERR_PTR(error); | |
2550 | } | |
395e0ddc | 2551 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2552 | |
46711810 | 2553 | /** |
1da177e4 | 2554 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2555 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2556 | */ | |
2557 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2558 | { | |
2559 | struct file *file; | |
2560 | loff_t size = vma->vm_end - vma->vm_start; | |
2561 | ||
2562 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2563 | if (IS_ERR(file)) | |
2564 | return PTR_ERR(file); | |
2565 | ||
2566 | if (vma->vm_file) | |
2567 | fput(vma->vm_file); | |
2568 | vma->vm_file = file; | |
2569 | vma->vm_ops = &shmem_vm_ops; | |
bee4c36a | 2570 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
2571 | return 0; |
2572 | } | |
d9d90e5e HD |
2573 | |
2574 | /** | |
2575 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
2576 | * @mapping: the page's address_space | |
2577 | * @index: the page index | |
2578 | * @gfp: the page allocator flags to use if allocating | |
2579 | * | |
2580 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
2581 | * with any new page allocations done using the specified allocation flags. | |
2582 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
2583 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
2584 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
2585 | * | |
68da9f05 HD |
2586 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
2587 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
2588 | */ |
2589 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
2590 | pgoff_t index, gfp_t gfp) | |
2591 | { | |
68da9f05 HD |
2592 | #ifdef CONFIG_SHMEM |
2593 | struct inode *inode = mapping->host; | |
9276aad6 | 2594 | struct page *page; |
68da9f05 HD |
2595 | int error; |
2596 | ||
2597 | BUG_ON(mapping->a_ops != &shmem_aops); | |
2598 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); | |
2599 | if (error) | |
2600 | page = ERR_PTR(error); | |
2601 | else | |
2602 | unlock_page(page); | |
2603 | return page; | |
2604 | #else | |
2605 | /* | |
2606 | * The tiny !SHMEM case uses ramfs without swap | |
2607 | */ | |
d9d90e5e | 2608 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 2609 | #endif |
d9d90e5e HD |
2610 | } |
2611 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |