Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
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> | |
31 | #include <linux/module.h> | |
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 | ||
b09e0fa4 EP |
76 | struct shmem_xattr { |
77 | struct list_head list; /* anchored by shmem_inode_info->xattr_list */ | |
78 | char *name; /* xattr name */ | |
79 | size_t size; | |
80 | char value[0]; | |
81 | }; | |
82 | ||
285b2c4f | 83 | /* Flag allocation requirements to shmem_getpage */ |
1da177e4 | 84 | enum sgp_type { |
1da177e4 LT |
85 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
86 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 87 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
88 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
89 | }; | |
90 | ||
b76db735 | 91 | #ifdef CONFIG_TMPFS |
680d794b AM |
92 | static unsigned long shmem_default_max_blocks(void) |
93 | { | |
94 | return totalram_pages / 2; | |
95 | } | |
96 | ||
97 | static unsigned long shmem_default_max_inodes(void) | |
98 | { | |
99 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
100 | } | |
b76db735 | 101 | #endif |
680d794b | 102 | |
68da9f05 HD |
103 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
104 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); | |
105 | ||
106 | static inline int shmem_getpage(struct inode *inode, pgoff_t index, | |
107 | struct page **pagep, enum sgp_type sgp, int *fault_type) | |
108 | { | |
109 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
110 | mapping_gfp_mask(inode->i_mapping), fault_type); | |
111 | } | |
1da177e4 | 112 | |
1da177e4 LT |
113 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
114 | { | |
115 | return sb->s_fs_info; | |
116 | } | |
117 | ||
118 | /* | |
119 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
120 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
121 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
122 | * consistent with the pre-accounting of private mappings ... | |
123 | */ | |
124 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
125 | { | |
0b0a0806 HD |
126 | return (flags & VM_NORESERVE) ? |
127 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
128 | } |
129 | ||
130 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
131 | { | |
0b0a0806 | 132 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
133 | vm_unacct_memory(VM_ACCT(size)); |
134 | } | |
135 | ||
136 | /* | |
137 | * ... whereas tmpfs objects are accounted incrementally as | |
138 | * pages are allocated, in order to allow huge sparse files. | |
139 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
140 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
141 | */ | |
142 | static inline int shmem_acct_block(unsigned long flags) | |
143 | { | |
0b0a0806 HD |
144 | return (flags & VM_NORESERVE) ? |
145 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
146 | } |
147 | ||
148 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
149 | { | |
0b0a0806 | 150 | if (flags & VM_NORESERVE) |
1da177e4 LT |
151 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
152 | } | |
153 | ||
759b9775 | 154 | static const struct super_operations shmem_ops; |
f5e54d6e | 155 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 156 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
157 | static const struct inode_operations shmem_inode_operations; |
158 | static const struct inode_operations shmem_dir_inode_operations; | |
159 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 160 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 161 | |
6c231b7b | 162 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 163 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 164 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
165 | }; |
166 | ||
167 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 168 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 | 169 | |
5b04c689 PE |
170 | static int shmem_reserve_inode(struct super_block *sb) |
171 | { | |
172 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
173 | if (sbinfo->max_inodes) { | |
174 | spin_lock(&sbinfo->stat_lock); | |
175 | if (!sbinfo->free_inodes) { | |
176 | spin_unlock(&sbinfo->stat_lock); | |
177 | return -ENOSPC; | |
178 | } | |
179 | sbinfo->free_inodes--; | |
180 | spin_unlock(&sbinfo->stat_lock); | |
181 | } | |
182 | return 0; | |
183 | } | |
184 | ||
185 | static void shmem_free_inode(struct super_block *sb) | |
186 | { | |
187 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
188 | if (sbinfo->max_inodes) { | |
189 | spin_lock(&sbinfo->stat_lock); | |
190 | sbinfo->free_inodes++; | |
191 | spin_unlock(&sbinfo->stat_lock); | |
192 | } | |
193 | } | |
194 | ||
46711810 | 195 | /** |
41ffe5d5 | 196 | * shmem_recalc_inode - recalculate the block usage of an inode |
1da177e4 LT |
197 | * @inode: inode to recalc |
198 | * | |
199 | * We have to calculate the free blocks since the mm can drop | |
200 | * undirtied hole pages behind our back. | |
201 | * | |
202 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
203 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
204 | * | |
205 | * It has to be called with the spinlock held. | |
206 | */ | |
207 | static void shmem_recalc_inode(struct inode *inode) | |
208 | { | |
209 | struct shmem_inode_info *info = SHMEM_I(inode); | |
210 | long freed; | |
211 | ||
212 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
213 | if (freed > 0) { | |
54af6042 HD |
214 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
215 | if (sbinfo->max_blocks) | |
216 | percpu_counter_add(&sbinfo->used_blocks, -freed); | |
1da177e4 | 217 | info->alloced -= freed; |
54af6042 | 218 | inode->i_blocks -= freed * BLOCKS_PER_PAGE; |
1da177e4 | 219 | shmem_unacct_blocks(info->flags, freed); |
1da177e4 LT |
220 | } |
221 | } | |
222 | ||
7a5d0fbb HD |
223 | /* |
224 | * Replace item expected in radix tree by a new item, while holding tree lock. | |
225 | */ | |
226 | static int shmem_radix_tree_replace(struct address_space *mapping, | |
227 | pgoff_t index, void *expected, void *replacement) | |
228 | { | |
229 | void **pslot; | |
230 | void *item = NULL; | |
231 | ||
232 | VM_BUG_ON(!expected); | |
233 | pslot = radix_tree_lookup_slot(&mapping->page_tree, index); | |
234 | if (pslot) | |
235 | item = radix_tree_deref_slot_protected(pslot, | |
236 | &mapping->tree_lock); | |
237 | if (item != expected) | |
238 | return -ENOENT; | |
239 | if (replacement) | |
240 | radix_tree_replace_slot(pslot, replacement); | |
241 | else | |
242 | radix_tree_delete(&mapping->page_tree, index); | |
243 | return 0; | |
244 | } | |
245 | ||
46f65ec1 HD |
246 | /* |
247 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
248 | */ | |
249 | static int shmem_add_to_page_cache(struct page *page, | |
250 | struct address_space *mapping, | |
251 | pgoff_t index, gfp_t gfp, void *expected) | |
252 | { | |
aa3b1895 | 253 | int error = 0; |
46f65ec1 HD |
254 | |
255 | VM_BUG_ON(!PageLocked(page)); | |
256 | VM_BUG_ON(!PageSwapBacked(page)); | |
257 | ||
46f65ec1 HD |
258 | if (!expected) |
259 | error = radix_tree_preload(gfp & GFP_RECLAIM_MASK); | |
260 | if (!error) { | |
261 | page_cache_get(page); | |
262 | page->mapping = mapping; | |
263 | page->index = index; | |
264 | ||
265 | spin_lock_irq(&mapping->tree_lock); | |
266 | if (!expected) | |
267 | error = radix_tree_insert(&mapping->page_tree, | |
268 | index, page); | |
269 | else | |
270 | error = shmem_radix_tree_replace(mapping, index, | |
271 | expected, page); | |
272 | if (!error) { | |
273 | mapping->nrpages++; | |
274 | __inc_zone_page_state(page, NR_FILE_PAGES); | |
275 | __inc_zone_page_state(page, NR_SHMEM); | |
276 | spin_unlock_irq(&mapping->tree_lock); | |
277 | } else { | |
278 | page->mapping = NULL; | |
279 | spin_unlock_irq(&mapping->tree_lock); | |
280 | page_cache_release(page); | |
281 | } | |
282 | if (!expected) | |
283 | radix_tree_preload_end(); | |
284 | } | |
285 | if (error) | |
286 | mem_cgroup_uncharge_cache_page(page); | |
46f65ec1 HD |
287 | return error; |
288 | } | |
289 | ||
6922c0c7 HD |
290 | /* |
291 | * Like delete_from_page_cache, but substitutes swap for page. | |
292 | */ | |
293 | static void shmem_delete_from_page_cache(struct page *page, void *radswap) | |
294 | { | |
295 | struct address_space *mapping = page->mapping; | |
296 | int error; | |
297 | ||
298 | spin_lock_irq(&mapping->tree_lock); | |
299 | error = shmem_radix_tree_replace(mapping, page->index, page, radswap); | |
300 | page->mapping = NULL; | |
301 | mapping->nrpages--; | |
302 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
303 | __dec_zone_page_state(page, NR_SHMEM); | |
304 | spin_unlock_irq(&mapping->tree_lock); | |
305 | page_cache_release(page); | |
306 | BUG_ON(error); | |
307 | } | |
308 | ||
7a5d0fbb HD |
309 | /* |
310 | * Like find_get_pages, but collecting swap entries as well as pages. | |
311 | */ | |
312 | static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping, | |
313 | pgoff_t start, unsigned int nr_pages, | |
314 | struct page **pages, pgoff_t *indices) | |
315 | { | |
316 | unsigned int i; | |
317 | unsigned int ret; | |
318 | unsigned int nr_found; | |
319 | ||
320 | rcu_read_lock(); | |
321 | restart: | |
322 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, | |
323 | (void ***)pages, indices, start, nr_pages); | |
324 | ret = 0; | |
325 | for (i = 0; i < nr_found; i++) { | |
326 | struct page *page; | |
327 | repeat: | |
328 | page = radix_tree_deref_slot((void **)pages[i]); | |
329 | if (unlikely(!page)) | |
330 | continue; | |
331 | if (radix_tree_exception(page)) { | |
332 | if (radix_tree_exceptional_entry(page)) | |
333 | goto export; | |
334 | /* radix_tree_deref_retry(page) */ | |
335 | goto restart; | |
336 | } | |
337 | if (!page_cache_get_speculative(page)) | |
338 | goto repeat; | |
339 | ||
340 | /* Has the page moved? */ | |
341 | if (unlikely(page != *((void **)pages[i]))) { | |
342 | page_cache_release(page); | |
343 | goto repeat; | |
344 | } | |
345 | export: | |
346 | indices[ret] = indices[i]; | |
347 | pages[ret] = page; | |
348 | ret++; | |
349 | } | |
350 | if (unlikely(!ret && nr_found)) | |
351 | goto restart; | |
352 | rcu_read_unlock(); | |
353 | return ret; | |
354 | } | |
355 | ||
46f65ec1 HD |
356 | /* |
357 | * Lockless lookup of swap entry in radix tree, avoiding refcount on pages. | |
358 | */ | |
359 | static pgoff_t shmem_find_swap(struct address_space *mapping, void *radswap) | |
360 | { | |
361 | void **slots[PAGEVEC_SIZE]; | |
362 | pgoff_t indices[PAGEVEC_SIZE]; | |
363 | unsigned int nr_found; | |
364 | ||
365 | restart: | |
366 | nr_found = 1; | |
367 | indices[0] = -1; | |
368 | while (nr_found) { | |
369 | pgoff_t index = indices[nr_found - 1] + 1; | |
370 | unsigned int i; | |
371 | ||
372 | rcu_read_lock(); | |
373 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, | |
374 | slots, indices, index, PAGEVEC_SIZE); | |
375 | for (i = 0; i < nr_found; i++) { | |
376 | void *item = radix_tree_deref_slot(slots[i]); | |
377 | if (radix_tree_deref_retry(item)) { | |
378 | rcu_read_unlock(); | |
379 | goto restart; | |
380 | } | |
381 | if (item == radswap) { | |
382 | rcu_read_unlock(); | |
383 | return indices[i]; | |
384 | } | |
385 | } | |
386 | rcu_read_unlock(); | |
387 | cond_resched(); | |
388 | } | |
389 | return -1; | |
390 | } | |
391 | ||
7a5d0fbb HD |
392 | /* |
393 | * Remove swap entry from radix tree, free the swap and its page cache. | |
394 | */ | |
395 | static int shmem_free_swap(struct address_space *mapping, | |
396 | pgoff_t index, void *radswap) | |
397 | { | |
398 | int error; | |
399 | ||
400 | spin_lock_irq(&mapping->tree_lock); | |
401 | error = shmem_radix_tree_replace(mapping, index, radswap, NULL); | |
402 | spin_unlock_irq(&mapping->tree_lock); | |
403 | if (!error) | |
404 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
405 | return error; | |
406 | } | |
407 | ||
408 | /* | |
409 | * Pagevec may contain swap entries, so shuffle up pages before releasing. | |
410 | */ | |
411 | static void shmem_pagevec_release(struct pagevec *pvec) | |
412 | { | |
413 | int i, j; | |
414 | ||
415 | for (i = 0, j = 0; i < pagevec_count(pvec); i++) { | |
416 | struct page *page = pvec->pages[i]; | |
417 | if (!radix_tree_exceptional_entry(page)) | |
418 | pvec->pages[j++] = page; | |
419 | } | |
420 | pvec->nr = j; | |
421 | pagevec_release(pvec); | |
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 | } | |
7a5d0fbb | 472 | shmem_pagevec_release(&pvec); |
bda97eab HD |
473 | mem_cgroup_uncharge_end(); |
474 | cond_resched(); | |
475 | index++; | |
476 | } | |
1da177e4 | 477 | |
bda97eab HD |
478 | if (partial) { |
479 | struct page *page = NULL; | |
480 | shmem_getpage(inode, start - 1, &page, SGP_READ, NULL); | |
481 | if (page) { | |
482 | zero_user_segment(page, partial, PAGE_CACHE_SIZE); | |
483 | set_page_dirty(page); | |
484 | unlock_page(page); | |
485 | page_cache_release(page); | |
486 | } | |
487 | } | |
488 | ||
489 | index = start; | |
490 | for ( ; ; ) { | |
491 | cond_resched(); | |
7a5d0fbb HD |
492 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, |
493 | min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1, | |
494 | pvec.pages, indices); | |
495 | if (!pvec.nr) { | |
bda97eab HD |
496 | if (index == start) |
497 | break; | |
498 | index = start; | |
499 | continue; | |
500 | } | |
7a5d0fbb HD |
501 | if (index == start && indices[0] > end) { |
502 | shmem_pagevec_release(&pvec); | |
bda97eab HD |
503 | break; |
504 | } | |
505 | mem_cgroup_uncharge_start(); | |
506 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
507 | struct page *page = pvec.pages[i]; | |
508 | ||
7a5d0fbb | 509 | index = indices[i]; |
bda97eab HD |
510 | if (index > end) |
511 | break; | |
512 | ||
7a5d0fbb HD |
513 | if (radix_tree_exceptional_entry(page)) { |
514 | nr_swaps_freed += !shmem_free_swap(mapping, | |
515 | index, page); | |
516 | continue; | |
517 | } | |
518 | ||
bda97eab | 519 | lock_page(page); |
7a5d0fbb HD |
520 | if (page->mapping == mapping) { |
521 | VM_BUG_ON(PageWriteback(page)); | |
522 | truncate_inode_page(mapping, page); | |
523 | } | |
bda97eab HD |
524 | unlock_page(page); |
525 | } | |
7a5d0fbb | 526 | shmem_pagevec_release(&pvec); |
bda97eab HD |
527 | mem_cgroup_uncharge_end(); |
528 | index++; | |
529 | } | |
94c1e62d | 530 | |
1da177e4 | 531 | spin_lock(&info->lock); |
7a5d0fbb | 532 | info->swapped -= nr_swaps_freed; |
1da177e4 LT |
533 | shmem_recalc_inode(inode); |
534 | spin_unlock(&info->lock); | |
535 | ||
285b2c4f | 536 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1da177e4 | 537 | } |
94c1e62d | 538 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 539 | |
94c1e62d | 540 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 LT |
541 | { |
542 | struct inode *inode = dentry->d_inode; | |
1da177e4 LT |
543 | int error; |
544 | ||
db78b877 CH |
545 | error = inode_change_ok(inode, attr); |
546 | if (error) | |
547 | return error; | |
548 | ||
94c1e62d HD |
549 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
550 | loff_t oldsize = inode->i_size; | |
551 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 552 | |
94c1e62d HD |
553 | if (newsize != oldsize) { |
554 | i_size_write(inode, newsize); | |
555 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
556 | } | |
557 | if (newsize < oldsize) { | |
558 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
559 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
560 | shmem_truncate_range(inode, newsize, (loff_t)-1); | |
561 | /* unmap again to remove racily COWed private pages */ | |
562 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
563 | } | |
1da177e4 LT |
564 | } |
565 | ||
db78b877 | 566 | setattr_copy(inode, attr); |
39f0247d | 567 | #ifdef CONFIG_TMPFS_POSIX_ACL |
db78b877 | 568 | if (attr->ia_valid & ATTR_MODE) |
1c7c474c | 569 | error = generic_acl_chmod(inode); |
39f0247d | 570 | #endif |
1da177e4 LT |
571 | return error; |
572 | } | |
573 | ||
1f895f75 | 574 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 575 | { |
1da177e4 | 576 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 577 | struct shmem_xattr *xattr, *nxattr; |
1da177e4 | 578 | |
3889e6e7 | 579 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
580 | shmem_unacct_size(info->flags, inode->i_size); |
581 | inode->i_size = 0; | |
3889e6e7 | 582 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 583 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 584 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 585 | list_del_init(&info->swaplist); |
cb5f7b9a | 586 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
587 | } |
588 | } | |
b09e0fa4 EP |
589 | |
590 | list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { | |
591 | kfree(xattr->name); | |
592 | kfree(xattr); | |
593 | } | |
0edd73b3 | 594 | BUG_ON(inode->i_blocks); |
5b04c689 | 595 | shmem_free_inode(inode->i_sb); |
1f895f75 | 596 | end_writeback(inode); |
1da177e4 LT |
597 | } |
598 | ||
46f65ec1 HD |
599 | /* |
600 | * If swap found in inode, free it and move page from swapcache to filecache. | |
601 | */ | |
41ffe5d5 HD |
602 | static int shmem_unuse_inode(struct shmem_inode_info *info, |
603 | swp_entry_t swap, struct page *page) | |
1da177e4 | 604 | { |
285b2c4f | 605 | struct address_space *mapping = info->vfs_inode.i_mapping; |
46f65ec1 | 606 | void *radswap; |
41ffe5d5 | 607 | pgoff_t index; |
d9fe526a | 608 | int error; |
1da177e4 | 609 | |
46f65ec1 HD |
610 | radswap = swp_to_radix_entry(swap); |
611 | index = shmem_find_swap(mapping, radswap); | |
612 | if (index == -1) | |
285b2c4f | 613 | return 0; |
2e0e26c7 | 614 | |
1b1b32f2 HD |
615 | /* |
616 | * Move _head_ to start search for next from here. | |
1f895f75 | 617 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 | 618 | * mutex, and there's an instant in list_move_tail when info->swaplist |
285b2c4f | 619 | * would appear empty, if it were the only one on shmem_swaplist. |
1b1b32f2 HD |
620 | */ |
621 | if (shmem_swaplist.next != &info->swaplist) | |
622 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 623 | |
d13d1443 | 624 | /* |
778dd893 HD |
625 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
626 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
627 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 628 | */ |
46f65ec1 HD |
629 | error = shmem_add_to_page_cache(page, mapping, index, |
630 | GFP_NOWAIT, radswap); | |
778dd893 | 631 | /* which does mem_cgroup_uncharge_cache_page on error */ |
69029cd5 | 632 | |
48f170fb | 633 | if (error != -ENOMEM) { |
46f65ec1 HD |
634 | /* |
635 | * Truncation and eviction use free_swap_and_cache(), which | |
636 | * only does trylock page: if we raced, best clean up here. | |
637 | */ | |
73b1262f HD |
638 | delete_from_swap_cache(page); |
639 | set_page_dirty(page); | |
46f65ec1 HD |
640 | if (!error) { |
641 | spin_lock(&info->lock); | |
642 | info->swapped--; | |
643 | spin_unlock(&info->lock); | |
644 | swap_free(swap); | |
645 | } | |
2e0e26c7 | 646 | error = 1; /* not an error, but entry was found */ |
1da177e4 | 647 | } |
2e0e26c7 | 648 | return error; |
1da177e4 LT |
649 | } |
650 | ||
651 | /* | |
46f65ec1 | 652 | * Search through swapped inodes to find and replace swap by page. |
1da177e4 | 653 | */ |
41ffe5d5 | 654 | int shmem_unuse(swp_entry_t swap, struct page *page) |
1da177e4 | 655 | { |
41ffe5d5 | 656 | struct list_head *this, *next; |
1da177e4 LT |
657 | struct shmem_inode_info *info; |
658 | int found = 0; | |
778dd893 HD |
659 | int error; |
660 | ||
661 | /* | |
662 | * Charge page using GFP_KERNEL while we can wait, before taking | |
663 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
664 | * Charged back to the user (not to caller) when swap account is used. | |
778dd893 HD |
665 | */ |
666 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
667 | if (error) | |
668 | goto out; | |
46f65ec1 | 669 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
1da177e4 | 670 | |
cb5f7b9a | 671 | mutex_lock(&shmem_swaplist_mutex); |
41ffe5d5 HD |
672 | list_for_each_safe(this, next, &shmem_swaplist) { |
673 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
285b2c4f | 674 | if (info->swapped) |
41ffe5d5 | 675 | found = shmem_unuse_inode(info, swap, page); |
6922c0c7 HD |
676 | else |
677 | list_del_init(&info->swaplist); | |
cb5f7b9a | 678 | cond_resched(); |
2e0e26c7 | 679 | if (found) |
778dd893 | 680 | break; |
1da177e4 | 681 | } |
cb5f7b9a | 682 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 | 683 | |
778dd893 HD |
684 | if (!found) |
685 | mem_cgroup_uncharge_cache_page(page); | |
686 | if (found < 0) | |
687 | error = found; | |
688 | out: | |
aaa46865 HD |
689 | unlock_page(page); |
690 | page_cache_release(page); | |
778dd893 | 691 | return error; |
1da177e4 LT |
692 | } |
693 | ||
694 | /* | |
695 | * Move the page from the page cache to the swap cache. | |
696 | */ | |
697 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
698 | { | |
699 | struct shmem_inode_info *info; | |
1da177e4 | 700 | struct address_space *mapping; |
1da177e4 | 701 | struct inode *inode; |
6922c0c7 HD |
702 | swp_entry_t swap; |
703 | pgoff_t index; | |
1da177e4 LT |
704 | |
705 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
706 | mapping = page->mapping; |
707 | index = page->index; | |
708 | inode = mapping->host; | |
709 | info = SHMEM_I(inode); | |
710 | if (info->flags & VM_LOCKED) | |
711 | goto redirty; | |
d9fe526a | 712 | if (!total_swap_pages) |
1da177e4 LT |
713 | goto redirty; |
714 | ||
d9fe526a HD |
715 | /* |
716 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
717 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
48f170fb | 718 | * might use ->writepage of its underlying filesystem, in which case |
d9fe526a | 719 | * tmpfs should write out to swap only in response to memory pressure, |
48f170fb | 720 | * and not for the writeback threads or sync. |
d9fe526a | 721 | */ |
48f170fb HD |
722 | if (!wbc->for_reclaim) { |
723 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
724 | goto redirty; | |
725 | } | |
726 | swap = get_swap_page(); | |
727 | if (!swap.val) | |
728 | goto redirty; | |
d9fe526a | 729 | |
b1dea800 HD |
730 | /* |
731 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
6922c0c7 HD |
732 | * if it's not already there. Do it now before the page is |
733 | * moved to swap cache, when its pagelock no longer protects | |
b1dea800 | 734 | * the inode from eviction. But don't unlock the mutex until |
6922c0c7 HD |
735 | * we've incremented swapped, because shmem_unuse_inode() will |
736 | * prune a !swapped inode from the swaplist under this mutex. | |
b1dea800 | 737 | */ |
48f170fb HD |
738 | mutex_lock(&shmem_swaplist_mutex); |
739 | if (list_empty(&info->swaplist)) | |
740 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 741 | |
48f170fb | 742 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
aaa46865 | 743 | swap_shmem_alloc(swap); |
6922c0c7 HD |
744 | shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); |
745 | ||
746 | spin_lock(&info->lock); | |
747 | info->swapped++; | |
748 | shmem_recalc_inode(inode); | |
826267cf | 749 | spin_unlock(&info->lock); |
6922c0c7 HD |
750 | |
751 | mutex_unlock(&shmem_swaplist_mutex); | |
d9fe526a | 752 | BUG_ON(page_mapped(page)); |
9fab5619 | 753 | swap_writepage(page, wbc); |
1da177e4 LT |
754 | return 0; |
755 | } | |
756 | ||
6922c0c7 | 757 | mutex_unlock(&shmem_swaplist_mutex); |
cb4b86ba | 758 | swapcache_free(swap, NULL); |
1da177e4 LT |
759 | redirty: |
760 | set_page_dirty(page); | |
d9fe526a HD |
761 | if (wbc->for_reclaim) |
762 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
763 | unlock_page(page); | |
764 | return 0; | |
1da177e4 LT |
765 | } |
766 | ||
767 | #ifdef CONFIG_NUMA | |
680d794b | 768 | #ifdef CONFIG_TMPFS |
71fe804b | 769 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 770 | { |
095f1fc4 | 771 | char buffer[64]; |
680d794b | 772 | |
71fe804b | 773 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 774 | return; /* show nothing */ |
680d794b | 775 | |
71fe804b | 776 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
777 | |
778 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 779 | } |
71fe804b LS |
780 | |
781 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
782 | { | |
783 | struct mempolicy *mpol = NULL; | |
784 | if (sbinfo->mpol) { | |
785 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
786 | mpol = sbinfo->mpol; | |
787 | mpol_get(mpol); | |
788 | spin_unlock(&sbinfo->stat_lock); | |
789 | } | |
790 | return mpol; | |
791 | } | |
680d794b AM |
792 | #endif /* CONFIG_TMPFS */ |
793 | ||
41ffe5d5 HD |
794 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
795 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 796 | { |
52cd3b07 | 797 | struct mempolicy mpol, *spol; |
1da177e4 LT |
798 | struct vm_area_struct pvma; |
799 | ||
52cd3b07 | 800 | spol = mpol_cond_copy(&mpol, |
41ffe5d5 | 801 | mpol_shared_policy_lookup(&info->policy, index)); |
52cd3b07 | 802 | |
1da177e4 | 803 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 804 | pvma.vm_start = 0; |
41ffe5d5 | 805 | pvma.vm_pgoff = index; |
c4cc6d07 | 806 | pvma.vm_ops = NULL; |
52cd3b07 | 807 | pvma.vm_policy = spol; |
41ffe5d5 | 808 | return swapin_readahead(swap, gfp, &pvma, 0); |
1da177e4 LT |
809 | } |
810 | ||
02098fea | 811 | static struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 812 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 LT |
813 | { |
814 | struct vm_area_struct pvma; | |
1da177e4 | 815 | |
c4cc6d07 HD |
816 | /* Create a pseudo vma that just contains the policy */ |
817 | pvma.vm_start = 0; | |
41ffe5d5 | 818 | pvma.vm_pgoff = index; |
c4cc6d07 | 819 | pvma.vm_ops = NULL; |
41ffe5d5 | 820 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
52cd3b07 LS |
821 | |
822 | /* | |
823 | * alloc_page_vma() will drop the shared policy reference | |
824 | */ | |
825 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 826 | } |
680d794b AM |
827 | #else /* !CONFIG_NUMA */ |
828 | #ifdef CONFIG_TMPFS | |
41ffe5d5 | 829 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b AM |
830 | { |
831 | } | |
832 | #endif /* CONFIG_TMPFS */ | |
833 | ||
41ffe5d5 HD |
834 | static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
835 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 836 | { |
41ffe5d5 | 837 | return swapin_readahead(swap, gfp, NULL, 0); |
1da177e4 LT |
838 | } |
839 | ||
02098fea | 840 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 841 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 842 | { |
e84e2e13 | 843 | return alloc_page(gfp); |
1da177e4 | 844 | } |
680d794b | 845 | #endif /* CONFIG_NUMA */ |
1da177e4 | 846 | |
71fe804b LS |
847 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
848 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
849 | { | |
850 | return NULL; | |
851 | } | |
852 | #endif | |
853 | ||
1da177e4 | 854 | /* |
68da9f05 | 855 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
856 | * |
857 | * If we allocate a new one we do not mark it dirty. That's up to the | |
858 | * vm. If we swap it in we mark it dirty since we also free the swap | |
859 | * entry since a page cannot live in both the swap and page cache | |
860 | */ | |
41ffe5d5 | 861 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
68da9f05 | 862 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) |
1da177e4 LT |
863 | { |
864 | struct address_space *mapping = inode->i_mapping; | |
54af6042 | 865 | struct shmem_inode_info *info; |
1da177e4 | 866 | struct shmem_sb_info *sbinfo; |
27ab7006 | 867 | struct page *page; |
1da177e4 LT |
868 | swp_entry_t swap; |
869 | int error; | |
54af6042 | 870 | int once = 0; |
1da177e4 | 871 | |
41ffe5d5 | 872 | if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
1da177e4 | 873 | return -EFBIG; |
1da177e4 | 874 | repeat: |
54af6042 | 875 | swap.val = 0; |
41ffe5d5 | 876 | page = find_lock_page(mapping, index); |
54af6042 HD |
877 | if (radix_tree_exceptional_entry(page)) { |
878 | swap = radix_to_swp_entry(page); | |
879 | page = NULL; | |
880 | } | |
881 | ||
882 | if (sgp != SGP_WRITE && | |
883 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
884 | error = -EINVAL; | |
885 | goto failed; | |
886 | } | |
887 | ||
888 | if (page || (sgp == SGP_READ && !swap.val)) { | |
b409f9fc | 889 | /* |
27ab7006 HD |
890 | * Once we can get the page lock, it must be uptodate: |
891 | * if there were an error in reading back from swap, | |
892 | * the page would not be inserted into the filecache. | |
b409f9fc | 893 | */ |
54af6042 HD |
894 | BUG_ON(page && !PageUptodate(page)); |
895 | *pagep = page; | |
896 | return 0; | |
27ab7006 HD |
897 | } |
898 | ||
899 | /* | |
54af6042 HD |
900 | * Fast cache lookup did not find it: |
901 | * bring it back from swap or allocate. | |
27ab7006 | 902 | */ |
54af6042 HD |
903 | info = SHMEM_I(inode); |
904 | sbinfo = SHMEM_SB(inode->i_sb); | |
1da177e4 | 905 | |
1da177e4 LT |
906 | if (swap.val) { |
907 | /* Look it up and read it in.. */ | |
27ab7006 HD |
908 | page = lookup_swap_cache(swap); |
909 | if (!page) { | |
1da177e4 | 910 | /* here we actually do the io */ |
68da9f05 HD |
911 | if (fault_type) |
912 | *fault_type |= VM_FAULT_MAJOR; | |
41ffe5d5 | 913 | page = shmem_swapin(swap, gfp, info, index); |
27ab7006 | 914 | if (!page) { |
54af6042 HD |
915 | error = -ENOMEM; |
916 | goto failed; | |
1da177e4 | 917 | } |
1da177e4 LT |
918 | } |
919 | ||
920 | /* We have to do this with page locked to prevent races */ | |
54af6042 | 921 | lock_page(page); |
27ab7006 | 922 | if (!PageUptodate(page)) { |
1da177e4 | 923 | error = -EIO; |
54af6042 | 924 | goto failed; |
1da177e4 | 925 | } |
54af6042 HD |
926 | wait_on_page_writeback(page); |
927 | ||
928 | /* Someone may have already done it for us */ | |
929 | if (page->mapping) { | |
930 | if (page->mapping == mapping && | |
931 | page->index == index) | |
932 | goto done; | |
933 | error = -EEXIST; | |
934 | goto failed; | |
1da177e4 | 935 | } |
27ab7006 | 936 | |
aa3b1895 HD |
937 | error = mem_cgroup_cache_charge(page, current->mm, |
938 | gfp & GFP_RECLAIM_MASK); | |
939 | if (!error) | |
940 | error = shmem_add_to_page_cache(page, mapping, index, | |
941 | gfp, swp_to_radix_entry(swap)); | |
54af6042 HD |
942 | if (error) |
943 | goto failed; | |
944 | ||
945 | spin_lock(&info->lock); | |
285b2c4f | 946 | info->swapped--; |
54af6042 | 947 | shmem_recalc_inode(inode); |
27ab7006 | 948 | spin_unlock(&info->lock); |
54af6042 HD |
949 | |
950 | delete_from_swap_cache(page); | |
27ab7006 HD |
951 | set_page_dirty(page); |
952 | swap_free(swap); | |
953 | ||
54af6042 HD |
954 | } else { |
955 | if (shmem_acct_block(info->flags)) { | |
956 | error = -ENOSPC; | |
957 | goto failed; | |
1da177e4 | 958 | } |
0edd73b3 | 959 | if (sbinfo->max_blocks) { |
fc5da22a | 960 | if (percpu_counter_compare(&sbinfo->used_blocks, |
54af6042 HD |
961 | sbinfo->max_blocks) >= 0) { |
962 | error = -ENOSPC; | |
963 | goto unacct; | |
964 | } | |
7e496299 | 965 | percpu_counter_inc(&sbinfo->used_blocks); |
54af6042 | 966 | } |
1da177e4 | 967 | |
54af6042 HD |
968 | page = shmem_alloc_page(gfp, info, index); |
969 | if (!page) { | |
970 | error = -ENOMEM; | |
971 | goto decused; | |
1da177e4 LT |
972 | } |
973 | ||
54af6042 HD |
974 | SetPageSwapBacked(page); |
975 | __set_page_locked(page); | |
aa3b1895 HD |
976 | error = mem_cgroup_cache_charge(page, current->mm, |
977 | gfp & GFP_RECLAIM_MASK); | |
978 | if (!error) | |
979 | error = shmem_add_to_page_cache(page, mapping, index, | |
980 | gfp, NULL); | |
54af6042 HD |
981 | if (error) |
982 | goto decused; | |
983 | lru_cache_add_anon(page); | |
984 | ||
985 | spin_lock(&info->lock); | |
1da177e4 | 986 | info->alloced++; |
54af6042 HD |
987 | inode->i_blocks += BLOCKS_PER_PAGE; |
988 | shmem_recalc_inode(inode); | |
1da177e4 | 989 | spin_unlock(&info->lock); |
54af6042 | 990 | |
27ab7006 HD |
991 | clear_highpage(page); |
992 | flush_dcache_page(page); | |
993 | SetPageUptodate(page); | |
a0ee5ec5 | 994 | if (sgp == SGP_DIRTY) |
27ab7006 | 995 | set_page_dirty(page); |
1da177e4 LT |
996 | } |
997 | done: | |
54af6042 HD |
998 | /* Perhaps the file has been truncated since we checked */ |
999 | if (sgp != SGP_WRITE && | |
1000 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
1001 | error = -EINVAL; | |
1002 | goto trunc; | |
e83c32e8 | 1003 | } |
54af6042 HD |
1004 | *pagep = page; |
1005 | return 0; | |
1da177e4 | 1006 | |
59a16ead | 1007 | /* |
54af6042 | 1008 | * Error recovery. |
59a16ead | 1009 | */ |
54af6042 HD |
1010 | trunc: |
1011 | ClearPageDirty(page); | |
1012 | delete_from_page_cache(page); | |
1013 | spin_lock(&info->lock); | |
1014 | info->alloced--; | |
1015 | inode->i_blocks -= BLOCKS_PER_PAGE; | |
59a16ead | 1016 | spin_unlock(&info->lock); |
54af6042 HD |
1017 | decused: |
1018 | if (sbinfo->max_blocks) | |
1019 | percpu_counter_add(&sbinfo->used_blocks, -1); | |
1020 | unacct: | |
1021 | shmem_unacct_blocks(info->flags, 1); | |
1022 | failed: | |
1023 | if (swap.val && error != -EINVAL) { | |
1024 | struct page *test = find_get_page(mapping, index); | |
1025 | if (test && !radix_tree_exceptional_entry(test)) | |
1026 | page_cache_release(test); | |
1027 | /* Have another try if the entry has changed */ | |
1028 | if (test != swp_to_radix_entry(swap)) | |
1029 | error = -EEXIST; | |
1030 | } | |
27ab7006 | 1031 | if (page) { |
54af6042 | 1032 | unlock_page(page); |
27ab7006 | 1033 | page_cache_release(page); |
54af6042 HD |
1034 | } |
1035 | if (error == -ENOSPC && !once++) { | |
1036 | info = SHMEM_I(inode); | |
1037 | spin_lock(&info->lock); | |
1038 | shmem_recalc_inode(inode); | |
1039 | spin_unlock(&info->lock); | |
27ab7006 | 1040 | goto repeat; |
ff36b801 | 1041 | } |
54af6042 HD |
1042 | if (error == -EEXIST) |
1043 | goto repeat; | |
1044 | return error; | |
1da177e4 LT |
1045 | } |
1046 | ||
d0217ac0 | 1047 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1048 | { |
d3ac7f89 | 1049 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1050 | int error; |
68da9f05 | 1051 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 1052 | |
27d54b39 | 1053 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1054 | if (error) |
1055 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 1056 | |
456f998e YH |
1057 | if (ret & VM_FAULT_MAJOR) { |
1058 | count_vm_event(PGMAJFAULT); | |
1059 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
1060 | } | |
68da9f05 | 1061 | return ret; |
1da177e4 LT |
1062 | } |
1063 | ||
1da177e4 | 1064 | #ifdef CONFIG_NUMA |
41ffe5d5 | 1065 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
1da177e4 | 1066 | { |
41ffe5d5 HD |
1067 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1068 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); | |
1da177e4 LT |
1069 | } |
1070 | ||
d8dc74f2 AB |
1071 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1072 | unsigned long addr) | |
1da177e4 | 1073 | { |
41ffe5d5 HD |
1074 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1075 | pgoff_t index; | |
1da177e4 | 1076 | |
41ffe5d5 HD |
1077 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
1078 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
1da177e4 LT |
1079 | } |
1080 | #endif | |
1081 | ||
1082 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1083 | { | |
d3ac7f89 | 1084 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1085 | struct shmem_inode_info *info = SHMEM_I(inode); |
1086 | int retval = -ENOMEM; | |
1087 | ||
1088 | spin_lock(&info->lock); | |
1089 | if (lock && !(info->flags & VM_LOCKED)) { | |
1090 | if (!user_shm_lock(inode->i_size, user)) | |
1091 | goto out_nomem; | |
1092 | info->flags |= VM_LOCKED; | |
89e004ea | 1093 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1094 | } |
1095 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1096 | user_shm_unlock(inode->i_size, user); | |
1097 | info->flags &= ~VM_LOCKED; | |
89e004ea LS |
1098 | mapping_clear_unevictable(file->f_mapping); |
1099 | scan_mapping_unevictable_pages(file->f_mapping); | |
1da177e4 LT |
1100 | } |
1101 | retval = 0; | |
89e004ea | 1102 | |
1da177e4 LT |
1103 | out_nomem: |
1104 | spin_unlock(&info->lock); | |
1105 | return retval; | |
1106 | } | |
1107 | ||
9b83a6a8 | 1108 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1109 | { |
1110 | file_accessed(file); | |
1111 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1112 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1113 | return 0; |
1114 | } | |
1115 | ||
454abafe DM |
1116 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
1117 | int mode, dev_t dev, unsigned long flags) | |
1da177e4 LT |
1118 | { |
1119 | struct inode *inode; | |
1120 | struct shmem_inode_info *info; | |
1121 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1122 | ||
5b04c689 PE |
1123 | if (shmem_reserve_inode(sb)) |
1124 | return NULL; | |
1da177e4 LT |
1125 | |
1126 | inode = new_inode(sb); | |
1127 | if (inode) { | |
85fe4025 | 1128 | inode->i_ino = get_next_ino(); |
454abafe | 1129 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1130 | inode->i_blocks = 0; |
1da177e4 LT |
1131 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1132 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1133 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1134 | info = SHMEM_I(inode); |
1135 | memset(info, 0, (char *)inode - (char *)info); | |
1136 | spin_lock_init(&info->lock); | |
0b0a0806 | 1137 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1138 | INIT_LIST_HEAD(&info->swaplist); |
b09e0fa4 | 1139 | INIT_LIST_HEAD(&info->xattr_list); |
72c04902 | 1140 | cache_no_acl(inode); |
1da177e4 LT |
1141 | |
1142 | switch (mode & S_IFMT) { | |
1143 | default: | |
39f0247d | 1144 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1145 | init_special_inode(inode, mode, dev); |
1146 | break; | |
1147 | case S_IFREG: | |
14fcc23f | 1148 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1149 | inode->i_op = &shmem_inode_operations; |
1150 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1151 | mpol_shared_policy_init(&info->policy, |
1152 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1153 | break; |
1154 | case S_IFDIR: | |
d8c76e6f | 1155 | inc_nlink(inode); |
1da177e4 LT |
1156 | /* Some things misbehave if size == 0 on a directory */ |
1157 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1158 | inode->i_op = &shmem_dir_inode_operations; | |
1159 | inode->i_fop = &simple_dir_operations; | |
1160 | break; | |
1161 | case S_IFLNK: | |
1162 | /* | |
1163 | * Must not load anything in the rbtree, | |
1164 | * mpol_free_shared_policy will not be called. | |
1165 | */ | |
71fe804b | 1166 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1167 | break; |
1168 | } | |
5b04c689 PE |
1169 | } else |
1170 | shmem_free_inode(sb); | |
1da177e4 LT |
1171 | return inode; |
1172 | } | |
1173 | ||
1174 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1175 | static const struct inode_operations shmem_symlink_inode_operations; |
1176 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 | 1177 | |
1da177e4 | 1178 | static int |
800d15a5 NP |
1179 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1180 | loff_t pos, unsigned len, unsigned flags, | |
1181 | struct page **pagep, void **fsdata) | |
1da177e4 | 1182 | { |
800d15a5 NP |
1183 | struct inode *inode = mapping->host; |
1184 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
800d15a5 NP |
1185 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
1186 | } | |
1187 | ||
1188 | static int | |
1189 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1190 | loff_t pos, unsigned len, unsigned copied, | |
1191 | struct page *page, void *fsdata) | |
1192 | { | |
1193 | struct inode *inode = mapping->host; | |
1194 | ||
d3602444 HD |
1195 | if (pos + copied > inode->i_size) |
1196 | i_size_write(inode, pos + copied); | |
1197 | ||
800d15a5 | 1198 | set_page_dirty(page); |
6746aff7 | 1199 | unlock_page(page); |
800d15a5 NP |
1200 | page_cache_release(page); |
1201 | ||
800d15a5 | 1202 | return copied; |
1da177e4 LT |
1203 | } |
1204 | ||
1da177e4 LT |
1205 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1206 | { | |
d3ac7f89 | 1207 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 | 1208 | struct address_space *mapping = inode->i_mapping; |
41ffe5d5 HD |
1209 | pgoff_t index; |
1210 | unsigned long offset; | |
a0ee5ec5 HD |
1211 | enum sgp_type sgp = SGP_READ; |
1212 | ||
1213 | /* | |
1214 | * Might this read be for a stacking filesystem? Then when reading | |
1215 | * holes of a sparse file, we actually need to allocate those pages, | |
1216 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1217 | */ | |
1218 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1219 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1220 | |
1221 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1222 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1223 | ||
1224 | for (;;) { | |
1225 | struct page *page = NULL; | |
41ffe5d5 HD |
1226 | pgoff_t end_index; |
1227 | unsigned long nr, ret; | |
1da177e4 LT |
1228 | loff_t i_size = i_size_read(inode); |
1229 | ||
1230 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1231 | if (index > end_index) | |
1232 | break; | |
1233 | if (index == end_index) { | |
1234 | nr = i_size & ~PAGE_CACHE_MASK; | |
1235 | if (nr <= offset) | |
1236 | break; | |
1237 | } | |
1238 | ||
a0ee5ec5 | 1239 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1240 | if (desc->error) { |
1241 | if (desc->error == -EINVAL) | |
1242 | desc->error = 0; | |
1243 | break; | |
1244 | } | |
d3602444 HD |
1245 | if (page) |
1246 | unlock_page(page); | |
1da177e4 LT |
1247 | |
1248 | /* | |
1249 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1250 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1251 | */ |
1252 | nr = PAGE_CACHE_SIZE; | |
1253 | i_size = i_size_read(inode); | |
1254 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1255 | if (index == end_index) { | |
1256 | nr = i_size & ~PAGE_CACHE_MASK; | |
1257 | if (nr <= offset) { | |
1258 | if (page) | |
1259 | page_cache_release(page); | |
1260 | break; | |
1261 | } | |
1262 | } | |
1263 | nr -= offset; | |
1264 | ||
1265 | if (page) { | |
1266 | /* | |
1267 | * If users can be writing to this page using arbitrary | |
1268 | * virtual addresses, take care about potential aliasing | |
1269 | * before reading the page on the kernel side. | |
1270 | */ | |
1271 | if (mapping_writably_mapped(mapping)) | |
1272 | flush_dcache_page(page); | |
1273 | /* | |
1274 | * Mark the page accessed if we read the beginning. | |
1275 | */ | |
1276 | if (!offset) | |
1277 | mark_page_accessed(page); | |
b5810039 | 1278 | } else { |
1da177e4 | 1279 | page = ZERO_PAGE(0); |
b5810039 NP |
1280 | page_cache_get(page); |
1281 | } | |
1da177e4 LT |
1282 | |
1283 | /* | |
1284 | * Ok, we have the page, and it's up-to-date, so | |
1285 | * now we can copy it to user space... | |
1286 | * | |
1287 | * The actor routine returns how many bytes were actually used.. | |
1288 | * NOTE! This may not be the same as how much of a user buffer | |
1289 | * we filled up (we may be padding etc), so we can only update | |
1290 | * "pos" here (the actor routine has to update the user buffer | |
1291 | * pointers and the remaining count). | |
1292 | */ | |
1293 | ret = actor(desc, page, offset, nr); | |
1294 | offset += ret; | |
1295 | index += offset >> PAGE_CACHE_SHIFT; | |
1296 | offset &= ~PAGE_CACHE_MASK; | |
1297 | ||
1298 | page_cache_release(page); | |
1299 | if (ret != nr || !desc->count) | |
1300 | break; | |
1301 | ||
1302 | cond_resched(); | |
1303 | } | |
1304 | ||
1305 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1306 | file_accessed(filp); | |
1307 | } | |
1308 | ||
bcd78e49 HD |
1309 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1310 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1311 | { | |
1312 | struct file *filp = iocb->ki_filp; | |
1313 | ssize_t retval; | |
1314 | unsigned long seg; | |
1315 | size_t count; | |
1316 | loff_t *ppos = &iocb->ki_pos; | |
1317 | ||
1318 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1319 | if (retval) | |
1320 | return retval; | |
1321 | ||
1322 | for (seg = 0; seg < nr_segs; seg++) { | |
1323 | read_descriptor_t desc; | |
1324 | ||
1325 | desc.written = 0; | |
1326 | desc.arg.buf = iov[seg].iov_base; | |
1327 | desc.count = iov[seg].iov_len; | |
1328 | if (desc.count == 0) | |
1329 | continue; | |
1330 | desc.error = 0; | |
1331 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1332 | retval += desc.written; | |
1333 | if (desc.error) { | |
1334 | retval = retval ?: desc.error; | |
1335 | break; | |
1336 | } | |
1337 | if (desc.count > 0) | |
1338 | break; | |
1339 | } | |
1340 | return retval; | |
1da177e4 LT |
1341 | } |
1342 | ||
708e3508 HD |
1343 | static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
1344 | struct pipe_inode_info *pipe, size_t len, | |
1345 | unsigned int flags) | |
1346 | { | |
1347 | struct address_space *mapping = in->f_mapping; | |
71f0e07a | 1348 | struct inode *inode = mapping->host; |
708e3508 HD |
1349 | unsigned int loff, nr_pages, req_pages; |
1350 | struct page *pages[PIPE_DEF_BUFFERS]; | |
1351 | struct partial_page partial[PIPE_DEF_BUFFERS]; | |
1352 | struct page *page; | |
1353 | pgoff_t index, end_index; | |
1354 | loff_t isize, left; | |
1355 | int error, page_nr; | |
1356 | struct splice_pipe_desc spd = { | |
1357 | .pages = pages, | |
1358 | .partial = partial, | |
1359 | .flags = flags, | |
1360 | .ops = &page_cache_pipe_buf_ops, | |
1361 | .spd_release = spd_release_page, | |
1362 | }; | |
1363 | ||
71f0e07a | 1364 | isize = i_size_read(inode); |
708e3508 HD |
1365 | if (unlikely(*ppos >= isize)) |
1366 | return 0; | |
1367 | ||
1368 | left = isize - *ppos; | |
1369 | if (unlikely(left < len)) | |
1370 | len = left; | |
1371 | ||
1372 | if (splice_grow_spd(pipe, &spd)) | |
1373 | return -ENOMEM; | |
1374 | ||
1375 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1376 | loff = *ppos & ~PAGE_CACHE_MASK; | |
1377 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1378 | nr_pages = min(req_pages, pipe->buffers); | |
1379 | ||
708e3508 HD |
1380 | spd.nr_pages = find_get_pages_contig(mapping, index, |
1381 | nr_pages, spd.pages); | |
1382 | index += spd.nr_pages; | |
708e3508 | 1383 | error = 0; |
708e3508 | 1384 | |
71f0e07a | 1385 | while (spd.nr_pages < nr_pages) { |
71f0e07a HD |
1386 | error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
1387 | if (error) | |
1388 | break; | |
1389 | unlock_page(page); | |
708e3508 HD |
1390 | spd.pages[spd.nr_pages++] = page; |
1391 | index++; | |
1392 | } | |
1393 | ||
708e3508 HD |
1394 | index = *ppos >> PAGE_CACHE_SHIFT; |
1395 | nr_pages = spd.nr_pages; | |
1396 | spd.nr_pages = 0; | |
71f0e07a | 1397 | |
708e3508 HD |
1398 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
1399 | unsigned int this_len; | |
1400 | ||
1401 | if (!len) | |
1402 | break; | |
1403 | ||
708e3508 HD |
1404 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
1405 | page = spd.pages[page_nr]; | |
1406 | ||
71f0e07a | 1407 | if (!PageUptodate(page) || page->mapping != mapping) { |
71f0e07a HD |
1408 | error = shmem_getpage(inode, index, &page, |
1409 | SGP_CACHE, NULL); | |
1410 | if (error) | |
708e3508 | 1411 | break; |
71f0e07a HD |
1412 | unlock_page(page); |
1413 | page_cache_release(spd.pages[page_nr]); | |
1414 | spd.pages[page_nr] = page; | |
708e3508 | 1415 | } |
71f0e07a HD |
1416 | |
1417 | isize = i_size_read(inode); | |
708e3508 HD |
1418 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
1419 | if (unlikely(!isize || index > end_index)) | |
1420 | break; | |
1421 | ||
708e3508 HD |
1422 | if (end_index == index) { |
1423 | unsigned int plen; | |
1424 | ||
708e3508 HD |
1425 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
1426 | if (plen <= loff) | |
1427 | break; | |
1428 | ||
708e3508 HD |
1429 | this_len = min(this_len, plen - loff); |
1430 | len = this_len; | |
1431 | } | |
1432 | ||
1433 | spd.partial[page_nr].offset = loff; | |
1434 | spd.partial[page_nr].len = this_len; | |
1435 | len -= this_len; | |
1436 | loff = 0; | |
1437 | spd.nr_pages++; | |
1438 | index++; | |
1439 | } | |
1440 | ||
708e3508 HD |
1441 | while (page_nr < nr_pages) |
1442 | page_cache_release(spd.pages[page_nr++]); | |
708e3508 HD |
1443 | |
1444 | if (spd.nr_pages) | |
1445 | error = splice_to_pipe(pipe, &spd); | |
1446 | ||
1447 | splice_shrink_spd(pipe, &spd); | |
1448 | ||
1449 | if (error > 0) { | |
1450 | *ppos += error; | |
1451 | file_accessed(in); | |
1452 | } | |
1453 | return error; | |
1454 | } | |
1455 | ||
726c3342 | 1456 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1457 | { |
726c3342 | 1458 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1459 | |
1460 | buf->f_type = TMPFS_MAGIC; | |
1461 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1462 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1463 | if (sbinfo->max_blocks) { |
1da177e4 | 1464 | buf->f_blocks = sbinfo->max_blocks; |
41ffe5d5 HD |
1465 | buf->f_bavail = |
1466 | buf->f_bfree = sbinfo->max_blocks - | |
1467 | percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1468 | } |
1469 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1470 | buf->f_files = sbinfo->max_inodes; |
1471 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1472 | } |
1473 | /* else leave those fields 0 like simple_statfs */ | |
1474 | return 0; | |
1475 | } | |
1476 | ||
1477 | /* | |
1478 | * File creation. Allocate an inode, and we're done.. | |
1479 | */ | |
1480 | static int | |
1481 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1482 | { | |
0b0a0806 | 1483 | struct inode *inode; |
1da177e4 LT |
1484 | int error = -ENOSPC; |
1485 | ||
454abafe | 1486 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1487 | if (inode) { |
2a7dba39 EP |
1488 | error = security_inode_init_security(inode, dir, |
1489 | &dentry->d_name, NULL, | |
1490 | NULL, NULL); | |
570bc1c2 SS |
1491 | if (error) { |
1492 | if (error != -EOPNOTSUPP) { | |
1493 | iput(inode); | |
1494 | return error; | |
1495 | } | |
39f0247d | 1496 | } |
1c7c474c CH |
1497 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1498 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1499 | if (error) { |
1500 | iput(inode); | |
1501 | return error; | |
570bc1c2 | 1502 | } |
718deb6b AV |
1503 | #else |
1504 | error = 0; | |
1c7c474c | 1505 | #endif |
1da177e4 LT |
1506 | dir->i_size += BOGO_DIRENT_SIZE; |
1507 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1508 | d_instantiate(dentry, inode); | |
1509 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1510 | } |
1511 | return error; | |
1512 | } | |
1513 | ||
1514 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1515 | { | |
1516 | int error; | |
1517 | ||
1518 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1519 | return error; | |
d8c76e6f | 1520 | inc_nlink(dir); |
1da177e4 LT |
1521 | return 0; |
1522 | } | |
1523 | ||
1524 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1525 | struct nameidata *nd) | |
1526 | { | |
1527 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1528 | } | |
1529 | ||
1530 | /* | |
1531 | * Link a file.. | |
1532 | */ | |
1533 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1534 | { | |
1535 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1536 | int ret; |
1da177e4 LT |
1537 | |
1538 | /* | |
1539 | * No ordinary (disk based) filesystem counts links as inodes; | |
1540 | * but each new link needs a new dentry, pinning lowmem, and | |
1541 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1542 | */ | |
5b04c689 PE |
1543 | ret = shmem_reserve_inode(inode->i_sb); |
1544 | if (ret) | |
1545 | goto out; | |
1da177e4 LT |
1546 | |
1547 | dir->i_size += BOGO_DIRENT_SIZE; | |
1548 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1549 | inc_nlink(inode); |
7de9c6ee | 1550 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1551 | dget(dentry); /* Extra pinning count for the created dentry */ |
1552 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1553 | out: |
1554 | return ret; | |
1da177e4 LT |
1555 | } |
1556 | ||
1557 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1558 | { | |
1559 | struct inode *inode = dentry->d_inode; | |
1560 | ||
5b04c689 PE |
1561 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1562 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1563 | |
1564 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1565 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1566 | drop_nlink(inode); |
1da177e4 LT |
1567 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1568 | return 0; | |
1569 | } | |
1570 | ||
1571 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1572 | { | |
1573 | if (!simple_empty(dentry)) | |
1574 | return -ENOTEMPTY; | |
1575 | ||
9a53c3a7 DH |
1576 | drop_nlink(dentry->d_inode); |
1577 | drop_nlink(dir); | |
1da177e4 LT |
1578 | return shmem_unlink(dir, dentry); |
1579 | } | |
1580 | ||
1581 | /* | |
1582 | * The VFS layer already does all the dentry stuff for rename, | |
1583 | * we just have to decrement the usage count for the target if | |
1584 | * it exists so that the VFS layer correctly free's it when it | |
1585 | * gets overwritten. | |
1586 | */ | |
1587 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1588 | { | |
1589 | struct inode *inode = old_dentry->d_inode; | |
1590 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1591 | ||
1592 | if (!simple_empty(new_dentry)) | |
1593 | return -ENOTEMPTY; | |
1594 | ||
1595 | if (new_dentry->d_inode) { | |
1596 | (void) shmem_unlink(new_dir, new_dentry); | |
1597 | if (they_are_dirs) | |
9a53c3a7 | 1598 | drop_nlink(old_dir); |
1da177e4 | 1599 | } else if (they_are_dirs) { |
9a53c3a7 | 1600 | drop_nlink(old_dir); |
d8c76e6f | 1601 | inc_nlink(new_dir); |
1da177e4 LT |
1602 | } |
1603 | ||
1604 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1605 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1606 | old_dir->i_ctime = old_dir->i_mtime = | |
1607 | new_dir->i_ctime = new_dir->i_mtime = | |
1608 | inode->i_ctime = CURRENT_TIME; | |
1609 | return 0; | |
1610 | } | |
1611 | ||
1612 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1613 | { | |
1614 | int error; | |
1615 | int len; | |
1616 | struct inode *inode; | |
9276aad6 | 1617 | struct page *page; |
1da177e4 LT |
1618 | char *kaddr; |
1619 | struct shmem_inode_info *info; | |
1620 | ||
1621 | len = strlen(symname) + 1; | |
1622 | if (len > PAGE_CACHE_SIZE) | |
1623 | return -ENAMETOOLONG; | |
1624 | ||
454abafe | 1625 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
1626 | if (!inode) |
1627 | return -ENOSPC; | |
1628 | ||
2a7dba39 EP |
1629 | error = security_inode_init_security(inode, dir, &dentry->d_name, NULL, |
1630 | NULL, NULL); | |
570bc1c2 SS |
1631 | if (error) { |
1632 | if (error != -EOPNOTSUPP) { | |
1633 | iput(inode); | |
1634 | return error; | |
1635 | } | |
1636 | error = 0; | |
1637 | } | |
1638 | ||
1da177e4 LT |
1639 | info = SHMEM_I(inode); |
1640 | inode->i_size = len-1; | |
b09e0fa4 | 1641 | if (len <= SHMEM_SYMLINK_INLINE_LEN) { |
1da177e4 | 1642 | /* do it inline */ |
b09e0fa4 | 1643 | memcpy(info->inline_symlink, symname, len); |
1da177e4 LT |
1644 | inode->i_op = &shmem_symlink_inline_operations; |
1645 | } else { | |
1646 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1647 | if (error) { | |
1648 | iput(inode); | |
1649 | return error; | |
1650 | } | |
14fcc23f | 1651 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1652 | inode->i_op = &shmem_symlink_inode_operations; |
1653 | kaddr = kmap_atomic(page, KM_USER0); | |
1654 | memcpy(kaddr, symname, len); | |
1655 | kunmap_atomic(kaddr, KM_USER0); | |
1656 | set_page_dirty(page); | |
6746aff7 | 1657 | unlock_page(page); |
1da177e4 LT |
1658 | page_cache_release(page); |
1659 | } | |
1da177e4 LT |
1660 | dir->i_size += BOGO_DIRENT_SIZE; |
1661 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1662 | d_instantiate(dentry, inode); | |
1663 | dget(dentry); | |
1664 | return 0; | |
1665 | } | |
1666 | ||
cc314eef | 1667 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 1668 | { |
b09e0fa4 | 1669 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink); |
cc314eef | 1670 | return NULL; |
1da177e4 LT |
1671 | } |
1672 | ||
cc314eef | 1673 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1674 | { |
1675 | struct page *page = NULL; | |
41ffe5d5 HD |
1676 | int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
1677 | nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); | |
d3602444 HD |
1678 | if (page) |
1679 | unlock_page(page); | |
cc314eef | 1680 | return page; |
1da177e4 LT |
1681 | } |
1682 | ||
cc314eef | 1683 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1684 | { |
1685 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1686 | struct page *page = cookie; |
1da177e4 LT |
1687 | kunmap(page); |
1688 | mark_page_accessed(page); | |
1689 | page_cache_release(page); | |
1da177e4 LT |
1690 | } |
1691 | } | |
1692 | ||
b09e0fa4 | 1693 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 1694 | /* |
b09e0fa4 EP |
1695 | * Superblocks without xattr inode operations may get some security.* xattr |
1696 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
1697 | * like ACLs, we also need to implement the security.* handlers at |
1698 | * filesystem level, though. | |
1699 | */ | |
1700 | ||
b09e0fa4 EP |
1701 | static int shmem_xattr_get(struct dentry *dentry, const char *name, |
1702 | void *buffer, size_t size) | |
39f0247d | 1703 | { |
b09e0fa4 EP |
1704 | struct shmem_inode_info *info; |
1705 | struct shmem_xattr *xattr; | |
1706 | int ret = -ENODATA; | |
39f0247d | 1707 | |
b09e0fa4 EP |
1708 | info = SHMEM_I(dentry->d_inode); |
1709 | ||
1710 | spin_lock(&info->lock); | |
1711 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1712 | if (strcmp(name, xattr->name)) | |
1713 | continue; | |
1714 | ||
1715 | ret = xattr->size; | |
1716 | if (buffer) { | |
1717 | if (size < xattr->size) | |
1718 | ret = -ERANGE; | |
1719 | else | |
1720 | memcpy(buffer, xattr->value, xattr->size); | |
1721 | } | |
1722 | break; | |
1723 | } | |
1724 | spin_unlock(&info->lock); | |
1725 | return ret; | |
39f0247d AG |
1726 | } |
1727 | ||
b09e0fa4 EP |
1728 | static int shmem_xattr_set(struct dentry *dentry, const char *name, |
1729 | const void *value, size_t size, int flags) | |
39f0247d | 1730 | { |
b09e0fa4 EP |
1731 | struct inode *inode = dentry->d_inode; |
1732 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1733 | struct shmem_xattr *xattr; | |
1734 | struct shmem_xattr *new_xattr = NULL; | |
1735 | size_t len; | |
1736 | int err = 0; | |
1737 | ||
1738 | /* value == NULL means remove */ | |
1739 | if (value) { | |
1740 | /* wrap around? */ | |
1741 | len = sizeof(*new_xattr) + size; | |
1742 | if (len <= sizeof(*new_xattr)) | |
1743 | return -ENOMEM; | |
1744 | ||
1745 | new_xattr = kmalloc(len, GFP_KERNEL); | |
1746 | if (!new_xattr) | |
1747 | return -ENOMEM; | |
1748 | ||
1749 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
1750 | if (!new_xattr->name) { | |
1751 | kfree(new_xattr); | |
1752 | return -ENOMEM; | |
1753 | } | |
1754 | ||
1755 | new_xattr->size = size; | |
1756 | memcpy(new_xattr->value, value, size); | |
1757 | } | |
1758 | ||
1759 | spin_lock(&info->lock); | |
1760 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1761 | if (!strcmp(name, xattr->name)) { | |
1762 | if (flags & XATTR_CREATE) { | |
1763 | xattr = new_xattr; | |
1764 | err = -EEXIST; | |
1765 | } else if (new_xattr) { | |
1766 | list_replace(&xattr->list, &new_xattr->list); | |
1767 | } else { | |
1768 | list_del(&xattr->list); | |
1769 | } | |
1770 | goto out; | |
1771 | } | |
1772 | } | |
1773 | if (flags & XATTR_REPLACE) { | |
1774 | xattr = new_xattr; | |
1775 | err = -ENODATA; | |
1776 | } else { | |
1777 | list_add(&new_xattr->list, &info->xattr_list); | |
1778 | xattr = NULL; | |
1779 | } | |
1780 | out: | |
1781 | spin_unlock(&info->lock); | |
1782 | if (xattr) | |
1783 | kfree(xattr->name); | |
1784 | kfree(xattr); | |
1785 | return err; | |
39f0247d AG |
1786 | } |
1787 | ||
bb435453 | 1788 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 1789 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1c7c474c CH |
1790 | &generic_acl_access_handler, |
1791 | &generic_acl_default_handler, | |
b09e0fa4 | 1792 | #endif |
39f0247d AG |
1793 | NULL |
1794 | }; | |
b09e0fa4 EP |
1795 | |
1796 | static int shmem_xattr_validate(const char *name) | |
1797 | { | |
1798 | struct { const char *prefix; size_t len; } arr[] = { | |
1799 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
1800 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
1801 | }; | |
1802 | int i; | |
1803 | ||
1804 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
1805 | size_t preflen = arr[i].len; | |
1806 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
1807 | if (!name[preflen]) | |
1808 | return -EINVAL; | |
1809 | return 0; | |
1810 | } | |
1811 | } | |
1812 | return -EOPNOTSUPP; | |
1813 | } | |
1814 | ||
1815 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
1816 | void *buffer, size_t size) | |
1817 | { | |
1818 | int err; | |
1819 | ||
1820 | /* | |
1821 | * If this is a request for a synthetic attribute in the system.* | |
1822 | * namespace use the generic infrastructure to resolve a handler | |
1823 | * for it via sb->s_xattr. | |
1824 | */ | |
1825 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1826 | return generic_getxattr(dentry, name, buffer, size); | |
1827 | ||
1828 | err = shmem_xattr_validate(name); | |
1829 | if (err) | |
1830 | return err; | |
1831 | ||
1832 | return shmem_xattr_get(dentry, name, buffer, size); | |
1833 | } | |
1834 | ||
1835 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
1836 | const void *value, size_t size, int flags) | |
1837 | { | |
1838 | int err; | |
1839 | ||
1840 | /* | |
1841 | * If this is a request for a synthetic attribute in the system.* | |
1842 | * namespace use the generic infrastructure to resolve a handler | |
1843 | * for it via sb->s_xattr. | |
1844 | */ | |
1845 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1846 | return generic_setxattr(dentry, name, value, size, flags); | |
1847 | ||
1848 | err = shmem_xattr_validate(name); | |
1849 | if (err) | |
1850 | return err; | |
1851 | ||
1852 | if (size == 0) | |
1853 | value = ""; /* empty EA, do not remove */ | |
1854 | ||
1855 | return shmem_xattr_set(dentry, name, value, size, flags); | |
1856 | ||
1857 | } | |
1858 | ||
1859 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
1860 | { | |
1861 | int err; | |
1862 | ||
1863 | /* | |
1864 | * If this is a request for a synthetic attribute in the system.* | |
1865 | * namespace use the generic infrastructure to resolve a handler | |
1866 | * for it via sb->s_xattr. | |
1867 | */ | |
1868 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1869 | return generic_removexattr(dentry, name); | |
1870 | ||
1871 | err = shmem_xattr_validate(name); | |
1872 | if (err) | |
1873 | return err; | |
1874 | ||
1875 | return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE); | |
1876 | } | |
1877 | ||
1878 | static bool xattr_is_trusted(const char *name) | |
1879 | { | |
1880 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
1881 | } | |
1882 | ||
1883 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
1884 | { | |
1885 | bool trusted = capable(CAP_SYS_ADMIN); | |
1886 | struct shmem_xattr *xattr; | |
1887 | struct shmem_inode_info *info; | |
1888 | size_t used = 0; | |
1889 | ||
1890 | info = SHMEM_I(dentry->d_inode); | |
1891 | ||
1892 | spin_lock(&info->lock); | |
1893 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1894 | size_t len; | |
1895 | ||
1896 | /* skip "trusted." attributes for unprivileged callers */ | |
1897 | if (!trusted && xattr_is_trusted(xattr->name)) | |
1898 | continue; | |
1899 | ||
1900 | len = strlen(xattr->name) + 1; | |
1901 | used += len; | |
1902 | if (buffer) { | |
1903 | if (size < used) { | |
1904 | used = -ERANGE; | |
1905 | break; | |
1906 | } | |
1907 | memcpy(buffer, xattr->name, len); | |
1908 | buffer += len; | |
1909 | } | |
1910 | } | |
1911 | spin_unlock(&info->lock); | |
1912 | ||
1913 | return used; | |
1914 | } | |
1915 | #endif /* CONFIG_TMPFS_XATTR */ | |
1916 | ||
1917 | static const struct inode_operations shmem_symlink_inline_operations = { | |
1918 | .readlink = generic_readlink, | |
1919 | .follow_link = shmem_follow_link_inline, | |
1920 | #ifdef CONFIG_TMPFS_XATTR | |
1921 | .setxattr = shmem_setxattr, | |
1922 | .getxattr = shmem_getxattr, | |
1923 | .listxattr = shmem_listxattr, | |
1924 | .removexattr = shmem_removexattr, | |
1925 | #endif | |
1926 | }; | |
1927 | ||
1928 | static const struct inode_operations shmem_symlink_inode_operations = { | |
1929 | .readlink = generic_readlink, | |
1930 | .follow_link = shmem_follow_link, | |
1931 | .put_link = shmem_put_link, | |
1932 | #ifdef CONFIG_TMPFS_XATTR | |
1933 | .setxattr = shmem_setxattr, | |
1934 | .getxattr = shmem_getxattr, | |
1935 | .listxattr = shmem_listxattr, | |
1936 | .removexattr = shmem_removexattr, | |
39f0247d | 1937 | #endif |
b09e0fa4 | 1938 | }; |
39f0247d | 1939 | |
91828a40 DG |
1940 | static struct dentry *shmem_get_parent(struct dentry *child) |
1941 | { | |
1942 | return ERR_PTR(-ESTALE); | |
1943 | } | |
1944 | ||
1945 | static int shmem_match(struct inode *ino, void *vfh) | |
1946 | { | |
1947 | __u32 *fh = vfh; | |
1948 | __u64 inum = fh[2]; | |
1949 | inum = (inum << 32) | fh[1]; | |
1950 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1951 | } | |
1952 | ||
480b116c CH |
1953 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
1954 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 1955 | { |
91828a40 | 1956 | struct inode *inode; |
480b116c CH |
1957 | struct dentry *dentry = NULL; |
1958 | u64 inum = fid->raw[2]; | |
1959 | inum = (inum << 32) | fid->raw[1]; | |
1960 | ||
1961 | if (fh_len < 3) | |
1962 | return NULL; | |
91828a40 | 1963 | |
480b116c CH |
1964 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
1965 | shmem_match, fid->raw); | |
91828a40 | 1966 | if (inode) { |
480b116c | 1967 | dentry = d_find_alias(inode); |
91828a40 DG |
1968 | iput(inode); |
1969 | } | |
1970 | ||
480b116c | 1971 | return dentry; |
91828a40 DG |
1972 | } |
1973 | ||
1974 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
1975 | int connectable) | |
1976 | { | |
1977 | struct inode *inode = dentry->d_inode; | |
1978 | ||
5fe0c237 AK |
1979 | if (*len < 3) { |
1980 | *len = 3; | |
91828a40 | 1981 | return 255; |
5fe0c237 | 1982 | } |
91828a40 | 1983 | |
1d3382cb | 1984 | if (inode_unhashed(inode)) { |
91828a40 DG |
1985 | /* Unfortunately insert_inode_hash is not idempotent, |
1986 | * so as we hash inodes here rather than at creation | |
1987 | * time, we need a lock to ensure we only try | |
1988 | * to do it once | |
1989 | */ | |
1990 | static DEFINE_SPINLOCK(lock); | |
1991 | spin_lock(&lock); | |
1d3382cb | 1992 | if (inode_unhashed(inode)) |
91828a40 DG |
1993 | __insert_inode_hash(inode, |
1994 | inode->i_ino + inode->i_generation); | |
1995 | spin_unlock(&lock); | |
1996 | } | |
1997 | ||
1998 | fh[0] = inode->i_generation; | |
1999 | fh[1] = inode->i_ino; | |
2000 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2001 | ||
2002 | *len = 3; | |
2003 | return 1; | |
2004 | } | |
2005 | ||
39655164 | 2006 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2007 | .get_parent = shmem_get_parent, |
91828a40 | 2008 | .encode_fh = shmem_encode_fh, |
480b116c | 2009 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2010 | }; |
2011 | ||
680d794b AM |
2012 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2013 | bool remount) | |
1da177e4 LT |
2014 | { |
2015 | char *this_char, *value, *rest; | |
2016 | ||
b00dc3ad HD |
2017 | while (options != NULL) { |
2018 | this_char = options; | |
2019 | for (;;) { | |
2020 | /* | |
2021 | * NUL-terminate this option: unfortunately, | |
2022 | * mount options form a comma-separated list, | |
2023 | * but mpol's nodelist may also contain commas. | |
2024 | */ | |
2025 | options = strchr(options, ','); | |
2026 | if (options == NULL) | |
2027 | break; | |
2028 | options++; | |
2029 | if (!isdigit(*options)) { | |
2030 | options[-1] = '\0'; | |
2031 | break; | |
2032 | } | |
2033 | } | |
1da177e4 LT |
2034 | if (!*this_char) |
2035 | continue; | |
2036 | if ((value = strchr(this_char,'=')) != NULL) { | |
2037 | *value++ = 0; | |
2038 | } else { | |
2039 | printk(KERN_ERR | |
2040 | "tmpfs: No value for mount option '%s'\n", | |
2041 | this_char); | |
2042 | return 1; | |
2043 | } | |
2044 | ||
2045 | if (!strcmp(this_char,"size")) { | |
2046 | unsigned long long size; | |
2047 | size = memparse(value,&rest); | |
2048 | if (*rest == '%') { | |
2049 | size <<= PAGE_SHIFT; | |
2050 | size *= totalram_pages; | |
2051 | do_div(size, 100); | |
2052 | rest++; | |
2053 | } | |
2054 | if (*rest) | |
2055 | goto bad_val; | |
680d794b AM |
2056 | sbinfo->max_blocks = |
2057 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2058 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2059 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2060 | if (*rest) |
2061 | goto bad_val; | |
2062 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2063 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2064 | if (*rest) |
2065 | goto bad_val; | |
2066 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2067 | if (remount) |
1da177e4 | 2068 | continue; |
680d794b | 2069 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2070 | if (*rest) |
2071 | goto bad_val; | |
2072 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2073 | if (remount) |
1da177e4 | 2074 | continue; |
680d794b | 2075 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2076 | if (*rest) |
2077 | goto bad_val; | |
2078 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2079 | if (remount) |
1da177e4 | 2080 | continue; |
680d794b | 2081 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2082 | if (*rest) |
2083 | goto bad_val; | |
7339ff83 | 2084 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2085 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2086 | goto bad_val; |
1da177e4 LT |
2087 | } else { |
2088 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2089 | this_char); | |
2090 | return 1; | |
2091 | } | |
2092 | } | |
2093 | return 0; | |
2094 | ||
2095 | bad_val: | |
2096 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2097 | value, this_char); | |
2098 | return 1; | |
2099 | ||
2100 | } | |
2101 | ||
2102 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2103 | { | |
2104 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2105 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2106 | unsigned long inodes; |
2107 | int error = -EINVAL; | |
2108 | ||
680d794b | 2109 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2110 | return error; |
1da177e4 | 2111 | |
0edd73b3 | 2112 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2113 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2114 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2115 | goto out; |
680d794b | 2116 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2117 | goto out; |
2118 | /* | |
54af6042 | 2119 | * Those tests disallow limited->unlimited while any are in use; |
0edd73b3 HD |
2120 | * but we must separately disallow unlimited->limited, because |
2121 | * in that case we have no record of how much is already in use. | |
2122 | */ | |
680d794b | 2123 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2124 | goto out; |
680d794b | 2125 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2126 | goto out; |
2127 | ||
2128 | error = 0; | |
680d794b | 2129 | sbinfo->max_blocks = config.max_blocks; |
680d794b AM |
2130 | sbinfo->max_inodes = config.max_inodes; |
2131 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2132 | |
2133 | mpol_put(sbinfo->mpol); | |
2134 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2135 | out: |
2136 | spin_unlock(&sbinfo->stat_lock); | |
2137 | return error; | |
1da177e4 | 2138 | } |
680d794b AM |
2139 | |
2140 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
2141 | { | |
2142 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
2143 | ||
2144 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2145 | seq_printf(seq, ",size=%luk", | |
2146 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2147 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2148 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2149 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
2150 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
2151 | if (sbinfo->uid != 0) | |
2152 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2153 | if (sbinfo->gid != 0) | |
2154 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 2155 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b AM |
2156 | return 0; |
2157 | } | |
2158 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2159 | |
2160 | static void shmem_put_super(struct super_block *sb) | |
2161 | { | |
602586a8 HD |
2162 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2163 | ||
2164 | percpu_counter_destroy(&sbinfo->used_blocks); | |
2165 | kfree(sbinfo); | |
1da177e4 LT |
2166 | sb->s_fs_info = NULL; |
2167 | } | |
2168 | ||
2b2af54a | 2169 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2170 | { |
2171 | struct inode *inode; | |
2172 | struct dentry *root; | |
0edd73b3 | 2173 | struct shmem_sb_info *sbinfo; |
680d794b AM |
2174 | int err = -ENOMEM; |
2175 | ||
2176 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2177 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b AM |
2178 | L1_CACHE_BYTES), GFP_KERNEL); |
2179 | if (!sbinfo) | |
2180 | return -ENOMEM; | |
2181 | ||
680d794b | 2182 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2183 | sbinfo->uid = current_fsuid(); |
2184 | sbinfo->gid = current_fsgid(); | |
680d794b | 2185 | sb->s_fs_info = sbinfo; |
1da177e4 | 2186 | |
0edd73b3 | 2187 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2188 | /* |
2189 | * Per default we only allow half of the physical ram per | |
2190 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2191 | * but the internal instance is left unlimited. | |
2192 | */ | |
2193 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b AM |
2194 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2195 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2196 | if (shmem_parse_options(data, sbinfo, false)) { | |
2197 | err = -EINVAL; | |
2198 | goto failed; | |
2199 | } | |
1da177e4 | 2200 | } |
91828a40 | 2201 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2202 | #else |
2203 | sb->s_flags |= MS_NOUSER; | |
2204 | #endif | |
2205 | ||
0edd73b3 | 2206 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2207 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2208 | goto failed; | |
680d794b | 2209 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2210 | |
285b2c4f | 2211 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 LT |
2212 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2213 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2214 | sb->s_magic = TMPFS_MAGIC; | |
2215 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2216 | sb->s_time_gran = 1; |
b09e0fa4 | 2217 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2218 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2219 | #endif |
2220 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2221 | sb->s_flags |= MS_POSIXACL; |
2222 | #endif | |
0edd73b3 | 2223 | |
454abafe | 2224 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2225 | if (!inode) |
2226 | goto failed; | |
680d794b AM |
2227 | inode->i_uid = sbinfo->uid; |
2228 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2229 | root = d_alloc_root(inode); |
2230 | if (!root) | |
2231 | goto failed_iput; | |
2232 | sb->s_root = root; | |
2233 | return 0; | |
2234 | ||
2235 | failed_iput: | |
2236 | iput(inode); | |
2237 | failed: | |
2238 | shmem_put_super(sb); | |
2239 | return err; | |
2240 | } | |
2241 | ||
fcc234f8 | 2242 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2243 | |
2244 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2245 | { | |
41ffe5d5 HD |
2246 | struct shmem_inode_info *info; |
2247 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
2248 | if (!info) | |
1da177e4 | 2249 | return NULL; |
41ffe5d5 | 2250 | return &info->vfs_inode; |
1da177e4 LT |
2251 | } |
2252 | ||
41ffe5d5 | 2253 | static void shmem_destroy_callback(struct rcu_head *head) |
fa0d7e3d NP |
2254 | { |
2255 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
2256 | INIT_LIST_HEAD(&inode->i_dentry); | |
2257 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2258 | } | |
2259 | ||
1da177e4 LT |
2260 | static void shmem_destroy_inode(struct inode *inode) |
2261 | { | |
2262 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2263 | /* only struct inode is valid if it's an inline symlink */ | |
2264 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2265 | } | |
41ffe5d5 | 2266 | call_rcu(&inode->i_rcu, shmem_destroy_callback); |
1da177e4 LT |
2267 | } |
2268 | ||
41ffe5d5 | 2269 | static void shmem_init_inode(void *foo) |
1da177e4 | 2270 | { |
41ffe5d5 HD |
2271 | struct shmem_inode_info *info = foo; |
2272 | inode_init_once(&info->vfs_inode); | |
1da177e4 LT |
2273 | } |
2274 | ||
41ffe5d5 | 2275 | static int shmem_init_inodecache(void) |
1da177e4 LT |
2276 | { |
2277 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2278 | sizeof(struct shmem_inode_info), | |
41ffe5d5 | 2279 | 0, SLAB_PANIC, shmem_init_inode); |
1da177e4 LT |
2280 | return 0; |
2281 | } | |
2282 | ||
41ffe5d5 | 2283 | static void shmem_destroy_inodecache(void) |
1da177e4 | 2284 | { |
1a1d92c1 | 2285 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2286 | } |
2287 | ||
f5e54d6e | 2288 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2289 | .writepage = shmem_writepage, |
76719325 | 2290 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2291 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
2292 | .write_begin = shmem_write_begin, |
2293 | .write_end = shmem_write_end, | |
1da177e4 | 2294 | #endif |
304dbdb7 | 2295 | .migratepage = migrate_page, |
aa261f54 | 2296 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2297 | }; |
2298 | ||
15ad7cdc | 2299 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2300 | .mmap = shmem_mmap, |
2301 | #ifdef CONFIG_TMPFS | |
2302 | .llseek = generic_file_llseek, | |
bcd78e49 | 2303 | .read = do_sync_read, |
5402b976 | 2304 | .write = do_sync_write, |
bcd78e49 | 2305 | .aio_read = shmem_file_aio_read, |
5402b976 | 2306 | .aio_write = generic_file_aio_write, |
1b061d92 | 2307 | .fsync = noop_fsync, |
708e3508 | 2308 | .splice_read = shmem_file_splice_read, |
ae976416 | 2309 | .splice_write = generic_file_splice_write, |
1da177e4 LT |
2310 | #endif |
2311 | }; | |
2312 | ||
92e1d5be | 2313 | static const struct inode_operations shmem_inode_operations = { |
94c1e62d | 2314 | .setattr = shmem_setattr, |
f6b3ec23 | 2315 | .truncate_range = shmem_truncate_range, |
b09e0fa4 EP |
2316 | #ifdef CONFIG_TMPFS_XATTR |
2317 | .setxattr = shmem_setxattr, | |
2318 | .getxattr = shmem_getxattr, | |
2319 | .listxattr = shmem_listxattr, | |
2320 | .removexattr = shmem_removexattr, | |
2321 | #endif | |
1da177e4 LT |
2322 | }; |
2323 | ||
92e1d5be | 2324 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2325 | #ifdef CONFIG_TMPFS |
2326 | .create = shmem_create, | |
2327 | .lookup = simple_lookup, | |
2328 | .link = shmem_link, | |
2329 | .unlink = shmem_unlink, | |
2330 | .symlink = shmem_symlink, | |
2331 | .mkdir = shmem_mkdir, | |
2332 | .rmdir = shmem_rmdir, | |
2333 | .mknod = shmem_mknod, | |
2334 | .rename = shmem_rename, | |
1da177e4 | 2335 | #endif |
b09e0fa4 EP |
2336 | #ifdef CONFIG_TMPFS_XATTR |
2337 | .setxattr = shmem_setxattr, | |
2338 | .getxattr = shmem_getxattr, | |
2339 | .listxattr = shmem_listxattr, | |
2340 | .removexattr = shmem_removexattr, | |
2341 | #endif | |
39f0247d | 2342 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2343 | .setattr = shmem_setattr, |
39f0247d AG |
2344 | #endif |
2345 | }; | |
2346 | ||
92e1d5be | 2347 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2348 | #ifdef CONFIG_TMPFS_XATTR |
2349 | .setxattr = shmem_setxattr, | |
2350 | .getxattr = shmem_getxattr, | |
2351 | .listxattr = shmem_listxattr, | |
2352 | .removexattr = shmem_removexattr, | |
2353 | #endif | |
39f0247d | 2354 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2355 | .setattr = shmem_setattr, |
39f0247d | 2356 | #endif |
1da177e4 LT |
2357 | }; |
2358 | ||
759b9775 | 2359 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2360 | .alloc_inode = shmem_alloc_inode, |
2361 | .destroy_inode = shmem_destroy_inode, | |
2362 | #ifdef CONFIG_TMPFS | |
2363 | .statfs = shmem_statfs, | |
2364 | .remount_fs = shmem_remount_fs, | |
680d794b | 2365 | .show_options = shmem_show_options, |
1da177e4 | 2366 | #endif |
1f895f75 | 2367 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2368 | .drop_inode = generic_delete_inode, |
2369 | .put_super = shmem_put_super, | |
2370 | }; | |
2371 | ||
f0f37e2f | 2372 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2373 | .fault = shmem_fault, |
1da177e4 LT |
2374 | #ifdef CONFIG_NUMA |
2375 | .set_policy = shmem_set_policy, | |
2376 | .get_policy = shmem_get_policy, | |
2377 | #endif | |
2378 | }; | |
2379 | ||
3c26ff6e AV |
2380 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2381 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2382 | { |
3c26ff6e | 2383 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2384 | } |
2385 | ||
41ffe5d5 | 2386 | static struct file_system_type shmem_fs_type = { |
1da177e4 LT |
2387 | .owner = THIS_MODULE, |
2388 | .name = "tmpfs", | |
3c26ff6e | 2389 | .mount = shmem_mount, |
1da177e4 LT |
2390 | .kill_sb = kill_litter_super, |
2391 | }; | |
1da177e4 | 2392 | |
41ffe5d5 | 2393 | int __init shmem_init(void) |
1da177e4 LT |
2394 | { |
2395 | int error; | |
2396 | ||
e0bf68dd PZ |
2397 | error = bdi_init(&shmem_backing_dev_info); |
2398 | if (error) | |
2399 | goto out4; | |
2400 | ||
41ffe5d5 | 2401 | error = shmem_init_inodecache(); |
1da177e4 LT |
2402 | if (error) |
2403 | goto out3; | |
2404 | ||
41ffe5d5 | 2405 | error = register_filesystem(&shmem_fs_type); |
1da177e4 LT |
2406 | if (error) { |
2407 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2408 | goto out2; | |
2409 | } | |
95dc112a | 2410 | |
41ffe5d5 HD |
2411 | shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER, |
2412 | shmem_fs_type.name, NULL); | |
1da177e4 LT |
2413 | if (IS_ERR(shm_mnt)) { |
2414 | error = PTR_ERR(shm_mnt); | |
2415 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2416 | goto out1; | |
2417 | } | |
2418 | return 0; | |
2419 | ||
2420 | out1: | |
41ffe5d5 | 2421 | unregister_filesystem(&shmem_fs_type); |
1da177e4 | 2422 | out2: |
41ffe5d5 | 2423 | shmem_destroy_inodecache(); |
1da177e4 | 2424 | out3: |
e0bf68dd PZ |
2425 | bdi_destroy(&shmem_backing_dev_info); |
2426 | out4: | |
1da177e4 LT |
2427 | shm_mnt = ERR_PTR(error); |
2428 | return error; | |
2429 | } | |
853ac43a MM |
2430 | |
2431 | #else /* !CONFIG_SHMEM */ | |
2432 | ||
2433 | /* | |
2434 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2435 | * | |
2436 | * This is intended for small system where the benefits of the full | |
2437 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2438 | * their complexity. On systems without swap this code should be | |
2439 | * effectively equivalent, but much lighter weight. | |
2440 | */ | |
2441 | ||
2442 | #include <linux/ramfs.h> | |
2443 | ||
41ffe5d5 | 2444 | static struct file_system_type shmem_fs_type = { |
853ac43a | 2445 | .name = "tmpfs", |
3c26ff6e | 2446 | .mount = ramfs_mount, |
853ac43a MM |
2447 | .kill_sb = kill_litter_super, |
2448 | }; | |
2449 | ||
41ffe5d5 | 2450 | int __init shmem_init(void) |
853ac43a | 2451 | { |
41ffe5d5 | 2452 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
853ac43a | 2453 | |
41ffe5d5 | 2454 | shm_mnt = kern_mount(&shmem_fs_type); |
853ac43a MM |
2455 | BUG_ON(IS_ERR(shm_mnt)); |
2456 | ||
2457 | return 0; | |
2458 | } | |
2459 | ||
41ffe5d5 | 2460 | int shmem_unuse(swp_entry_t swap, struct page *page) |
853ac43a MM |
2461 | { |
2462 | return 0; | |
2463 | } | |
2464 | ||
3f96b79a HD |
2465 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2466 | { | |
2467 | return 0; | |
2468 | } | |
2469 | ||
41ffe5d5 | 2470 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
94c1e62d | 2471 | { |
41ffe5d5 | 2472 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
94c1e62d HD |
2473 | } |
2474 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
2475 | ||
0b0a0806 HD |
2476 | #define shmem_vm_ops generic_file_vm_ops |
2477 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2478 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2479 | #define shmem_acct_size(flags, size) 0 |
2480 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
2481 | |
2482 | #endif /* CONFIG_SHMEM */ | |
2483 | ||
2484 | /* common code */ | |
1da177e4 | 2485 | |
46711810 | 2486 | /** |
1da177e4 | 2487 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2488 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2489 | * @size: size to be set for the file | |
0b0a0806 | 2490 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2491 | */ |
168f5ac6 | 2492 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2493 | { |
2494 | int error; | |
2495 | struct file *file; | |
2496 | struct inode *inode; | |
2c48b9c4 AV |
2497 | struct path path; |
2498 | struct dentry *root; | |
1da177e4 LT |
2499 | struct qstr this; |
2500 | ||
2501 | if (IS_ERR(shm_mnt)) | |
2502 | return (void *)shm_mnt; | |
2503 | ||
285b2c4f | 2504 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
2505 | return ERR_PTR(-EINVAL); |
2506 | ||
2507 | if (shmem_acct_size(flags, size)) | |
2508 | return ERR_PTR(-ENOMEM); | |
2509 | ||
2510 | error = -ENOMEM; | |
2511 | this.name = name; | |
2512 | this.len = strlen(name); | |
2513 | this.hash = 0; /* will go */ | |
2514 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2515 | path.dentry = d_alloc(root, &this); |
2516 | if (!path.dentry) | |
1da177e4 | 2517 | goto put_memory; |
2c48b9c4 | 2518 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2519 | |
1da177e4 | 2520 | error = -ENOSPC; |
454abafe | 2521 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2522 | if (!inode) |
4b42af81 | 2523 | goto put_dentry; |
1da177e4 | 2524 | |
2c48b9c4 | 2525 | d_instantiate(path.dentry, inode); |
1da177e4 LT |
2526 | inode->i_size = size; |
2527 | inode->i_nlink = 0; /* It is unlinked */ | |
853ac43a MM |
2528 | #ifndef CONFIG_MMU |
2529 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2530 | if (error) | |
4b42af81 | 2531 | goto put_dentry; |
853ac43a | 2532 | #endif |
4b42af81 AV |
2533 | |
2534 | error = -ENFILE; | |
2c48b9c4 | 2535 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2536 | &shmem_file_operations); |
2537 | if (!file) | |
2538 | goto put_dentry; | |
2539 | ||
1da177e4 LT |
2540 | return file; |
2541 | ||
1da177e4 | 2542 | put_dentry: |
2c48b9c4 | 2543 | path_put(&path); |
1da177e4 LT |
2544 | put_memory: |
2545 | shmem_unacct_size(flags, size); | |
2546 | return ERR_PTR(error); | |
2547 | } | |
395e0ddc | 2548 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2549 | |
46711810 | 2550 | /** |
1da177e4 | 2551 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2552 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2553 | */ | |
2554 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2555 | { | |
2556 | struct file *file; | |
2557 | loff_t size = vma->vm_end - vma->vm_start; | |
2558 | ||
2559 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2560 | if (IS_ERR(file)) | |
2561 | return PTR_ERR(file); | |
2562 | ||
2563 | if (vma->vm_file) | |
2564 | fput(vma->vm_file); | |
2565 | vma->vm_file = file; | |
2566 | vma->vm_ops = &shmem_vm_ops; | |
bee4c36a | 2567 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
2568 | return 0; |
2569 | } | |
d9d90e5e HD |
2570 | |
2571 | /** | |
2572 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
2573 | * @mapping: the page's address_space | |
2574 | * @index: the page index | |
2575 | * @gfp: the page allocator flags to use if allocating | |
2576 | * | |
2577 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
2578 | * with any new page allocations done using the specified allocation flags. | |
2579 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
2580 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
2581 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
2582 | * | |
68da9f05 HD |
2583 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
2584 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
2585 | */ |
2586 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
2587 | pgoff_t index, gfp_t gfp) | |
2588 | { | |
68da9f05 HD |
2589 | #ifdef CONFIG_SHMEM |
2590 | struct inode *inode = mapping->host; | |
9276aad6 | 2591 | struct page *page; |
68da9f05 HD |
2592 | int error; |
2593 | ||
2594 | BUG_ON(mapping->a_ops != &shmem_aops); | |
2595 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); | |
2596 | if (error) | |
2597 | page = ERR_PTR(error); | |
2598 | else | |
2599 | unlock_page(page); | |
2600 | return page; | |
2601 | #else | |
2602 | /* | |
2603 | * The tiny !SHMEM case uses ramfs without swap | |
2604 | */ | |
d9d90e5e | 2605 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 2606 | #endif |
d9d90e5e HD |
2607 | } |
2608 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |