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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
6922c0c7 HD |
9 | * Copyright (C) 2002-2011 Hugh Dickins. |
10 | * Copyright (C) 2011 Google Inc. | |
0edd73b3 | 11 | * Copyright (C) 2002-2005 VERITAS Software Corporation. |
1da177e4 LT |
12 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
13 | * | |
14 | * Extended attribute support for tmpfs: | |
15 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
16 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
17 | * | |
853ac43a MM |
18 | * tiny-shmem: |
19 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
20 | * | |
1da177e4 LT |
21 | * This file is released under the GPL. |
22 | */ | |
23 | ||
853ac43a MM |
24 | #include <linux/fs.h> |
25 | #include <linux/init.h> | |
26 | #include <linux/vfs.h> | |
27 | #include <linux/mount.h> | |
caefba17 | 28 | #include <linux/pagemap.h> |
853ac43a MM |
29 | #include <linux/file.h> |
30 | #include <linux/mm.h> | |
b95f1b31 | 31 | #include <linux/export.h> |
853ac43a MM |
32 | #include <linux/swap.h> |
33 | ||
34 | static struct vfsmount *shm_mnt; | |
35 | ||
36 | #ifdef CONFIG_SHMEM | |
1da177e4 LT |
37 | /* |
38 | * This virtual memory filesystem is heavily based on the ramfs. It | |
39 | * extends ramfs by the ability to use swap and honor resource limits | |
40 | * which makes it a completely usable filesystem. | |
41 | */ | |
42 | ||
39f0247d | 43 | #include <linux/xattr.h> |
a5694255 | 44 | #include <linux/exportfs.h> |
1c7c474c | 45 | #include <linux/posix_acl.h> |
39f0247d | 46 | #include <linux/generic_acl.h> |
1da177e4 | 47 | #include <linux/mman.h> |
1da177e4 LT |
48 | #include <linux/string.h> |
49 | #include <linux/slab.h> | |
50 | #include <linux/backing-dev.h> | |
51 | #include <linux/shmem_fs.h> | |
1da177e4 | 52 | #include <linux/writeback.h> |
1da177e4 | 53 | #include <linux/blkdev.h> |
bda97eab | 54 | #include <linux/pagevec.h> |
41ffe5d5 | 55 | #include <linux/percpu_counter.h> |
83e4fa9c | 56 | #include <linux/falloc.h> |
708e3508 | 57 | #include <linux/splice.h> |
1da177e4 LT |
58 | #include <linux/security.h> |
59 | #include <linux/swapops.h> | |
60 | #include <linux/mempolicy.h> | |
61 | #include <linux/namei.h> | |
b00dc3ad | 62 | #include <linux/ctype.h> |
304dbdb7 | 63 | #include <linux/migrate.h> |
c1f60a5a | 64 | #include <linux/highmem.h> |
680d794b | 65 | #include <linux/seq_file.h> |
92562927 | 66 | #include <linux/magic.h> |
304dbdb7 | 67 | |
1da177e4 | 68 | #include <asm/uaccess.h> |
1da177e4 LT |
69 | #include <asm/pgtable.h> |
70 | ||
caefba17 | 71 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
1da177e4 LT |
72 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
73 | ||
1da177e4 LT |
74 | /* Pretend that each entry is of this size in directory's i_size */ |
75 | #define BOGO_DIRENT_SIZE 20 | |
76 | ||
69f07ec9 HD |
77 | /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ |
78 | #define SHORT_SYMLINK_LEN 128 | |
79 | ||
b09e0fa4 EP |
80 | struct shmem_xattr { |
81 | struct list_head list; /* anchored by shmem_inode_info->xattr_list */ | |
82 | char *name; /* xattr name */ | |
83 | size_t size; | |
84 | char value[0]; | |
85 | }; | |
86 | ||
285b2c4f | 87 | /* Flag allocation requirements to shmem_getpage */ |
1da177e4 | 88 | enum sgp_type { |
1da177e4 LT |
89 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
90 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 91 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
92 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
93 | }; | |
94 | ||
b76db735 | 95 | #ifdef CONFIG_TMPFS |
680d794b AM |
96 | static unsigned long shmem_default_max_blocks(void) |
97 | { | |
98 | return totalram_pages / 2; | |
99 | } | |
100 | ||
101 | static unsigned long shmem_default_max_inodes(void) | |
102 | { | |
103 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
104 | } | |
b76db735 | 105 | #endif |
680d794b | 106 | |
bde05d1c HD |
107 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp); |
108 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
109 | struct shmem_inode_info *info, pgoff_t index); | |
68da9f05 HD |
110 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
111 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); | |
112 | ||
113 | static inline int shmem_getpage(struct inode *inode, pgoff_t index, | |
114 | struct page **pagep, enum sgp_type sgp, int *fault_type) | |
115 | { | |
116 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
117 | mapping_gfp_mask(inode->i_mapping), fault_type); | |
118 | } | |
1da177e4 | 119 | |
1da177e4 LT |
120 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
121 | { | |
122 | return sb->s_fs_info; | |
123 | } | |
124 | ||
125 | /* | |
126 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
127 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
128 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
129 | * consistent with the pre-accounting of private mappings ... | |
130 | */ | |
131 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
132 | { | |
0b0a0806 | 133 | return (flags & VM_NORESERVE) ? |
191c5424 | 134 | 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size)); |
1da177e4 LT |
135 | } |
136 | ||
137 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
138 | { | |
0b0a0806 | 139 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
140 | vm_unacct_memory(VM_ACCT(size)); |
141 | } | |
142 | ||
143 | /* | |
144 | * ... whereas tmpfs objects are accounted incrementally as | |
145 | * pages are allocated, in order to allow huge sparse files. | |
146 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
147 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
148 | */ | |
149 | static inline int shmem_acct_block(unsigned long flags) | |
150 | { | |
0b0a0806 | 151 | return (flags & VM_NORESERVE) ? |
191c5424 | 152 | security_vm_enough_memory_mm(current->mm, VM_ACCT(PAGE_CACHE_SIZE)) : 0; |
1da177e4 LT |
153 | } |
154 | ||
155 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
156 | { | |
0b0a0806 | 157 | if (flags & VM_NORESERVE) |
1da177e4 LT |
158 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
159 | } | |
160 | ||
759b9775 | 161 | static const struct super_operations shmem_ops; |
f5e54d6e | 162 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 163 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
164 | static const struct inode_operations shmem_inode_operations; |
165 | static const struct inode_operations shmem_dir_inode_operations; | |
166 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 167 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 168 | |
6c231b7b | 169 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 170 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 171 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
172 | }; |
173 | ||
174 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 175 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 | 176 | |
5b04c689 PE |
177 | static int shmem_reserve_inode(struct super_block *sb) |
178 | { | |
179 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
180 | if (sbinfo->max_inodes) { | |
181 | spin_lock(&sbinfo->stat_lock); | |
182 | if (!sbinfo->free_inodes) { | |
183 | spin_unlock(&sbinfo->stat_lock); | |
184 | return -ENOSPC; | |
185 | } | |
186 | sbinfo->free_inodes--; | |
187 | spin_unlock(&sbinfo->stat_lock); | |
188 | } | |
189 | return 0; | |
190 | } | |
191 | ||
192 | static void shmem_free_inode(struct super_block *sb) | |
193 | { | |
194 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
195 | if (sbinfo->max_inodes) { | |
196 | spin_lock(&sbinfo->stat_lock); | |
197 | sbinfo->free_inodes++; | |
198 | spin_unlock(&sbinfo->stat_lock); | |
199 | } | |
200 | } | |
201 | ||
46711810 | 202 | /** |
41ffe5d5 | 203 | * shmem_recalc_inode - recalculate the block usage of an inode |
1da177e4 LT |
204 | * @inode: inode to recalc |
205 | * | |
206 | * We have to calculate the free blocks since the mm can drop | |
207 | * undirtied hole pages behind our back. | |
208 | * | |
209 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
210 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
211 | * | |
212 | * It has to be called with the spinlock held. | |
213 | */ | |
214 | static void shmem_recalc_inode(struct inode *inode) | |
215 | { | |
216 | struct shmem_inode_info *info = SHMEM_I(inode); | |
217 | long freed; | |
218 | ||
219 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
220 | if (freed > 0) { | |
54af6042 HD |
221 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
222 | if (sbinfo->max_blocks) | |
223 | percpu_counter_add(&sbinfo->used_blocks, -freed); | |
1da177e4 | 224 | info->alloced -= freed; |
54af6042 | 225 | inode->i_blocks -= freed * BLOCKS_PER_PAGE; |
1da177e4 | 226 | shmem_unacct_blocks(info->flags, freed); |
1da177e4 LT |
227 | } |
228 | } | |
229 | ||
7a5d0fbb HD |
230 | /* |
231 | * Replace item expected in radix tree by a new item, while holding tree lock. | |
232 | */ | |
233 | static int shmem_radix_tree_replace(struct address_space *mapping, | |
234 | pgoff_t index, void *expected, void *replacement) | |
235 | { | |
236 | void **pslot; | |
237 | void *item = NULL; | |
238 | ||
239 | VM_BUG_ON(!expected); | |
240 | pslot = radix_tree_lookup_slot(&mapping->page_tree, index); | |
241 | if (pslot) | |
242 | item = radix_tree_deref_slot_protected(pslot, | |
243 | &mapping->tree_lock); | |
244 | if (item != expected) | |
245 | return -ENOENT; | |
246 | if (replacement) | |
247 | radix_tree_replace_slot(pslot, replacement); | |
248 | else | |
249 | radix_tree_delete(&mapping->page_tree, index); | |
250 | return 0; | |
251 | } | |
252 | ||
46f65ec1 HD |
253 | /* |
254 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
255 | */ | |
256 | static int shmem_add_to_page_cache(struct page *page, | |
257 | struct address_space *mapping, | |
258 | pgoff_t index, gfp_t gfp, void *expected) | |
259 | { | |
aa3b1895 | 260 | int error = 0; |
46f65ec1 HD |
261 | |
262 | VM_BUG_ON(!PageLocked(page)); | |
263 | VM_BUG_ON(!PageSwapBacked(page)); | |
264 | ||
46f65ec1 HD |
265 | if (!expected) |
266 | error = radix_tree_preload(gfp & GFP_RECLAIM_MASK); | |
267 | if (!error) { | |
268 | page_cache_get(page); | |
269 | page->mapping = mapping; | |
270 | page->index = index; | |
271 | ||
272 | spin_lock_irq(&mapping->tree_lock); | |
273 | if (!expected) | |
274 | error = radix_tree_insert(&mapping->page_tree, | |
275 | index, page); | |
276 | else | |
277 | error = shmem_radix_tree_replace(mapping, index, | |
278 | expected, page); | |
279 | if (!error) { | |
280 | mapping->nrpages++; | |
281 | __inc_zone_page_state(page, NR_FILE_PAGES); | |
282 | __inc_zone_page_state(page, NR_SHMEM); | |
283 | spin_unlock_irq(&mapping->tree_lock); | |
284 | } else { | |
285 | page->mapping = NULL; | |
286 | spin_unlock_irq(&mapping->tree_lock); | |
287 | page_cache_release(page); | |
288 | } | |
289 | if (!expected) | |
290 | radix_tree_preload_end(); | |
291 | } | |
292 | if (error) | |
293 | mem_cgroup_uncharge_cache_page(page); | |
46f65ec1 HD |
294 | return error; |
295 | } | |
296 | ||
6922c0c7 HD |
297 | /* |
298 | * Like delete_from_page_cache, but substitutes swap for page. | |
299 | */ | |
300 | static void shmem_delete_from_page_cache(struct page *page, void *radswap) | |
301 | { | |
302 | struct address_space *mapping = page->mapping; | |
303 | int error; | |
304 | ||
305 | spin_lock_irq(&mapping->tree_lock); | |
306 | error = shmem_radix_tree_replace(mapping, page->index, page, radswap); | |
307 | page->mapping = NULL; | |
308 | mapping->nrpages--; | |
309 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
310 | __dec_zone_page_state(page, NR_SHMEM); | |
311 | spin_unlock_irq(&mapping->tree_lock); | |
312 | page_cache_release(page); | |
313 | BUG_ON(error); | |
314 | } | |
315 | ||
7a5d0fbb HD |
316 | /* |
317 | * Like find_get_pages, but collecting swap entries as well as pages. | |
318 | */ | |
319 | static unsigned shmem_find_get_pages_and_swap(struct address_space *mapping, | |
320 | pgoff_t start, unsigned int nr_pages, | |
321 | struct page **pages, pgoff_t *indices) | |
322 | { | |
323 | unsigned int i; | |
324 | unsigned int ret; | |
325 | unsigned int nr_found; | |
326 | ||
327 | rcu_read_lock(); | |
328 | restart: | |
329 | nr_found = radix_tree_gang_lookup_slot(&mapping->page_tree, | |
330 | (void ***)pages, indices, start, nr_pages); | |
331 | ret = 0; | |
332 | for (i = 0; i < nr_found; i++) { | |
333 | struct page *page; | |
334 | repeat: | |
335 | page = radix_tree_deref_slot((void **)pages[i]); | |
336 | if (unlikely(!page)) | |
337 | continue; | |
338 | if (radix_tree_exception(page)) { | |
8079b1c8 HD |
339 | if (radix_tree_deref_retry(page)) |
340 | goto restart; | |
341 | /* | |
342 | * Otherwise, we must be storing a swap entry | |
343 | * here as an exceptional entry: so return it | |
344 | * without attempting to raise page count. | |
345 | */ | |
346 | goto export; | |
7a5d0fbb HD |
347 | } |
348 | if (!page_cache_get_speculative(page)) | |
349 | goto repeat; | |
350 | ||
351 | /* Has the page moved? */ | |
352 | if (unlikely(page != *((void **)pages[i]))) { | |
353 | page_cache_release(page); | |
354 | goto repeat; | |
355 | } | |
356 | export: | |
357 | indices[ret] = indices[i]; | |
358 | pages[ret] = page; | |
359 | ret++; | |
360 | } | |
361 | if (unlikely(!ret && nr_found)) | |
362 | goto restart; | |
363 | rcu_read_unlock(); | |
364 | return ret; | |
365 | } | |
366 | ||
367 | /* | |
368 | * Remove swap entry from radix tree, free the swap and its page cache. | |
369 | */ | |
370 | static int shmem_free_swap(struct address_space *mapping, | |
371 | pgoff_t index, void *radswap) | |
372 | { | |
373 | int error; | |
374 | ||
375 | spin_lock_irq(&mapping->tree_lock); | |
376 | error = shmem_radix_tree_replace(mapping, index, radswap, NULL); | |
377 | spin_unlock_irq(&mapping->tree_lock); | |
378 | if (!error) | |
379 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
380 | return error; | |
381 | } | |
382 | ||
383 | /* | |
384 | * Pagevec may contain swap entries, so shuffle up pages before releasing. | |
385 | */ | |
24513264 | 386 | static void shmem_deswap_pagevec(struct pagevec *pvec) |
7a5d0fbb HD |
387 | { |
388 | int i, j; | |
389 | ||
390 | for (i = 0, j = 0; i < pagevec_count(pvec); i++) { | |
391 | struct page *page = pvec->pages[i]; | |
392 | if (!radix_tree_exceptional_entry(page)) | |
393 | pvec->pages[j++] = page; | |
394 | } | |
395 | pvec->nr = j; | |
24513264 HD |
396 | } |
397 | ||
398 | /* | |
399 | * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. | |
400 | */ | |
401 | void shmem_unlock_mapping(struct address_space *mapping) | |
402 | { | |
403 | struct pagevec pvec; | |
404 | pgoff_t indices[PAGEVEC_SIZE]; | |
405 | pgoff_t index = 0; | |
406 | ||
407 | pagevec_init(&pvec, 0); | |
408 | /* | |
409 | * Minor point, but we might as well stop if someone else SHM_LOCKs it. | |
410 | */ | |
411 | while (!mapping_unevictable(mapping)) { | |
412 | /* | |
413 | * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it | |
414 | * has finished, if it hits a row of PAGEVEC_SIZE swap entries. | |
415 | */ | |
416 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, | |
417 | PAGEVEC_SIZE, pvec.pages, indices); | |
418 | if (!pvec.nr) | |
419 | break; | |
420 | index = indices[pvec.nr - 1] + 1; | |
421 | shmem_deswap_pagevec(&pvec); | |
422 | check_move_unevictable_pages(pvec.pages, pvec.nr); | |
423 | pagevec_release(&pvec); | |
424 | cond_resched(); | |
425 | } | |
7a5d0fbb HD |
426 | } |
427 | ||
428 | /* | |
429 | * Remove range of pages and swap entries from radix tree, and free them. | |
430 | */ | |
285b2c4f | 431 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
1da177e4 | 432 | { |
285b2c4f | 433 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 434 | struct shmem_inode_info *info = SHMEM_I(inode); |
285b2c4f | 435 | pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
83e4fa9c HD |
436 | pgoff_t end = (lend + 1) >> PAGE_CACHE_SHIFT; |
437 | unsigned int partial_start = lstart & (PAGE_CACHE_SIZE - 1); | |
438 | unsigned int partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1); | |
bda97eab | 439 | struct pagevec pvec; |
7a5d0fbb HD |
440 | pgoff_t indices[PAGEVEC_SIZE]; |
441 | long nr_swaps_freed = 0; | |
285b2c4f | 442 | pgoff_t index; |
bda97eab HD |
443 | int i; |
444 | ||
83e4fa9c HD |
445 | if (lend == -1) |
446 | end = -1; /* unsigned, so actually very big */ | |
bda97eab HD |
447 | |
448 | pagevec_init(&pvec, 0); | |
449 | index = start; | |
83e4fa9c | 450 | while (index < end) { |
7a5d0fbb | 451 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, |
83e4fa9c | 452 | min(end - index, (pgoff_t)PAGEVEC_SIZE), |
7a5d0fbb HD |
453 | pvec.pages, indices); |
454 | if (!pvec.nr) | |
455 | break; | |
bda97eab HD |
456 | mem_cgroup_uncharge_start(); |
457 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
458 | struct page *page = pvec.pages[i]; | |
459 | ||
7a5d0fbb | 460 | index = indices[i]; |
83e4fa9c | 461 | if (index >= end) |
bda97eab HD |
462 | break; |
463 | ||
7a5d0fbb HD |
464 | if (radix_tree_exceptional_entry(page)) { |
465 | nr_swaps_freed += !shmem_free_swap(mapping, | |
466 | index, page); | |
bda97eab | 467 | continue; |
7a5d0fbb HD |
468 | } |
469 | ||
470 | if (!trylock_page(page)) | |
bda97eab | 471 | continue; |
7a5d0fbb HD |
472 | if (page->mapping == mapping) { |
473 | VM_BUG_ON(PageWriteback(page)); | |
474 | truncate_inode_page(mapping, page); | |
bda97eab | 475 | } |
bda97eab HD |
476 | unlock_page(page); |
477 | } | |
24513264 HD |
478 | shmem_deswap_pagevec(&pvec); |
479 | pagevec_release(&pvec); | |
bda97eab HD |
480 | mem_cgroup_uncharge_end(); |
481 | cond_resched(); | |
482 | index++; | |
483 | } | |
1da177e4 | 484 | |
83e4fa9c | 485 | if (partial_start) { |
bda97eab HD |
486 | struct page *page = NULL; |
487 | shmem_getpage(inode, start - 1, &page, SGP_READ, NULL); | |
488 | if (page) { | |
83e4fa9c HD |
489 | unsigned int top = PAGE_CACHE_SIZE; |
490 | if (start > end) { | |
491 | top = partial_end; | |
492 | partial_end = 0; | |
493 | } | |
494 | zero_user_segment(page, partial_start, top); | |
495 | set_page_dirty(page); | |
496 | unlock_page(page); | |
497 | page_cache_release(page); | |
498 | } | |
499 | } | |
500 | if (partial_end) { | |
501 | struct page *page = NULL; | |
502 | shmem_getpage(inode, end, &page, SGP_READ, NULL); | |
503 | if (page) { | |
504 | zero_user_segment(page, 0, partial_end); | |
bda97eab HD |
505 | set_page_dirty(page); |
506 | unlock_page(page); | |
507 | page_cache_release(page); | |
508 | } | |
509 | } | |
83e4fa9c HD |
510 | if (start >= end) |
511 | return; | |
bda97eab HD |
512 | |
513 | index = start; | |
514 | for ( ; ; ) { | |
515 | cond_resched(); | |
7a5d0fbb | 516 | pvec.nr = shmem_find_get_pages_and_swap(mapping, index, |
83e4fa9c | 517 | min(end - index, (pgoff_t)PAGEVEC_SIZE), |
7a5d0fbb HD |
518 | pvec.pages, indices); |
519 | if (!pvec.nr) { | |
bda97eab HD |
520 | if (index == start) |
521 | break; | |
522 | index = start; | |
523 | continue; | |
524 | } | |
83e4fa9c | 525 | if (index == start && indices[0] >= end) { |
24513264 HD |
526 | shmem_deswap_pagevec(&pvec); |
527 | pagevec_release(&pvec); | |
bda97eab HD |
528 | break; |
529 | } | |
530 | mem_cgroup_uncharge_start(); | |
531 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
532 | struct page *page = pvec.pages[i]; | |
533 | ||
7a5d0fbb | 534 | index = indices[i]; |
83e4fa9c | 535 | if (index >= end) |
bda97eab HD |
536 | break; |
537 | ||
7a5d0fbb HD |
538 | if (radix_tree_exceptional_entry(page)) { |
539 | nr_swaps_freed += !shmem_free_swap(mapping, | |
540 | index, page); | |
541 | continue; | |
542 | } | |
543 | ||
bda97eab | 544 | lock_page(page); |
7a5d0fbb HD |
545 | if (page->mapping == mapping) { |
546 | VM_BUG_ON(PageWriteback(page)); | |
547 | truncate_inode_page(mapping, page); | |
548 | } | |
bda97eab HD |
549 | unlock_page(page); |
550 | } | |
24513264 HD |
551 | shmem_deswap_pagevec(&pvec); |
552 | pagevec_release(&pvec); | |
bda97eab HD |
553 | mem_cgroup_uncharge_end(); |
554 | index++; | |
555 | } | |
94c1e62d | 556 | |
1da177e4 | 557 | spin_lock(&info->lock); |
7a5d0fbb | 558 | info->swapped -= nr_swaps_freed; |
1da177e4 LT |
559 | shmem_recalc_inode(inode); |
560 | spin_unlock(&info->lock); | |
561 | ||
285b2c4f | 562 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1da177e4 | 563 | } |
94c1e62d | 564 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 565 | |
94c1e62d | 566 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 LT |
567 | { |
568 | struct inode *inode = dentry->d_inode; | |
1da177e4 LT |
569 | int error; |
570 | ||
db78b877 CH |
571 | error = inode_change_ok(inode, attr); |
572 | if (error) | |
573 | return error; | |
574 | ||
94c1e62d HD |
575 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
576 | loff_t oldsize = inode->i_size; | |
577 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 578 | |
94c1e62d HD |
579 | if (newsize != oldsize) { |
580 | i_size_write(inode, newsize); | |
581 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
582 | } | |
583 | if (newsize < oldsize) { | |
584 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
585 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
586 | shmem_truncate_range(inode, newsize, (loff_t)-1); | |
587 | /* unmap again to remove racily COWed private pages */ | |
588 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
589 | } | |
1da177e4 LT |
590 | } |
591 | ||
db78b877 | 592 | setattr_copy(inode, attr); |
39f0247d | 593 | #ifdef CONFIG_TMPFS_POSIX_ACL |
db78b877 | 594 | if (attr->ia_valid & ATTR_MODE) |
1c7c474c | 595 | error = generic_acl_chmod(inode); |
39f0247d | 596 | #endif |
1da177e4 LT |
597 | return error; |
598 | } | |
599 | ||
1f895f75 | 600 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 601 | { |
1da177e4 | 602 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 603 | struct shmem_xattr *xattr, *nxattr; |
1da177e4 | 604 | |
3889e6e7 | 605 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
606 | shmem_unacct_size(info->flags, inode->i_size); |
607 | inode->i_size = 0; | |
3889e6e7 | 608 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 609 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 610 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 611 | list_del_init(&info->swaplist); |
cb5f7b9a | 612 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 | 613 | } |
69f07ec9 HD |
614 | } else |
615 | kfree(info->symlink); | |
b09e0fa4 EP |
616 | |
617 | list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { | |
618 | kfree(xattr->name); | |
619 | kfree(xattr); | |
620 | } | |
0edd73b3 | 621 | BUG_ON(inode->i_blocks); |
5b04c689 | 622 | shmem_free_inode(inode->i_sb); |
dbd5768f | 623 | clear_inode(inode); |
1da177e4 LT |
624 | } |
625 | ||
46f65ec1 HD |
626 | /* |
627 | * If swap found in inode, free it and move page from swapcache to filecache. | |
628 | */ | |
41ffe5d5 | 629 | static int shmem_unuse_inode(struct shmem_inode_info *info, |
bde05d1c | 630 | swp_entry_t swap, struct page **pagep) |
1da177e4 | 631 | { |
285b2c4f | 632 | struct address_space *mapping = info->vfs_inode.i_mapping; |
46f65ec1 | 633 | void *radswap; |
41ffe5d5 | 634 | pgoff_t index; |
bde05d1c HD |
635 | gfp_t gfp; |
636 | int error = 0; | |
1da177e4 | 637 | |
46f65ec1 | 638 | radswap = swp_to_radix_entry(swap); |
e504f3fd | 639 | index = radix_tree_locate_item(&mapping->page_tree, radswap); |
46f65ec1 | 640 | if (index == -1) |
285b2c4f | 641 | return 0; |
2e0e26c7 | 642 | |
1b1b32f2 HD |
643 | /* |
644 | * Move _head_ to start search for next from here. | |
1f895f75 | 645 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 | 646 | * mutex, and there's an instant in list_move_tail when info->swaplist |
285b2c4f | 647 | * would appear empty, if it were the only one on shmem_swaplist. |
1b1b32f2 HD |
648 | */ |
649 | if (shmem_swaplist.next != &info->swaplist) | |
650 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 651 | |
bde05d1c HD |
652 | gfp = mapping_gfp_mask(mapping); |
653 | if (shmem_should_replace_page(*pagep, gfp)) { | |
654 | mutex_unlock(&shmem_swaplist_mutex); | |
655 | error = shmem_replace_page(pagep, gfp, info, index); | |
656 | mutex_lock(&shmem_swaplist_mutex); | |
657 | /* | |
658 | * We needed to drop mutex to make that restrictive page | |
659 | * allocation; but the inode might already be freed by now, | |
660 | * and we cannot refer to inode or mapping or info to check. | |
661 | * However, we do hold page lock on the PageSwapCache page, | |
662 | * so can check if that still has our reference remaining. | |
663 | */ | |
664 | if (!page_swapcount(*pagep)) | |
665 | error = -ENOENT; | |
666 | } | |
667 | ||
d13d1443 | 668 | /* |
778dd893 HD |
669 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
670 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
671 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 672 | */ |
bde05d1c HD |
673 | if (!error) |
674 | error = shmem_add_to_page_cache(*pagep, mapping, index, | |
46f65ec1 | 675 | GFP_NOWAIT, radswap); |
48f170fb | 676 | if (error != -ENOMEM) { |
46f65ec1 HD |
677 | /* |
678 | * Truncation and eviction use free_swap_and_cache(), which | |
679 | * only does trylock page: if we raced, best clean up here. | |
680 | */ | |
bde05d1c HD |
681 | delete_from_swap_cache(*pagep); |
682 | set_page_dirty(*pagep); | |
46f65ec1 HD |
683 | if (!error) { |
684 | spin_lock(&info->lock); | |
685 | info->swapped--; | |
686 | spin_unlock(&info->lock); | |
687 | swap_free(swap); | |
688 | } | |
2e0e26c7 | 689 | error = 1; /* not an error, but entry was found */ |
1da177e4 | 690 | } |
2e0e26c7 | 691 | return error; |
1da177e4 LT |
692 | } |
693 | ||
694 | /* | |
46f65ec1 | 695 | * Search through swapped inodes to find and replace swap by page. |
1da177e4 | 696 | */ |
41ffe5d5 | 697 | int shmem_unuse(swp_entry_t swap, struct page *page) |
1da177e4 | 698 | { |
41ffe5d5 | 699 | struct list_head *this, *next; |
1da177e4 LT |
700 | struct shmem_inode_info *info; |
701 | int found = 0; | |
bde05d1c HD |
702 | int error = 0; |
703 | ||
704 | /* | |
705 | * There's a faint possibility that swap page was replaced before | |
706 | * caller locked it: it will come back later with the right page. | |
707 | */ | |
708 | if (unlikely(!PageSwapCache(page))) | |
709 | goto out; | |
778dd893 HD |
710 | |
711 | /* | |
712 | * Charge page using GFP_KERNEL while we can wait, before taking | |
713 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
714 | * Charged back to the user (not to caller) when swap account is used. | |
778dd893 HD |
715 | */ |
716 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
717 | if (error) | |
718 | goto out; | |
46f65ec1 | 719 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
1da177e4 | 720 | |
cb5f7b9a | 721 | mutex_lock(&shmem_swaplist_mutex); |
41ffe5d5 HD |
722 | list_for_each_safe(this, next, &shmem_swaplist) { |
723 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
285b2c4f | 724 | if (info->swapped) |
bde05d1c | 725 | found = shmem_unuse_inode(info, swap, &page); |
6922c0c7 HD |
726 | else |
727 | list_del_init(&info->swaplist); | |
cb5f7b9a | 728 | cond_resched(); |
2e0e26c7 | 729 | if (found) |
778dd893 | 730 | break; |
1da177e4 | 731 | } |
cb5f7b9a | 732 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 | 733 | |
778dd893 HD |
734 | if (found < 0) |
735 | error = found; | |
736 | out: | |
aaa46865 HD |
737 | unlock_page(page); |
738 | page_cache_release(page); | |
778dd893 | 739 | return error; |
1da177e4 LT |
740 | } |
741 | ||
742 | /* | |
743 | * Move the page from the page cache to the swap cache. | |
744 | */ | |
745 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
746 | { | |
747 | struct shmem_inode_info *info; | |
1da177e4 | 748 | struct address_space *mapping; |
1da177e4 | 749 | struct inode *inode; |
6922c0c7 HD |
750 | swp_entry_t swap; |
751 | pgoff_t index; | |
1da177e4 LT |
752 | |
753 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
754 | mapping = page->mapping; |
755 | index = page->index; | |
756 | inode = mapping->host; | |
757 | info = SHMEM_I(inode); | |
758 | if (info->flags & VM_LOCKED) | |
759 | goto redirty; | |
d9fe526a | 760 | if (!total_swap_pages) |
1da177e4 LT |
761 | goto redirty; |
762 | ||
d9fe526a HD |
763 | /* |
764 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
765 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
48f170fb | 766 | * might use ->writepage of its underlying filesystem, in which case |
d9fe526a | 767 | * tmpfs should write out to swap only in response to memory pressure, |
48f170fb | 768 | * and not for the writeback threads or sync. |
d9fe526a | 769 | */ |
48f170fb HD |
770 | if (!wbc->for_reclaim) { |
771 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
772 | goto redirty; | |
773 | } | |
774 | swap = get_swap_page(); | |
775 | if (!swap.val) | |
776 | goto redirty; | |
d9fe526a | 777 | |
b1dea800 HD |
778 | /* |
779 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
6922c0c7 HD |
780 | * if it's not already there. Do it now before the page is |
781 | * moved to swap cache, when its pagelock no longer protects | |
b1dea800 | 782 | * the inode from eviction. But don't unlock the mutex until |
6922c0c7 HD |
783 | * we've incremented swapped, because shmem_unuse_inode() will |
784 | * prune a !swapped inode from the swaplist under this mutex. | |
b1dea800 | 785 | */ |
48f170fb HD |
786 | mutex_lock(&shmem_swaplist_mutex); |
787 | if (list_empty(&info->swaplist)) | |
788 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 789 | |
48f170fb | 790 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
aaa46865 | 791 | swap_shmem_alloc(swap); |
6922c0c7 HD |
792 | shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); |
793 | ||
794 | spin_lock(&info->lock); | |
795 | info->swapped++; | |
796 | shmem_recalc_inode(inode); | |
826267cf | 797 | spin_unlock(&info->lock); |
6922c0c7 HD |
798 | |
799 | mutex_unlock(&shmem_swaplist_mutex); | |
d9fe526a | 800 | BUG_ON(page_mapped(page)); |
9fab5619 | 801 | swap_writepage(page, wbc); |
1da177e4 LT |
802 | return 0; |
803 | } | |
804 | ||
6922c0c7 | 805 | mutex_unlock(&shmem_swaplist_mutex); |
cb4b86ba | 806 | swapcache_free(swap, NULL); |
1da177e4 LT |
807 | redirty: |
808 | set_page_dirty(page); | |
d9fe526a HD |
809 | if (wbc->for_reclaim) |
810 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
811 | unlock_page(page); | |
812 | return 0; | |
1da177e4 LT |
813 | } |
814 | ||
815 | #ifdef CONFIG_NUMA | |
680d794b | 816 | #ifdef CONFIG_TMPFS |
71fe804b | 817 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 818 | { |
095f1fc4 | 819 | char buffer[64]; |
680d794b | 820 | |
71fe804b | 821 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 822 | return; /* show nothing */ |
680d794b | 823 | |
71fe804b | 824 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
825 | |
826 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 827 | } |
71fe804b LS |
828 | |
829 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
830 | { | |
831 | struct mempolicy *mpol = NULL; | |
832 | if (sbinfo->mpol) { | |
833 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
834 | mpol = sbinfo->mpol; | |
835 | mpol_get(mpol); | |
836 | spin_unlock(&sbinfo->stat_lock); | |
837 | } | |
838 | return mpol; | |
839 | } | |
680d794b AM |
840 | #endif /* CONFIG_TMPFS */ |
841 | ||
41ffe5d5 HD |
842 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
843 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 844 | { |
52cd3b07 | 845 | struct mempolicy mpol, *spol; |
1da177e4 LT |
846 | struct vm_area_struct pvma; |
847 | ||
52cd3b07 | 848 | spol = mpol_cond_copy(&mpol, |
41ffe5d5 | 849 | mpol_shared_policy_lookup(&info->policy, index)); |
52cd3b07 | 850 | |
1da177e4 | 851 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 852 | pvma.vm_start = 0; |
41ffe5d5 | 853 | pvma.vm_pgoff = index; |
c4cc6d07 | 854 | pvma.vm_ops = NULL; |
52cd3b07 | 855 | pvma.vm_policy = spol; |
41ffe5d5 | 856 | return swapin_readahead(swap, gfp, &pvma, 0); |
1da177e4 LT |
857 | } |
858 | ||
02098fea | 859 | static struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 860 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 LT |
861 | { |
862 | struct vm_area_struct pvma; | |
1da177e4 | 863 | |
c4cc6d07 HD |
864 | /* Create a pseudo vma that just contains the policy */ |
865 | pvma.vm_start = 0; | |
41ffe5d5 | 866 | pvma.vm_pgoff = index; |
c4cc6d07 | 867 | pvma.vm_ops = NULL; |
41ffe5d5 | 868 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
52cd3b07 LS |
869 | |
870 | /* | |
871 | * alloc_page_vma() will drop the shared policy reference | |
872 | */ | |
873 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 874 | } |
680d794b AM |
875 | #else /* !CONFIG_NUMA */ |
876 | #ifdef CONFIG_TMPFS | |
41ffe5d5 | 877 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b AM |
878 | { |
879 | } | |
880 | #endif /* CONFIG_TMPFS */ | |
881 | ||
41ffe5d5 HD |
882 | static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
883 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 884 | { |
41ffe5d5 | 885 | return swapin_readahead(swap, gfp, NULL, 0); |
1da177e4 LT |
886 | } |
887 | ||
02098fea | 888 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 889 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 890 | { |
e84e2e13 | 891 | return alloc_page(gfp); |
1da177e4 | 892 | } |
680d794b | 893 | #endif /* CONFIG_NUMA */ |
1da177e4 | 894 | |
71fe804b LS |
895 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
896 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
897 | { | |
898 | return NULL; | |
899 | } | |
900 | #endif | |
901 | ||
bde05d1c HD |
902 | /* |
903 | * When a page is moved from swapcache to shmem filecache (either by the | |
904 | * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of | |
905 | * shmem_unuse_inode()), it may have been read in earlier from swap, in | |
906 | * ignorance of the mapping it belongs to. If that mapping has special | |
907 | * constraints (like the gma500 GEM driver, which requires RAM below 4GB), | |
908 | * we may need to copy to a suitable page before moving to filecache. | |
909 | * | |
910 | * In a future release, this may well be extended to respect cpuset and | |
911 | * NUMA mempolicy, and applied also to anonymous pages in do_swap_page(); | |
912 | * but for now it is a simple matter of zone. | |
913 | */ | |
914 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp) | |
915 | { | |
916 | return page_zonenum(page) > gfp_zone(gfp); | |
917 | } | |
918 | ||
919 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
920 | struct shmem_inode_info *info, pgoff_t index) | |
921 | { | |
922 | struct page *oldpage, *newpage; | |
923 | struct address_space *swap_mapping; | |
924 | pgoff_t swap_index; | |
925 | int error; | |
926 | ||
927 | oldpage = *pagep; | |
928 | swap_index = page_private(oldpage); | |
929 | swap_mapping = page_mapping(oldpage); | |
930 | ||
931 | /* | |
932 | * We have arrived here because our zones are constrained, so don't | |
933 | * limit chance of success by further cpuset and node constraints. | |
934 | */ | |
935 | gfp &= ~GFP_CONSTRAINT_MASK; | |
936 | newpage = shmem_alloc_page(gfp, info, index); | |
937 | if (!newpage) | |
938 | return -ENOMEM; | |
939 | VM_BUG_ON(shmem_should_replace_page(newpage, gfp)); | |
940 | ||
941 | *pagep = newpage; | |
942 | page_cache_get(newpage); | |
943 | copy_highpage(newpage, oldpage); | |
944 | ||
945 | VM_BUG_ON(!PageLocked(oldpage)); | |
946 | __set_page_locked(newpage); | |
947 | VM_BUG_ON(!PageUptodate(oldpage)); | |
948 | SetPageUptodate(newpage); | |
949 | VM_BUG_ON(!PageSwapBacked(oldpage)); | |
950 | SetPageSwapBacked(newpage); | |
951 | VM_BUG_ON(!swap_index); | |
952 | set_page_private(newpage, swap_index); | |
953 | VM_BUG_ON(!PageSwapCache(oldpage)); | |
954 | SetPageSwapCache(newpage); | |
955 | ||
956 | /* | |
957 | * Our caller will very soon move newpage out of swapcache, but it's | |
958 | * a nice clean interface for us to replace oldpage by newpage there. | |
959 | */ | |
960 | spin_lock_irq(&swap_mapping->tree_lock); | |
961 | error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage, | |
962 | newpage); | |
963 | __inc_zone_page_state(newpage, NR_FILE_PAGES); | |
964 | __dec_zone_page_state(oldpage, NR_FILE_PAGES); | |
965 | spin_unlock_irq(&swap_mapping->tree_lock); | |
966 | BUG_ON(error); | |
967 | ||
968 | mem_cgroup_replace_page_cache(oldpage, newpage); | |
969 | lru_cache_add_anon(newpage); | |
970 | ||
971 | ClearPageSwapCache(oldpage); | |
972 | set_page_private(oldpage, 0); | |
973 | ||
974 | unlock_page(oldpage); | |
975 | page_cache_release(oldpage); | |
976 | page_cache_release(oldpage); | |
977 | return 0; | |
978 | } | |
979 | ||
1da177e4 | 980 | /* |
68da9f05 | 981 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
982 | * |
983 | * If we allocate a new one we do not mark it dirty. That's up to the | |
984 | * vm. If we swap it in we mark it dirty since we also free the swap | |
985 | * entry since a page cannot live in both the swap and page cache | |
986 | */ | |
41ffe5d5 | 987 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
68da9f05 | 988 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) |
1da177e4 LT |
989 | { |
990 | struct address_space *mapping = inode->i_mapping; | |
54af6042 | 991 | struct shmem_inode_info *info; |
1da177e4 | 992 | struct shmem_sb_info *sbinfo; |
27ab7006 | 993 | struct page *page; |
1da177e4 LT |
994 | swp_entry_t swap; |
995 | int error; | |
54af6042 | 996 | int once = 0; |
1da177e4 | 997 | |
41ffe5d5 | 998 | if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
1da177e4 | 999 | return -EFBIG; |
1da177e4 | 1000 | repeat: |
54af6042 | 1001 | swap.val = 0; |
41ffe5d5 | 1002 | page = find_lock_page(mapping, index); |
54af6042 HD |
1003 | if (radix_tree_exceptional_entry(page)) { |
1004 | swap = radix_to_swp_entry(page); | |
1005 | page = NULL; | |
1006 | } | |
1007 | ||
1008 | if (sgp != SGP_WRITE && | |
1009 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
1010 | error = -EINVAL; | |
1011 | goto failed; | |
1012 | } | |
1013 | ||
1014 | if (page || (sgp == SGP_READ && !swap.val)) { | |
b409f9fc | 1015 | /* |
27ab7006 HD |
1016 | * Once we can get the page lock, it must be uptodate: |
1017 | * if there were an error in reading back from swap, | |
1018 | * the page would not be inserted into the filecache. | |
b409f9fc | 1019 | */ |
54af6042 HD |
1020 | BUG_ON(page && !PageUptodate(page)); |
1021 | *pagep = page; | |
1022 | return 0; | |
27ab7006 HD |
1023 | } |
1024 | ||
1025 | /* | |
54af6042 HD |
1026 | * Fast cache lookup did not find it: |
1027 | * bring it back from swap or allocate. | |
27ab7006 | 1028 | */ |
54af6042 HD |
1029 | info = SHMEM_I(inode); |
1030 | sbinfo = SHMEM_SB(inode->i_sb); | |
1da177e4 | 1031 | |
1da177e4 LT |
1032 | if (swap.val) { |
1033 | /* Look it up and read it in.. */ | |
27ab7006 HD |
1034 | page = lookup_swap_cache(swap); |
1035 | if (!page) { | |
1da177e4 | 1036 | /* here we actually do the io */ |
68da9f05 HD |
1037 | if (fault_type) |
1038 | *fault_type |= VM_FAULT_MAJOR; | |
41ffe5d5 | 1039 | page = shmem_swapin(swap, gfp, info, index); |
27ab7006 | 1040 | if (!page) { |
54af6042 HD |
1041 | error = -ENOMEM; |
1042 | goto failed; | |
1da177e4 | 1043 | } |
1da177e4 LT |
1044 | } |
1045 | ||
1046 | /* We have to do this with page locked to prevent races */ | |
54af6042 | 1047 | lock_page(page); |
bde05d1c HD |
1048 | if (!PageSwapCache(page) || page->mapping) { |
1049 | error = -EEXIST; /* try again */ | |
1050 | goto failed; | |
1051 | } | |
27ab7006 | 1052 | if (!PageUptodate(page)) { |
1da177e4 | 1053 | error = -EIO; |
54af6042 | 1054 | goto failed; |
1da177e4 | 1055 | } |
54af6042 HD |
1056 | wait_on_page_writeback(page); |
1057 | ||
bde05d1c HD |
1058 | if (shmem_should_replace_page(page, gfp)) { |
1059 | error = shmem_replace_page(&page, gfp, info, index); | |
1060 | if (error) | |
1061 | goto failed; | |
1da177e4 | 1062 | } |
27ab7006 | 1063 | |
aa3b1895 HD |
1064 | error = mem_cgroup_cache_charge(page, current->mm, |
1065 | gfp & GFP_RECLAIM_MASK); | |
1066 | if (!error) | |
1067 | error = shmem_add_to_page_cache(page, mapping, index, | |
1068 | gfp, swp_to_radix_entry(swap)); | |
54af6042 HD |
1069 | if (error) |
1070 | goto failed; | |
1071 | ||
1072 | spin_lock(&info->lock); | |
285b2c4f | 1073 | info->swapped--; |
54af6042 | 1074 | shmem_recalc_inode(inode); |
27ab7006 | 1075 | spin_unlock(&info->lock); |
54af6042 HD |
1076 | |
1077 | delete_from_swap_cache(page); | |
27ab7006 HD |
1078 | set_page_dirty(page); |
1079 | swap_free(swap); | |
1080 | ||
54af6042 HD |
1081 | } else { |
1082 | if (shmem_acct_block(info->flags)) { | |
1083 | error = -ENOSPC; | |
1084 | goto failed; | |
1da177e4 | 1085 | } |
0edd73b3 | 1086 | if (sbinfo->max_blocks) { |
fc5da22a | 1087 | if (percpu_counter_compare(&sbinfo->used_blocks, |
54af6042 HD |
1088 | sbinfo->max_blocks) >= 0) { |
1089 | error = -ENOSPC; | |
1090 | goto unacct; | |
1091 | } | |
7e496299 | 1092 | percpu_counter_inc(&sbinfo->used_blocks); |
54af6042 | 1093 | } |
1da177e4 | 1094 | |
54af6042 HD |
1095 | page = shmem_alloc_page(gfp, info, index); |
1096 | if (!page) { | |
1097 | error = -ENOMEM; | |
1098 | goto decused; | |
1da177e4 LT |
1099 | } |
1100 | ||
54af6042 HD |
1101 | SetPageSwapBacked(page); |
1102 | __set_page_locked(page); | |
aa3b1895 HD |
1103 | error = mem_cgroup_cache_charge(page, current->mm, |
1104 | gfp & GFP_RECLAIM_MASK); | |
1105 | if (!error) | |
1106 | error = shmem_add_to_page_cache(page, mapping, index, | |
1107 | gfp, NULL); | |
54af6042 HD |
1108 | if (error) |
1109 | goto decused; | |
1110 | lru_cache_add_anon(page); | |
1111 | ||
1112 | spin_lock(&info->lock); | |
1da177e4 | 1113 | info->alloced++; |
54af6042 HD |
1114 | inode->i_blocks += BLOCKS_PER_PAGE; |
1115 | shmem_recalc_inode(inode); | |
1da177e4 | 1116 | spin_unlock(&info->lock); |
54af6042 | 1117 | |
ec9516fb HD |
1118 | /* |
1119 | * Let SGP_WRITE caller clear ends if write does not fill page | |
1120 | */ | |
1121 | if (sgp != SGP_WRITE) { | |
1122 | clear_highpage(page); | |
1123 | flush_dcache_page(page); | |
1124 | SetPageUptodate(page); | |
1125 | } | |
a0ee5ec5 | 1126 | if (sgp == SGP_DIRTY) |
27ab7006 | 1127 | set_page_dirty(page); |
1da177e4 | 1128 | } |
bde05d1c | 1129 | |
54af6042 HD |
1130 | /* Perhaps the file has been truncated since we checked */ |
1131 | if (sgp != SGP_WRITE && | |
1132 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
1133 | error = -EINVAL; | |
1134 | goto trunc; | |
e83c32e8 | 1135 | } |
54af6042 HD |
1136 | *pagep = page; |
1137 | return 0; | |
1da177e4 | 1138 | |
59a16ead | 1139 | /* |
54af6042 | 1140 | * Error recovery. |
59a16ead | 1141 | */ |
54af6042 HD |
1142 | trunc: |
1143 | ClearPageDirty(page); | |
1144 | delete_from_page_cache(page); | |
1145 | spin_lock(&info->lock); | |
1146 | info->alloced--; | |
1147 | inode->i_blocks -= BLOCKS_PER_PAGE; | |
59a16ead | 1148 | spin_unlock(&info->lock); |
54af6042 HD |
1149 | decused: |
1150 | if (sbinfo->max_blocks) | |
1151 | percpu_counter_add(&sbinfo->used_blocks, -1); | |
1152 | unacct: | |
1153 | shmem_unacct_blocks(info->flags, 1); | |
1154 | failed: | |
1155 | if (swap.val && error != -EINVAL) { | |
1156 | struct page *test = find_get_page(mapping, index); | |
1157 | if (test && !radix_tree_exceptional_entry(test)) | |
1158 | page_cache_release(test); | |
1159 | /* Have another try if the entry has changed */ | |
1160 | if (test != swp_to_radix_entry(swap)) | |
1161 | error = -EEXIST; | |
1162 | } | |
27ab7006 | 1163 | if (page) { |
54af6042 | 1164 | unlock_page(page); |
27ab7006 | 1165 | page_cache_release(page); |
54af6042 HD |
1166 | } |
1167 | if (error == -ENOSPC && !once++) { | |
1168 | info = SHMEM_I(inode); | |
1169 | spin_lock(&info->lock); | |
1170 | shmem_recalc_inode(inode); | |
1171 | spin_unlock(&info->lock); | |
27ab7006 | 1172 | goto repeat; |
ff36b801 | 1173 | } |
54af6042 HD |
1174 | if (error == -EEXIST) |
1175 | goto repeat; | |
1176 | return error; | |
1da177e4 LT |
1177 | } |
1178 | ||
d0217ac0 | 1179 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1180 | { |
d3ac7f89 | 1181 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1182 | int error; |
68da9f05 | 1183 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 1184 | |
27d54b39 | 1185 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1186 | if (error) |
1187 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 1188 | |
456f998e YH |
1189 | if (ret & VM_FAULT_MAJOR) { |
1190 | count_vm_event(PGMAJFAULT); | |
1191 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
1192 | } | |
68da9f05 | 1193 | return ret; |
1da177e4 LT |
1194 | } |
1195 | ||
1da177e4 | 1196 | #ifdef CONFIG_NUMA |
41ffe5d5 | 1197 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
1da177e4 | 1198 | { |
41ffe5d5 HD |
1199 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1200 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); | |
1da177e4 LT |
1201 | } |
1202 | ||
d8dc74f2 AB |
1203 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1204 | unsigned long addr) | |
1da177e4 | 1205 | { |
41ffe5d5 HD |
1206 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1207 | pgoff_t index; | |
1da177e4 | 1208 | |
41ffe5d5 HD |
1209 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
1210 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
1da177e4 LT |
1211 | } |
1212 | #endif | |
1213 | ||
1214 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1215 | { | |
d3ac7f89 | 1216 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1217 | struct shmem_inode_info *info = SHMEM_I(inode); |
1218 | int retval = -ENOMEM; | |
1219 | ||
1220 | spin_lock(&info->lock); | |
1221 | if (lock && !(info->flags & VM_LOCKED)) { | |
1222 | if (!user_shm_lock(inode->i_size, user)) | |
1223 | goto out_nomem; | |
1224 | info->flags |= VM_LOCKED; | |
89e004ea | 1225 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1226 | } |
1227 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1228 | user_shm_unlock(inode->i_size, user); | |
1229 | info->flags &= ~VM_LOCKED; | |
89e004ea | 1230 | mapping_clear_unevictable(file->f_mapping); |
1da177e4 LT |
1231 | } |
1232 | retval = 0; | |
89e004ea | 1233 | |
1da177e4 LT |
1234 | out_nomem: |
1235 | spin_unlock(&info->lock); | |
1236 | return retval; | |
1237 | } | |
1238 | ||
9b83a6a8 | 1239 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1240 | { |
1241 | file_accessed(file); | |
1242 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1243 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1244 | return 0; |
1245 | } | |
1246 | ||
454abafe | 1247 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
09208d15 | 1248 | umode_t mode, dev_t dev, unsigned long flags) |
1da177e4 LT |
1249 | { |
1250 | struct inode *inode; | |
1251 | struct shmem_inode_info *info; | |
1252 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1253 | ||
5b04c689 PE |
1254 | if (shmem_reserve_inode(sb)) |
1255 | return NULL; | |
1da177e4 LT |
1256 | |
1257 | inode = new_inode(sb); | |
1258 | if (inode) { | |
85fe4025 | 1259 | inode->i_ino = get_next_ino(); |
454abafe | 1260 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1261 | inode->i_blocks = 0; |
1da177e4 LT |
1262 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1263 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1264 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1265 | info = SHMEM_I(inode); |
1266 | memset(info, 0, (char *)inode - (char *)info); | |
1267 | spin_lock_init(&info->lock); | |
0b0a0806 | 1268 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1269 | INIT_LIST_HEAD(&info->swaplist); |
b09e0fa4 | 1270 | INIT_LIST_HEAD(&info->xattr_list); |
72c04902 | 1271 | cache_no_acl(inode); |
1da177e4 LT |
1272 | |
1273 | switch (mode & S_IFMT) { | |
1274 | default: | |
39f0247d | 1275 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1276 | init_special_inode(inode, mode, dev); |
1277 | break; | |
1278 | case S_IFREG: | |
14fcc23f | 1279 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1280 | inode->i_op = &shmem_inode_operations; |
1281 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1282 | mpol_shared_policy_init(&info->policy, |
1283 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1284 | break; |
1285 | case S_IFDIR: | |
d8c76e6f | 1286 | inc_nlink(inode); |
1da177e4 LT |
1287 | /* Some things misbehave if size == 0 on a directory */ |
1288 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1289 | inode->i_op = &shmem_dir_inode_operations; | |
1290 | inode->i_fop = &simple_dir_operations; | |
1291 | break; | |
1292 | case S_IFLNK: | |
1293 | /* | |
1294 | * Must not load anything in the rbtree, | |
1295 | * mpol_free_shared_policy will not be called. | |
1296 | */ | |
71fe804b | 1297 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1298 | break; |
1299 | } | |
5b04c689 PE |
1300 | } else |
1301 | shmem_free_inode(sb); | |
1da177e4 LT |
1302 | return inode; |
1303 | } | |
1304 | ||
1305 | #ifdef CONFIG_TMPFS | |
92e1d5be | 1306 | static const struct inode_operations shmem_symlink_inode_operations; |
69f07ec9 | 1307 | static const struct inode_operations shmem_short_symlink_operations; |
1da177e4 | 1308 | |
6d9d88d0 JS |
1309 | #ifdef CONFIG_TMPFS_XATTR |
1310 | static int shmem_initxattrs(struct inode *, const struct xattr *, void *); | |
1311 | #else | |
1312 | #define shmem_initxattrs NULL | |
1313 | #endif | |
1314 | ||
1da177e4 | 1315 | static int |
800d15a5 NP |
1316 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1317 | loff_t pos, unsigned len, unsigned flags, | |
1318 | struct page **pagep, void **fsdata) | |
1da177e4 | 1319 | { |
800d15a5 NP |
1320 | struct inode *inode = mapping->host; |
1321 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
800d15a5 NP |
1322 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
1323 | } | |
1324 | ||
1325 | static int | |
1326 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1327 | loff_t pos, unsigned len, unsigned copied, | |
1328 | struct page *page, void *fsdata) | |
1329 | { | |
1330 | struct inode *inode = mapping->host; | |
1331 | ||
d3602444 HD |
1332 | if (pos + copied > inode->i_size) |
1333 | i_size_write(inode, pos + copied); | |
1334 | ||
ec9516fb HD |
1335 | if (!PageUptodate(page)) { |
1336 | if (copied < PAGE_CACHE_SIZE) { | |
1337 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
1338 | zero_user_segments(page, 0, from, | |
1339 | from + copied, PAGE_CACHE_SIZE); | |
1340 | } | |
1341 | SetPageUptodate(page); | |
1342 | } | |
800d15a5 | 1343 | set_page_dirty(page); |
6746aff7 | 1344 | unlock_page(page); |
800d15a5 NP |
1345 | page_cache_release(page); |
1346 | ||
800d15a5 | 1347 | return copied; |
1da177e4 LT |
1348 | } |
1349 | ||
1da177e4 LT |
1350 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1351 | { | |
d3ac7f89 | 1352 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 | 1353 | struct address_space *mapping = inode->i_mapping; |
41ffe5d5 HD |
1354 | pgoff_t index; |
1355 | unsigned long offset; | |
a0ee5ec5 HD |
1356 | enum sgp_type sgp = SGP_READ; |
1357 | ||
1358 | /* | |
1359 | * Might this read be for a stacking filesystem? Then when reading | |
1360 | * holes of a sparse file, we actually need to allocate those pages, | |
1361 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1362 | */ | |
1363 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1364 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1365 | |
1366 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1367 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1368 | ||
1369 | for (;;) { | |
1370 | struct page *page = NULL; | |
41ffe5d5 HD |
1371 | pgoff_t end_index; |
1372 | unsigned long nr, ret; | |
1da177e4 LT |
1373 | loff_t i_size = i_size_read(inode); |
1374 | ||
1375 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1376 | if (index > end_index) | |
1377 | break; | |
1378 | if (index == end_index) { | |
1379 | nr = i_size & ~PAGE_CACHE_MASK; | |
1380 | if (nr <= offset) | |
1381 | break; | |
1382 | } | |
1383 | ||
a0ee5ec5 | 1384 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1385 | if (desc->error) { |
1386 | if (desc->error == -EINVAL) | |
1387 | desc->error = 0; | |
1388 | break; | |
1389 | } | |
d3602444 HD |
1390 | if (page) |
1391 | unlock_page(page); | |
1da177e4 LT |
1392 | |
1393 | /* | |
1394 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1395 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1396 | */ |
1397 | nr = PAGE_CACHE_SIZE; | |
1398 | i_size = i_size_read(inode); | |
1399 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1400 | if (index == end_index) { | |
1401 | nr = i_size & ~PAGE_CACHE_MASK; | |
1402 | if (nr <= offset) { | |
1403 | if (page) | |
1404 | page_cache_release(page); | |
1405 | break; | |
1406 | } | |
1407 | } | |
1408 | nr -= offset; | |
1409 | ||
1410 | if (page) { | |
1411 | /* | |
1412 | * If users can be writing to this page using arbitrary | |
1413 | * virtual addresses, take care about potential aliasing | |
1414 | * before reading the page on the kernel side. | |
1415 | */ | |
1416 | if (mapping_writably_mapped(mapping)) | |
1417 | flush_dcache_page(page); | |
1418 | /* | |
1419 | * Mark the page accessed if we read the beginning. | |
1420 | */ | |
1421 | if (!offset) | |
1422 | mark_page_accessed(page); | |
b5810039 | 1423 | } else { |
1da177e4 | 1424 | page = ZERO_PAGE(0); |
b5810039 NP |
1425 | page_cache_get(page); |
1426 | } | |
1da177e4 LT |
1427 | |
1428 | /* | |
1429 | * Ok, we have the page, and it's up-to-date, so | |
1430 | * now we can copy it to user space... | |
1431 | * | |
1432 | * The actor routine returns how many bytes were actually used.. | |
1433 | * NOTE! This may not be the same as how much of a user buffer | |
1434 | * we filled up (we may be padding etc), so we can only update | |
1435 | * "pos" here (the actor routine has to update the user buffer | |
1436 | * pointers and the remaining count). | |
1437 | */ | |
1438 | ret = actor(desc, page, offset, nr); | |
1439 | offset += ret; | |
1440 | index += offset >> PAGE_CACHE_SHIFT; | |
1441 | offset &= ~PAGE_CACHE_MASK; | |
1442 | ||
1443 | page_cache_release(page); | |
1444 | if (ret != nr || !desc->count) | |
1445 | break; | |
1446 | ||
1447 | cond_resched(); | |
1448 | } | |
1449 | ||
1450 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1451 | file_accessed(filp); | |
1452 | } | |
1453 | ||
bcd78e49 HD |
1454 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1455 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1456 | { | |
1457 | struct file *filp = iocb->ki_filp; | |
1458 | ssize_t retval; | |
1459 | unsigned long seg; | |
1460 | size_t count; | |
1461 | loff_t *ppos = &iocb->ki_pos; | |
1462 | ||
1463 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1464 | if (retval) | |
1465 | return retval; | |
1466 | ||
1467 | for (seg = 0; seg < nr_segs; seg++) { | |
1468 | read_descriptor_t desc; | |
1469 | ||
1470 | desc.written = 0; | |
1471 | desc.arg.buf = iov[seg].iov_base; | |
1472 | desc.count = iov[seg].iov_len; | |
1473 | if (desc.count == 0) | |
1474 | continue; | |
1475 | desc.error = 0; | |
1476 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1477 | retval += desc.written; | |
1478 | if (desc.error) { | |
1479 | retval = retval ?: desc.error; | |
1480 | break; | |
1481 | } | |
1482 | if (desc.count > 0) | |
1483 | break; | |
1484 | } | |
1485 | return retval; | |
1da177e4 LT |
1486 | } |
1487 | ||
708e3508 HD |
1488 | static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
1489 | struct pipe_inode_info *pipe, size_t len, | |
1490 | unsigned int flags) | |
1491 | { | |
1492 | struct address_space *mapping = in->f_mapping; | |
71f0e07a | 1493 | struct inode *inode = mapping->host; |
708e3508 HD |
1494 | unsigned int loff, nr_pages, req_pages; |
1495 | struct page *pages[PIPE_DEF_BUFFERS]; | |
1496 | struct partial_page partial[PIPE_DEF_BUFFERS]; | |
1497 | struct page *page; | |
1498 | pgoff_t index, end_index; | |
1499 | loff_t isize, left; | |
1500 | int error, page_nr; | |
1501 | struct splice_pipe_desc spd = { | |
1502 | .pages = pages, | |
1503 | .partial = partial, | |
1504 | .flags = flags, | |
1505 | .ops = &page_cache_pipe_buf_ops, | |
1506 | .spd_release = spd_release_page, | |
1507 | }; | |
1508 | ||
71f0e07a | 1509 | isize = i_size_read(inode); |
708e3508 HD |
1510 | if (unlikely(*ppos >= isize)) |
1511 | return 0; | |
1512 | ||
1513 | left = isize - *ppos; | |
1514 | if (unlikely(left < len)) | |
1515 | len = left; | |
1516 | ||
1517 | if (splice_grow_spd(pipe, &spd)) | |
1518 | return -ENOMEM; | |
1519 | ||
1520 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1521 | loff = *ppos & ~PAGE_CACHE_MASK; | |
1522 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1523 | nr_pages = min(req_pages, pipe->buffers); | |
1524 | ||
708e3508 HD |
1525 | spd.nr_pages = find_get_pages_contig(mapping, index, |
1526 | nr_pages, spd.pages); | |
1527 | index += spd.nr_pages; | |
708e3508 | 1528 | error = 0; |
708e3508 | 1529 | |
71f0e07a | 1530 | while (spd.nr_pages < nr_pages) { |
71f0e07a HD |
1531 | error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
1532 | if (error) | |
1533 | break; | |
1534 | unlock_page(page); | |
708e3508 HD |
1535 | spd.pages[spd.nr_pages++] = page; |
1536 | index++; | |
1537 | } | |
1538 | ||
708e3508 HD |
1539 | index = *ppos >> PAGE_CACHE_SHIFT; |
1540 | nr_pages = spd.nr_pages; | |
1541 | spd.nr_pages = 0; | |
71f0e07a | 1542 | |
708e3508 HD |
1543 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
1544 | unsigned int this_len; | |
1545 | ||
1546 | if (!len) | |
1547 | break; | |
1548 | ||
708e3508 HD |
1549 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
1550 | page = spd.pages[page_nr]; | |
1551 | ||
71f0e07a | 1552 | if (!PageUptodate(page) || page->mapping != mapping) { |
71f0e07a HD |
1553 | error = shmem_getpage(inode, index, &page, |
1554 | SGP_CACHE, NULL); | |
1555 | if (error) | |
708e3508 | 1556 | break; |
71f0e07a HD |
1557 | unlock_page(page); |
1558 | page_cache_release(spd.pages[page_nr]); | |
1559 | spd.pages[page_nr] = page; | |
708e3508 | 1560 | } |
71f0e07a HD |
1561 | |
1562 | isize = i_size_read(inode); | |
708e3508 HD |
1563 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
1564 | if (unlikely(!isize || index > end_index)) | |
1565 | break; | |
1566 | ||
708e3508 HD |
1567 | if (end_index == index) { |
1568 | unsigned int plen; | |
1569 | ||
708e3508 HD |
1570 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
1571 | if (plen <= loff) | |
1572 | break; | |
1573 | ||
708e3508 HD |
1574 | this_len = min(this_len, plen - loff); |
1575 | len = this_len; | |
1576 | } | |
1577 | ||
1578 | spd.partial[page_nr].offset = loff; | |
1579 | spd.partial[page_nr].len = this_len; | |
1580 | len -= this_len; | |
1581 | loff = 0; | |
1582 | spd.nr_pages++; | |
1583 | index++; | |
1584 | } | |
1585 | ||
708e3508 HD |
1586 | while (page_nr < nr_pages) |
1587 | page_cache_release(spd.pages[page_nr++]); | |
708e3508 HD |
1588 | |
1589 | if (spd.nr_pages) | |
1590 | error = splice_to_pipe(pipe, &spd); | |
1591 | ||
1592 | splice_shrink_spd(pipe, &spd); | |
1593 | ||
1594 | if (error > 0) { | |
1595 | *ppos += error; | |
1596 | file_accessed(in); | |
1597 | } | |
1598 | return error; | |
1599 | } | |
1600 | ||
83e4fa9c HD |
1601 | static long shmem_fallocate(struct file *file, int mode, loff_t offset, |
1602 | loff_t len) | |
1603 | { | |
1604 | struct inode *inode = file->f_path.dentry->d_inode; | |
1605 | int error = -EOPNOTSUPP; | |
1606 | ||
1607 | mutex_lock(&inode->i_mutex); | |
1608 | ||
1609 | if (mode & FALLOC_FL_PUNCH_HOLE) { | |
1610 | struct address_space *mapping = file->f_mapping; | |
1611 | loff_t unmap_start = round_up(offset, PAGE_SIZE); | |
1612 | loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1; | |
1613 | ||
1614 | if ((u64)unmap_end > (u64)unmap_start) | |
1615 | unmap_mapping_range(mapping, unmap_start, | |
1616 | 1 + unmap_end - unmap_start, 0); | |
1617 | shmem_truncate_range(inode, offset, offset + len - 1); | |
1618 | /* No need to unmap again: hole-punching leaves COWed pages */ | |
1619 | error = 0; | |
1620 | } | |
1621 | ||
1622 | mutex_unlock(&inode->i_mutex); | |
1623 | return error; | |
1624 | } | |
1625 | ||
726c3342 | 1626 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1627 | { |
726c3342 | 1628 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1629 | |
1630 | buf->f_type = TMPFS_MAGIC; | |
1631 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1632 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1633 | if (sbinfo->max_blocks) { |
1da177e4 | 1634 | buf->f_blocks = sbinfo->max_blocks; |
41ffe5d5 HD |
1635 | buf->f_bavail = |
1636 | buf->f_bfree = sbinfo->max_blocks - | |
1637 | percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1638 | } |
1639 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1640 | buf->f_files = sbinfo->max_inodes; |
1641 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1642 | } |
1643 | /* else leave those fields 0 like simple_statfs */ | |
1644 | return 0; | |
1645 | } | |
1646 | ||
1647 | /* | |
1648 | * File creation. Allocate an inode, and we're done.. | |
1649 | */ | |
1650 | static int | |
1a67aafb | 1651 | shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 | 1652 | { |
0b0a0806 | 1653 | struct inode *inode; |
1da177e4 LT |
1654 | int error = -ENOSPC; |
1655 | ||
454abafe | 1656 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1657 | if (inode) { |
2a7dba39 | 1658 | error = security_inode_init_security(inode, dir, |
9d8f13ba | 1659 | &dentry->d_name, |
6d9d88d0 | 1660 | shmem_initxattrs, NULL); |
570bc1c2 SS |
1661 | if (error) { |
1662 | if (error != -EOPNOTSUPP) { | |
1663 | iput(inode); | |
1664 | return error; | |
1665 | } | |
39f0247d | 1666 | } |
1c7c474c CH |
1667 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1668 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1669 | if (error) { |
1670 | iput(inode); | |
1671 | return error; | |
570bc1c2 | 1672 | } |
718deb6b AV |
1673 | #else |
1674 | error = 0; | |
1c7c474c | 1675 | #endif |
1da177e4 LT |
1676 | dir->i_size += BOGO_DIRENT_SIZE; |
1677 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1678 | d_instantiate(dentry, inode); | |
1679 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1680 | } |
1681 | return error; | |
1682 | } | |
1683 | ||
18bb1db3 | 1684 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
1685 | { |
1686 | int error; | |
1687 | ||
1688 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1689 | return error; | |
d8c76e6f | 1690 | inc_nlink(dir); |
1da177e4 LT |
1691 | return 0; |
1692 | } | |
1693 | ||
4acdaf27 | 1694 | static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
1da177e4 LT |
1695 | struct nameidata *nd) |
1696 | { | |
1697 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1698 | } | |
1699 | ||
1700 | /* | |
1701 | * Link a file.. | |
1702 | */ | |
1703 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1704 | { | |
1705 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1706 | int ret; |
1da177e4 LT |
1707 | |
1708 | /* | |
1709 | * No ordinary (disk based) filesystem counts links as inodes; | |
1710 | * but each new link needs a new dentry, pinning lowmem, and | |
1711 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1712 | */ | |
5b04c689 PE |
1713 | ret = shmem_reserve_inode(inode->i_sb); |
1714 | if (ret) | |
1715 | goto out; | |
1da177e4 LT |
1716 | |
1717 | dir->i_size += BOGO_DIRENT_SIZE; | |
1718 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1719 | inc_nlink(inode); |
7de9c6ee | 1720 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1721 | dget(dentry); /* Extra pinning count for the created dentry */ |
1722 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1723 | out: |
1724 | return ret; | |
1da177e4 LT |
1725 | } |
1726 | ||
1727 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1728 | { | |
1729 | struct inode *inode = dentry->d_inode; | |
1730 | ||
5b04c689 PE |
1731 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1732 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1733 | |
1734 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1735 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1736 | drop_nlink(inode); |
1da177e4 LT |
1737 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1738 | return 0; | |
1739 | } | |
1740 | ||
1741 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1742 | { | |
1743 | if (!simple_empty(dentry)) | |
1744 | return -ENOTEMPTY; | |
1745 | ||
9a53c3a7 DH |
1746 | drop_nlink(dentry->d_inode); |
1747 | drop_nlink(dir); | |
1da177e4 LT |
1748 | return shmem_unlink(dir, dentry); |
1749 | } | |
1750 | ||
1751 | /* | |
1752 | * The VFS layer already does all the dentry stuff for rename, | |
1753 | * we just have to decrement the usage count for the target if | |
1754 | * it exists so that the VFS layer correctly free's it when it | |
1755 | * gets overwritten. | |
1756 | */ | |
1757 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1758 | { | |
1759 | struct inode *inode = old_dentry->d_inode; | |
1760 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1761 | ||
1762 | if (!simple_empty(new_dentry)) | |
1763 | return -ENOTEMPTY; | |
1764 | ||
1765 | if (new_dentry->d_inode) { | |
1766 | (void) shmem_unlink(new_dir, new_dentry); | |
1767 | if (they_are_dirs) | |
9a53c3a7 | 1768 | drop_nlink(old_dir); |
1da177e4 | 1769 | } else if (they_are_dirs) { |
9a53c3a7 | 1770 | drop_nlink(old_dir); |
d8c76e6f | 1771 | inc_nlink(new_dir); |
1da177e4 LT |
1772 | } |
1773 | ||
1774 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1775 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1776 | old_dir->i_ctime = old_dir->i_mtime = | |
1777 | new_dir->i_ctime = new_dir->i_mtime = | |
1778 | inode->i_ctime = CURRENT_TIME; | |
1779 | return 0; | |
1780 | } | |
1781 | ||
1782 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1783 | { | |
1784 | int error; | |
1785 | int len; | |
1786 | struct inode *inode; | |
9276aad6 | 1787 | struct page *page; |
1da177e4 LT |
1788 | char *kaddr; |
1789 | struct shmem_inode_info *info; | |
1790 | ||
1791 | len = strlen(symname) + 1; | |
1792 | if (len > PAGE_CACHE_SIZE) | |
1793 | return -ENAMETOOLONG; | |
1794 | ||
454abafe | 1795 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
1796 | if (!inode) |
1797 | return -ENOSPC; | |
1798 | ||
9d8f13ba | 1799 | error = security_inode_init_security(inode, dir, &dentry->d_name, |
6d9d88d0 | 1800 | shmem_initxattrs, NULL); |
570bc1c2 SS |
1801 | if (error) { |
1802 | if (error != -EOPNOTSUPP) { | |
1803 | iput(inode); | |
1804 | return error; | |
1805 | } | |
1806 | error = 0; | |
1807 | } | |
1808 | ||
1da177e4 LT |
1809 | info = SHMEM_I(inode); |
1810 | inode->i_size = len-1; | |
69f07ec9 HD |
1811 | if (len <= SHORT_SYMLINK_LEN) { |
1812 | info->symlink = kmemdup(symname, len, GFP_KERNEL); | |
1813 | if (!info->symlink) { | |
1814 | iput(inode); | |
1815 | return -ENOMEM; | |
1816 | } | |
1817 | inode->i_op = &shmem_short_symlink_operations; | |
1da177e4 LT |
1818 | } else { |
1819 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1820 | if (error) { | |
1821 | iput(inode); | |
1822 | return error; | |
1823 | } | |
14fcc23f | 1824 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 | 1825 | inode->i_op = &shmem_symlink_inode_operations; |
9b04c5fe | 1826 | kaddr = kmap_atomic(page); |
1da177e4 | 1827 | memcpy(kaddr, symname, len); |
9b04c5fe | 1828 | kunmap_atomic(kaddr); |
ec9516fb | 1829 | SetPageUptodate(page); |
1da177e4 | 1830 | set_page_dirty(page); |
6746aff7 | 1831 | unlock_page(page); |
1da177e4 LT |
1832 | page_cache_release(page); |
1833 | } | |
1da177e4 LT |
1834 | dir->i_size += BOGO_DIRENT_SIZE; |
1835 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1836 | d_instantiate(dentry, inode); | |
1837 | dget(dentry); | |
1838 | return 0; | |
1839 | } | |
1840 | ||
69f07ec9 | 1841 | static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 1842 | { |
69f07ec9 | 1843 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->symlink); |
cc314eef | 1844 | return NULL; |
1da177e4 LT |
1845 | } |
1846 | ||
cc314eef | 1847 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1848 | { |
1849 | struct page *page = NULL; | |
41ffe5d5 HD |
1850 | int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
1851 | nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); | |
d3602444 HD |
1852 | if (page) |
1853 | unlock_page(page); | |
cc314eef | 1854 | return page; |
1da177e4 LT |
1855 | } |
1856 | ||
cc314eef | 1857 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1858 | { |
1859 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1860 | struct page *page = cookie; |
1da177e4 LT |
1861 | kunmap(page); |
1862 | mark_page_accessed(page); | |
1863 | page_cache_release(page); | |
1da177e4 LT |
1864 | } |
1865 | } | |
1866 | ||
b09e0fa4 | 1867 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 1868 | /* |
b09e0fa4 EP |
1869 | * Superblocks without xattr inode operations may get some security.* xattr |
1870 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
1871 | * like ACLs, we also need to implement the security.* handlers at |
1872 | * filesystem level, though. | |
1873 | */ | |
1874 | ||
6d9d88d0 JS |
1875 | /* |
1876 | * Allocate new xattr and copy in the value; but leave the name to callers. | |
1877 | */ | |
1878 | static struct shmem_xattr *shmem_xattr_alloc(const void *value, size_t size) | |
1879 | { | |
1880 | struct shmem_xattr *new_xattr; | |
1881 | size_t len; | |
1882 | ||
1883 | /* wrap around? */ | |
1884 | len = sizeof(*new_xattr) + size; | |
1885 | if (len <= sizeof(*new_xattr)) | |
1886 | return NULL; | |
1887 | ||
1888 | new_xattr = kmalloc(len, GFP_KERNEL); | |
1889 | if (!new_xattr) | |
1890 | return NULL; | |
1891 | ||
1892 | new_xattr->size = size; | |
1893 | memcpy(new_xattr->value, value, size); | |
1894 | return new_xattr; | |
1895 | } | |
1896 | ||
1897 | /* | |
1898 | * Callback for security_inode_init_security() for acquiring xattrs. | |
1899 | */ | |
1900 | static int shmem_initxattrs(struct inode *inode, | |
1901 | const struct xattr *xattr_array, | |
1902 | void *fs_info) | |
1903 | { | |
1904 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1905 | const struct xattr *xattr; | |
1906 | struct shmem_xattr *new_xattr; | |
1907 | size_t len; | |
1908 | ||
1909 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { | |
1910 | new_xattr = shmem_xattr_alloc(xattr->value, xattr->value_len); | |
1911 | if (!new_xattr) | |
1912 | return -ENOMEM; | |
1913 | ||
1914 | len = strlen(xattr->name) + 1; | |
1915 | new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len, | |
1916 | GFP_KERNEL); | |
1917 | if (!new_xattr->name) { | |
1918 | kfree(new_xattr); | |
1919 | return -ENOMEM; | |
1920 | } | |
1921 | ||
1922 | memcpy(new_xattr->name, XATTR_SECURITY_PREFIX, | |
1923 | XATTR_SECURITY_PREFIX_LEN); | |
1924 | memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, | |
1925 | xattr->name, len); | |
1926 | ||
1927 | spin_lock(&info->lock); | |
1928 | list_add(&new_xattr->list, &info->xattr_list); | |
1929 | spin_unlock(&info->lock); | |
1930 | } | |
1931 | ||
1932 | return 0; | |
1933 | } | |
1934 | ||
b09e0fa4 EP |
1935 | static int shmem_xattr_get(struct dentry *dentry, const char *name, |
1936 | void *buffer, size_t size) | |
39f0247d | 1937 | { |
b09e0fa4 EP |
1938 | struct shmem_inode_info *info; |
1939 | struct shmem_xattr *xattr; | |
1940 | int ret = -ENODATA; | |
39f0247d | 1941 | |
b09e0fa4 EP |
1942 | info = SHMEM_I(dentry->d_inode); |
1943 | ||
1944 | spin_lock(&info->lock); | |
1945 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1946 | if (strcmp(name, xattr->name)) | |
1947 | continue; | |
1948 | ||
1949 | ret = xattr->size; | |
1950 | if (buffer) { | |
1951 | if (size < xattr->size) | |
1952 | ret = -ERANGE; | |
1953 | else | |
1954 | memcpy(buffer, xattr->value, xattr->size); | |
1955 | } | |
1956 | break; | |
1957 | } | |
1958 | spin_unlock(&info->lock); | |
1959 | return ret; | |
39f0247d AG |
1960 | } |
1961 | ||
6d9d88d0 | 1962 | static int shmem_xattr_set(struct inode *inode, const char *name, |
b09e0fa4 | 1963 | const void *value, size_t size, int flags) |
39f0247d | 1964 | { |
b09e0fa4 EP |
1965 | struct shmem_inode_info *info = SHMEM_I(inode); |
1966 | struct shmem_xattr *xattr; | |
1967 | struct shmem_xattr *new_xattr = NULL; | |
b09e0fa4 EP |
1968 | int err = 0; |
1969 | ||
1970 | /* value == NULL means remove */ | |
1971 | if (value) { | |
6d9d88d0 | 1972 | new_xattr = shmem_xattr_alloc(value, size); |
b09e0fa4 EP |
1973 | if (!new_xattr) |
1974 | return -ENOMEM; | |
1975 | ||
1976 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
1977 | if (!new_xattr->name) { | |
1978 | kfree(new_xattr); | |
1979 | return -ENOMEM; | |
1980 | } | |
b09e0fa4 EP |
1981 | } |
1982 | ||
1983 | spin_lock(&info->lock); | |
1984 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1985 | if (!strcmp(name, xattr->name)) { | |
1986 | if (flags & XATTR_CREATE) { | |
1987 | xattr = new_xattr; | |
1988 | err = -EEXIST; | |
1989 | } else if (new_xattr) { | |
1990 | list_replace(&xattr->list, &new_xattr->list); | |
1991 | } else { | |
1992 | list_del(&xattr->list); | |
1993 | } | |
1994 | goto out; | |
1995 | } | |
1996 | } | |
1997 | if (flags & XATTR_REPLACE) { | |
1998 | xattr = new_xattr; | |
1999 | err = -ENODATA; | |
2000 | } else { | |
2001 | list_add(&new_xattr->list, &info->xattr_list); | |
2002 | xattr = NULL; | |
2003 | } | |
2004 | out: | |
2005 | spin_unlock(&info->lock); | |
2006 | if (xattr) | |
2007 | kfree(xattr->name); | |
2008 | kfree(xattr); | |
2009 | return err; | |
39f0247d AG |
2010 | } |
2011 | ||
bb435453 | 2012 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 2013 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1c7c474c CH |
2014 | &generic_acl_access_handler, |
2015 | &generic_acl_default_handler, | |
b09e0fa4 | 2016 | #endif |
39f0247d AG |
2017 | NULL |
2018 | }; | |
b09e0fa4 EP |
2019 | |
2020 | static int shmem_xattr_validate(const char *name) | |
2021 | { | |
2022 | struct { const char *prefix; size_t len; } arr[] = { | |
2023 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
2024 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
2025 | }; | |
2026 | int i; | |
2027 | ||
2028 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
2029 | size_t preflen = arr[i].len; | |
2030 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
2031 | if (!name[preflen]) | |
2032 | return -EINVAL; | |
2033 | return 0; | |
2034 | } | |
2035 | } | |
2036 | return -EOPNOTSUPP; | |
2037 | } | |
2038 | ||
2039 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
2040 | void *buffer, size_t size) | |
2041 | { | |
2042 | int err; | |
2043 | ||
2044 | /* | |
2045 | * If this is a request for a synthetic attribute in the system.* | |
2046 | * namespace use the generic infrastructure to resolve a handler | |
2047 | * for it via sb->s_xattr. | |
2048 | */ | |
2049 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2050 | return generic_getxattr(dentry, name, buffer, size); | |
2051 | ||
2052 | err = shmem_xattr_validate(name); | |
2053 | if (err) | |
2054 | return err; | |
2055 | ||
2056 | return shmem_xattr_get(dentry, name, buffer, size); | |
2057 | } | |
2058 | ||
2059 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
2060 | const void *value, size_t size, int flags) | |
2061 | { | |
2062 | int err; | |
2063 | ||
2064 | /* | |
2065 | * If this is a request for a synthetic attribute in the system.* | |
2066 | * namespace use the generic infrastructure to resolve a handler | |
2067 | * for it via sb->s_xattr. | |
2068 | */ | |
2069 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2070 | return generic_setxattr(dentry, name, value, size, flags); | |
2071 | ||
2072 | err = shmem_xattr_validate(name); | |
2073 | if (err) | |
2074 | return err; | |
2075 | ||
2076 | if (size == 0) | |
2077 | value = ""; /* empty EA, do not remove */ | |
2078 | ||
6d9d88d0 | 2079 | return shmem_xattr_set(dentry->d_inode, name, value, size, flags); |
b09e0fa4 EP |
2080 | |
2081 | } | |
2082 | ||
2083 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
2084 | { | |
2085 | int err; | |
2086 | ||
2087 | /* | |
2088 | * If this is a request for a synthetic attribute in the system.* | |
2089 | * namespace use the generic infrastructure to resolve a handler | |
2090 | * for it via sb->s_xattr. | |
2091 | */ | |
2092 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2093 | return generic_removexattr(dentry, name); | |
2094 | ||
2095 | err = shmem_xattr_validate(name); | |
2096 | if (err) | |
2097 | return err; | |
2098 | ||
6d9d88d0 | 2099 | return shmem_xattr_set(dentry->d_inode, name, NULL, 0, XATTR_REPLACE); |
b09e0fa4 EP |
2100 | } |
2101 | ||
2102 | static bool xattr_is_trusted(const char *name) | |
2103 | { | |
2104 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
2105 | } | |
2106 | ||
2107 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
2108 | { | |
2109 | bool trusted = capable(CAP_SYS_ADMIN); | |
2110 | struct shmem_xattr *xattr; | |
2111 | struct shmem_inode_info *info; | |
2112 | size_t used = 0; | |
2113 | ||
2114 | info = SHMEM_I(dentry->d_inode); | |
2115 | ||
2116 | spin_lock(&info->lock); | |
2117 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
2118 | size_t len; | |
2119 | ||
2120 | /* skip "trusted." attributes for unprivileged callers */ | |
2121 | if (!trusted && xattr_is_trusted(xattr->name)) | |
2122 | continue; | |
2123 | ||
2124 | len = strlen(xattr->name) + 1; | |
2125 | used += len; | |
2126 | if (buffer) { | |
2127 | if (size < used) { | |
2128 | used = -ERANGE; | |
2129 | break; | |
2130 | } | |
2131 | memcpy(buffer, xattr->name, len); | |
2132 | buffer += len; | |
2133 | } | |
2134 | } | |
2135 | spin_unlock(&info->lock); | |
2136 | ||
2137 | return used; | |
2138 | } | |
2139 | #endif /* CONFIG_TMPFS_XATTR */ | |
2140 | ||
69f07ec9 | 2141 | static const struct inode_operations shmem_short_symlink_operations = { |
b09e0fa4 | 2142 | .readlink = generic_readlink, |
69f07ec9 | 2143 | .follow_link = shmem_follow_short_symlink, |
b09e0fa4 EP |
2144 | #ifdef CONFIG_TMPFS_XATTR |
2145 | .setxattr = shmem_setxattr, | |
2146 | .getxattr = shmem_getxattr, | |
2147 | .listxattr = shmem_listxattr, | |
2148 | .removexattr = shmem_removexattr, | |
2149 | #endif | |
2150 | }; | |
2151 | ||
2152 | static const struct inode_operations shmem_symlink_inode_operations = { | |
2153 | .readlink = generic_readlink, | |
2154 | .follow_link = shmem_follow_link, | |
2155 | .put_link = shmem_put_link, | |
2156 | #ifdef CONFIG_TMPFS_XATTR | |
2157 | .setxattr = shmem_setxattr, | |
2158 | .getxattr = shmem_getxattr, | |
2159 | .listxattr = shmem_listxattr, | |
2160 | .removexattr = shmem_removexattr, | |
39f0247d | 2161 | #endif |
b09e0fa4 | 2162 | }; |
39f0247d | 2163 | |
91828a40 DG |
2164 | static struct dentry *shmem_get_parent(struct dentry *child) |
2165 | { | |
2166 | return ERR_PTR(-ESTALE); | |
2167 | } | |
2168 | ||
2169 | static int shmem_match(struct inode *ino, void *vfh) | |
2170 | { | |
2171 | __u32 *fh = vfh; | |
2172 | __u64 inum = fh[2]; | |
2173 | inum = (inum << 32) | fh[1]; | |
2174 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2175 | } | |
2176 | ||
480b116c CH |
2177 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2178 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2179 | { |
91828a40 | 2180 | struct inode *inode; |
480b116c CH |
2181 | struct dentry *dentry = NULL; |
2182 | u64 inum = fid->raw[2]; | |
2183 | inum = (inum << 32) | fid->raw[1]; | |
2184 | ||
2185 | if (fh_len < 3) | |
2186 | return NULL; | |
91828a40 | 2187 | |
480b116c CH |
2188 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2189 | shmem_match, fid->raw); | |
91828a40 | 2190 | if (inode) { |
480b116c | 2191 | dentry = d_find_alias(inode); |
91828a40 DG |
2192 | iput(inode); |
2193 | } | |
2194 | ||
480b116c | 2195 | return dentry; |
91828a40 DG |
2196 | } |
2197 | ||
2198 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2199 | int connectable) | |
2200 | { | |
2201 | struct inode *inode = dentry->d_inode; | |
2202 | ||
5fe0c237 AK |
2203 | if (*len < 3) { |
2204 | *len = 3; | |
91828a40 | 2205 | return 255; |
5fe0c237 | 2206 | } |
91828a40 | 2207 | |
1d3382cb | 2208 | if (inode_unhashed(inode)) { |
91828a40 DG |
2209 | /* Unfortunately insert_inode_hash is not idempotent, |
2210 | * so as we hash inodes here rather than at creation | |
2211 | * time, we need a lock to ensure we only try | |
2212 | * to do it once | |
2213 | */ | |
2214 | static DEFINE_SPINLOCK(lock); | |
2215 | spin_lock(&lock); | |
1d3382cb | 2216 | if (inode_unhashed(inode)) |
91828a40 DG |
2217 | __insert_inode_hash(inode, |
2218 | inode->i_ino + inode->i_generation); | |
2219 | spin_unlock(&lock); | |
2220 | } | |
2221 | ||
2222 | fh[0] = inode->i_generation; | |
2223 | fh[1] = inode->i_ino; | |
2224 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2225 | ||
2226 | *len = 3; | |
2227 | return 1; | |
2228 | } | |
2229 | ||
39655164 | 2230 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2231 | .get_parent = shmem_get_parent, |
91828a40 | 2232 | .encode_fh = shmem_encode_fh, |
480b116c | 2233 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2234 | }; |
2235 | ||
680d794b AM |
2236 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2237 | bool remount) | |
1da177e4 LT |
2238 | { |
2239 | char *this_char, *value, *rest; | |
8751e039 EB |
2240 | uid_t uid; |
2241 | gid_t gid; | |
1da177e4 | 2242 | |
b00dc3ad HD |
2243 | while (options != NULL) { |
2244 | this_char = options; | |
2245 | for (;;) { | |
2246 | /* | |
2247 | * NUL-terminate this option: unfortunately, | |
2248 | * mount options form a comma-separated list, | |
2249 | * but mpol's nodelist may also contain commas. | |
2250 | */ | |
2251 | options = strchr(options, ','); | |
2252 | if (options == NULL) | |
2253 | break; | |
2254 | options++; | |
2255 | if (!isdigit(*options)) { | |
2256 | options[-1] = '\0'; | |
2257 | break; | |
2258 | } | |
2259 | } | |
1da177e4 LT |
2260 | if (!*this_char) |
2261 | continue; | |
2262 | if ((value = strchr(this_char,'=')) != NULL) { | |
2263 | *value++ = 0; | |
2264 | } else { | |
2265 | printk(KERN_ERR | |
2266 | "tmpfs: No value for mount option '%s'\n", | |
2267 | this_char); | |
2268 | return 1; | |
2269 | } | |
2270 | ||
2271 | if (!strcmp(this_char,"size")) { | |
2272 | unsigned long long size; | |
2273 | size = memparse(value,&rest); | |
2274 | if (*rest == '%') { | |
2275 | size <<= PAGE_SHIFT; | |
2276 | size *= totalram_pages; | |
2277 | do_div(size, 100); | |
2278 | rest++; | |
2279 | } | |
2280 | if (*rest) | |
2281 | goto bad_val; | |
680d794b AM |
2282 | sbinfo->max_blocks = |
2283 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2284 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2285 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2286 | if (*rest) |
2287 | goto bad_val; | |
2288 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2289 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2290 | if (*rest) |
2291 | goto bad_val; | |
2292 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2293 | if (remount) |
1da177e4 | 2294 | continue; |
680d794b | 2295 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2296 | if (*rest) |
2297 | goto bad_val; | |
2298 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2299 | if (remount) |
1da177e4 | 2300 | continue; |
8751e039 | 2301 | uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2302 | if (*rest) |
2303 | goto bad_val; | |
8751e039 EB |
2304 | sbinfo->uid = make_kuid(current_user_ns(), uid); |
2305 | if (!uid_valid(sbinfo->uid)) | |
2306 | goto bad_val; | |
1da177e4 | 2307 | } else if (!strcmp(this_char,"gid")) { |
680d794b | 2308 | if (remount) |
1da177e4 | 2309 | continue; |
8751e039 | 2310 | gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2311 | if (*rest) |
2312 | goto bad_val; | |
8751e039 EB |
2313 | sbinfo->gid = make_kgid(current_user_ns(), gid); |
2314 | if (!gid_valid(sbinfo->gid)) | |
2315 | goto bad_val; | |
7339ff83 | 2316 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2317 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2318 | goto bad_val; |
1da177e4 LT |
2319 | } else { |
2320 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2321 | this_char); | |
2322 | return 1; | |
2323 | } | |
2324 | } | |
2325 | return 0; | |
2326 | ||
2327 | bad_val: | |
2328 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2329 | value, this_char); | |
2330 | return 1; | |
2331 | ||
2332 | } | |
2333 | ||
2334 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2335 | { | |
2336 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2337 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2338 | unsigned long inodes; |
2339 | int error = -EINVAL; | |
2340 | ||
680d794b | 2341 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2342 | return error; |
1da177e4 | 2343 | |
0edd73b3 | 2344 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2345 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2346 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2347 | goto out; |
680d794b | 2348 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2349 | goto out; |
2350 | /* | |
54af6042 | 2351 | * Those tests disallow limited->unlimited while any are in use; |
0edd73b3 HD |
2352 | * but we must separately disallow unlimited->limited, because |
2353 | * in that case we have no record of how much is already in use. | |
2354 | */ | |
680d794b | 2355 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2356 | goto out; |
680d794b | 2357 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2358 | goto out; |
2359 | ||
2360 | error = 0; | |
680d794b | 2361 | sbinfo->max_blocks = config.max_blocks; |
680d794b AM |
2362 | sbinfo->max_inodes = config.max_inodes; |
2363 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2364 | |
2365 | mpol_put(sbinfo->mpol); | |
2366 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2367 | out: |
2368 | spin_unlock(&sbinfo->stat_lock); | |
2369 | return error; | |
1da177e4 | 2370 | } |
680d794b | 2371 | |
34c80b1d | 2372 | static int shmem_show_options(struct seq_file *seq, struct dentry *root) |
680d794b | 2373 | { |
34c80b1d | 2374 | struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); |
680d794b AM |
2375 | |
2376 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2377 | seq_printf(seq, ",size=%luk", | |
2378 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2379 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2380 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2381 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
09208d15 | 2382 | seq_printf(seq, ",mode=%03ho", sbinfo->mode); |
8751e039 EB |
2383 | if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) |
2384 | seq_printf(seq, ",uid=%u", | |
2385 | from_kuid_munged(&init_user_ns, sbinfo->uid)); | |
2386 | if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) | |
2387 | seq_printf(seq, ",gid=%u", | |
2388 | from_kgid_munged(&init_user_ns, sbinfo->gid)); | |
71fe804b | 2389 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b AM |
2390 | return 0; |
2391 | } | |
2392 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2393 | |
2394 | static void shmem_put_super(struct super_block *sb) | |
2395 | { | |
602586a8 HD |
2396 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2397 | ||
2398 | percpu_counter_destroy(&sbinfo->used_blocks); | |
2399 | kfree(sbinfo); | |
1da177e4 LT |
2400 | sb->s_fs_info = NULL; |
2401 | } | |
2402 | ||
2b2af54a | 2403 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2404 | { |
2405 | struct inode *inode; | |
0edd73b3 | 2406 | struct shmem_sb_info *sbinfo; |
680d794b AM |
2407 | int err = -ENOMEM; |
2408 | ||
2409 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2410 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b AM |
2411 | L1_CACHE_BYTES), GFP_KERNEL); |
2412 | if (!sbinfo) | |
2413 | return -ENOMEM; | |
2414 | ||
680d794b | 2415 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2416 | sbinfo->uid = current_fsuid(); |
2417 | sbinfo->gid = current_fsgid(); | |
680d794b | 2418 | sb->s_fs_info = sbinfo; |
1da177e4 | 2419 | |
0edd73b3 | 2420 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2421 | /* |
2422 | * Per default we only allow half of the physical ram per | |
2423 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2424 | * but the internal instance is left unlimited. | |
2425 | */ | |
2426 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b AM |
2427 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2428 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2429 | if (shmem_parse_options(data, sbinfo, false)) { | |
2430 | err = -EINVAL; | |
2431 | goto failed; | |
2432 | } | |
1da177e4 | 2433 | } |
91828a40 | 2434 | sb->s_export_op = &shmem_export_ops; |
2f6e38f3 | 2435 | sb->s_flags |= MS_NOSEC; |
1da177e4 LT |
2436 | #else |
2437 | sb->s_flags |= MS_NOUSER; | |
2438 | #endif | |
2439 | ||
0edd73b3 | 2440 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2441 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2442 | goto failed; | |
680d794b | 2443 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2444 | |
285b2c4f | 2445 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 LT |
2446 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2447 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2448 | sb->s_magic = TMPFS_MAGIC; | |
2449 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2450 | sb->s_time_gran = 1; |
b09e0fa4 | 2451 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2452 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2453 | #endif |
2454 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2455 | sb->s_flags |= MS_POSIXACL; |
2456 | #endif | |
0edd73b3 | 2457 | |
454abafe | 2458 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2459 | if (!inode) |
2460 | goto failed; | |
680d794b AM |
2461 | inode->i_uid = sbinfo->uid; |
2462 | inode->i_gid = sbinfo->gid; | |
318ceed0 AV |
2463 | sb->s_root = d_make_root(inode); |
2464 | if (!sb->s_root) | |
48fde701 | 2465 | goto failed; |
1da177e4 LT |
2466 | return 0; |
2467 | ||
1da177e4 LT |
2468 | failed: |
2469 | shmem_put_super(sb); | |
2470 | return err; | |
2471 | } | |
2472 | ||
fcc234f8 | 2473 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2474 | |
2475 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2476 | { | |
41ffe5d5 HD |
2477 | struct shmem_inode_info *info; |
2478 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
2479 | if (!info) | |
1da177e4 | 2480 | return NULL; |
41ffe5d5 | 2481 | return &info->vfs_inode; |
1da177e4 LT |
2482 | } |
2483 | ||
41ffe5d5 | 2484 | static void shmem_destroy_callback(struct rcu_head *head) |
fa0d7e3d NP |
2485 | { |
2486 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
fa0d7e3d NP |
2487 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2488 | } | |
2489 | ||
1da177e4 LT |
2490 | static void shmem_destroy_inode(struct inode *inode) |
2491 | { | |
09208d15 | 2492 | if (S_ISREG(inode->i_mode)) |
1da177e4 | 2493 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
41ffe5d5 | 2494 | call_rcu(&inode->i_rcu, shmem_destroy_callback); |
1da177e4 LT |
2495 | } |
2496 | ||
41ffe5d5 | 2497 | static void shmem_init_inode(void *foo) |
1da177e4 | 2498 | { |
41ffe5d5 HD |
2499 | struct shmem_inode_info *info = foo; |
2500 | inode_init_once(&info->vfs_inode); | |
1da177e4 LT |
2501 | } |
2502 | ||
41ffe5d5 | 2503 | static int shmem_init_inodecache(void) |
1da177e4 LT |
2504 | { |
2505 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2506 | sizeof(struct shmem_inode_info), | |
41ffe5d5 | 2507 | 0, SLAB_PANIC, shmem_init_inode); |
1da177e4 LT |
2508 | return 0; |
2509 | } | |
2510 | ||
41ffe5d5 | 2511 | static void shmem_destroy_inodecache(void) |
1da177e4 | 2512 | { |
1a1d92c1 | 2513 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2514 | } |
2515 | ||
f5e54d6e | 2516 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2517 | .writepage = shmem_writepage, |
76719325 | 2518 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2519 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
2520 | .write_begin = shmem_write_begin, |
2521 | .write_end = shmem_write_end, | |
1da177e4 | 2522 | #endif |
304dbdb7 | 2523 | .migratepage = migrate_page, |
aa261f54 | 2524 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2525 | }; |
2526 | ||
15ad7cdc | 2527 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2528 | .mmap = shmem_mmap, |
2529 | #ifdef CONFIG_TMPFS | |
2530 | .llseek = generic_file_llseek, | |
bcd78e49 | 2531 | .read = do_sync_read, |
5402b976 | 2532 | .write = do_sync_write, |
bcd78e49 | 2533 | .aio_read = shmem_file_aio_read, |
5402b976 | 2534 | .aio_write = generic_file_aio_write, |
1b061d92 | 2535 | .fsync = noop_fsync, |
708e3508 | 2536 | .splice_read = shmem_file_splice_read, |
ae976416 | 2537 | .splice_write = generic_file_splice_write, |
83e4fa9c | 2538 | .fallocate = shmem_fallocate, |
1da177e4 LT |
2539 | #endif |
2540 | }; | |
2541 | ||
92e1d5be | 2542 | static const struct inode_operations shmem_inode_operations = { |
94c1e62d | 2543 | .setattr = shmem_setattr, |
b09e0fa4 EP |
2544 | #ifdef CONFIG_TMPFS_XATTR |
2545 | .setxattr = shmem_setxattr, | |
2546 | .getxattr = shmem_getxattr, | |
2547 | .listxattr = shmem_listxattr, | |
2548 | .removexattr = shmem_removexattr, | |
2549 | #endif | |
1da177e4 LT |
2550 | }; |
2551 | ||
92e1d5be | 2552 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2553 | #ifdef CONFIG_TMPFS |
2554 | .create = shmem_create, | |
2555 | .lookup = simple_lookup, | |
2556 | .link = shmem_link, | |
2557 | .unlink = shmem_unlink, | |
2558 | .symlink = shmem_symlink, | |
2559 | .mkdir = shmem_mkdir, | |
2560 | .rmdir = shmem_rmdir, | |
2561 | .mknod = shmem_mknod, | |
2562 | .rename = shmem_rename, | |
1da177e4 | 2563 | #endif |
b09e0fa4 EP |
2564 | #ifdef CONFIG_TMPFS_XATTR |
2565 | .setxattr = shmem_setxattr, | |
2566 | .getxattr = shmem_getxattr, | |
2567 | .listxattr = shmem_listxattr, | |
2568 | .removexattr = shmem_removexattr, | |
2569 | #endif | |
39f0247d | 2570 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2571 | .setattr = shmem_setattr, |
39f0247d AG |
2572 | #endif |
2573 | }; | |
2574 | ||
92e1d5be | 2575 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2576 | #ifdef CONFIG_TMPFS_XATTR |
2577 | .setxattr = shmem_setxattr, | |
2578 | .getxattr = shmem_getxattr, | |
2579 | .listxattr = shmem_listxattr, | |
2580 | .removexattr = shmem_removexattr, | |
2581 | #endif | |
39f0247d | 2582 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2583 | .setattr = shmem_setattr, |
39f0247d | 2584 | #endif |
1da177e4 LT |
2585 | }; |
2586 | ||
759b9775 | 2587 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2588 | .alloc_inode = shmem_alloc_inode, |
2589 | .destroy_inode = shmem_destroy_inode, | |
2590 | #ifdef CONFIG_TMPFS | |
2591 | .statfs = shmem_statfs, | |
2592 | .remount_fs = shmem_remount_fs, | |
680d794b | 2593 | .show_options = shmem_show_options, |
1da177e4 | 2594 | #endif |
1f895f75 | 2595 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2596 | .drop_inode = generic_delete_inode, |
2597 | .put_super = shmem_put_super, | |
2598 | }; | |
2599 | ||
f0f37e2f | 2600 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2601 | .fault = shmem_fault, |
1da177e4 LT |
2602 | #ifdef CONFIG_NUMA |
2603 | .set_policy = shmem_set_policy, | |
2604 | .get_policy = shmem_get_policy, | |
2605 | #endif | |
2606 | }; | |
2607 | ||
3c26ff6e AV |
2608 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2609 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2610 | { |
3c26ff6e | 2611 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2612 | } |
2613 | ||
41ffe5d5 | 2614 | static struct file_system_type shmem_fs_type = { |
1da177e4 LT |
2615 | .owner = THIS_MODULE, |
2616 | .name = "tmpfs", | |
3c26ff6e | 2617 | .mount = shmem_mount, |
1da177e4 LT |
2618 | .kill_sb = kill_litter_super, |
2619 | }; | |
1da177e4 | 2620 | |
41ffe5d5 | 2621 | int __init shmem_init(void) |
1da177e4 LT |
2622 | { |
2623 | int error; | |
2624 | ||
e0bf68dd PZ |
2625 | error = bdi_init(&shmem_backing_dev_info); |
2626 | if (error) | |
2627 | goto out4; | |
2628 | ||
41ffe5d5 | 2629 | error = shmem_init_inodecache(); |
1da177e4 LT |
2630 | if (error) |
2631 | goto out3; | |
2632 | ||
41ffe5d5 | 2633 | error = register_filesystem(&shmem_fs_type); |
1da177e4 LT |
2634 | if (error) { |
2635 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2636 | goto out2; | |
2637 | } | |
95dc112a | 2638 | |
41ffe5d5 HD |
2639 | shm_mnt = vfs_kern_mount(&shmem_fs_type, MS_NOUSER, |
2640 | shmem_fs_type.name, NULL); | |
1da177e4 LT |
2641 | if (IS_ERR(shm_mnt)) { |
2642 | error = PTR_ERR(shm_mnt); | |
2643 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2644 | goto out1; | |
2645 | } | |
2646 | return 0; | |
2647 | ||
2648 | out1: | |
41ffe5d5 | 2649 | unregister_filesystem(&shmem_fs_type); |
1da177e4 | 2650 | out2: |
41ffe5d5 | 2651 | shmem_destroy_inodecache(); |
1da177e4 | 2652 | out3: |
e0bf68dd PZ |
2653 | bdi_destroy(&shmem_backing_dev_info); |
2654 | out4: | |
1da177e4 LT |
2655 | shm_mnt = ERR_PTR(error); |
2656 | return error; | |
2657 | } | |
853ac43a MM |
2658 | |
2659 | #else /* !CONFIG_SHMEM */ | |
2660 | ||
2661 | /* | |
2662 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2663 | * | |
2664 | * This is intended for small system where the benefits of the full | |
2665 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2666 | * their complexity. On systems without swap this code should be | |
2667 | * effectively equivalent, but much lighter weight. | |
2668 | */ | |
2669 | ||
2670 | #include <linux/ramfs.h> | |
2671 | ||
41ffe5d5 | 2672 | static struct file_system_type shmem_fs_type = { |
853ac43a | 2673 | .name = "tmpfs", |
3c26ff6e | 2674 | .mount = ramfs_mount, |
853ac43a MM |
2675 | .kill_sb = kill_litter_super, |
2676 | }; | |
2677 | ||
41ffe5d5 | 2678 | int __init shmem_init(void) |
853ac43a | 2679 | { |
41ffe5d5 | 2680 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
853ac43a | 2681 | |
41ffe5d5 | 2682 | shm_mnt = kern_mount(&shmem_fs_type); |
853ac43a MM |
2683 | BUG_ON(IS_ERR(shm_mnt)); |
2684 | ||
2685 | return 0; | |
2686 | } | |
2687 | ||
41ffe5d5 | 2688 | int shmem_unuse(swp_entry_t swap, struct page *page) |
853ac43a MM |
2689 | { |
2690 | return 0; | |
2691 | } | |
2692 | ||
3f96b79a HD |
2693 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2694 | { | |
2695 | return 0; | |
2696 | } | |
2697 | ||
24513264 HD |
2698 | void shmem_unlock_mapping(struct address_space *mapping) |
2699 | { | |
2700 | } | |
2701 | ||
41ffe5d5 | 2702 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
94c1e62d | 2703 | { |
41ffe5d5 | 2704 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
94c1e62d HD |
2705 | } |
2706 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
2707 | ||
0b0a0806 HD |
2708 | #define shmem_vm_ops generic_file_vm_ops |
2709 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2710 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2711 | #define shmem_acct_size(flags, size) 0 |
2712 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
2713 | |
2714 | #endif /* CONFIG_SHMEM */ | |
2715 | ||
2716 | /* common code */ | |
1da177e4 | 2717 | |
46711810 | 2718 | /** |
1da177e4 | 2719 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2720 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2721 | * @size: size to be set for the file | |
0b0a0806 | 2722 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2723 | */ |
168f5ac6 | 2724 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2725 | { |
2726 | int error; | |
2727 | struct file *file; | |
2728 | struct inode *inode; | |
2c48b9c4 AV |
2729 | struct path path; |
2730 | struct dentry *root; | |
1da177e4 LT |
2731 | struct qstr this; |
2732 | ||
2733 | if (IS_ERR(shm_mnt)) | |
2734 | return (void *)shm_mnt; | |
2735 | ||
285b2c4f | 2736 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
2737 | return ERR_PTR(-EINVAL); |
2738 | ||
2739 | if (shmem_acct_size(flags, size)) | |
2740 | return ERR_PTR(-ENOMEM); | |
2741 | ||
2742 | error = -ENOMEM; | |
2743 | this.name = name; | |
2744 | this.len = strlen(name); | |
2745 | this.hash = 0; /* will go */ | |
2746 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2747 | path.dentry = d_alloc(root, &this); |
2748 | if (!path.dentry) | |
1da177e4 | 2749 | goto put_memory; |
2c48b9c4 | 2750 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2751 | |
1da177e4 | 2752 | error = -ENOSPC; |
454abafe | 2753 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2754 | if (!inode) |
4b42af81 | 2755 | goto put_dentry; |
1da177e4 | 2756 | |
2c48b9c4 | 2757 | d_instantiate(path.dentry, inode); |
1da177e4 | 2758 | inode->i_size = size; |
6d6b77f1 | 2759 | clear_nlink(inode); /* It is unlinked */ |
853ac43a MM |
2760 | #ifndef CONFIG_MMU |
2761 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2762 | if (error) | |
4b42af81 | 2763 | goto put_dentry; |
853ac43a | 2764 | #endif |
4b42af81 AV |
2765 | |
2766 | error = -ENFILE; | |
2c48b9c4 | 2767 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2768 | &shmem_file_operations); |
2769 | if (!file) | |
2770 | goto put_dentry; | |
2771 | ||
1da177e4 LT |
2772 | return file; |
2773 | ||
1da177e4 | 2774 | put_dentry: |
2c48b9c4 | 2775 | path_put(&path); |
1da177e4 LT |
2776 | put_memory: |
2777 | shmem_unacct_size(flags, size); | |
2778 | return ERR_PTR(error); | |
2779 | } | |
395e0ddc | 2780 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2781 | |
46711810 | 2782 | /** |
1da177e4 | 2783 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2784 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2785 | */ | |
2786 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2787 | { | |
2788 | struct file *file; | |
2789 | loff_t size = vma->vm_end - vma->vm_start; | |
2790 | ||
2791 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2792 | if (IS_ERR(file)) | |
2793 | return PTR_ERR(file); | |
2794 | ||
2795 | if (vma->vm_file) | |
2796 | fput(vma->vm_file); | |
2797 | vma->vm_file = file; | |
2798 | vma->vm_ops = &shmem_vm_ops; | |
bee4c36a | 2799 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
2800 | return 0; |
2801 | } | |
d9d90e5e HD |
2802 | |
2803 | /** | |
2804 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
2805 | * @mapping: the page's address_space | |
2806 | * @index: the page index | |
2807 | * @gfp: the page allocator flags to use if allocating | |
2808 | * | |
2809 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
2810 | * with any new page allocations done using the specified allocation flags. | |
2811 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
2812 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
2813 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
2814 | * | |
68da9f05 HD |
2815 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
2816 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
2817 | */ |
2818 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
2819 | pgoff_t index, gfp_t gfp) | |
2820 | { | |
68da9f05 HD |
2821 | #ifdef CONFIG_SHMEM |
2822 | struct inode *inode = mapping->host; | |
9276aad6 | 2823 | struct page *page; |
68da9f05 HD |
2824 | int error; |
2825 | ||
2826 | BUG_ON(mapping->a_ops != &shmem_aops); | |
2827 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); | |
2828 | if (error) | |
2829 | page = ERR_PTR(error); | |
2830 | else | |
2831 | unlock_page(page); | |
2832 | return page; | |
2833 | #else | |
2834 | /* | |
2835 | * The tiny !SHMEM case uses ramfs without swap | |
2836 | */ | |
d9d90e5e | 2837 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 2838 | #endif |
d9d90e5e HD |
2839 | } |
2840 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |