Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
6922c0c7 HD |
9 | * Copyright (C) 2002-2011 Hugh Dickins. |
10 | * Copyright (C) 2011 Google Inc. | |
0edd73b3 | 11 | * Copyright (C) 2002-2005 VERITAS Software Corporation. |
1da177e4 LT |
12 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
13 | * | |
14 | * Extended attribute support for tmpfs: | |
15 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
16 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
17 | * | |
853ac43a MM |
18 | * tiny-shmem: |
19 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
20 | * | |
1da177e4 LT |
21 | * This file is released under the GPL. |
22 | */ | |
23 | ||
853ac43a MM |
24 | #include <linux/fs.h> |
25 | #include <linux/init.h> | |
26 | #include <linux/vfs.h> | |
27 | #include <linux/mount.h> | |
250297ed | 28 | #include <linux/ramfs.h> |
caefba17 | 29 | #include <linux/pagemap.h> |
853ac43a MM |
30 | #include <linux/file.h> |
31 | #include <linux/mm.h> | |
b95f1b31 | 32 | #include <linux/export.h> |
853ac43a | 33 | #include <linux/swap.h> |
a27bb332 | 34 | #include <linux/aio.h> |
853ac43a MM |
35 | |
36 | static struct vfsmount *shm_mnt; | |
37 | ||
38 | #ifdef CONFIG_SHMEM | |
1da177e4 LT |
39 | /* |
40 | * This virtual memory filesystem is heavily based on the ramfs. It | |
41 | * extends ramfs by the ability to use swap and honor resource limits | |
42 | * which makes it a completely usable filesystem. | |
43 | */ | |
44 | ||
39f0247d | 45 | #include <linux/xattr.h> |
a5694255 | 46 | #include <linux/exportfs.h> |
1c7c474c | 47 | #include <linux/posix_acl.h> |
feda821e | 48 | #include <linux/posix_acl_xattr.h> |
1da177e4 | 49 | #include <linux/mman.h> |
1da177e4 LT |
50 | #include <linux/string.h> |
51 | #include <linux/slab.h> | |
52 | #include <linux/backing-dev.h> | |
53 | #include <linux/shmem_fs.h> | |
1da177e4 | 54 | #include <linux/writeback.h> |
1da177e4 | 55 | #include <linux/blkdev.h> |
bda97eab | 56 | #include <linux/pagevec.h> |
41ffe5d5 | 57 | #include <linux/percpu_counter.h> |
83e4fa9c | 58 | #include <linux/falloc.h> |
708e3508 | 59 | #include <linux/splice.h> |
1da177e4 LT |
60 | #include <linux/security.h> |
61 | #include <linux/swapops.h> | |
62 | #include <linux/mempolicy.h> | |
63 | #include <linux/namei.h> | |
b00dc3ad | 64 | #include <linux/ctype.h> |
304dbdb7 | 65 | #include <linux/migrate.h> |
c1f60a5a | 66 | #include <linux/highmem.h> |
680d794b | 67 | #include <linux/seq_file.h> |
92562927 | 68 | #include <linux/magic.h> |
304dbdb7 | 69 | |
1da177e4 | 70 | #include <asm/uaccess.h> |
1da177e4 LT |
71 | #include <asm/pgtable.h> |
72 | ||
caefba17 | 73 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
1da177e4 LT |
74 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
75 | ||
1da177e4 LT |
76 | /* Pretend that each entry is of this size in directory's i_size */ |
77 | #define BOGO_DIRENT_SIZE 20 | |
78 | ||
69f07ec9 HD |
79 | /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ |
80 | #define SHORT_SYMLINK_LEN 128 | |
81 | ||
1aac1400 | 82 | /* |
f00cdc6d HD |
83 | * shmem_fallocate communicates with shmem_fault or shmem_writepage via |
84 | * inode->i_private (with i_mutex making sure that it has only one user at | |
85 | * a time): we would prefer not to enlarge the shmem inode just for that. | |
1aac1400 HD |
86 | */ |
87 | struct shmem_falloc { | |
f00cdc6d | 88 | int mode; /* FALLOC_FL mode currently operating */ |
1aac1400 HD |
89 | pgoff_t start; /* start of range currently being fallocated */ |
90 | pgoff_t next; /* the next page offset to be fallocated */ | |
91 | pgoff_t nr_falloced; /* how many new pages have been fallocated */ | |
92 | pgoff_t nr_unswapped; /* how often writepage refused to swap out */ | |
93 | }; | |
94 | ||
285b2c4f | 95 | /* Flag allocation requirements to shmem_getpage */ |
1da177e4 | 96 | enum sgp_type { |
1da177e4 LT |
97 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
98 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 99 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1635f6a7 HD |
100 | SGP_WRITE, /* may exceed i_size, may allocate !Uptodate page */ |
101 | SGP_FALLOC, /* like SGP_WRITE, but make existing page Uptodate */ | |
1da177e4 LT |
102 | }; |
103 | ||
b76db735 | 104 | #ifdef CONFIG_TMPFS |
680d794b | 105 | static unsigned long shmem_default_max_blocks(void) |
106 | { | |
107 | return totalram_pages / 2; | |
108 | } | |
109 | ||
110 | static unsigned long shmem_default_max_inodes(void) | |
111 | { | |
112 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
113 | } | |
b76db735 | 114 | #endif |
680d794b | 115 | |
bde05d1c HD |
116 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp); |
117 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
118 | struct shmem_inode_info *info, pgoff_t index); | |
68da9f05 HD |
119 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
120 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); | |
121 | ||
122 | static inline int shmem_getpage(struct inode *inode, pgoff_t index, | |
123 | struct page **pagep, enum sgp_type sgp, int *fault_type) | |
124 | { | |
125 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
126 | mapping_gfp_mask(inode->i_mapping), fault_type); | |
127 | } | |
1da177e4 | 128 | |
1da177e4 LT |
129 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
130 | { | |
131 | return sb->s_fs_info; | |
132 | } | |
133 | ||
134 | /* | |
135 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
136 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
137 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
138 | * consistent with the pre-accounting of private mappings ... | |
139 | */ | |
140 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
141 | { | |
0b0a0806 | 142 | return (flags & VM_NORESERVE) ? |
191c5424 | 143 | 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size)); |
1da177e4 LT |
144 | } |
145 | ||
146 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
147 | { | |
0b0a0806 | 148 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
149 | vm_unacct_memory(VM_ACCT(size)); |
150 | } | |
151 | ||
152 | /* | |
153 | * ... whereas tmpfs objects are accounted incrementally as | |
154 | * pages are allocated, in order to allow huge sparse files. | |
155 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
156 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
157 | */ | |
158 | static inline int shmem_acct_block(unsigned long flags) | |
159 | { | |
0b0a0806 | 160 | return (flags & VM_NORESERVE) ? |
191c5424 | 161 | security_vm_enough_memory_mm(current->mm, VM_ACCT(PAGE_CACHE_SIZE)) : 0; |
1da177e4 LT |
162 | } |
163 | ||
164 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
165 | { | |
0b0a0806 | 166 | if (flags & VM_NORESERVE) |
1da177e4 LT |
167 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
168 | } | |
169 | ||
759b9775 | 170 | static const struct super_operations shmem_ops; |
f5e54d6e | 171 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 172 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
173 | static const struct inode_operations shmem_inode_operations; |
174 | static const struct inode_operations shmem_dir_inode_operations; | |
175 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 176 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 177 | |
6c231b7b | 178 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 179 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 180 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
181 | }; |
182 | ||
183 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 184 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 | 185 | |
5b04c689 PE |
186 | static int shmem_reserve_inode(struct super_block *sb) |
187 | { | |
188 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
189 | if (sbinfo->max_inodes) { | |
190 | spin_lock(&sbinfo->stat_lock); | |
191 | if (!sbinfo->free_inodes) { | |
192 | spin_unlock(&sbinfo->stat_lock); | |
193 | return -ENOSPC; | |
194 | } | |
195 | sbinfo->free_inodes--; | |
196 | spin_unlock(&sbinfo->stat_lock); | |
197 | } | |
198 | return 0; | |
199 | } | |
200 | ||
201 | static void shmem_free_inode(struct super_block *sb) | |
202 | { | |
203 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
204 | if (sbinfo->max_inodes) { | |
205 | spin_lock(&sbinfo->stat_lock); | |
206 | sbinfo->free_inodes++; | |
207 | spin_unlock(&sbinfo->stat_lock); | |
208 | } | |
209 | } | |
210 | ||
46711810 | 211 | /** |
41ffe5d5 | 212 | * shmem_recalc_inode - recalculate the block usage of an inode |
1da177e4 LT |
213 | * @inode: inode to recalc |
214 | * | |
215 | * We have to calculate the free blocks since the mm can drop | |
216 | * undirtied hole pages behind our back. | |
217 | * | |
218 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
219 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
220 | * | |
221 | * It has to be called with the spinlock held. | |
222 | */ | |
223 | static void shmem_recalc_inode(struct inode *inode) | |
224 | { | |
225 | struct shmem_inode_info *info = SHMEM_I(inode); | |
226 | long freed; | |
227 | ||
228 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
229 | if (freed > 0) { | |
54af6042 HD |
230 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
231 | if (sbinfo->max_blocks) | |
232 | percpu_counter_add(&sbinfo->used_blocks, -freed); | |
1da177e4 | 233 | info->alloced -= freed; |
54af6042 | 234 | inode->i_blocks -= freed * BLOCKS_PER_PAGE; |
1da177e4 | 235 | shmem_unacct_blocks(info->flags, freed); |
1da177e4 LT |
236 | } |
237 | } | |
238 | ||
7a5d0fbb HD |
239 | /* |
240 | * Replace item expected in radix tree by a new item, while holding tree lock. | |
241 | */ | |
242 | static int shmem_radix_tree_replace(struct address_space *mapping, | |
243 | pgoff_t index, void *expected, void *replacement) | |
244 | { | |
245 | void **pslot; | |
6dbaf22c | 246 | void *item; |
7a5d0fbb HD |
247 | |
248 | VM_BUG_ON(!expected); | |
6dbaf22c | 249 | VM_BUG_ON(!replacement); |
7a5d0fbb | 250 | pslot = radix_tree_lookup_slot(&mapping->page_tree, index); |
6dbaf22c JW |
251 | if (!pslot) |
252 | return -ENOENT; | |
253 | item = radix_tree_deref_slot_protected(pslot, &mapping->tree_lock); | |
7a5d0fbb HD |
254 | if (item != expected) |
255 | return -ENOENT; | |
6dbaf22c | 256 | radix_tree_replace_slot(pslot, replacement); |
7a5d0fbb HD |
257 | return 0; |
258 | } | |
259 | ||
d1899228 HD |
260 | /* |
261 | * Sometimes, before we decide whether to proceed or to fail, we must check | |
262 | * that an entry was not already brought back from swap by a racing thread. | |
263 | * | |
264 | * Checking page is not enough: by the time a SwapCache page is locked, it | |
265 | * might be reused, and again be SwapCache, using the same swap as before. | |
266 | */ | |
267 | static bool shmem_confirm_swap(struct address_space *mapping, | |
268 | pgoff_t index, swp_entry_t swap) | |
269 | { | |
270 | void *item; | |
271 | ||
272 | rcu_read_lock(); | |
273 | item = radix_tree_lookup(&mapping->page_tree, index); | |
274 | rcu_read_unlock(); | |
275 | return item == swp_to_radix_entry(swap); | |
276 | } | |
277 | ||
46f65ec1 HD |
278 | /* |
279 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
280 | */ | |
281 | static int shmem_add_to_page_cache(struct page *page, | |
282 | struct address_space *mapping, | |
283 | pgoff_t index, gfp_t gfp, void *expected) | |
284 | { | |
b065b432 | 285 | int error; |
46f65ec1 | 286 | |
309381fe SL |
287 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
288 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); | |
46f65ec1 | 289 | |
b065b432 HD |
290 | page_cache_get(page); |
291 | page->mapping = mapping; | |
292 | page->index = index; | |
293 | ||
294 | spin_lock_irq(&mapping->tree_lock); | |
46f65ec1 | 295 | if (!expected) |
b065b432 HD |
296 | error = radix_tree_insert(&mapping->page_tree, index, page); |
297 | else | |
298 | error = shmem_radix_tree_replace(mapping, index, expected, | |
299 | page); | |
46f65ec1 | 300 | if (!error) { |
b065b432 HD |
301 | mapping->nrpages++; |
302 | __inc_zone_page_state(page, NR_FILE_PAGES); | |
303 | __inc_zone_page_state(page, NR_SHMEM); | |
304 | spin_unlock_irq(&mapping->tree_lock); | |
305 | } else { | |
306 | page->mapping = NULL; | |
307 | spin_unlock_irq(&mapping->tree_lock); | |
308 | page_cache_release(page); | |
46f65ec1 | 309 | } |
46f65ec1 HD |
310 | return error; |
311 | } | |
312 | ||
6922c0c7 HD |
313 | /* |
314 | * Like delete_from_page_cache, but substitutes swap for page. | |
315 | */ | |
316 | static void shmem_delete_from_page_cache(struct page *page, void *radswap) | |
317 | { | |
318 | struct address_space *mapping = page->mapping; | |
319 | int error; | |
320 | ||
321 | spin_lock_irq(&mapping->tree_lock); | |
322 | error = shmem_radix_tree_replace(mapping, page->index, page, radswap); | |
323 | page->mapping = NULL; | |
324 | mapping->nrpages--; | |
325 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
326 | __dec_zone_page_state(page, NR_SHMEM); | |
327 | spin_unlock_irq(&mapping->tree_lock); | |
328 | page_cache_release(page); | |
329 | BUG_ON(error); | |
330 | } | |
331 | ||
7a5d0fbb HD |
332 | /* |
333 | * Remove swap entry from radix tree, free the swap and its page cache. | |
334 | */ | |
335 | static int shmem_free_swap(struct address_space *mapping, | |
336 | pgoff_t index, void *radswap) | |
337 | { | |
6dbaf22c | 338 | void *old; |
7a5d0fbb HD |
339 | |
340 | spin_lock_irq(&mapping->tree_lock); | |
6dbaf22c | 341 | old = radix_tree_delete_item(&mapping->page_tree, index, radswap); |
7a5d0fbb | 342 | spin_unlock_irq(&mapping->tree_lock); |
6dbaf22c JW |
343 | if (old != radswap) |
344 | return -ENOENT; | |
345 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
346 | return 0; | |
7a5d0fbb HD |
347 | } |
348 | ||
24513264 HD |
349 | /* |
350 | * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. | |
351 | */ | |
352 | void shmem_unlock_mapping(struct address_space *mapping) | |
353 | { | |
354 | struct pagevec pvec; | |
355 | pgoff_t indices[PAGEVEC_SIZE]; | |
356 | pgoff_t index = 0; | |
357 | ||
358 | pagevec_init(&pvec, 0); | |
359 | /* | |
360 | * Minor point, but we might as well stop if someone else SHM_LOCKs it. | |
361 | */ | |
362 | while (!mapping_unevictable(mapping)) { | |
363 | /* | |
364 | * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it | |
365 | * has finished, if it hits a row of PAGEVEC_SIZE swap entries. | |
366 | */ | |
0cd6144a JW |
367 | pvec.nr = find_get_entries(mapping, index, |
368 | PAGEVEC_SIZE, pvec.pages, indices); | |
24513264 HD |
369 | if (!pvec.nr) |
370 | break; | |
371 | index = indices[pvec.nr - 1] + 1; | |
0cd6144a | 372 | pagevec_remove_exceptionals(&pvec); |
24513264 HD |
373 | check_move_unevictable_pages(pvec.pages, pvec.nr); |
374 | pagevec_release(&pvec); | |
375 | cond_resched(); | |
376 | } | |
7a5d0fbb HD |
377 | } |
378 | ||
379 | /* | |
380 | * Remove range of pages and swap entries from radix tree, and free them. | |
1635f6a7 | 381 | * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate. |
7a5d0fbb | 382 | */ |
1635f6a7 HD |
383 | static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, |
384 | bool unfalloc) | |
1da177e4 | 385 | { |
285b2c4f | 386 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 387 | struct shmem_inode_info *info = SHMEM_I(inode); |
285b2c4f | 388 | pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
83e4fa9c HD |
389 | pgoff_t end = (lend + 1) >> PAGE_CACHE_SHIFT; |
390 | unsigned int partial_start = lstart & (PAGE_CACHE_SIZE - 1); | |
391 | unsigned int partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1); | |
bda97eab | 392 | struct pagevec pvec; |
7a5d0fbb HD |
393 | pgoff_t indices[PAGEVEC_SIZE]; |
394 | long nr_swaps_freed = 0; | |
285b2c4f | 395 | pgoff_t index; |
bda97eab HD |
396 | int i; |
397 | ||
83e4fa9c HD |
398 | if (lend == -1) |
399 | end = -1; /* unsigned, so actually very big */ | |
bda97eab HD |
400 | |
401 | pagevec_init(&pvec, 0); | |
402 | index = start; | |
83e4fa9c | 403 | while (index < end) { |
0cd6144a JW |
404 | pvec.nr = find_get_entries(mapping, index, |
405 | min(end - index, (pgoff_t)PAGEVEC_SIZE), | |
406 | pvec.pages, indices); | |
7a5d0fbb HD |
407 | if (!pvec.nr) |
408 | break; | |
bda97eab HD |
409 | mem_cgroup_uncharge_start(); |
410 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
411 | struct page *page = pvec.pages[i]; | |
412 | ||
7a5d0fbb | 413 | index = indices[i]; |
83e4fa9c | 414 | if (index >= end) |
bda97eab HD |
415 | break; |
416 | ||
7a5d0fbb | 417 | if (radix_tree_exceptional_entry(page)) { |
1635f6a7 HD |
418 | if (unfalloc) |
419 | continue; | |
7a5d0fbb HD |
420 | nr_swaps_freed += !shmem_free_swap(mapping, |
421 | index, page); | |
bda97eab | 422 | continue; |
7a5d0fbb HD |
423 | } |
424 | ||
425 | if (!trylock_page(page)) | |
bda97eab | 426 | continue; |
1635f6a7 HD |
427 | if (!unfalloc || !PageUptodate(page)) { |
428 | if (page->mapping == mapping) { | |
309381fe | 429 | VM_BUG_ON_PAGE(PageWriteback(page), page); |
1635f6a7 HD |
430 | truncate_inode_page(mapping, page); |
431 | } | |
bda97eab | 432 | } |
bda97eab HD |
433 | unlock_page(page); |
434 | } | |
0cd6144a | 435 | pagevec_remove_exceptionals(&pvec); |
24513264 | 436 | pagevec_release(&pvec); |
bda97eab HD |
437 | mem_cgroup_uncharge_end(); |
438 | cond_resched(); | |
439 | index++; | |
440 | } | |
1da177e4 | 441 | |
83e4fa9c | 442 | if (partial_start) { |
bda97eab HD |
443 | struct page *page = NULL; |
444 | shmem_getpage(inode, start - 1, &page, SGP_READ, NULL); | |
445 | if (page) { | |
83e4fa9c HD |
446 | unsigned int top = PAGE_CACHE_SIZE; |
447 | if (start > end) { | |
448 | top = partial_end; | |
449 | partial_end = 0; | |
450 | } | |
451 | zero_user_segment(page, partial_start, top); | |
452 | set_page_dirty(page); | |
453 | unlock_page(page); | |
454 | page_cache_release(page); | |
455 | } | |
456 | } | |
457 | if (partial_end) { | |
458 | struct page *page = NULL; | |
459 | shmem_getpage(inode, end, &page, SGP_READ, NULL); | |
460 | if (page) { | |
461 | zero_user_segment(page, 0, partial_end); | |
bda97eab HD |
462 | set_page_dirty(page); |
463 | unlock_page(page); | |
464 | page_cache_release(page); | |
465 | } | |
466 | } | |
83e4fa9c HD |
467 | if (start >= end) |
468 | return; | |
bda97eab HD |
469 | |
470 | index = start; | |
471 | for ( ; ; ) { | |
472 | cond_resched(); | |
0cd6144a JW |
473 | |
474 | pvec.nr = find_get_entries(mapping, index, | |
83e4fa9c | 475 | min(end - index, (pgoff_t)PAGEVEC_SIZE), |
0cd6144a | 476 | pvec.pages, indices); |
7a5d0fbb | 477 | if (!pvec.nr) { |
1635f6a7 | 478 | if (index == start || unfalloc) |
bda97eab HD |
479 | break; |
480 | index = start; | |
481 | continue; | |
482 | } | |
1635f6a7 | 483 | if ((index == start || unfalloc) && indices[0] >= end) { |
0cd6144a | 484 | pagevec_remove_exceptionals(&pvec); |
24513264 | 485 | pagevec_release(&pvec); |
bda97eab HD |
486 | break; |
487 | } | |
488 | mem_cgroup_uncharge_start(); | |
489 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
490 | struct page *page = pvec.pages[i]; | |
491 | ||
7a5d0fbb | 492 | index = indices[i]; |
83e4fa9c | 493 | if (index >= end) |
bda97eab HD |
494 | break; |
495 | ||
7a5d0fbb | 496 | if (radix_tree_exceptional_entry(page)) { |
1635f6a7 HD |
497 | if (unfalloc) |
498 | continue; | |
7a5d0fbb HD |
499 | nr_swaps_freed += !shmem_free_swap(mapping, |
500 | index, page); | |
501 | continue; | |
502 | } | |
503 | ||
bda97eab | 504 | lock_page(page); |
1635f6a7 HD |
505 | if (!unfalloc || !PageUptodate(page)) { |
506 | if (page->mapping == mapping) { | |
309381fe | 507 | VM_BUG_ON_PAGE(PageWriteback(page), page); |
1635f6a7 HD |
508 | truncate_inode_page(mapping, page); |
509 | } | |
7a5d0fbb | 510 | } |
bda97eab HD |
511 | unlock_page(page); |
512 | } | |
0cd6144a | 513 | pagevec_remove_exceptionals(&pvec); |
24513264 | 514 | pagevec_release(&pvec); |
bda97eab HD |
515 | mem_cgroup_uncharge_end(); |
516 | index++; | |
517 | } | |
94c1e62d | 518 | |
1da177e4 | 519 | spin_lock(&info->lock); |
7a5d0fbb | 520 | info->swapped -= nr_swaps_freed; |
1da177e4 LT |
521 | shmem_recalc_inode(inode); |
522 | spin_unlock(&info->lock); | |
1635f6a7 | 523 | } |
1da177e4 | 524 | |
1635f6a7 HD |
525 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
526 | { | |
527 | shmem_undo_range(inode, lstart, lend, false); | |
285b2c4f | 528 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1da177e4 | 529 | } |
94c1e62d | 530 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 531 | |
94c1e62d | 532 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 LT |
533 | { |
534 | struct inode *inode = dentry->d_inode; | |
1da177e4 LT |
535 | int error; |
536 | ||
db78b877 CH |
537 | error = inode_change_ok(inode, attr); |
538 | if (error) | |
539 | return error; | |
540 | ||
94c1e62d HD |
541 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
542 | loff_t oldsize = inode->i_size; | |
543 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 544 | |
94c1e62d HD |
545 | if (newsize != oldsize) { |
546 | i_size_write(inode, newsize); | |
547 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
548 | } | |
549 | if (newsize < oldsize) { | |
550 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
551 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
552 | shmem_truncate_range(inode, newsize, (loff_t)-1); | |
553 | /* unmap again to remove racily COWed private pages */ | |
554 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
555 | } | |
1da177e4 LT |
556 | } |
557 | ||
db78b877 | 558 | setattr_copy(inode, attr); |
db78b877 | 559 | if (attr->ia_valid & ATTR_MODE) |
feda821e | 560 | error = posix_acl_chmod(inode, inode->i_mode); |
1da177e4 LT |
561 | return error; |
562 | } | |
563 | ||
1f895f75 | 564 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 565 | { |
1da177e4 LT |
566 | struct shmem_inode_info *info = SHMEM_I(inode); |
567 | ||
3889e6e7 | 568 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
569 | shmem_unacct_size(info->flags, inode->i_size); |
570 | inode->i_size = 0; | |
3889e6e7 | 571 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 572 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 573 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 574 | list_del_init(&info->swaplist); |
cb5f7b9a | 575 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 | 576 | } |
69f07ec9 HD |
577 | } else |
578 | kfree(info->symlink); | |
b09e0fa4 | 579 | |
38f38657 | 580 | simple_xattrs_free(&info->xattrs); |
0f3c42f5 | 581 | WARN_ON(inode->i_blocks); |
5b04c689 | 582 | shmem_free_inode(inode->i_sb); |
dbd5768f | 583 | clear_inode(inode); |
1da177e4 LT |
584 | } |
585 | ||
46f65ec1 HD |
586 | /* |
587 | * If swap found in inode, free it and move page from swapcache to filecache. | |
588 | */ | |
41ffe5d5 | 589 | static int shmem_unuse_inode(struct shmem_inode_info *info, |
bde05d1c | 590 | swp_entry_t swap, struct page **pagep) |
1da177e4 | 591 | { |
285b2c4f | 592 | struct address_space *mapping = info->vfs_inode.i_mapping; |
46f65ec1 | 593 | void *radswap; |
41ffe5d5 | 594 | pgoff_t index; |
bde05d1c HD |
595 | gfp_t gfp; |
596 | int error = 0; | |
1da177e4 | 597 | |
46f65ec1 | 598 | radswap = swp_to_radix_entry(swap); |
e504f3fd | 599 | index = radix_tree_locate_item(&mapping->page_tree, radswap); |
46f65ec1 | 600 | if (index == -1) |
285b2c4f | 601 | return 0; |
2e0e26c7 | 602 | |
1b1b32f2 HD |
603 | /* |
604 | * Move _head_ to start search for next from here. | |
1f895f75 | 605 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 | 606 | * mutex, and there's an instant in list_move_tail when info->swaplist |
285b2c4f | 607 | * would appear empty, if it were the only one on shmem_swaplist. |
1b1b32f2 HD |
608 | */ |
609 | if (shmem_swaplist.next != &info->swaplist) | |
610 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 611 | |
bde05d1c HD |
612 | gfp = mapping_gfp_mask(mapping); |
613 | if (shmem_should_replace_page(*pagep, gfp)) { | |
614 | mutex_unlock(&shmem_swaplist_mutex); | |
615 | error = shmem_replace_page(pagep, gfp, info, index); | |
616 | mutex_lock(&shmem_swaplist_mutex); | |
617 | /* | |
618 | * We needed to drop mutex to make that restrictive page | |
0142ef6c HD |
619 | * allocation, but the inode might have been freed while we |
620 | * dropped it: although a racing shmem_evict_inode() cannot | |
621 | * complete without emptying the radix_tree, our page lock | |
622 | * on this swapcache page is not enough to prevent that - | |
623 | * free_swap_and_cache() of our swap entry will only | |
624 | * trylock_page(), removing swap from radix_tree whatever. | |
625 | * | |
626 | * We must not proceed to shmem_add_to_page_cache() if the | |
627 | * inode has been freed, but of course we cannot rely on | |
628 | * inode or mapping or info to check that. However, we can | |
629 | * safely check if our swap entry is still in use (and here | |
630 | * it can't have got reused for another page): if it's still | |
631 | * in use, then the inode cannot have been freed yet, and we | |
632 | * can safely proceed (if it's no longer in use, that tells | |
633 | * nothing about the inode, but we don't need to unuse swap). | |
bde05d1c HD |
634 | */ |
635 | if (!page_swapcount(*pagep)) | |
636 | error = -ENOENT; | |
637 | } | |
638 | ||
d13d1443 | 639 | /* |
778dd893 HD |
640 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
641 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
642 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 643 | */ |
bde05d1c HD |
644 | if (!error) |
645 | error = shmem_add_to_page_cache(*pagep, mapping, index, | |
46f65ec1 | 646 | GFP_NOWAIT, radswap); |
48f170fb | 647 | if (error != -ENOMEM) { |
46f65ec1 HD |
648 | /* |
649 | * Truncation and eviction use free_swap_and_cache(), which | |
650 | * only does trylock page: if we raced, best clean up here. | |
651 | */ | |
bde05d1c HD |
652 | delete_from_swap_cache(*pagep); |
653 | set_page_dirty(*pagep); | |
46f65ec1 HD |
654 | if (!error) { |
655 | spin_lock(&info->lock); | |
656 | info->swapped--; | |
657 | spin_unlock(&info->lock); | |
658 | swap_free(swap); | |
659 | } | |
2e0e26c7 | 660 | error = 1; /* not an error, but entry was found */ |
1da177e4 | 661 | } |
2e0e26c7 | 662 | return error; |
1da177e4 LT |
663 | } |
664 | ||
665 | /* | |
46f65ec1 | 666 | * Search through swapped inodes to find and replace swap by page. |
1da177e4 | 667 | */ |
41ffe5d5 | 668 | int shmem_unuse(swp_entry_t swap, struct page *page) |
1da177e4 | 669 | { |
41ffe5d5 | 670 | struct list_head *this, *next; |
1da177e4 LT |
671 | struct shmem_inode_info *info; |
672 | int found = 0; | |
bde05d1c HD |
673 | int error = 0; |
674 | ||
675 | /* | |
676 | * There's a faint possibility that swap page was replaced before | |
0142ef6c | 677 | * caller locked it: caller will come back later with the right page. |
bde05d1c | 678 | */ |
0142ef6c | 679 | if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val)) |
bde05d1c | 680 | goto out; |
778dd893 HD |
681 | |
682 | /* | |
683 | * Charge page using GFP_KERNEL while we can wait, before taking | |
684 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
685 | * Charged back to the user (not to caller) when swap account is used. | |
778dd893 | 686 | */ |
d715ae08 | 687 | error = mem_cgroup_charge_file(page, current->mm, GFP_KERNEL); |
778dd893 HD |
688 | if (error) |
689 | goto out; | |
46f65ec1 | 690 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
1da177e4 | 691 | |
cb5f7b9a | 692 | mutex_lock(&shmem_swaplist_mutex); |
41ffe5d5 HD |
693 | list_for_each_safe(this, next, &shmem_swaplist) { |
694 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
285b2c4f | 695 | if (info->swapped) |
bde05d1c | 696 | found = shmem_unuse_inode(info, swap, &page); |
6922c0c7 HD |
697 | else |
698 | list_del_init(&info->swaplist); | |
cb5f7b9a | 699 | cond_resched(); |
2e0e26c7 | 700 | if (found) |
778dd893 | 701 | break; |
1da177e4 | 702 | } |
cb5f7b9a | 703 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 | 704 | |
778dd893 HD |
705 | if (found < 0) |
706 | error = found; | |
707 | out: | |
aaa46865 HD |
708 | unlock_page(page); |
709 | page_cache_release(page); | |
778dd893 | 710 | return error; |
1da177e4 LT |
711 | } |
712 | ||
713 | /* | |
714 | * Move the page from the page cache to the swap cache. | |
715 | */ | |
716 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
717 | { | |
718 | struct shmem_inode_info *info; | |
1da177e4 | 719 | struct address_space *mapping; |
1da177e4 | 720 | struct inode *inode; |
6922c0c7 HD |
721 | swp_entry_t swap; |
722 | pgoff_t index; | |
1da177e4 LT |
723 | |
724 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
725 | mapping = page->mapping; |
726 | index = page->index; | |
727 | inode = mapping->host; | |
728 | info = SHMEM_I(inode); | |
729 | if (info->flags & VM_LOCKED) | |
730 | goto redirty; | |
d9fe526a | 731 | if (!total_swap_pages) |
1da177e4 LT |
732 | goto redirty; |
733 | ||
d9fe526a HD |
734 | /* |
735 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
736 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
48f170fb | 737 | * might use ->writepage of its underlying filesystem, in which case |
d9fe526a | 738 | * tmpfs should write out to swap only in response to memory pressure, |
48f170fb | 739 | * and not for the writeback threads or sync. |
d9fe526a | 740 | */ |
48f170fb HD |
741 | if (!wbc->for_reclaim) { |
742 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
743 | goto redirty; | |
744 | } | |
1635f6a7 HD |
745 | |
746 | /* | |
747 | * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC | |
748 | * value into swapfile.c, the only way we can correctly account for a | |
749 | * fallocated page arriving here is now to initialize it and write it. | |
1aac1400 HD |
750 | * |
751 | * That's okay for a page already fallocated earlier, but if we have | |
752 | * not yet completed the fallocation, then (a) we want to keep track | |
753 | * of this page in case we have to undo it, and (b) it may not be a | |
754 | * good idea to continue anyway, once we're pushing into swap. So | |
755 | * reactivate the page, and let shmem_fallocate() quit when too many. | |
1635f6a7 HD |
756 | */ |
757 | if (!PageUptodate(page)) { | |
1aac1400 HD |
758 | if (inode->i_private) { |
759 | struct shmem_falloc *shmem_falloc; | |
760 | spin_lock(&inode->i_lock); | |
761 | shmem_falloc = inode->i_private; | |
762 | if (shmem_falloc && | |
f00cdc6d | 763 | !shmem_falloc->mode && |
1aac1400 HD |
764 | index >= shmem_falloc->start && |
765 | index < shmem_falloc->next) | |
766 | shmem_falloc->nr_unswapped++; | |
767 | else | |
768 | shmem_falloc = NULL; | |
769 | spin_unlock(&inode->i_lock); | |
770 | if (shmem_falloc) | |
771 | goto redirty; | |
772 | } | |
1635f6a7 HD |
773 | clear_highpage(page); |
774 | flush_dcache_page(page); | |
775 | SetPageUptodate(page); | |
776 | } | |
777 | ||
48f170fb HD |
778 | swap = get_swap_page(); |
779 | if (!swap.val) | |
780 | goto redirty; | |
d9fe526a | 781 | |
b1dea800 HD |
782 | /* |
783 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
6922c0c7 HD |
784 | * if it's not already there. Do it now before the page is |
785 | * moved to swap cache, when its pagelock no longer protects | |
b1dea800 | 786 | * the inode from eviction. But don't unlock the mutex until |
6922c0c7 HD |
787 | * we've incremented swapped, because shmem_unuse_inode() will |
788 | * prune a !swapped inode from the swaplist under this mutex. | |
b1dea800 | 789 | */ |
48f170fb HD |
790 | mutex_lock(&shmem_swaplist_mutex); |
791 | if (list_empty(&info->swaplist)) | |
792 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 793 | |
48f170fb | 794 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
aaa46865 | 795 | swap_shmem_alloc(swap); |
6922c0c7 HD |
796 | shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); |
797 | ||
798 | spin_lock(&info->lock); | |
799 | info->swapped++; | |
800 | shmem_recalc_inode(inode); | |
826267cf | 801 | spin_unlock(&info->lock); |
6922c0c7 HD |
802 | |
803 | mutex_unlock(&shmem_swaplist_mutex); | |
d9fe526a | 804 | BUG_ON(page_mapped(page)); |
9fab5619 | 805 | swap_writepage(page, wbc); |
1da177e4 LT |
806 | return 0; |
807 | } | |
808 | ||
6922c0c7 | 809 | mutex_unlock(&shmem_swaplist_mutex); |
cb4b86ba | 810 | swapcache_free(swap, NULL); |
1da177e4 LT |
811 | redirty: |
812 | set_page_dirty(page); | |
d9fe526a HD |
813 | if (wbc->for_reclaim) |
814 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
815 | unlock_page(page); | |
816 | return 0; | |
1da177e4 LT |
817 | } |
818 | ||
819 | #ifdef CONFIG_NUMA | |
680d794b | 820 | #ifdef CONFIG_TMPFS |
71fe804b | 821 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 822 | { |
095f1fc4 | 823 | char buffer[64]; |
680d794b | 824 | |
71fe804b | 825 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 826 | return; /* show nothing */ |
680d794b | 827 | |
a7a88b23 | 828 | mpol_to_str(buffer, sizeof(buffer), mpol); |
095f1fc4 LS |
829 | |
830 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 831 | } |
71fe804b LS |
832 | |
833 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
834 | { | |
835 | struct mempolicy *mpol = NULL; | |
836 | if (sbinfo->mpol) { | |
837 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
838 | mpol = sbinfo->mpol; | |
839 | mpol_get(mpol); | |
840 | spin_unlock(&sbinfo->stat_lock); | |
841 | } | |
842 | return mpol; | |
843 | } | |
680d794b | 844 | #endif /* CONFIG_TMPFS */ |
845 | ||
41ffe5d5 HD |
846 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
847 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 848 | { |
1da177e4 | 849 | struct vm_area_struct pvma; |
18a2f371 | 850 | struct page *page; |
52cd3b07 | 851 | |
1da177e4 | 852 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 853 | pvma.vm_start = 0; |
09c231cb NZ |
854 | /* Bias interleave by inode number to distribute better across nodes */ |
855 | pvma.vm_pgoff = index + info->vfs_inode.i_ino; | |
c4cc6d07 | 856 | pvma.vm_ops = NULL; |
18a2f371 MG |
857 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
858 | ||
859 | page = swapin_readahead(swap, gfp, &pvma, 0); | |
860 | ||
861 | /* Drop reference taken by mpol_shared_policy_lookup() */ | |
862 | mpol_cond_put(pvma.vm_policy); | |
863 | ||
864 | return page; | |
1da177e4 LT |
865 | } |
866 | ||
02098fea | 867 | static struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 868 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 LT |
869 | { |
870 | struct vm_area_struct pvma; | |
18a2f371 | 871 | struct page *page; |
1da177e4 | 872 | |
c4cc6d07 HD |
873 | /* Create a pseudo vma that just contains the policy */ |
874 | pvma.vm_start = 0; | |
09c231cb NZ |
875 | /* Bias interleave by inode number to distribute better across nodes */ |
876 | pvma.vm_pgoff = index + info->vfs_inode.i_ino; | |
c4cc6d07 | 877 | pvma.vm_ops = NULL; |
41ffe5d5 | 878 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
52cd3b07 | 879 | |
18a2f371 MG |
880 | page = alloc_page_vma(gfp, &pvma, 0); |
881 | ||
882 | /* Drop reference taken by mpol_shared_policy_lookup() */ | |
883 | mpol_cond_put(pvma.vm_policy); | |
884 | ||
885 | return page; | |
1da177e4 | 886 | } |
680d794b | 887 | #else /* !CONFIG_NUMA */ |
888 | #ifdef CONFIG_TMPFS | |
41ffe5d5 | 889 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 890 | { |
891 | } | |
892 | #endif /* CONFIG_TMPFS */ | |
893 | ||
41ffe5d5 HD |
894 | static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
895 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 896 | { |
41ffe5d5 | 897 | return swapin_readahead(swap, gfp, NULL, 0); |
1da177e4 LT |
898 | } |
899 | ||
02098fea | 900 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 901 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 902 | { |
e84e2e13 | 903 | return alloc_page(gfp); |
1da177e4 | 904 | } |
680d794b | 905 | #endif /* CONFIG_NUMA */ |
1da177e4 | 906 | |
71fe804b LS |
907 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
908 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
909 | { | |
910 | return NULL; | |
911 | } | |
912 | #endif | |
913 | ||
bde05d1c HD |
914 | /* |
915 | * When a page is moved from swapcache to shmem filecache (either by the | |
916 | * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of | |
917 | * shmem_unuse_inode()), it may have been read in earlier from swap, in | |
918 | * ignorance of the mapping it belongs to. If that mapping has special | |
919 | * constraints (like the gma500 GEM driver, which requires RAM below 4GB), | |
920 | * we may need to copy to a suitable page before moving to filecache. | |
921 | * | |
922 | * In a future release, this may well be extended to respect cpuset and | |
923 | * NUMA mempolicy, and applied also to anonymous pages in do_swap_page(); | |
924 | * but for now it is a simple matter of zone. | |
925 | */ | |
926 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp) | |
927 | { | |
928 | return page_zonenum(page) > gfp_zone(gfp); | |
929 | } | |
930 | ||
931 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
932 | struct shmem_inode_info *info, pgoff_t index) | |
933 | { | |
934 | struct page *oldpage, *newpage; | |
935 | struct address_space *swap_mapping; | |
936 | pgoff_t swap_index; | |
937 | int error; | |
938 | ||
939 | oldpage = *pagep; | |
940 | swap_index = page_private(oldpage); | |
941 | swap_mapping = page_mapping(oldpage); | |
942 | ||
943 | /* | |
944 | * We have arrived here because our zones are constrained, so don't | |
945 | * limit chance of success by further cpuset and node constraints. | |
946 | */ | |
947 | gfp &= ~GFP_CONSTRAINT_MASK; | |
948 | newpage = shmem_alloc_page(gfp, info, index); | |
949 | if (!newpage) | |
950 | return -ENOMEM; | |
bde05d1c | 951 | |
bde05d1c HD |
952 | page_cache_get(newpage); |
953 | copy_highpage(newpage, oldpage); | |
0142ef6c | 954 | flush_dcache_page(newpage); |
bde05d1c | 955 | |
bde05d1c | 956 | __set_page_locked(newpage); |
bde05d1c | 957 | SetPageUptodate(newpage); |
bde05d1c | 958 | SetPageSwapBacked(newpage); |
bde05d1c | 959 | set_page_private(newpage, swap_index); |
bde05d1c HD |
960 | SetPageSwapCache(newpage); |
961 | ||
962 | /* | |
963 | * Our caller will very soon move newpage out of swapcache, but it's | |
964 | * a nice clean interface for us to replace oldpage by newpage there. | |
965 | */ | |
966 | spin_lock_irq(&swap_mapping->tree_lock); | |
967 | error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage, | |
968 | newpage); | |
0142ef6c HD |
969 | if (!error) { |
970 | __inc_zone_page_state(newpage, NR_FILE_PAGES); | |
971 | __dec_zone_page_state(oldpage, NR_FILE_PAGES); | |
972 | } | |
bde05d1c | 973 | spin_unlock_irq(&swap_mapping->tree_lock); |
bde05d1c | 974 | |
0142ef6c HD |
975 | if (unlikely(error)) { |
976 | /* | |
977 | * Is this possible? I think not, now that our callers check | |
978 | * both PageSwapCache and page_private after getting page lock; | |
979 | * but be defensive. Reverse old to newpage for clear and free. | |
980 | */ | |
981 | oldpage = newpage; | |
982 | } else { | |
983 | mem_cgroup_replace_page_cache(oldpage, newpage); | |
984 | lru_cache_add_anon(newpage); | |
985 | *pagep = newpage; | |
986 | } | |
bde05d1c HD |
987 | |
988 | ClearPageSwapCache(oldpage); | |
989 | set_page_private(oldpage, 0); | |
990 | ||
991 | unlock_page(oldpage); | |
992 | page_cache_release(oldpage); | |
993 | page_cache_release(oldpage); | |
0142ef6c | 994 | return error; |
bde05d1c HD |
995 | } |
996 | ||
1da177e4 | 997 | /* |
68da9f05 | 998 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
999 | * |
1000 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1001 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1002 | * entry since a page cannot live in both the swap and page cache | |
1003 | */ | |
41ffe5d5 | 1004 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
68da9f05 | 1005 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) |
1da177e4 LT |
1006 | { |
1007 | struct address_space *mapping = inode->i_mapping; | |
54af6042 | 1008 | struct shmem_inode_info *info; |
1da177e4 | 1009 | struct shmem_sb_info *sbinfo; |
27ab7006 | 1010 | struct page *page; |
1da177e4 LT |
1011 | swp_entry_t swap; |
1012 | int error; | |
54af6042 | 1013 | int once = 0; |
1635f6a7 | 1014 | int alloced = 0; |
1da177e4 | 1015 | |
41ffe5d5 | 1016 | if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
1da177e4 | 1017 | return -EFBIG; |
1da177e4 | 1018 | repeat: |
54af6042 | 1019 | swap.val = 0; |
0cd6144a | 1020 | page = find_lock_entry(mapping, index); |
54af6042 HD |
1021 | if (radix_tree_exceptional_entry(page)) { |
1022 | swap = radix_to_swp_entry(page); | |
1023 | page = NULL; | |
1024 | } | |
1025 | ||
1635f6a7 | 1026 | if (sgp != SGP_WRITE && sgp != SGP_FALLOC && |
54af6042 HD |
1027 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { |
1028 | error = -EINVAL; | |
1029 | goto failed; | |
1030 | } | |
1031 | ||
66d2f4d2 HD |
1032 | if (page && sgp == SGP_WRITE) |
1033 | mark_page_accessed(page); | |
1034 | ||
1635f6a7 HD |
1035 | /* fallocated page? */ |
1036 | if (page && !PageUptodate(page)) { | |
1037 | if (sgp != SGP_READ) | |
1038 | goto clear; | |
1039 | unlock_page(page); | |
1040 | page_cache_release(page); | |
1041 | page = NULL; | |
1042 | } | |
54af6042 | 1043 | if (page || (sgp == SGP_READ && !swap.val)) { |
54af6042 HD |
1044 | *pagep = page; |
1045 | return 0; | |
27ab7006 HD |
1046 | } |
1047 | ||
1048 | /* | |
54af6042 HD |
1049 | * Fast cache lookup did not find it: |
1050 | * bring it back from swap or allocate. | |
27ab7006 | 1051 | */ |
54af6042 HD |
1052 | info = SHMEM_I(inode); |
1053 | sbinfo = SHMEM_SB(inode->i_sb); | |
1da177e4 | 1054 | |
1da177e4 LT |
1055 | if (swap.val) { |
1056 | /* Look it up and read it in.. */ | |
27ab7006 HD |
1057 | page = lookup_swap_cache(swap); |
1058 | if (!page) { | |
1da177e4 | 1059 | /* here we actually do the io */ |
68da9f05 HD |
1060 | if (fault_type) |
1061 | *fault_type |= VM_FAULT_MAJOR; | |
41ffe5d5 | 1062 | page = shmem_swapin(swap, gfp, info, index); |
27ab7006 | 1063 | if (!page) { |
54af6042 HD |
1064 | error = -ENOMEM; |
1065 | goto failed; | |
1da177e4 | 1066 | } |
1da177e4 LT |
1067 | } |
1068 | ||
1069 | /* We have to do this with page locked to prevent races */ | |
54af6042 | 1070 | lock_page(page); |
0142ef6c | 1071 | if (!PageSwapCache(page) || page_private(page) != swap.val || |
d1899228 | 1072 | !shmem_confirm_swap(mapping, index, swap)) { |
bde05d1c | 1073 | error = -EEXIST; /* try again */ |
d1899228 | 1074 | goto unlock; |
bde05d1c | 1075 | } |
27ab7006 | 1076 | if (!PageUptodate(page)) { |
1da177e4 | 1077 | error = -EIO; |
54af6042 | 1078 | goto failed; |
1da177e4 | 1079 | } |
54af6042 HD |
1080 | wait_on_page_writeback(page); |
1081 | ||
bde05d1c HD |
1082 | if (shmem_should_replace_page(page, gfp)) { |
1083 | error = shmem_replace_page(&page, gfp, info, index); | |
1084 | if (error) | |
1085 | goto failed; | |
1da177e4 | 1086 | } |
27ab7006 | 1087 | |
d715ae08 | 1088 | error = mem_cgroup_charge_file(page, current->mm, |
aa3b1895 | 1089 | gfp & GFP_RECLAIM_MASK); |
d1899228 | 1090 | if (!error) { |
aa3b1895 HD |
1091 | error = shmem_add_to_page_cache(page, mapping, index, |
1092 | gfp, swp_to_radix_entry(swap)); | |
215c02bc HD |
1093 | /* |
1094 | * We already confirmed swap under page lock, and make | |
1095 | * no memory allocation here, so usually no possibility | |
1096 | * of error; but free_swap_and_cache() only trylocks a | |
1097 | * page, so it is just possible that the entry has been | |
1098 | * truncated or holepunched since swap was confirmed. | |
1099 | * shmem_undo_range() will have done some of the | |
1100 | * unaccounting, now delete_from_swap_cache() will do | |
1101 | * the rest (including mem_cgroup_uncharge_swapcache). | |
1102 | * Reset swap.val? No, leave it so "failed" goes back to | |
1103 | * "repeat": reading a hole and writing should succeed. | |
1104 | */ | |
1105 | if (error) | |
1106 | delete_from_swap_cache(page); | |
d1899228 | 1107 | } |
54af6042 HD |
1108 | if (error) |
1109 | goto failed; | |
1110 | ||
1111 | spin_lock(&info->lock); | |
285b2c4f | 1112 | info->swapped--; |
54af6042 | 1113 | shmem_recalc_inode(inode); |
27ab7006 | 1114 | spin_unlock(&info->lock); |
54af6042 | 1115 | |
66d2f4d2 HD |
1116 | if (sgp == SGP_WRITE) |
1117 | mark_page_accessed(page); | |
1118 | ||
54af6042 | 1119 | delete_from_swap_cache(page); |
27ab7006 HD |
1120 | set_page_dirty(page); |
1121 | swap_free(swap); | |
1122 | ||
54af6042 HD |
1123 | } else { |
1124 | if (shmem_acct_block(info->flags)) { | |
1125 | error = -ENOSPC; | |
1126 | goto failed; | |
1da177e4 | 1127 | } |
0edd73b3 | 1128 | if (sbinfo->max_blocks) { |
fc5da22a | 1129 | if (percpu_counter_compare(&sbinfo->used_blocks, |
54af6042 HD |
1130 | sbinfo->max_blocks) >= 0) { |
1131 | error = -ENOSPC; | |
1132 | goto unacct; | |
1133 | } | |
7e496299 | 1134 | percpu_counter_inc(&sbinfo->used_blocks); |
54af6042 | 1135 | } |
1da177e4 | 1136 | |
54af6042 HD |
1137 | page = shmem_alloc_page(gfp, info, index); |
1138 | if (!page) { | |
1139 | error = -ENOMEM; | |
1140 | goto decused; | |
1da177e4 LT |
1141 | } |
1142 | ||
07a42788 | 1143 | __SetPageSwapBacked(page); |
54af6042 | 1144 | __set_page_locked(page); |
66d2f4d2 HD |
1145 | if (sgp == SGP_WRITE) |
1146 | init_page_accessed(page); | |
1147 | ||
d715ae08 | 1148 | error = mem_cgroup_charge_file(page, current->mm, |
aa3b1895 | 1149 | gfp & GFP_RECLAIM_MASK); |
54af6042 HD |
1150 | if (error) |
1151 | goto decused; | |
5e4c0d97 | 1152 | error = radix_tree_maybe_preload(gfp & GFP_RECLAIM_MASK); |
b065b432 HD |
1153 | if (!error) { |
1154 | error = shmem_add_to_page_cache(page, mapping, index, | |
1155 | gfp, NULL); | |
1156 | radix_tree_preload_end(); | |
1157 | } | |
1158 | if (error) { | |
1159 | mem_cgroup_uncharge_cache_page(page); | |
1160 | goto decused; | |
1161 | } | |
54af6042 HD |
1162 | lru_cache_add_anon(page); |
1163 | ||
1164 | spin_lock(&info->lock); | |
1da177e4 | 1165 | info->alloced++; |
54af6042 HD |
1166 | inode->i_blocks += BLOCKS_PER_PAGE; |
1167 | shmem_recalc_inode(inode); | |
1da177e4 | 1168 | spin_unlock(&info->lock); |
1635f6a7 | 1169 | alloced = true; |
54af6042 | 1170 | |
ec9516fb | 1171 | /* |
1635f6a7 HD |
1172 | * Let SGP_FALLOC use the SGP_WRITE optimization on a new page. |
1173 | */ | |
1174 | if (sgp == SGP_FALLOC) | |
1175 | sgp = SGP_WRITE; | |
1176 | clear: | |
1177 | /* | |
1178 | * Let SGP_WRITE caller clear ends if write does not fill page; | |
1179 | * but SGP_FALLOC on a page fallocated earlier must initialize | |
1180 | * it now, lest undo on failure cancel our earlier guarantee. | |
ec9516fb HD |
1181 | */ |
1182 | if (sgp != SGP_WRITE) { | |
1183 | clear_highpage(page); | |
1184 | flush_dcache_page(page); | |
1185 | SetPageUptodate(page); | |
1186 | } | |
a0ee5ec5 | 1187 | if (sgp == SGP_DIRTY) |
27ab7006 | 1188 | set_page_dirty(page); |
1da177e4 | 1189 | } |
bde05d1c | 1190 | |
54af6042 | 1191 | /* Perhaps the file has been truncated since we checked */ |
1635f6a7 | 1192 | if (sgp != SGP_WRITE && sgp != SGP_FALLOC && |
54af6042 HD |
1193 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { |
1194 | error = -EINVAL; | |
1635f6a7 HD |
1195 | if (alloced) |
1196 | goto trunc; | |
1197 | else | |
1198 | goto failed; | |
e83c32e8 | 1199 | } |
54af6042 HD |
1200 | *pagep = page; |
1201 | return 0; | |
1da177e4 | 1202 | |
59a16ead | 1203 | /* |
54af6042 | 1204 | * Error recovery. |
59a16ead | 1205 | */ |
54af6042 | 1206 | trunc: |
1635f6a7 | 1207 | info = SHMEM_I(inode); |
54af6042 HD |
1208 | ClearPageDirty(page); |
1209 | delete_from_page_cache(page); | |
1210 | spin_lock(&info->lock); | |
1211 | info->alloced--; | |
1212 | inode->i_blocks -= BLOCKS_PER_PAGE; | |
59a16ead | 1213 | spin_unlock(&info->lock); |
54af6042 | 1214 | decused: |
1635f6a7 | 1215 | sbinfo = SHMEM_SB(inode->i_sb); |
54af6042 HD |
1216 | if (sbinfo->max_blocks) |
1217 | percpu_counter_add(&sbinfo->used_blocks, -1); | |
1218 | unacct: | |
1219 | shmem_unacct_blocks(info->flags, 1); | |
1220 | failed: | |
d1899228 HD |
1221 | if (swap.val && error != -EINVAL && |
1222 | !shmem_confirm_swap(mapping, index, swap)) | |
1223 | error = -EEXIST; | |
1224 | unlock: | |
27ab7006 | 1225 | if (page) { |
54af6042 | 1226 | unlock_page(page); |
27ab7006 | 1227 | page_cache_release(page); |
54af6042 HD |
1228 | } |
1229 | if (error == -ENOSPC && !once++) { | |
1230 | info = SHMEM_I(inode); | |
1231 | spin_lock(&info->lock); | |
1232 | shmem_recalc_inode(inode); | |
1233 | spin_unlock(&info->lock); | |
27ab7006 | 1234 | goto repeat; |
ff36b801 | 1235 | } |
d1899228 | 1236 | if (error == -EEXIST) /* from above or from radix_tree_insert */ |
54af6042 HD |
1237 | goto repeat; |
1238 | return error; | |
1da177e4 LT |
1239 | } |
1240 | ||
d0217ac0 | 1241 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1242 | { |
496ad9aa | 1243 | struct inode *inode = file_inode(vma->vm_file); |
1da177e4 | 1244 | int error; |
68da9f05 | 1245 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 1246 | |
f00cdc6d HD |
1247 | /* |
1248 | * Trinity finds that probing a hole which tmpfs is punching can | |
1249 | * prevent the hole-punch from ever completing: which in turn | |
1250 | * locks writers out with its hold on i_mutex. So refrain from | |
1251 | * faulting pages into the hole while it's being punched, and | |
1252 | * wait on i_mutex to be released if vmf->flags permits. | |
1253 | */ | |
1254 | if (unlikely(inode->i_private)) { | |
1255 | struct shmem_falloc *shmem_falloc; | |
1256 | ||
1257 | spin_lock(&inode->i_lock); | |
1258 | shmem_falloc = inode->i_private; | |
1259 | if (!shmem_falloc || | |
1260 | shmem_falloc->mode != FALLOC_FL_PUNCH_HOLE || | |
1261 | vmf->pgoff < shmem_falloc->start || | |
1262 | vmf->pgoff >= shmem_falloc->next) | |
1263 | shmem_falloc = NULL; | |
1264 | spin_unlock(&inode->i_lock); | |
1265 | /* | |
1266 | * i_lock has protected us from taking shmem_falloc seriously | |
1267 | * once return from shmem_fallocate() went back up that stack. | |
1268 | * i_lock does not serialize with i_mutex at all, but it does | |
1269 | * not matter if sometimes we wait unnecessarily, or sometimes | |
1270 | * miss out on waiting: we just need to make those cases rare. | |
1271 | */ | |
1272 | if (shmem_falloc) { | |
1273 | if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && | |
1274 | !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { | |
1275 | up_read(&vma->vm_mm->mmap_sem); | |
1276 | mutex_lock(&inode->i_mutex); | |
1277 | mutex_unlock(&inode->i_mutex); | |
1278 | return VM_FAULT_RETRY; | |
1279 | } | |
1280 | /* cond_resched? Leave that to GUP or return to user */ | |
1281 | return VM_FAULT_NOPAGE; | |
1282 | } | |
1283 | } | |
1284 | ||
27d54b39 | 1285 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1286 | if (error) |
1287 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 1288 | |
456f998e YH |
1289 | if (ret & VM_FAULT_MAJOR) { |
1290 | count_vm_event(PGMAJFAULT); | |
1291 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
1292 | } | |
68da9f05 | 1293 | return ret; |
1da177e4 LT |
1294 | } |
1295 | ||
1da177e4 | 1296 | #ifdef CONFIG_NUMA |
41ffe5d5 | 1297 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
1da177e4 | 1298 | { |
496ad9aa | 1299 | struct inode *inode = file_inode(vma->vm_file); |
41ffe5d5 | 1300 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); |
1da177e4 LT |
1301 | } |
1302 | ||
d8dc74f2 AB |
1303 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1304 | unsigned long addr) | |
1da177e4 | 1305 | { |
496ad9aa | 1306 | struct inode *inode = file_inode(vma->vm_file); |
41ffe5d5 | 1307 | pgoff_t index; |
1da177e4 | 1308 | |
41ffe5d5 HD |
1309 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
1310 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
1da177e4 LT |
1311 | } |
1312 | #endif | |
1313 | ||
1314 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1315 | { | |
496ad9aa | 1316 | struct inode *inode = file_inode(file); |
1da177e4 LT |
1317 | struct shmem_inode_info *info = SHMEM_I(inode); |
1318 | int retval = -ENOMEM; | |
1319 | ||
1320 | spin_lock(&info->lock); | |
1321 | if (lock && !(info->flags & VM_LOCKED)) { | |
1322 | if (!user_shm_lock(inode->i_size, user)) | |
1323 | goto out_nomem; | |
1324 | info->flags |= VM_LOCKED; | |
89e004ea | 1325 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1326 | } |
1327 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1328 | user_shm_unlock(inode->i_size, user); | |
1329 | info->flags &= ~VM_LOCKED; | |
89e004ea | 1330 | mapping_clear_unevictable(file->f_mapping); |
1da177e4 LT |
1331 | } |
1332 | retval = 0; | |
89e004ea | 1333 | |
1da177e4 LT |
1334 | out_nomem: |
1335 | spin_unlock(&info->lock); | |
1336 | return retval; | |
1337 | } | |
1338 | ||
9b83a6a8 | 1339 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1340 | { |
1341 | file_accessed(file); | |
1342 | vma->vm_ops = &shmem_vm_ops; | |
1343 | return 0; | |
1344 | } | |
1345 | ||
454abafe | 1346 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
09208d15 | 1347 | umode_t mode, dev_t dev, unsigned long flags) |
1da177e4 LT |
1348 | { |
1349 | struct inode *inode; | |
1350 | struct shmem_inode_info *info; | |
1351 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1352 | ||
5b04c689 PE |
1353 | if (shmem_reserve_inode(sb)) |
1354 | return NULL; | |
1da177e4 LT |
1355 | |
1356 | inode = new_inode(sb); | |
1357 | if (inode) { | |
85fe4025 | 1358 | inode->i_ino = get_next_ino(); |
454abafe | 1359 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1360 | inode->i_blocks = 0; |
1da177e4 LT |
1361 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1362 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1363 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1364 | info = SHMEM_I(inode); |
1365 | memset(info, 0, (char *)inode - (char *)info); | |
1366 | spin_lock_init(&info->lock); | |
0b0a0806 | 1367 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1368 | INIT_LIST_HEAD(&info->swaplist); |
38f38657 | 1369 | simple_xattrs_init(&info->xattrs); |
72c04902 | 1370 | cache_no_acl(inode); |
1da177e4 LT |
1371 | |
1372 | switch (mode & S_IFMT) { | |
1373 | default: | |
39f0247d | 1374 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1375 | init_special_inode(inode, mode, dev); |
1376 | break; | |
1377 | case S_IFREG: | |
14fcc23f | 1378 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1379 | inode->i_op = &shmem_inode_operations; |
1380 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1381 | mpol_shared_policy_init(&info->policy, |
1382 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1383 | break; |
1384 | case S_IFDIR: | |
d8c76e6f | 1385 | inc_nlink(inode); |
1da177e4 LT |
1386 | /* Some things misbehave if size == 0 on a directory */ |
1387 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1388 | inode->i_op = &shmem_dir_inode_operations; | |
1389 | inode->i_fop = &simple_dir_operations; | |
1390 | break; | |
1391 | case S_IFLNK: | |
1392 | /* | |
1393 | * Must not load anything in the rbtree, | |
1394 | * mpol_free_shared_policy will not be called. | |
1395 | */ | |
71fe804b | 1396 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1397 | break; |
1398 | } | |
5b04c689 PE |
1399 | } else |
1400 | shmem_free_inode(sb); | |
1da177e4 LT |
1401 | return inode; |
1402 | } | |
1403 | ||
0cd6144a JW |
1404 | bool shmem_mapping(struct address_space *mapping) |
1405 | { | |
1406 | return mapping->backing_dev_info == &shmem_backing_dev_info; | |
1407 | } | |
1408 | ||
1da177e4 | 1409 | #ifdef CONFIG_TMPFS |
92e1d5be | 1410 | static const struct inode_operations shmem_symlink_inode_operations; |
69f07ec9 | 1411 | static const struct inode_operations shmem_short_symlink_operations; |
1da177e4 | 1412 | |
6d9d88d0 JS |
1413 | #ifdef CONFIG_TMPFS_XATTR |
1414 | static int shmem_initxattrs(struct inode *, const struct xattr *, void *); | |
1415 | #else | |
1416 | #define shmem_initxattrs NULL | |
1417 | #endif | |
1418 | ||
1da177e4 | 1419 | static int |
800d15a5 NP |
1420 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1421 | loff_t pos, unsigned len, unsigned flags, | |
1422 | struct page **pagep, void **fsdata) | |
1da177e4 | 1423 | { |
800d15a5 NP |
1424 | struct inode *inode = mapping->host; |
1425 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
66d2f4d2 | 1426 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
800d15a5 NP |
1427 | } |
1428 | ||
1429 | static int | |
1430 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1431 | loff_t pos, unsigned len, unsigned copied, | |
1432 | struct page *page, void *fsdata) | |
1433 | { | |
1434 | struct inode *inode = mapping->host; | |
1435 | ||
d3602444 HD |
1436 | if (pos + copied > inode->i_size) |
1437 | i_size_write(inode, pos + copied); | |
1438 | ||
ec9516fb HD |
1439 | if (!PageUptodate(page)) { |
1440 | if (copied < PAGE_CACHE_SIZE) { | |
1441 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
1442 | zero_user_segments(page, 0, from, | |
1443 | from + copied, PAGE_CACHE_SIZE); | |
1444 | } | |
1445 | SetPageUptodate(page); | |
1446 | } | |
800d15a5 | 1447 | set_page_dirty(page); |
6746aff7 | 1448 | unlock_page(page); |
800d15a5 NP |
1449 | page_cache_release(page); |
1450 | ||
800d15a5 | 1451 | return copied; |
1da177e4 LT |
1452 | } |
1453 | ||
2ba5bbed | 1454 | static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) |
1da177e4 | 1455 | { |
6e58e79d AV |
1456 | struct file *file = iocb->ki_filp; |
1457 | struct inode *inode = file_inode(file); | |
1da177e4 | 1458 | struct address_space *mapping = inode->i_mapping; |
41ffe5d5 HD |
1459 | pgoff_t index; |
1460 | unsigned long offset; | |
a0ee5ec5 | 1461 | enum sgp_type sgp = SGP_READ; |
f7c1d074 | 1462 | int error = 0; |
cb66a7a1 | 1463 | ssize_t retval = 0; |
6e58e79d | 1464 | loff_t *ppos = &iocb->ki_pos; |
a0ee5ec5 HD |
1465 | |
1466 | /* | |
1467 | * Might this read be for a stacking filesystem? Then when reading | |
1468 | * holes of a sparse file, we actually need to allocate those pages, | |
1469 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1470 | */ | |
1471 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1472 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1473 | |
1474 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1475 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1476 | ||
1477 | for (;;) { | |
1478 | struct page *page = NULL; | |
41ffe5d5 HD |
1479 | pgoff_t end_index; |
1480 | unsigned long nr, ret; | |
1da177e4 LT |
1481 | loff_t i_size = i_size_read(inode); |
1482 | ||
1483 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1484 | if (index > end_index) | |
1485 | break; | |
1486 | if (index == end_index) { | |
1487 | nr = i_size & ~PAGE_CACHE_MASK; | |
1488 | if (nr <= offset) | |
1489 | break; | |
1490 | } | |
1491 | ||
6e58e79d AV |
1492 | error = shmem_getpage(inode, index, &page, sgp, NULL); |
1493 | if (error) { | |
1494 | if (error == -EINVAL) | |
1495 | error = 0; | |
1da177e4 LT |
1496 | break; |
1497 | } | |
d3602444 HD |
1498 | if (page) |
1499 | unlock_page(page); | |
1da177e4 LT |
1500 | |
1501 | /* | |
1502 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1503 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1504 | */ |
1505 | nr = PAGE_CACHE_SIZE; | |
1506 | i_size = i_size_read(inode); | |
1507 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1508 | if (index == end_index) { | |
1509 | nr = i_size & ~PAGE_CACHE_MASK; | |
1510 | if (nr <= offset) { | |
1511 | if (page) | |
1512 | page_cache_release(page); | |
1513 | break; | |
1514 | } | |
1515 | } | |
1516 | nr -= offset; | |
1517 | ||
1518 | if (page) { | |
1519 | /* | |
1520 | * If users can be writing to this page using arbitrary | |
1521 | * virtual addresses, take care about potential aliasing | |
1522 | * before reading the page on the kernel side. | |
1523 | */ | |
1524 | if (mapping_writably_mapped(mapping)) | |
1525 | flush_dcache_page(page); | |
1526 | /* | |
1527 | * Mark the page accessed if we read the beginning. | |
1528 | */ | |
1529 | if (!offset) | |
1530 | mark_page_accessed(page); | |
b5810039 | 1531 | } else { |
1da177e4 | 1532 | page = ZERO_PAGE(0); |
b5810039 NP |
1533 | page_cache_get(page); |
1534 | } | |
1da177e4 LT |
1535 | |
1536 | /* | |
1537 | * Ok, we have the page, and it's up-to-date, so | |
1538 | * now we can copy it to user space... | |
1da177e4 | 1539 | */ |
2ba5bbed | 1540 | ret = copy_page_to_iter(page, offset, nr, to); |
6e58e79d | 1541 | retval += ret; |
1da177e4 LT |
1542 | offset += ret; |
1543 | index += offset >> PAGE_CACHE_SHIFT; | |
1544 | offset &= ~PAGE_CACHE_MASK; | |
1545 | ||
1546 | page_cache_release(page); | |
2ba5bbed | 1547 | if (!iov_iter_count(to)) |
1da177e4 | 1548 | break; |
6e58e79d AV |
1549 | if (ret < nr) { |
1550 | error = -EFAULT; | |
1551 | break; | |
1552 | } | |
1da177e4 LT |
1553 | cond_resched(); |
1554 | } | |
1555 | ||
1556 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
6e58e79d AV |
1557 | file_accessed(file); |
1558 | return retval ? retval : error; | |
1da177e4 LT |
1559 | } |
1560 | ||
708e3508 HD |
1561 | static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
1562 | struct pipe_inode_info *pipe, size_t len, | |
1563 | unsigned int flags) | |
1564 | { | |
1565 | struct address_space *mapping = in->f_mapping; | |
71f0e07a | 1566 | struct inode *inode = mapping->host; |
708e3508 HD |
1567 | unsigned int loff, nr_pages, req_pages; |
1568 | struct page *pages[PIPE_DEF_BUFFERS]; | |
1569 | struct partial_page partial[PIPE_DEF_BUFFERS]; | |
1570 | struct page *page; | |
1571 | pgoff_t index, end_index; | |
1572 | loff_t isize, left; | |
1573 | int error, page_nr; | |
1574 | struct splice_pipe_desc spd = { | |
1575 | .pages = pages, | |
1576 | .partial = partial, | |
047fe360 | 1577 | .nr_pages_max = PIPE_DEF_BUFFERS, |
708e3508 HD |
1578 | .flags = flags, |
1579 | .ops = &page_cache_pipe_buf_ops, | |
1580 | .spd_release = spd_release_page, | |
1581 | }; | |
1582 | ||
71f0e07a | 1583 | isize = i_size_read(inode); |
708e3508 HD |
1584 | if (unlikely(*ppos >= isize)) |
1585 | return 0; | |
1586 | ||
1587 | left = isize - *ppos; | |
1588 | if (unlikely(left < len)) | |
1589 | len = left; | |
1590 | ||
1591 | if (splice_grow_spd(pipe, &spd)) | |
1592 | return -ENOMEM; | |
1593 | ||
1594 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1595 | loff = *ppos & ~PAGE_CACHE_MASK; | |
1596 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
a786c06d | 1597 | nr_pages = min(req_pages, spd.nr_pages_max); |
708e3508 | 1598 | |
708e3508 HD |
1599 | spd.nr_pages = find_get_pages_contig(mapping, index, |
1600 | nr_pages, spd.pages); | |
1601 | index += spd.nr_pages; | |
708e3508 | 1602 | error = 0; |
708e3508 | 1603 | |
71f0e07a | 1604 | while (spd.nr_pages < nr_pages) { |
71f0e07a HD |
1605 | error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
1606 | if (error) | |
1607 | break; | |
1608 | unlock_page(page); | |
708e3508 HD |
1609 | spd.pages[spd.nr_pages++] = page; |
1610 | index++; | |
1611 | } | |
1612 | ||
708e3508 HD |
1613 | index = *ppos >> PAGE_CACHE_SHIFT; |
1614 | nr_pages = spd.nr_pages; | |
1615 | spd.nr_pages = 0; | |
71f0e07a | 1616 | |
708e3508 HD |
1617 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
1618 | unsigned int this_len; | |
1619 | ||
1620 | if (!len) | |
1621 | break; | |
1622 | ||
708e3508 HD |
1623 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
1624 | page = spd.pages[page_nr]; | |
1625 | ||
71f0e07a | 1626 | if (!PageUptodate(page) || page->mapping != mapping) { |
71f0e07a HD |
1627 | error = shmem_getpage(inode, index, &page, |
1628 | SGP_CACHE, NULL); | |
1629 | if (error) | |
708e3508 | 1630 | break; |
71f0e07a HD |
1631 | unlock_page(page); |
1632 | page_cache_release(spd.pages[page_nr]); | |
1633 | spd.pages[page_nr] = page; | |
708e3508 | 1634 | } |
71f0e07a HD |
1635 | |
1636 | isize = i_size_read(inode); | |
708e3508 HD |
1637 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
1638 | if (unlikely(!isize || index > end_index)) | |
1639 | break; | |
1640 | ||
708e3508 HD |
1641 | if (end_index == index) { |
1642 | unsigned int plen; | |
1643 | ||
708e3508 HD |
1644 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
1645 | if (plen <= loff) | |
1646 | break; | |
1647 | ||
708e3508 HD |
1648 | this_len = min(this_len, plen - loff); |
1649 | len = this_len; | |
1650 | } | |
1651 | ||
1652 | spd.partial[page_nr].offset = loff; | |
1653 | spd.partial[page_nr].len = this_len; | |
1654 | len -= this_len; | |
1655 | loff = 0; | |
1656 | spd.nr_pages++; | |
1657 | index++; | |
1658 | } | |
1659 | ||
708e3508 HD |
1660 | while (page_nr < nr_pages) |
1661 | page_cache_release(spd.pages[page_nr++]); | |
708e3508 HD |
1662 | |
1663 | if (spd.nr_pages) | |
1664 | error = splice_to_pipe(pipe, &spd); | |
1665 | ||
047fe360 | 1666 | splice_shrink_spd(&spd); |
708e3508 HD |
1667 | |
1668 | if (error > 0) { | |
1669 | *ppos += error; | |
1670 | file_accessed(in); | |
1671 | } | |
1672 | return error; | |
1673 | } | |
1674 | ||
220f2ac9 HD |
1675 | /* |
1676 | * llseek SEEK_DATA or SEEK_HOLE through the radix_tree. | |
1677 | */ | |
1678 | static pgoff_t shmem_seek_hole_data(struct address_space *mapping, | |
965c8e59 | 1679 | pgoff_t index, pgoff_t end, int whence) |
220f2ac9 HD |
1680 | { |
1681 | struct page *page; | |
1682 | struct pagevec pvec; | |
1683 | pgoff_t indices[PAGEVEC_SIZE]; | |
1684 | bool done = false; | |
1685 | int i; | |
1686 | ||
1687 | pagevec_init(&pvec, 0); | |
1688 | pvec.nr = 1; /* start small: we may be there already */ | |
1689 | while (!done) { | |
0cd6144a | 1690 | pvec.nr = find_get_entries(mapping, index, |
220f2ac9 HD |
1691 | pvec.nr, pvec.pages, indices); |
1692 | if (!pvec.nr) { | |
965c8e59 | 1693 | if (whence == SEEK_DATA) |
220f2ac9 HD |
1694 | index = end; |
1695 | break; | |
1696 | } | |
1697 | for (i = 0; i < pvec.nr; i++, index++) { | |
1698 | if (index < indices[i]) { | |
965c8e59 | 1699 | if (whence == SEEK_HOLE) { |
220f2ac9 HD |
1700 | done = true; |
1701 | break; | |
1702 | } | |
1703 | index = indices[i]; | |
1704 | } | |
1705 | page = pvec.pages[i]; | |
1706 | if (page && !radix_tree_exceptional_entry(page)) { | |
1707 | if (!PageUptodate(page)) | |
1708 | page = NULL; | |
1709 | } | |
1710 | if (index >= end || | |
965c8e59 AM |
1711 | (page && whence == SEEK_DATA) || |
1712 | (!page && whence == SEEK_HOLE)) { | |
220f2ac9 HD |
1713 | done = true; |
1714 | break; | |
1715 | } | |
1716 | } | |
0cd6144a | 1717 | pagevec_remove_exceptionals(&pvec); |
220f2ac9 HD |
1718 | pagevec_release(&pvec); |
1719 | pvec.nr = PAGEVEC_SIZE; | |
1720 | cond_resched(); | |
1721 | } | |
1722 | return index; | |
1723 | } | |
1724 | ||
965c8e59 | 1725 | static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence) |
220f2ac9 HD |
1726 | { |
1727 | struct address_space *mapping = file->f_mapping; | |
1728 | struct inode *inode = mapping->host; | |
1729 | pgoff_t start, end; | |
1730 | loff_t new_offset; | |
1731 | ||
965c8e59 AM |
1732 | if (whence != SEEK_DATA && whence != SEEK_HOLE) |
1733 | return generic_file_llseek_size(file, offset, whence, | |
220f2ac9 HD |
1734 | MAX_LFS_FILESIZE, i_size_read(inode)); |
1735 | mutex_lock(&inode->i_mutex); | |
1736 | /* We're holding i_mutex so we can access i_size directly */ | |
1737 | ||
1738 | if (offset < 0) | |
1739 | offset = -EINVAL; | |
1740 | else if (offset >= inode->i_size) | |
1741 | offset = -ENXIO; | |
1742 | else { | |
1743 | start = offset >> PAGE_CACHE_SHIFT; | |
1744 | end = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
965c8e59 | 1745 | new_offset = shmem_seek_hole_data(mapping, start, end, whence); |
220f2ac9 HD |
1746 | new_offset <<= PAGE_CACHE_SHIFT; |
1747 | if (new_offset > offset) { | |
1748 | if (new_offset < inode->i_size) | |
1749 | offset = new_offset; | |
965c8e59 | 1750 | else if (whence == SEEK_DATA) |
220f2ac9 HD |
1751 | offset = -ENXIO; |
1752 | else | |
1753 | offset = inode->i_size; | |
1754 | } | |
1755 | } | |
1756 | ||
387aae6f HD |
1757 | if (offset >= 0) |
1758 | offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE); | |
220f2ac9 HD |
1759 | mutex_unlock(&inode->i_mutex); |
1760 | return offset; | |
1761 | } | |
1762 | ||
83e4fa9c HD |
1763 | static long shmem_fallocate(struct file *file, int mode, loff_t offset, |
1764 | loff_t len) | |
1765 | { | |
496ad9aa | 1766 | struct inode *inode = file_inode(file); |
e2d12e22 | 1767 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
1aac1400 | 1768 | struct shmem_falloc shmem_falloc; |
e2d12e22 HD |
1769 | pgoff_t start, index, end; |
1770 | int error; | |
83e4fa9c | 1771 | |
13ace4d0 HD |
1772 | if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) |
1773 | return -EOPNOTSUPP; | |
1774 | ||
83e4fa9c HD |
1775 | mutex_lock(&inode->i_mutex); |
1776 | ||
f00cdc6d HD |
1777 | shmem_falloc.mode = mode & ~FALLOC_FL_KEEP_SIZE; |
1778 | ||
83e4fa9c HD |
1779 | if (mode & FALLOC_FL_PUNCH_HOLE) { |
1780 | struct address_space *mapping = file->f_mapping; | |
1781 | loff_t unmap_start = round_up(offset, PAGE_SIZE); | |
1782 | loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1; | |
1783 | ||
f00cdc6d HD |
1784 | shmem_falloc.start = unmap_start >> PAGE_SHIFT; |
1785 | shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT; | |
1786 | spin_lock(&inode->i_lock); | |
1787 | inode->i_private = &shmem_falloc; | |
1788 | spin_unlock(&inode->i_lock); | |
1789 | ||
83e4fa9c HD |
1790 | if ((u64)unmap_end > (u64)unmap_start) |
1791 | unmap_mapping_range(mapping, unmap_start, | |
1792 | 1 + unmap_end - unmap_start, 0); | |
1793 | shmem_truncate_range(inode, offset, offset + len - 1); | |
1794 | /* No need to unmap again: hole-punching leaves COWed pages */ | |
1795 | error = 0; | |
f00cdc6d | 1796 | goto undone; |
e2d12e22 HD |
1797 | } |
1798 | ||
1799 | /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ | |
1800 | error = inode_newsize_ok(inode, offset + len); | |
1801 | if (error) | |
1802 | goto out; | |
1803 | ||
1804 | start = offset >> PAGE_CACHE_SHIFT; | |
1805 | end = (offset + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1806 | /* Try to avoid a swapstorm if len is impossible to satisfy */ | |
1807 | if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) { | |
1808 | error = -ENOSPC; | |
1809 | goto out; | |
83e4fa9c HD |
1810 | } |
1811 | ||
1aac1400 HD |
1812 | shmem_falloc.start = start; |
1813 | shmem_falloc.next = start; | |
1814 | shmem_falloc.nr_falloced = 0; | |
1815 | shmem_falloc.nr_unswapped = 0; | |
1816 | spin_lock(&inode->i_lock); | |
1817 | inode->i_private = &shmem_falloc; | |
1818 | spin_unlock(&inode->i_lock); | |
1819 | ||
e2d12e22 HD |
1820 | for (index = start; index < end; index++) { |
1821 | struct page *page; | |
1822 | ||
1823 | /* | |
1824 | * Good, the fallocate(2) manpage permits EINTR: we may have | |
1825 | * been interrupted because we are using up too much memory. | |
1826 | */ | |
1827 | if (signal_pending(current)) | |
1828 | error = -EINTR; | |
1aac1400 HD |
1829 | else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced) |
1830 | error = -ENOMEM; | |
e2d12e22 | 1831 | else |
1635f6a7 | 1832 | error = shmem_getpage(inode, index, &page, SGP_FALLOC, |
e2d12e22 HD |
1833 | NULL); |
1834 | if (error) { | |
1635f6a7 HD |
1835 | /* Remove the !PageUptodate pages we added */ |
1836 | shmem_undo_range(inode, | |
1837 | (loff_t)start << PAGE_CACHE_SHIFT, | |
1838 | (loff_t)index << PAGE_CACHE_SHIFT, true); | |
1aac1400 | 1839 | goto undone; |
e2d12e22 HD |
1840 | } |
1841 | ||
1aac1400 HD |
1842 | /* |
1843 | * Inform shmem_writepage() how far we have reached. | |
1844 | * No need for lock or barrier: we have the page lock. | |
1845 | */ | |
1846 | shmem_falloc.next++; | |
1847 | if (!PageUptodate(page)) | |
1848 | shmem_falloc.nr_falloced++; | |
1849 | ||
e2d12e22 | 1850 | /* |
1635f6a7 HD |
1851 | * If !PageUptodate, leave it that way so that freeable pages |
1852 | * can be recognized if we need to rollback on error later. | |
1853 | * But set_page_dirty so that memory pressure will swap rather | |
e2d12e22 HD |
1854 | * than free the pages we are allocating (and SGP_CACHE pages |
1855 | * might still be clean: we now need to mark those dirty too). | |
1856 | */ | |
1857 | set_page_dirty(page); | |
1858 | unlock_page(page); | |
1859 | page_cache_release(page); | |
1860 | cond_resched(); | |
1861 | } | |
1862 | ||
1863 | if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) | |
1864 | i_size_write(inode, offset + len); | |
e2d12e22 | 1865 | inode->i_ctime = CURRENT_TIME; |
1aac1400 HD |
1866 | undone: |
1867 | spin_lock(&inode->i_lock); | |
1868 | inode->i_private = NULL; | |
1869 | spin_unlock(&inode->i_lock); | |
e2d12e22 | 1870 | out: |
83e4fa9c HD |
1871 | mutex_unlock(&inode->i_mutex); |
1872 | return error; | |
1873 | } | |
1874 | ||
726c3342 | 1875 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1876 | { |
726c3342 | 1877 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1878 | |
1879 | buf->f_type = TMPFS_MAGIC; | |
1880 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1881 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1882 | if (sbinfo->max_blocks) { |
1da177e4 | 1883 | buf->f_blocks = sbinfo->max_blocks; |
41ffe5d5 HD |
1884 | buf->f_bavail = |
1885 | buf->f_bfree = sbinfo->max_blocks - | |
1886 | percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1887 | } |
1888 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1889 | buf->f_files = sbinfo->max_inodes; |
1890 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1891 | } |
1892 | /* else leave those fields 0 like simple_statfs */ | |
1893 | return 0; | |
1894 | } | |
1895 | ||
1896 | /* | |
1897 | * File creation. Allocate an inode, and we're done.. | |
1898 | */ | |
1899 | static int | |
1a67aafb | 1900 | shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 | 1901 | { |
0b0a0806 | 1902 | struct inode *inode; |
1da177e4 LT |
1903 | int error = -ENOSPC; |
1904 | ||
454abafe | 1905 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1906 | if (inode) { |
feda821e CH |
1907 | error = simple_acl_create(dir, inode); |
1908 | if (error) | |
1909 | goto out_iput; | |
2a7dba39 | 1910 | error = security_inode_init_security(inode, dir, |
9d8f13ba | 1911 | &dentry->d_name, |
6d9d88d0 | 1912 | shmem_initxattrs, NULL); |
feda821e CH |
1913 | if (error && error != -EOPNOTSUPP) |
1914 | goto out_iput; | |
37ec43cd | 1915 | |
718deb6b | 1916 | error = 0; |
1da177e4 LT |
1917 | dir->i_size += BOGO_DIRENT_SIZE; |
1918 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1919 | d_instantiate(dentry, inode); | |
1920 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1921 | } |
1922 | return error; | |
feda821e CH |
1923 | out_iput: |
1924 | iput(inode); | |
1925 | return error; | |
1da177e4 LT |
1926 | } |
1927 | ||
60545d0d AV |
1928 | static int |
1929 | shmem_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) | |
1930 | { | |
1931 | struct inode *inode; | |
1932 | int error = -ENOSPC; | |
1933 | ||
1934 | inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE); | |
1935 | if (inode) { | |
1936 | error = security_inode_init_security(inode, dir, | |
1937 | NULL, | |
1938 | shmem_initxattrs, NULL); | |
feda821e CH |
1939 | if (error && error != -EOPNOTSUPP) |
1940 | goto out_iput; | |
1941 | error = simple_acl_create(dir, inode); | |
1942 | if (error) | |
1943 | goto out_iput; | |
60545d0d AV |
1944 | d_tmpfile(dentry, inode); |
1945 | } | |
1946 | return error; | |
feda821e CH |
1947 | out_iput: |
1948 | iput(inode); | |
1949 | return error; | |
60545d0d AV |
1950 | } |
1951 | ||
18bb1db3 | 1952 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
1953 | { |
1954 | int error; | |
1955 | ||
1956 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1957 | return error; | |
d8c76e6f | 1958 | inc_nlink(dir); |
1da177e4 LT |
1959 | return 0; |
1960 | } | |
1961 | ||
4acdaf27 | 1962 | static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
ebfc3b49 | 1963 | bool excl) |
1da177e4 LT |
1964 | { |
1965 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1966 | } | |
1967 | ||
1968 | /* | |
1969 | * Link a file.. | |
1970 | */ | |
1971 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1972 | { | |
1973 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1974 | int ret; |
1da177e4 LT |
1975 | |
1976 | /* | |
1977 | * No ordinary (disk based) filesystem counts links as inodes; | |
1978 | * but each new link needs a new dentry, pinning lowmem, and | |
1979 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1980 | */ | |
5b04c689 PE |
1981 | ret = shmem_reserve_inode(inode->i_sb); |
1982 | if (ret) | |
1983 | goto out; | |
1da177e4 LT |
1984 | |
1985 | dir->i_size += BOGO_DIRENT_SIZE; | |
1986 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1987 | inc_nlink(inode); |
7de9c6ee | 1988 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1989 | dget(dentry); /* Extra pinning count for the created dentry */ |
1990 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1991 | out: |
1992 | return ret; | |
1da177e4 LT |
1993 | } |
1994 | ||
1995 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1996 | { | |
1997 | struct inode *inode = dentry->d_inode; | |
1998 | ||
5b04c689 PE |
1999 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
2000 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
2001 | |
2002 | dir->i_size -= BOGO_DIRENT_SIZE; | |
2003 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 2004 | drop_nlink(inode); |
1da177e4 LT |
2005 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
2006 | return 0; | |
2007 | } | |
2008 | ||
2009 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
2010 | { | |
2011 | if (!simple_empty(dentry)) | |
2012 | return -ENOTEMPTY; | |
2013 | ||
9a53c3a7 DH |
2014 | drop_nlink(dentry->d_inode); |
2015 | drop_nlink(dir); | |
1da177e4 LT |
2016 | return shmem_unlink(dir, dentry); |
2017 | } | |
2018 | ||
2019 | /* | |
2020 | * The VFS layer already does all the dentry stuff for rename, | |
2021 | * we just have to decrement the usage count for the target if | |
2022 | * it exists so that the VFS layer correctly free's it when it | |
2023 | * gets overwritten. | |
2024 | */ | |
2025 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
2026 | { | |
2027 | struct inode *inode = old_dentry->d_inode; | |
2028 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
2029 | ||
2030 | if (!simple_empty(new_dentry)) | |
2031 | return -ENOTEMPTY; | |
2032 | ||
2033 | if (new_dentry->d_inode) { | |
2034 | (void) shmem_unlink(new_dir, new_dentry); | |
2035 | if (they_are_dirs) | |
9a53c3a7 | 2036 | drop_nlink(old_dir); |
1da177e4 | 2037 | } else if (they_are_dirs) { |
9a53c3a7 | 2038 | drop_nlink(old_dir); |
d8c76e6f | 2039 | inc_nlink(new_dir); |
1da177e4 LT |
2040 | } |
2041 | ||
2042 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
2043 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
2044 | old_dir->i_ctime = old_dir->i_mtime = | |
2045 | new_dir->i_ctime = new_dir->i_mtime = | |
2046 | inode->i_ctime = CURRENT_TIME; | |
2047 | return 0; | |
2048 | } | |
2049 | ||
2050 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
2051 | { | |
2052 | int error; | |
2053 | int len; | |
2054 | struct inode *inode; | |
9276aad6 | 2055 | struct page *page; |
1da177e4 LT |
2056 | char *kaddr; |
2057 | struct shmem_inode_info *info; | |
2058 | ||
2059 | len = strlen(symname) + 1; | |
2060 | if (len > PAGE_CACHE_SIZE) | |
2061 | return -ENAMETOOLONG; | |
2062 | ||
454abafe | 2063 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
2064 | if (!inode) |
2065 | return -ENOSPC; | |
2066 | ||
9d8f13ba | 2067 | error = security_inode_init_security(inode, dir, &dentry->d_name, |
6d9d88d0 | 2068 | shmem_initxattrs, NULL); |
570bc1c2 SS |
2069 | if (error) { |
2070 | if (error != -EOPNOTSUPP) { | |
2071 | iput(inode); | |
2072 | return error; | |
2073 | } | |
2074 | error = 0; | |
2075 | } | |
2076 | ||
1da177e4 LT |
2077 | info = SHMEM_I(inode); |
2078 | inode->i_size = len-1; | |
69f07ec9 HD |
2079 | if (len <= SHORT_SYMLINK_LEN) { |
2080 | info->symlink = kmemdup(symname, len, GFP_KERNEL); | |
2081 | if (!info->symlink) { | |
2082 | iput(inode); | |
2083 | return -ENOMEM; | |
2084 | } | |
2085 | inode->i_op = &shmem_short_symlink_operations; | |
1da177e4 LT |
2086 | } else { |
2087 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
2088 | if (error) { | |
2089 | iput(inode); | |
2090 | return error; | |
2091 | } | |
14fcc23f | 2092 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 | 2093 | inode->i_op = &shmem_symlink_inode_operations; |
9b04c5fe | 2094 | kaddr = kmap_atomic(page); |
1da177e4 | 2095 | memcpy(kaddr, symname, len); |
9b04c5fe | 2096 | kunmap_atomic(kaddr); |
ec9516fb | 2097 | SetPageUptodate(page); |
1da177e4 | 2098 | set_page_dirty(page); |
6746aff7 | 2099 | unlock_page(page); |
1da177e4 LT |
2100 | page_cache_release(page); |
2101 | } | |
1da177e4 LT |
2102 | dir->i_size += BOGO_DIRENT_SIZE; |
2103 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
2104 | d_instantiate(dentry, inode); | |
2105 | dget(dentry); | |
2106 | return 0; | |
2107 | } | |
2108 | ||
69f07ec9 | 2109 | static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 2110 | { |
69f07ec9 | 2111 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->symlink); |
cc314eef | 2112 | return NULL; |
1da177e4 LT |
2113 | } |
2114 | ||
cc314eef | 2115 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
2116 | { |
2117 | struct page *page = NULL; | |
41ffe5d5 HD |
2118 | int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
2119 | nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); | |
d3602444 HD |
2120 | if (page) |
2121 | unlock_page(page); | |
cc314eef | 2122 | return page; |
1da177e4 LT |
2123 | } |
2124 | ||
cc314eef | 2125 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
2126 | { |
2127 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 2128 | struct page *page = cookie; |
1da177e4 LT |
2129 | kunmap(page); |
2130 | mark_page_accessed(page); | |
2131 | page_cache_release(page); | |
1da177e4 LT |
2132 | } |
2133 | } | |
2134 | ||
b09e0fa4 | 2135 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 2136 | /* |
b09e0fa4 EP |
2137 | * Superblocks without xattr inode operations may get some security.* xattr |
2138 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
2139 | * like ACLs, we also need to implement the security.* handlers at |
2140 | * filesystem level, though. | |
2141 | */ | |
2142 | ||
6d9d88d0 JS |
2143 | /* |
2144 | * Callback for security_inode_init_security() for acquiring xattrs. | |
2145 | */ | |
2146 | static int shmem_initxattrs(struct inode *inode, | |
2147 | const struct xattr *xattr_array, | |
2148 | void *fs_info) | |
2149 | { | |
2150 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2151 | const struct xattr *xattr; | |
38f38657 | 2152 | struct simple_xattr *new_xattr; |
6d9d88d0 JS |
2153 | size_t len; |
2154 | ||
2155 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { | |
38f38657 | 2156 | new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); |
6d9d88d0 JS |
2157 | if (!new_xattr) |
2158 | return -ENOMEM; | |
2159 | ||
2160 | len = strlen(xattr->name) + 1; | |
2161 | new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len, | |
2162 | GFP_KERNEL); | |
2163 | if (!new_xattr->name) { | |
2164 | kfree(new_xattr); | |
2165 | return -ENOMEM; | |
2166 | } | |
2167 | ||
2168 | memcpy(new_xattr->name, XATTR_SECURITY_PREFIX, | |
2169 | XATTR_SECURITY_PREFIX_LEN); | |
2170 | memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, | |
2171 | xattr->name, len); | |
2172 | ||
38f38657 | 2173 | simple_xattr_list_add(&info->xattrs, new_xattr); |
6d9d88d0 JS |
2174 | } |
2175 | ||
2176 | return 0; | |
2177 | } | |
2178 | ||
bb435453 | 2179 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 2180 | #ifdef CONFIG_TMPFS_POSIX_ACL |
feda821e CH |
2181 | &posix_acl_access_xattr_handler, |
2182 | &posix_acl_default_xattr_handler, | |
b09e0fa4 | 2183 | #endif |
39f0247d AG |
2184 | NULL |
2185 | }; | |
b09e0fa4 EP |
2186 | |
2187 | static int shmem_xattr_validate(const char *name) | |
2188 | { | |
2189 | struct { const char *prefix; size_t len; } arr[] = { | |
2190 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
2191 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
2192 | }; | |
2193 | int i; | |
2194 | ||
2195 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
2196 | size_t preflen = arr[i].len; | |
2197 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
2198 | if (!name[preflen]) | |
2199 | return -EINVAL; | |
2200 | return 0; | |
2201 | } | |
2202 | } | |
2203 | return -EOPNOTSUPP; | |
2204 | } | |
2205 | ||
2206 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
2207 | void *buffer, size_t size) | |
2208 | { | |
38f38657 | 2209 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
b09e0fa4 EP |
2210 | int err; |
2211 | ||
2212 | /* | |
2213 | * If this is a request for a synthetic attribute in the system.* | |
2214 | * namespace use the generic infrastructure to resolve a handler | |
2215 | * for it via sb->s_xattr. | |
2216 | */ | |
2217 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2218 | return generic_getxattr(dentry, name, buffer, size); | |
2219 | ||
2220 | err = shmem_xattr_validate(name); | |
2221 | if (err) | |
2222 | return err; | |
2223 | ||
38f38657 | 2224 | return simple_xattr_get(&info->xattrs, name, buffer, size); |
b09e0fa4 EP |
2225 | } |
2226 | ||
2227 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
2228 | const void *value, size_t size, int flags) | |
2229 | { | |
38f38657 | 2230 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
b09e0fa4 EP |
2231 | int err; |
2232 | ||
2233 | /* | |
2234 | * If this is a request for a synthetic attribute in the system.* | |
2235 | * namespace use the generic infrastructure to resolve a handler | |
2236 | * for it via sb->s_xattr. | |
2237 | */ | |
2238 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2239 | return generic_setxattr(dentry, name, value, size, flags); | |
2240 | ||
2241 | err = shmem_xattr_validate(name); | |
2242 | if (err) | |
2243 | return err; | |
2244 | ||
38f38657 | 2245 | return simple_xattr_set(&info->xattrs, name, value, size, flags); |
b09e0fa4 EP |
2246 | } |
2247 | ||
2248 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
2249 | { | |
38f38657 | 2250 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
b09e0fa4 EP |
2251 | int err; |
2252 | ||
2253 | /* | |
2254 | * If this is a request for a synthetic attribute in the system.* | |
2255 | * namespace use the generic infrastructure to resolve a handler | |
2256 | * for it via sb->s_xattr. | |
2257 | */ | |
2258 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2259 | return generic_removexattr(dentry, name); | |
2260 | ||
2261 | err = shmem_xattr_validate(name); | |
2262 | if (err) | |
2263 | return err; | |
2264 | ||
38f38657 | 2265 | return simple_xattr_remove(&info->xattrs, name); |
b09e0fa4 EP |
2266 | } |
2267 | ||
2268 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
2269 | { | |
38f38657 AR |
2270 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
2271 | return simple_xattr_list(&info->xattrs, buffer, size); | |
b09e0fa4 EP |
2272 | } |
2273 | #endif /* CONFIG_TMPFS_XATTR */ | |
2274 | ||
69f07ec9 | 2275 | static const struct inode_operations shmem_short_symlink_operations = { |
b09e0fa4 | 2276 | .readlink = generic_readlink, |
69f07ec9 | 2277 | .follow_link = shmem_follow_short_symlink, |
b09e0fa4 EP |
2278 | #ifdef CONFIG_TMPFS_XATTR |
2279 | .setxattr = shmem_setxattr, | |
2280 | .getxattr = shmem_getxattr, | |
2281 | .listxattr = shmem_listxattr, | |
2282 | .removexattr = shmem_removexattr, | |
2283 | #endif | |
2284 | }; | |
2285 | ||
2286 | static const struct inode_operations shmem_symlink_inode_operations = { | |
2287 | .readlink = generic_readlink, | |
2288 | .follow_link = shmem_follow_link, | |
2289 | .put_link = shmem_put_link, | |
2290 | #ifdef CONFIG_TMPFS_XATTR | |
2291 | .setxattr = shmem_setxattr, | |
2292 | .getxattr = shmem_getxattr, | |
2293 | .listxattr = shmem_listxattr, | |
2294 | .removexattr = shmem_removexattr, | |
39f0247d | 2295 | #endif |
b09e0fa4 | 2296 | }; |
39f0247d | 2297 | |
91828a40 DG |
2298 | static struct dentry *shmem_get_parent(struct dentry *child) |
2299 | { | |
2300 | return ERR_PTR(-ESTALE); | |
2301 | } | |
2302 | ||
2303 | static int shmem_match(struct inode *ino, void *vfh) | |
2304 | { | |
2305 | __u32 *fh = vfh; | |
2306 | __u64 inum = fh[2]; | |
2307 | inum = (inum << 32) | fh[1]; | |
2308 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2309 | } | |
2310 | ||
480b116c CH |
2311 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2312 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2313 | { |
91828a40 | 2314 | struct inode *inode; |
480b116c | 2315 | struct dentry *dentry = NULL; |
35c2a7f4 | 2316 | u64 inum; |
480b116c CH |
2317 | |
2318 | if (fh_len < 3) | |
2319 | return NULL; | |
91828a40 | 2320 | |
35c2a7f4 HD |
2321 | inum = fid->raw[2]; |
2322 | inum = (inum << 32) | fid->raw[1]; | |
2323 | ||
480b116c CH |
2324 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2325 | shmem_match, fid->raw); | |
91828a40 | 2326 | if (inode) { |
480b116c | 2327 | dentry = d_find_alias(inode); |
91828a40 DG |
2328 | iput(inode); |
2329 | } | |
2330 | ||
480b116c | 2331 | return dentry; |
91828a40 DG |
2332 | } |
2333 | ||
b0b0382b AV |
2334 | static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len, |
2335 | struct inode *parent) | |
91828a40 | 2336 | { |
5fe0c237 AK |
2337 | if (*len < 3) { |
2338 | *len = 3; | |
94e07a75 | 2339 | return FILEID_INVALID; |
5fe0c237 | 2340 | } |
91828a40 | 2341 | |
1d3382cb | 2342 | if (inode_unhashed(inode)) { |
91828a40 DG |
2343 | /* Unfortunately insert_inode_hash is not idempotent, |
2344 | * so as we hash inodes here rather than at creation | |
2345 | * time, we need a lock to ensure we only try | |
2346 | * to do it once | |
2347 | */ | |
2348 | static DEFINE_SPINLOCK(lock); | |
2349 | spin_lock(&lock); | |
1d3382cb | 2350 | if (inode_unhashed(inode)) |
91828a40 DG |
2351 | __insert_inode_hash(inode, |
2352 | inode->i_ino + inode->i_generation); | |
2353 | spin_unlock(&lock); | |
2354 | } | |
2355 | ||
2356 | fh[0] = inode->i_generation; | |
2357 | fh[1] = inode->i_ino; | |
2358 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2359 | ||
2360 | *len = 3; | |
2361 | return 1; | |
2362 | } | |
2363 | ||
39655164 | 2364 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2365 | .get_parent = shmem_get_parent, |
91828a40 | 2366 | .encode_fh = shmem_encode_fh, |
480b116c | 2367 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2368 | }; |
2369 | ||
680d794b | 2370 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2371 | bool remount) | |
1da177e4 LT |
2372 | { |
2373 | char *this_char, *value, *rest; | |
49cd0a5c | 2374 | struct mempolicy *mpol = NULL; |
8751e039 EB |
2375 | uid_t uid; |
2376 | gid_t gid; | |
1da177e4 | 2377 | |
b00dc3ad HD |
2378 | while (options != NULL) { |
2379 | this_char = options; | |
2380 | for (;;) { | |
2381 | /* | |
2382 | * NUL-terminate this option: unfortunately, | |
2383 | * mount options form a comma-separated list, | |
2384 | * but mpol's nodelist may also contain commas. | |
2385 | */ | |
2386 | options = strchr(options, ','); | |
2387 | if (options == NULL) | |
2388 | break; | |
2389 | options++; | |
2390 | if (!isdigit(*options)) { | |
2391 | options[-1] = '\0'; | |
2392 | break; | |
2393 | } | |
2394 | } | |
1da177e4 LT |
2395 | if (!*this_char) |
2396 | continue; | |
2397 | if ((value = strchr(this_char,'=')) != NULL) { | |
2398 | *value++ = 0; | |
2399 | } else { | |
2400 | printk(KERN_ERR | |
2401 | "tmpfs: No value for mount option '%s'\n", | |
2402 | this_char); | |
49cd0a5c | 2403 | goto error; |
1da177e4 LT |
2404 | } |
2405 | ||
2406 | if (!strcmp(this_char,"size")) { | |
2407 | unsigned long long size; | |
2408 | size = memparse(value,&rest); | |
2409 | if (*rest == '%') { | |
2410 | size <<= PAGE_SHIFT; | |
2411 | size *= totalram_pages; | |
2412 | do_div(size, 100); | |
2413 | rest++; | |
2414 | } | |
2415 | if (*rest) | |
2416 | goto bad_val; | |
680d794b | 2417 | sbinfo->max_blocks = |
2418 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2419 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2420 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2421 | if (*rest) |
2422 | goto bad_val; | |
2423 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2424 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2425 | if (*rest) |
2426 | goto bad_val; | |
2427 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2428 | if (remount) |
1da177e4 | 2429 | continue; |
680d794b | 2430 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2431 | if (*rest) |
2432 | goto bad_val; | |
2433 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2434 | if (remount) |
1da177e4 | 2435 | continue; |
8751e039 | 2436 | uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2437 | if (*rest) |
2438 | goto bad_val; | |
8751e039 EB |
2439 | sbinfo->uid = make_kuid(current_user_ns(), uid); |
2440 | if (!uid_valid(sbinfo->uid)) | |
2441 | goto bad_val; | |
1da177e4 | 2442 | } else if (!strcmp(this_char,"gid")) { |
680d794b | 2443 | if (remount) |
1da177e4 | 2444 | continue; |
8751e039 | 2445 | gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2446 | if (*rest) |
2447 | goto bad_val; | |
8751e039 EB |
2448 | sbinfo->gid = make_kgid(current_user_ns(), gid); |
2449 | if (!gid_valid(sbinfo->gid)) | |
2450 | goto bad_val; | |
7339ff83 | 2451 | } else if (!strcmp(this_char,"mpol")) { |
49cd0a5c GT |
2452 | mpol_put(mpol); |
2453 | mpol = NULL; | |
2454 | if (mpol_parse_str(value, &mpol)) | |
7339ff83 | 2455 | goto bad_val; |
1da177e4 LT |
2456 | } else { |
2457 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2458 | this_char); | |
49cd0a5c | 2459 | goto error; |
1da177e4 LT |
2460 | } |
2461 | } | |
49cd0a5c | 2462 | sbinfo->mpol = mpol; |
1da177e4 LT |
2463 | return 0; |
2464 | ||
2465 | bad_val: | |
2466 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2467 | value, this_char); | |
49cd0a5c GT |
2468 | error: |
2469 | mpol_put(mpol); | |
1da177e4 LT |
2470 | return 1; |
2471 | ||
2472 | } | |
2473 | ||
2474 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2475 | { | |
2476 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2477 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2478 | unsigned long inodes; |
2479 | int error = -EINVAL; | |
2480 | ||
5f00110f | 2481 | config.mpol = NULL; |
680d794b | 2482 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2483 | return error; |
1da177e4 | 2484 | |
0edd73b3 | 2485 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2486 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2487 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2488 | goto out; |
680d794b | 2489 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2490 | goto out; |
2491 | /* | |
54af6042 | 2492 | * Those tests disallow limited->unlimited while any are in use; |
0edd73b3 HD |
2493 | * but we must separately disallow unlimited->limited, because |
2494 | * in that case we have no record of how much is already in use. | |
2495 | */ | |
680d794b | 2496 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2497 | goto out; |
680d794b | 2498 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2499 | goto out; |
2500 | ||
2501 | error = 0; | |
680d794b | 2502 | sbinfo->max_blocks = config.max_blocks; |
680d794b | 2503 | sbinfo->max_inodes = config.max_inodes; |
2504 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b | 2505 | |
5f00110f GT |
2506 | /* |
2507 | * Preserve previous mempolicy unless mpol remount option was specified. | |
2508 | */ | |
2509 | if (config.mpol) { | |
2510 | mpol_put(sbinfo->mpol); | |
2511 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
2512 | } | |
0edd73b3 HD |
2513 | out: |
2514 | spin_unlock(&sbinfo->stat_lock); | |
2515 | return error; | |
1da177e4 | 2516 | } |
680d794b | 2517 | |
34c80b1d | 2518 | static int shmem_show_options(struct seq_file *seq, struct dentry *root) |
680d794b | 2519 | { |
34c80b1d | 2520 | struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); |
680d794b | 2521 | |
2522 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2523 | seq_printf(seq, ",size=%luk", | |
2524 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2525 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2526 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2527 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
09208d15 | 2528 | seq_printf(seq, ",mode=%03ho", sbinfo->mode); |
8751e039 EB |
2529 | if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) |
2530 | seq_printf(seq, ",uid=%u", | |
2531 | from_kuid_munged(&init_user_ns, sbinfo->uid)); | |
2532 | if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) | |
2533 | seq_printf(seq, ",gid=%u", | |
2534 | from_kgid_munged(&init_user_ns, sbinfo->gid)); | |
71fe804b | 2535 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b | 2536 | return 0; |
2537 | } | |
2538 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2539 | |
2540 | static void shmem_put_super(struct super_block *sb) | |
2541 | { | |
602586a8 HD |
2542 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2543 | ||
2544 | percpu_counter_destroy(&sbinfo->used_blocks); | |
49cd0a5c | 2545 | mpol_put(sbinfo->mpol); |
602586a8 | 2546 | kfree(sbinfo); |
1da177e4 LT |
2547 | sb->s_fs_info = NULL; |
2548 | } | |
2549 | ||
2b2af54a | 2550 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2551 | { |
2552 | struct inode *inode; | |
0edd73b3 | 2553 | struct shmem_sb_info *sbinfo; |
680d794b | 2554 | int err = -ENOMEM; |
2555 | ||
2556 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2557 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b | 2558 | L1_CACHE_BYTES), GFP_KERNEL); |
2559 | if (!sbinfo) | |
2560 | return -ENOMEM; | |
2561 | ||
680d794b | 2562 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2563 | sbinfo->uid = current_fsuid(); |
2564 | sbinfo->gid = current_fsgid(); | |
680d794b | 2565 | sb->s_fs_info = sbinfo; |
1da177e4 | 2566 | |
0edd73b3 | 2567 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2568 | /* |
2569 | * Per default we only allow half of the physical ram per | |
2570 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2571 | * but the internal instance is left unlimited. | |
2572 | */ | |
ca4e0519 | 2573 | if (!(sb->s_flags & MS_KERNMOUNT)) { |
680d794b | 2574 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2575 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2576 | if (shmem_parse_options(data, sbinfo, false)) { | |
2577 | err = -EINVAL; | |
2578 | goto failed; | |
2579 | } | |
ca4e0519 AV |
2580 | } else { |
2581 | sb->s_flags |= MS_NOUSER; | |
1da177e4 | 2582 | } |
91828a40 | 2583 | sb->s_export_op = &shmem_export_ops; |
2f6e38f3 | 2584 | sb->s_flags |= MS_NOSEC; |
1da177e4 LT |
2585 | #else |
2586 | sb->s_flags |= MS_NOUSER; | |
2587 | #endif | |
2588 | ||
0edd73b3 | 2589 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2590 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2591 | goto failed; | |
680d794b | 2592 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2593 | |
285b2c4f | 2594 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 LT |
2595 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2596 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2597 | sb->s_magic = TMPFS_MAGIC; | |
2598 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2599 | sb->s_time_gran = 1; |
b09e0fa4 | 2600 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2601 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2602 | #endif |
2603 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2604 | sb->s_flags |= MS_POSIXACL; |
2605 | #endif | |
0edd73b3 | 2606 | |
454abafe | 2607 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2608 | if (!inode) |
2609 | goto failed; | |
680d794b | 2610 | inode->i_uid = sbinfo->uid; |
2611 | inode->i_gid = sbinfo->gid; | |
318ceed0 AV |
2612 | sb->s_root = d_make_root(inode); |
2613 | if (!sb->s_root) | |
48fde701 | 2614 | goto failed; |
1da177e4 LT |
2615 | return 0; |
2616 | ||
1da177e4 LT |
2617 | failed: |
2618 | shmem_put_super(sb); | |
2619 | return err; | |
2620 | } | |
2621 | ||
fcc234f8 | 2622 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2623 | |
2624 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2625 | { | |
41ffe5d5 HD |
2626 | struct shmem_inode_info *info; |
2627 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
2628 | if (!info) | |
1da177e4 | 2629 | return NULL; |
41ffe5d5 | 2630 | return &info->vfs_inode; |
1da177e4 LT |
2631 | } |
2632 | ||
41ffe5d5 | 2633 | static void shmem_destroy_callback(struct rcu_head *head) |
fa0d7e3d NP |
2634 | { |
2635 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
fa0d7e3d NP |
2636 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2637 | } | |
2638 | ||
1da177e4 LT |
2639 | static void shmem_destroy_inode(struct inode *inode) |
2640 | { | |
09208d15 | 2641 | if (S_ISREG(inode->i_mode)) |
1da177e4 | 2642 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
41ffe5d5 | 2643 | call_rcu(&inode->i_rcu, shmem_destroy_callback); |
1da177e4 LT |
2644 | } |
2645 | ||
41ffe5d5 | 2646 | static void shmem_init_inode(void *foo) |
1da177e4 | 2647 | { |
41ffe5d5 HD |
2648 | struct shmem_inode_info *info = foo; |
2649 | inode_init_once(&info->vfs_inode); | |
1da177e4 LT |
2650 | } |
2651 | ||
41ffe5d5 | 2652 | static int shmem_init_inodecache(void) |
1da177e4 LT |
2653 | { |
2654 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2655 | sizeof(struct shmem_inode_info), | |
41ffe5d5 | 2656 | 0, SLAB_PANIC, shmem_init_inode); |
1da177e4 LT |
2657 | return 0; |
2658 | } | |
2659 | ||
41ffe5d5 | 2660 | static void shmem_destroy_inodecache(void) |
1da177e4 | 2661 | { |
1a1d92c1 | 2662 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2663 | } |
2664 | ||
f5e54d6e | 2665 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2666 | .writepage = shmem_writepage, |
76719325 | 2667 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2668 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
2669 | .write_begin = shmem_write_begin, |
2670 | .write_end = shmem_write_end, | |
1da177e4 | 2671 | #endif |
304dbdb7 | 2672 | .migratepage = migrate_page, |
aa261f54 | 2673 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2674 | }; |
2675 | ||
15ad7cdc | 2676 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2677 | .mmap = shmem_mmap, |
2678 | #ifdef CONFIG_TMPFS | |
220f2ac9 | 2679 | .llseek = shmem_file_llseek, |
2ba5bbed | 2680 | .read = new_sync_read, |
8174202b | 2681 | .write = new_sync_write, |
2ba5bbed | 2682 | .read_iter = shmem_file_read_iter, |
8174202b | 2683 | .write_iter = generic_file_write_iter, |
1b061d92 | 2684 | .fsync = noop_fsync, |
708e3508 | 2685 | .splice_read = shmem_file_splice_read, |
f6cb85d0 | 2686 | .splice_write = iter_file_splice_write, |
83e4fa9c | 2687 | .fallocate = shmem_fallocate, |
1da177e4 LT |
2688 | #endif |
2689 | }; | |
2690 | ||
92e1d5be | 2691 | static const struct inode_operations shmem_inode_operations = { |
94c1e62d | 2692 | .setattr = shmem_setattr, |
b09e0fa4 EP |
2693 | #ifdef CONFIG_TMPFS_XATTR |
2694 | .setxattr = shmem_setxattr, | |
2695 | .getxattr = shmem_getxattr, | |
2696 | .listxattr = shmem_listxattr, | |
2697 | .removexattr = shmem_removexattr, | |
feda821e | 2698 | .set_acl = simple_set_acl, |
b09e0fa4 | 2699 | #endif |
1da177e4 LT |
2700 | }; |
2701 | ||
92e1d5be | 2702 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2703 | #ifdef CONFIG_TMPFS |
2704 | .create = shmem_create, | |
2705 | .lookup = simple_lookup, | |
2706 | .link = shmem_link, | |
2707 | .unlink = shmem_unlink, | |
2708 | .symlink = shmem_symlink, | |
2709 | .mkdir = shmem_mkdir, | |
2710 | .rmdir = shmem_rmdir, | |
2711 | .mknod = shmem_mknod, | |
2712 | .rename = shmem_rename, | |
60545d0d | 2713 | .tmpfile = shmem_tmpfile, |
1da177e4 | 2714 | #endif |
b09e0fa4 EP |
2715 | #ifdef CONFIG_TMPFS_XATTR |
2716 | .setxattr = shmem_setxattr, | |
2717 | .getxattr = shmem_getxattr, | |
2718 | .listxattr = shmem_listxattr, | |
2719 | .removexattr = shmem_removexattr, | |
2720 | #endif | |
39f0247d | 2721 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2722 | .setattr = shmem_setattr, |
feda821e | 2723 | .set_acl = simple_set_acl, |
39f0247d AG |
2724 | #endif |
2725 | }; | |
2726 | ||
92e1d5be | 2727 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2728 | #ifdef CONFIG_TMPFS_XATTR |
2729 | .setxattr = shmem_setxattr, | |
2730 | .getxattr = shmem_getxattr, | |
2731 | .listxattr = shmem_listxattr, | |
2732 | .removexattr = shmem_removexattr, | |
2733 | #endif | |
39f0247d | 2734 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2735 | .setattr = shmem_setattr, |
feda821e | 2736 | .set_acl = simple_set_acl, |
39f0247d | 2737 | #endif |
1da177e4 LT |
2738 | }; |
2739 | ||
759b9775 | 2740 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2741 | .alloc_inode = shmem_alloc_inode, |
2742 | .destroy_inode = shmem_destroy_inode, | |
2743 | #ifdef CONFIG_TMPFS | |
2744 | .statfs = shmem_statfs, | |
2745 | .remount_fs = shmem_remount_fs, | |
680d794b | 2746 | .show_options = shmem_show_options, |
1da177e4 | 2747 | #endif |
1f895f75 | 2748 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2749 | .drop_inode = generic_delete_inode, |
2750 | .put_super = shmem_put_super, | |
2751 | }; | |
2752 | ||
f0f37e2f | 2753 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2754 | .fault = shmem_fault, |
d7c17551 | 2755 | .map_pages = filemap_map_pages, |
1da177e4 LT |
2756 | #ifdef CONFIG_NUMA |
2757 | .set_policy = shmem_set_policy, | |
2758 | .get_policy = shmem_get_policy, | |
2759 | #endif | |
0b173bc4 | 2760 | .remap_pages = generic_file_remap_pages, |
1da177e4 LT |
2761 | }; |
2762 | ||
3c26ff6e AV |
2763 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2764 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2765 | { |
3c26ff6e | 2766 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2767 | } |
2768 | ||
41ffe5d5 | 2769 | static struct file_system_type shmem_fs_type = { |
1da177e4 LT |
2770 | .owner = THIS_MODULE, |
2771 | .name = "tmpfs", | |
3c26ff6e | 2772 | .mount = shmem_mount, |
1da177e4 | 2773 | .kill_sb = kill_litter_super, |
2b8576cb | 2774 | .fs_flags = FS_USERNS_MOUNT, |
1da177e4 | 2775 | }; |
1da177e4 | 2776 | |
41ffe5d5 | 2777 | int __init shmem_init(void) |
1da177e4 LT |
2778 | { |
2779 | int error; | |
2780 | ||
16203a7a RL |
2781 | /* If rootfs called this, don't re-init */ |
2782 | if (shmem_inode_cachep) | |
2783 | return 0; | |
2784 | ||
e0bf68dd PZ |
2785 | error = bdi_init(&shmem_backing_dev_info); |
2786 | if (error) | |
2787 | goto out4; | |
2788 | ||
41ffe5d5 | 2789 | error = shmem_init_inodecache(); |
1da177e4 LT |
2790 | if (error) |
2791 | goto out3; | |
2792 | ||
41ffe5d5 | 2793 | error = register_filesystem(&shmem_fs_type); |
1da177e4 LT |
2794 | if (error) { |
2795 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2796 | goto out2; | |
2797 | } | |
95dc112a | 2798 | |
ca4e0519 | 2799 | shm_mnt = kern_mount(&shmem_fs_type); |
1da177e4 LT |
2800 | if (IS_ERR(shm_mnt)) { |
2801 | error = PTR_ERR(shm_mnt); | |
2802 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2803 | goto out1; | |
2804 | } | |
2805 | return 0; | |
2806 | ||
2807 | out1: | |
41ffe5d5 | 2808 | unregister_filesystem(&shmem_fs_type); |
1da177e4 | 2809 | out2: |
41ffe5d5 | 2810 | shmem_destroy_inodecache(); |
1da177e4 | 2811 | out3: |
e0bf68dd PZ |
2812 | bdi_destroy(&shmem_backing_dev_info); |
2813 | out4: | |
1da177e4 LT |
2814 | shm_mnt = ERR_PTR(error); |
2815 | return error; | |
2816 | } | |
853ac43a MM |
2817 | |
2818 | #else /* !CONFIG_SHMEM */ | |
2819 | ||
2820 | /* | |
2821 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2822 | * | |
2823 | * This is intended for small system where the benefits of the full | |
2824 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2825 | * their complexity. On systems without swap this code should be | |
2826 | * effectively equivalent, but much lighter weight. | |
2827 | */ | |
2828 | ||
41ffe5d5 | 2829 | static struct file_system_type shmem_fs_type = { |
853ac43a | 2830 | .name = "tmpfs", |
3c26ff6e | 2831 | .mount = ramfs_mount, |
853ac43a | 2832 | .kill_sb = kill_litter_super, |
2b8576cb | 2833 | .fs_flags = FS_USERNS_MOUNT, |
853ac43a MM |
2834 | }; |
2835 | ||
41ffe5d5 | 2836 | int __init shmem_init(void) |
853ac43a | 2837 | { |
41ffe5d5 | 2838 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
853ac43a | 2839 | |
41ffe5d5 | 2840 | shm_mnt = kern_mount(&shmem_fs_type); |
853ac43a MM |
2841 | BUG_ON(IS_ERR(shm_mnt)); |
2842 | ||
2843 | return 0; | |
2844 | } | |
2845 | ||
41ffe5d5 | 2846 | int shmem_unuse(swp_entry_t swap, struct page *page) |
853ac43a MM |
2847 | { |
2848 | return 0; | |
2849 | } | |
2850 | ||
3f96b79a HD |
2851 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2852 | { | |
2853 | return 0; | |
2854 | } | |
2855 | ||
24513264 HD |
2856 | void shmem_unlock_mapping(struct address_space *mapping) |
2857 | { | |
2858 | } | |
2859 | ||
41ffe5d5 | 2860 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
94c1e62d | 2861 | { |
41ffe5d5 | 2862 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
94c1e62d HD |
2863 | } |
2864 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
2865 | ||
0b0a0806 HD |
2866 | #define shmem_vm_ops generic_file_vm_ops |
2867 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2868 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2869 | #define shmem_acct_size(flags, size) 0 |
2870 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
2871 | |
2872 | #endif /* CONFIG_SHMEM */ | |
2873 | ||
2874 | /* common code */ | |
1da177e4 | 2875 | |
3451538a | 2876 | static struct dentry_operations anon_ops = { |
118b2302 | 2877 | .d_dname = simple_dname |
3451538a AV |
2878 | }; |
2879 | ||
c7277090 EP |
2880 | static struct file *__shmem_file_setup(const char *name, loff_t size, |
2881 | unsigned long flags, unsigned int i_flags) | |
1da177e4 | 2882 | { |
6b4d0b27 | 2883 | struct file *res; |
1da177e4 | 2884 | struct inode *inode; |
2c48b9c4 | 2885 | struct path path; |
3451538a | 2886 | struct super_block *sb; |
1da177e4 LT |
2887 | struct qstr this; |
2888 | ||
2889 | if (IS_ERR(shm_mnt)) | |
6b4d0b27 | 2890 | return ERR_CAST(shm_mnt); |
1da177e4 | 2891 | |
285b2c4f | 2892 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
2893 | return ERR_PTR(-EINVAL); |
2894 | ||
2895 | if (shmem_acct_size(flags, size)) | |
2896 | return ERR_PTR(-ENOMEM); | |
2897 | ||
6b4d0b27 | 2898 | res = ERR_PTR(-ENOMEM); |
1da177e4 LT |
2899 | this.name = name; |
2900 | this.len = strlen(name); | |
2901 | this.hash = 0; /* will go */ | |
3451538a AV |
2902 | sb = shm_mnt->mnt_sb; |
2903 | path.dentry = d_alloc_pseudo(sb, &this); | |
2c48b9c4 | 2904 | if (!path.dentry) |
1da177e4 | 2905 | goto put_memory; |
3451538a | 2906 | d_set_d_op(path.dentry, &anon_ops); |
2c48b9c4 | 2907 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2908 | |
6b4d0b27 | 2909 | res = ERR_PTR(-ENOSPC); |
3451538a | 2910 | inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2911 | if (!inode) |
4b42af81 | 2912 | goto put_dentry; |
1da177e4 | 2913 | |
c7277090 | 2914 | inode->i_flags |= i_flags; |
2c48b9c4 | 2915 | d_instantiate(path.dentry, inode); |
1da177e4 | 2916 | inode->i_size = size; |
6d6b77f1 | 2917 | clear_nlink(inode); /* It is unlinked */ |
26567cdb AV |
2918 | res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size)); |
2919 | if (IS_ERR(res)) | |
4b42af81 | 2920 | goto put_dentry; |
4b42af81 | 2921 | |
6b4d0b27 | 2922 | res = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 | 2923 | &shmem_file_operations); |
6b4d0b27 | 2924 | if (IS_ERR(res)) |
4b42af81 AV |
2925 | goto put_dentry; |
2926 | ||
6b4d0b27 | 2927 | return res; |
1da177e4 | 2928 | |
1da177e4 | 2929 | put_dentry: |
2c48b9c4 | 2930 | path_put(&path); |
1da177e4 LT |
2931 | put_memory: |
2932 | shmem_unacct_size(flags, size); | |
6b4d0b27 | 2933 | return res; |
1da177e4 | 2934 | } |
c7277090 EP |
2935 | |
2936 | /** | |
2937 | * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be | |
2938 | * kernel internal. There will be NO LSM permission checks against the | |
2939 | * underlying inode. So users of this interface must do LSM checks at a | |
2940 | * higher layer. The one user is the big_key implementation. LSM checks | |
2941 | * are provided at the key level rather than the inode level. | |
2942 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2943 | * @size: size to be set for the file | |
2944 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
2945 | */ | |
2946 | struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags) | |
2947 | { | |
2948 | return __shmem_file_setup(name, size, flags, S_PRIVATE); | |
2949 | } | |
2950 | ||
2951 | /** | |
2952 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2953 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2954 | * @size: size to be set for the file | |
2955 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
2956 | */ | |
2957 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) | |
2958 | { | |
2959 | return __shmem_file_setup(name, size, flags, 0); | |
2960 | } | |
395e0ddc | 2961 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2962 | |
46711810 | 2963 | /** |
1da177e4 | 2964 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2965 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2966 | */ | |
2967 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2968 | { | |
2969 | struct file *file; | |
2970 | loff_t size = vma->vm_end - vma->vm_start; | |
2971 | ||
2972 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2973 | if (IS_ERR(file)) | |
2974 | return PTR_ERR(file); | |
2975 | ||
2976 | if (vma->vm_file) | |
2977 | fput(vma->vm_file); | |
2978 | vma->vm_file = file; | |
2979 | vma->vm_ops = &shmem_vm_ops; | |
2980 | return 0; | |
2981 | } | |
d9d90e5e HD |
2982 | |
2983 | /** | |
2984 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
2985 | * @mapping: the page's address_space | |
2986 | * @index: the page index | |
2987 | * @gfp: the page allocator flags to use if allocating | |
2988 | * | |
2989 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
2990 | * with any new page allocations done using the specified allocation flags. | |
2991 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
2992 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
2993 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
2994 | * | |
68da9f05 HD |
2995 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
2996 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
2997 | */ |
2998 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
2999 | pgoff_t index, gfp_t gfp) | |
3000 | { | |
68da9f05 HD |
3001 | #ifdef CONFIG_SHMEM |
3002 | struct inode *inode = mapping->host; | |
9276aad6 | 3003 | struct page *page; |
68da9f05 HD |
3004 | int error; |
3005 | ||
3006 | BUG_ON(mapping->a_ops != &shmem_aops); | |
3007 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); | |
3008 | if (error) | |
3009 | page = ERR_PTR(error); | |
3010 | else | |
3011 | unlock_page(page); | |
3012 | return page; | |
3013 | #else | |
3014 | /* | |
3015 | * The tiny !SHMEM case uses ramfs without swap | |
3016 | */ | |
d9d90e5e | 3017 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 3018 | #endif |
d9d90e5e HD |
3019 | } |
3020 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |