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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
6922c0c7 HD |
9 | * Copyright (C) 2002-2011 Hugh Dickins. |
10 | * Copyright (C) 2011 Google Inc. | |
0edd73b3 | 11 | * Copyright (C) 2002-2005 VERITAS Software Corporation. |
1da177e4 LT |
12 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
13 | * | |
14 | * Extended attribute support for tmpfs: | |
15 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
16 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
17 | * | |
853ac43a MM |
18 | * tiny-shmem: |
19 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
20 | * | |
1da177e4 LT |
21 | * This file is released under the GPL. |
22 | */ | |
23 | ||
853ac43a MM |
24 | #include <linux/fs.h> |
25 | #include <linux/init.h> | |
26 | #include <linux/vfs.h> | |
27 | #include <linux/mount.h> | |
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 { | |
8e205f77 | 88 | wait_queue_head_t *waitq; /* faults into hole wait for punch to end */ |
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 AM |
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 | ||
77142517 KK |
152 | static inline int shmem_reacct_size(unsigned long flags, |
153 | loff_t oldsize, loff_t newsize) | |
154 | { | |
155 | if (!(flags & VM_NORESERVE)) { | |
156 | if (VM_ACCT(newsize) > VM_ACCT(oldsize)) | |
157 | return security_vm_enough_memory_mm(current->mm, | |
158 | VM_ACCT(newsize) - VM_ACCT(oldsize)); | |
159 | else if (VM_ACCT(newsize) < VM_ACCT(oldsize)) | |
160 | vm_unacct_memory(VM_ACCT(oldsize) - VM_ACCT(newsize)); | |
161 | } | |
162 | return 0; | |
163 | } | |
164 | ||
1da177e4 LT |
165 | /* |
166 | * ... whereas tmpfs objects are accounted incrementally as | |
167 | * pages are allocated, in order to allow huge sparse files. | |
168 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
169 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
170 | */ | |
171 | static inline int shmem_acct_block(unsigned long flags) | |
172 | { | |
0b0a0806 | 173 | return (flags & VM_NORESERVE) ? |
191c5424 | 174 | security_vm_enough_memory_mm(current->mm, VM_ACCT(PAGE_CACHE_SIZE)) : 0; |
1da177e4 LT |
175 | } |
176 | ||
177 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
178 | { | |
0b0a0806 | 179 | if (flags & VM_NORESERVE) |
1da177e4 LT |
180 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
181 | } | |
182 | ||
759b9775 | 183 | static const struct super_operations shmem_ops; |
f5e54d6e | 184 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 185 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
186 | static const struct inode_operations shmem_inode_operations; |
187 | static const struct inode_operations shmem_dir_inode_operations; | |
188 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 189 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 190 | |
6c231b7b | 191 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 192 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 193 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
194 | }; |
195 | ||
196 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 197 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 | 198 | |
5b04c689 PE |
199 | static int shmem_reserve_inode(struct super_block *sb) |
200 | { | |
201 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
202 | if (sbinfo->max_inodes) { | |
203 | spin_lock(&sbinfo->stat_lock); | |
204 | if (!sbinfo->free_inodes) { | |
205 | spin_unlock(&sbinfo->stat_lock); | |
206 | return -ENOSPC; | |
207 | } | |
208 | sbinfo->free_inodes--; | |
209 | spin_unlock(&sbinfo->stat_lock); | |
210 | } | |
211 | return 0; | |
212 | } | |
213 | ||
214 | static void shmem_free_inode(struct super_block *sb) | |
215 | { | |
216 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
217 | if (sbinfo->max_inodes) { | |
218 | spin_lock(&sbinfo->stat_lock); | |
219 | sbinfo->free_inodes++; | |
220 | spin_unlock(&sbinfo->stat_lock); | |
221 | } | |
222 | } | |
223 | ||
46711810 | 224 | /** |
41ffe5d5 | 225 | * shmem_recalc_inode - recalculate the block usage of an inode |
1da177e4 LT |
226 | * @inode: inode to recalc |
227 | * | |
228 | * We have to calculate the free blocks since the mm can drop | |
229 | * undirtied hole pages behind our back. | |
230 | * | |
231 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
232 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
233 | * | |
234 | * It has to be called with the spinlock held. | |
235 | */ | |
236 | static void shmem_recalc_inode(struct inode *inode) | |
237 | { | |
238 | struct shmem_inode_info *info = SHMEM_I(inode); | |
239 | long freed; | |
240 | ||
241 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
242 | if (freed > 0) { | |
54af6042 HD |
243 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
244 | if (sbinfo->max_blocks) | |
245 | percpu_counter_add(&sbinfo->used_blocks, -freed); | |
1da177e4 | 246 | info->alloced -= freed; |
54af6042 | 247 | inode->i_blocks -= freed * BLOCKS_PER_PAGE; |
1da177e4 | 248 | shmem_unacct_blocks(info->flags, freed); |
1da177e4 LT |
249 | } |
250 | } | |
251 | ||
7a5d0fbb HD |
252 | /* |
253 | * Replace item expected in radix tree by a new item, while holding tree lock. | |
254 | */ | |
255 | static int shmem_radix_tree_replace(struct address_space *mapping, | |
256 | pgoff_t index, void *expected, void *replacement) | |
257 | { | |
258 | void **pslot; | |
6dbaf22c | 259 | void *item; |
7a5d0fbb HD |
260 | |
261 | VM_BUG_ON(!expected); | |
6dbaf22c | 262 | VM_BUG_ON(!replacement); |
7a5d0fbb | 263 | pslot = radix_tree_lookup_slot(&mapping->page_tree, index); |
6dbaf22c JW |
264 | if (!pslot) |
265 | return -ENOENT; | |
266 | item = radix_tree_deref_slot_protected(pslot, &mapping->tree_lock); | |
7a5d0fbb HD |
267 | if (item != expected) |
268 | return -ENOENT; | |
6dbaf22c | 269 | radix_tree_replace_slot(pslot, replacement); |
7a5d0fbb HD |
270 | return 0; |
271 | } | |
272 | ||
d1899228 HD |
273 | /* |
274 | * Sometimes, before we decide whether to proceed or to fail, we must check | |
275 | * that an entry was not already brought back from swap by a racing thread. | |
276 | * | |
277 | * Checking page is not enough: by the time a SwapCache page is locked, it | |
278 | * might be reused, and again be SwapCache, using the same swap as before. | |
279 | */ | |
280 | static bool shmem_confirm_swap(struct address_space *mapping, | |
281 | pgoff_t index, swp_entry_t swap) | |
282 | { | |
283 | void *item; | |
284 | ||
285 | rcu_read_lock(); | |
286 | item = radix_tree_lookup(&mapping->page_tree, index); | |
287 | rcu_read_unlock(); | |
288 | return item == swp_to_radix_entry(swap); | |
289 | } | |
290 | ||
46f65ec1 HD |
291 | /* |
292 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
293 | */ | |
294 | static int shmem_add_to_page_cache(struct page *page, | |
295 | struct address_space *mapping, | |
fed400a1 | 296 | pgoff_t index, void *expected) |
46f65ec1 | 297 | { |
b065b432 | 298 | int error; |
46f65ec1 | 299 | |
309381fe SL |
300 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
301 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); | |
46f65ec1 | 302 | |
b065b432 HD |
303 | page_cache_get(page); |
304 | page->mapping = mapping; | |
305 | page->index = index; | |
306 | ||
307 | spin_lock_irq(&mapping->tree_lock); | |
46f65ec1 | 308 | if (!expected) |
b065b432 HD |
309 | error = radix_tree_insert(&mapping->page_tree, index, page); |
310 | else | |
311 | error = shmem_radix_tree_replace(mapping, index, expected, | |
312 | page); | |
46f65ec1 | 313 | if (!error) { |
b065b432 HD |
314 | mapping->nrpages++; |
315 | __inc_zone_page_state(page, NR_FILE_PAGES); | |
316 | __inc_zone_page_state(page, NR_SHMEM); | |
317 | spin_unlock_irq(&mapping->tree_lock); | |
318 | } else { | |
319 | page->mapping = NULL; | |
320 | spin_unlock_irq(&mapping->tree_lock); | |
321 | page_cache_release(page); | |
46f65ec1 | 322 | } |
46f65ec1 HD |
323 | return error; |
324 | } | |
325 | ||
6922c0c7 HD |
326 | /* |
327 | * Like delete_from_page_cache, but substitutes swap for page. | |
328 | */ | |
329 | static void shmem_delete_from_page_cache(struct page *page, void *radswap) | |
330 | { | |
331 | struct address_space *mapping = page->mapping; | |
332 | int error; | |
333 | ||
334 | spin_lock_irq(&mapping->tree_lock); | |
335 | error = shmem_radix_tree_replace(mapping, page->index, page, radswap); | |
336 | page->mapping = NULL; | |
337 | mapping->nrpages--; | |
338 | __dec_zone_page_state(page, NR_FILE_PAGES); | |
339 | __dec_zone_page_state(page, NR_SHMEM); | |
340 | spin_unlock_irq(&mapping->tree_lock); | |
341 | page_cache_release(page); | |
342 | BUG_ON(error); | |
343 | } | |
344 | ||
7a5d0fbb HD |
345 | /* |
346 | * Remove swap entry from radix tree, free the swap and its page cache. | |
347 | */ | |
348 | static int shmem_free_swap(struct address_space *mapping, | |
349 | pgoff_t index, void *radswap) | |
350 | { | |
6dbaf22c | 351 | void *old; |
7a5d0fbb HD |
352 | |
353 | spin_lock_irq(&mapping->tree_lock); | |
6dbaf22c | 354 | old = radix_tree_delete_item(&mapping->page_tree, index, radswap); |
7a5d0fbb | 355 | spin_unlock_irq(&mapping->tree_lock); |
6dbaf22c JW |
356 | if (old != radswap) |
357 | return -ENOENT; | |
358 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
359 | return 0; | |
7a5d0fbb HD |
360 | } |
361 | ||
24513264 HD |
362 | /* |
363 | * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. | |
364 | */ | |
365 | void shmem_unlock_mapping(struct address_space *mapping) | |
366 | { | |
367 | struct pagevec pvec; | |
368 | pgoff_t indices[PAGEVEC_SIZE]; | |
369 | pgoff_t index = 0; | |
370 | ||
371 | pagevec_init(&pvec, 0); | |
372 | /* | |
373 | * Minor point, but we might as well stop if someone else SHM_LOCKs it. | |
374 | */ | |
375 | while (!mapping_unevictable(mapping)) { | |
376 | /* | |
377 | * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it | |
378 | * has finished, if it hits a row of PAGEVEC_SIZE swap entries. | |
379 | */ | |
0cd6144a JW |
380 | pvec.nr = find_get_entries(mapping, index, |
381 | PAGEVEC_SIZE, pvec.pages, indices); | |
24513264 HD |
382 | if (!pvec.nr) |
383 | break; | |
384 | index = indices[pvec.nr - 1] + 1; | |
0cd6144a | 385 | pagevec_remove_exceptionals(&pvec); |
24513264 HD |
386 | check_move_unevictable_pages(pvec.pages, pvec.nr); |
387 | pagevec_release(&pvec); | |
388 | cond_resched(); | |
389 | } | |
7a5d0fbb HD |
390 | } |
391 | ||
392 | /* | |
393 | * Remove range of pages and swap entries from radix tree, and free them. | |
1635f6a7 | 394 | * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate. |
7a5d0fbb | 395 | */ |
1635f6a7 HD |
396 | static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, |
397 | bool unfalloc) | |
1da177e4 | 398 | { |
285b2c4f | 399 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 400 | struct shmem_inode_info *info = SHMEM_I(inode); |
285b2c4f | 401 | pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
83e4fa9c HD |
402 | pgoff_t end = (lend + 1) >> PAGE_CACHE_SHIFT; |
403 | unsigned int partial_start = lstart & (PAGE_CACHE_SIZE - 1); | |
404 | unsigned int partial_end = (lend + 1) & (PAGE_CACHE_SIZE - 1); | |
bda97eab | 405 | struct pagevec pvec; |
7a5d0fbb HD |
406 | pgoff_t indices[PAGEVEC_SIZE]; |
407 | long nr_swaps_freed = 0; | |
285b2c4f | 408 | pgoff_t index; |
bda97eab HD |
409 | int i; |
410 | ||
83e4fa9c HD |
411 | if (lend == -1) |
412 | end = -1; /* unsigned, so actually very big */ | |
bda97eab HD |
413 | |
414 | pagevec_init(&pvec, 0); | |
415 | index = start; | |
83e4fa9c | 416 | while (index < end) { |
0cd6144a JW |
417 | pvec.nr = find_get_entries(mapping, index, |
418 | min(end - index, (pgoff_t)PAGEVEC_SIZE), | |
419 | pvec.pages, indices); | |
7a5d0fbb HD |
420 | if (!pvec.nr) |
421 | break; | |
bda97eab HD |
422 | for (i = 0; i < pagevec_count(&pvec); i++) { |
423 | struct page *page = pvec.pages[i]; | |
424 | ||
7a5d0fbb | 425 | index = indices[i]; |
83e4fa9c | 426 | if (index >= end) |
bda97eab HD |
427 | break; |
428 | ||
7a5d0fbb | 429 | if (radix_tree_exceptional_entry(page)) { |
1635f6a7 HD |
430 | if (unfalloc) |
431 | continue; | |
7a5d0fbb HD |
432 | nr_swaps_freed += !shmem_free_swap(mapping, |
433 | index, page); | |
bda97eab | 434 | continue; |
7a5d0fbb HD |
435 | } |
436 | ||
437 | if (!trylock_page(page)) | |
bda97eab | 438 | continue; |
1635f6a7 HD |
439 | if (!unfalloc || !PageUptodate(page)) { |
440 | if (page->mapping == mapping) { | |
309381fe | 441 | VM_BUG_ON_PAGE(PageWriteback(page), page); |
1635f6a7 HD |
442 | truncate_inode_page(mapping, page); |
443 | } | |
bda97eab | 444 | } |
bda97eab HD |
445 | unlock_page(page); |
446 | } | |
0cd6144a | 447 | pagevec_remove_exceptionals(&pvec); |
24513264 | 448 | pagevec_release(&pvec); |
bda97eab HD |
449 | cond_resched(); |
450 | index++; | |
451 | } | |
1da177e4 | 452 | |
83e4fa9c | 453 | if (partial_start) { |
bda97eab HD |
454 | struct page *page = NULL; |
455 | shmem_getpage(inode, start - 1, &page, SGP_READ, NULL); | |
456 | if (page) { | |
83e4fa9c HD |
457 | unsigned int top = PAGE_CACHE_SIZE; |
458 | if (start > end) { | |
459 | top = partial_end; | |
460 | partial_end = 0; | |
461 | } | |
462 | zero_user_segment(page, partial_start, top); | |
463 | set_page_dirty(page); | |
464 | unlock_page(page); | |
465 | page_cache_release(page); | |
466 | } | |
467 | } | |
468 | if (partial_end) { | |
469 | struct page *page = NULL; | |
470 | shmem_getpage(inode, end, &page, SGP_READ, NULL); | |
471 | if (page) { | |
472 | zero_user_segment(page, 0, partial_end); | |
bda97eab HD |
473 | set_page_dirty(page); |
474 | unlock_page(page); | |
475 | page_cache_release(page); | |
476 | } | |
477 | } | |
83e4fa9c HD |
478 | if (start >= end) |
479 | return; | |
bda97eab HD |
480 | |
481 | index = start; | |
b1a36650 | 482 | while (index < end) { |
bda97eab | 483 | cond_resched(); |
0cd6144a JW |
484 | |
485 | pvec.nr = find_get_entries(mapping, index, | |
83e4fa9c | 486 | min(end - index, (pgoff_t)PAGEVEC_SIZE), |
0cd6144a | 487 | pvec.pages, indices); |
7a5d0fbb | 488 | if (!pvec.nr) { |
b1a36650 HD |
489 | /* If all gone or hole-punch or unfalloc, we're done */ |
490 | if (index == start || end != -1) | |
bda97eab | 491 | break; |
b1a36650 | 492 | /* But if truncating, restart to make sure all gone */ |
bda97eab HD |
493 | index = start; |
494 | continue; | |
495 | } | |
bda97eab HD |
496 | for (i = 0; i < pagevec_count(&pvec); i++) { |
497 | struct page *page = pvec.pages[i]; | |
498 | ||
7a5d0fbb | 499 | index = indices[i]; |
83e4fa9c | 500 | if (index >= end) |
bda97eab HD |
501 | break; |
502 | ||
7a5d0fbb | 503 | if (radix_tree_exceptional_entry(page)) { |
1635f6a7 HD |
504 | if (unfalloc) |
505 | continue; | |
b1a36650 HD |
506 | if (shmem_free_swap(mapping, index, page)) { |
507 | /* Swap was replaced by page: retry */ | |
508 | index--; | |
509 | break; | |
510 | } | |
511 | nr_swaps_freed++; | |
7a5d0fbb HD |
512 | continue; |
513 | } | |
514 | ||
bda97eab | 515 | lock_page(page); |
1635f6a7 HD |
516 | if (!unfalloc || !PageUptodate(page)) { |
517 | if (page->mapping == mapping) { | |
309381fe | 518 | VM_BUG_ON_PAGE(PageWriteback(page), page); |
1635f6a7 | 519 | truncate_inode_page(mapping, page); |
b1a36650 HD |
520 | } else { |
521 | /* Page was replaced by swap: retry */ | |
522 | unlock_page(page); | |
523 | index--; | |
524 | break; | |
1635f6a7 | 525 | } |
7a5d0fbb | 526 | } |
bda97eab HD |
527 | unlock_page(page); |
528 | } | |
0cd6144a | 529 | pagevec_remove_exceptionals(&pvec); |
24513264 | 530 | pagevec_release(&pvec); |
bda97eab HD |
531 | index++; |
532 | } | |
94c1e62d | 533 | |
1da177e4 | 534 | spin_lock(&info->lock); |
7a5d0fbb | 535 | info->swapped -= nr_swaps_freed; |
1da177e4 LT |
536 | shmem_recalc_inode(inode); |
537 | spin_unlock(&info->lock); | |
1635f6a7 | 538 | } |
1da177e4 | 539 | |
1635f6a7 HD |
540 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
541 | { | |
542 | shmem_undo_range(inode, lstart, lend, false); | |
285b2c4f | 543 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1da177e4 | 544 | } |
94c1e62d | 545 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 546 | |
94c1e62d | 547 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 LT |
548 | { |
549 | struct inode *inode = dentry->d_inode; | |
1da177e4 LT |
550 | int error; |
551 | ||
db78b877 CH |
552 | error = inode_change_ok(inode, attr); |
553 | if (error) | |
554 | return error; | |
555 | ||
94c1e62d HD |
556 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
557 | loff_t oldsize = inode->i_size; | |
558 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 559 | |
94c1e62d | 560 | if (newsize != oldsize) { |
77142517 KK |
561 | error = shmem_reacct_size(SHMEM_I(inode)->flags, |
562 | oldsize, newsize); | |
563 | if (error) | |
564 | return error; | |
94c1e62d HD |
565 | i_size_write(inode, newsize); |
566 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
567 | } | |
568 | if (newsize < oldsize) { | |
569 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
570 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
571 | shmem_truncate_range(inode, newsize, (loff_t)-1); | |
572 | /* unmap again to remove racily COWed private pages */ | |
573 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
574 | } | |
1da177e4 LT |
575 | } |
576 | ||
db78b877 | 577 | setattr_copy(inode, attr); |
db78b877 | 578 | if (attr->ia_valid & ATTR_MODE) |
feda821e | 579 | error = posix_acl_chmod(inode, inode->i_mode); |
1da177e4 LT |
580 | return error; |
581 | } | |
582 | ||
1f895f75 | 583 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 584 | { |
1da177e4 LT |
585 | struct shmem_inode_info *info = SHMEM_I(inode); |
586 | ||
3889e6e7 | 587 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
588 | shmem_unacct_size(info->flags, inode->i_size); |
589 | inode->i_size = 0; | |
3889e6e7 | 590 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 591 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 592 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 593 | list_del_init(&info->swaplist); |
cb5f7b9a | 594 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 | 595 | } |
69f07ec9 HD |
596 | } else |
597 | kfree(info->symlink); | |
b09e0fa4 | 598 | |
38f38657 | 599 | simple_xattrs_free(&info->xattrs); |
0f3c42f5 | 600 | WARN_ON(inode->i_blocks); |
5b04c689 | 601 | shmem_free_inode(inode->i_sb); |
dbd5768f | 602 | clear_inode(inode); |
1da177e4 LT |
603 | } |
604 | ||
46f65ec1 HD |
605 | /* |
606 | * If swap found in inode, free it and move page from swapcache to filecache. | |
607 | */ | |
41ffe5d5 | 608 | static int shmem_unuse_inode(struct shmem_inode_info *info, |
bde05d1c | 609 | swp_entry_t swap, struct page **pagep) |
1da177e4 | 610 | { |
285b2c4f | 611 | struct address_space *mapping = info->vfs_inode.i_mapping; |
46f65ec1 | 612 | void *radswap; |
41ffe5d5 | 613 | pgoff_t index; |
bde05d1c HD |
614 | gfp_t gfp; |
615 | int error = 0; | |
1da177e4 | 616 | |
46f65ec1 | 617 | radswap = swp_to_radix_entry(swap); |
e504f3fd | 618 | index = radix_tree_locate_item(&mapping->page_tree, radswap); |
46f65ec1 | 619 | if (index == -1) |
00501b53 | 620 | return -EAGAIN; /* tell shmem_unuse we found nothing */ |
2e0e26c7 | 621 | |
1b1b32f2 HD |
622 | /* |
623 | * Move _head_ to start search for next from here. | |
1f895f75 | 624 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 | 625 | * mutex, and there's an instant in list_move_tail when info->swaplist |
285b2c4f | 626 | * would appear empty, if it were the only one on shmem_swaplist. |
1b1b32f2 HD |
627 | */ |
628 | if (shmem_swaplist.next != &info->swaplist) | |
629 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 630 | |
bde05d1c HD |
631 | gfp = mapping_gfp_mask(mapping); |
632 | if (shmem_should_replace_page(*pagep, gfp)) { | |
633 | mutex_unlock(&shmem_swaplist_mutex); | |
634 | error = shmem_replace_page(pagep, gfp, info, index); | |
635 | mutex_lock(&shmem_swaplist_mutex); | |
636 | /* | |
637 | * We needed to drop mutex to make that restrictive page | |
0142ef6c HD |
638 | * allocation, but the inode might have been freed while we |
639 | * dropped it: although a racing shmem_evict_inode() cannot | |
640 | * complete without emptying the radix_tree, our page lock | |
641 | * on this swapcache page is not enough to prevent that - | |
642 | * free_swap_and_cache() of our swap entry will only | |
643 | * trylock_page(), removing swap from radix_tree whatever. | |
644 | * | |
645 | * We must not proceed to shmem_add_to_page_cache() if the | |
646 | * inode has been freed, but of course we cannot rely on | |
647 | * inode or mapping or info to check that. However, we can | |
648 | * safely check if our swap entry is still in use (and here | |
649 | * it can't have got reused for another page): if it's still | |
650 | * in use, then the inode cannot have been freed yet, and we | |
651 | * can safely proceed (if it's no longer in use, that tells | |
652 | * nothing about the inode, but we don't need to unuse swap). | |
bde05d1c HD |
653 | */ |
654 | if (!page_swapcount(*pagep)) | |
655 | error = -ENOENT; | |
656 | } | |
657 | ||
d13d1443 | 658 | /* |
778dd893 HD |
659 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
660 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
661 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 662 | */ |
bde05d1c HD |
663 | if (!error) |
664 | error = shmem_add_to_page_cache(*pagep, mapping, index, | |
fed400a1 | 665 | radswap); |
48f170fb | 666 | if (error != -ENOMEM) { |
46f65ec1 HD |
667 | /* |
668 | * Truncation and eviction use free_swap_and_cache(), which | |
669 | * only does trylock page: if we raced, best clean up here. | |
670 | */ | |
bde05d1c HD |
671 | delete_from_swap_cache(*pagep); |
672 | set_page_dirty(*pagep); | |
46f65ec1 HD |
673 | if (!error) { |
674 | spin_lock(&info->lock); | |
675 | info->swapped--; | |
676 | spin_unlock(&info->lock); | |
677 | swap_free(swap); | |
678 | } | |
1da177e4 | 679 | } |
2e0e26c7 | 680 | return error; |
1da177e4 LT |
681 | } |
682 | ||
683 | /* | |
46f65ec1 | 684 | * Search through swapped inodes to find and replace swap by page. |
1da177e4 | 685 | */ |
41ffe5d5 | 686 | int shmem_unuse(swp_entry_t swap, struct page *page) |
1da177e4 | 687 | { |
41ffe5d5 | 688 | struct list_head *this, *next; |
1da177e4 | 689 | struct shmem_inode_info *info; |
00501b53 | 690 | struct mem_cgroup *memcg; |
bde05d1c HD |
691 | int error = 0; |
692 | ||
693 | /* | |
694 | * There's a faint possibility that swap page was replaced before | |
0142ef6c | 695 | * caller locked it: caller will come back later with the right page. |
bde05d1c | 696 | */ |
0142ef6c | 697 | if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val)) |
bde05d1c | 698 | goto out; |
778dd893 HD |
699 | |
700 | /* | |
701 | * Charge page using GFP_KERNEL while we can wait, before taking | |
702 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
703 | * Charged back to the user (not to caller) when swap account is used. | |
778dd893 | 704 | */ |
00501b53 | 705 | error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg); |
778dd893 HD |
706 | if (error) |
707 | goto out; | |
46f65ec1 | 708 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
00501b53 | 709 | error = -EAGAIN; |
1da177e4 | 710 | |
cb5f7b9a | 711 | mutex_lock(&shmem_swaplist_mutex); |
41ffe5d5 HD |
712 | list_for_each_safe(this, next, &shmem_swaplist) { |
713 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
285b2c4f | 714 | if (info->swapped) |
00501b53 | 715 | error = shmem_unuse_inode(info, swap, &page); |
6922c0c7 HD |
716 | else |
717 | list_del_init(&info->swaplist); | |
cb5f7b9a | 718 | cond_resched(); |
00501b53 | 719 | if (error != -EAGAIN) |
778dd893 | 720 | break; |
00501b53 | 721 | /* found nothing in this: move on to search the next */ |
1da177e4 | 722 | } |
cb5f7b9a | 723 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 | 724 | |
00501b53 JW |
725 | if (error) { |
726 | if (error != -ENOMEM) | |
727 | error = 0; | |
728 | mem_cgroup_cancel_charge(page, memcg); | |
729 | } else | |
730 | mem_cgroup_commit_charge(page, memcg, true); | |
778dd893 | 731 | out: |
aaa46865 HD |
732 | unlock_page(page); |
733 | page_cache_release(page); | |
778dd893 | 734 | return error; |
1da177e4 LT |
735 | } |
736 | ||
737 | /* | |
738 | * Move the page from the page cache to the swap cache. | |
739 | */ | |
740 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
741 | { | |
742 | struct shmem_inode_info *info; | |
1da177e4 | 743 | struct address_space *mapping; |
1da177e4 | 744 | struct inode *inode; |
6922c0c7 HD |
745 | swp_entry_t swap; |
746 | pgoff_t index; | |
1da177e4 LT |
747 | |
748 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
749 | mapping = page->mapping; |
750 | index = page->index; | |
751 | inode = mapping->host; | |
752 | info = SHMEM_I(inode); | |
753 | if (info->flags & VM_LOCKED) | |
754 | goto redirty; | |
d9fe526a | 755 | if (!total_swap_pages) |
1da177e4 LT |
756 | goto redirty; |
757 | ||
d9fe526a HD |
758 | /* |
759 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
760 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
48f170fb | 761 | * might use ->writepage of its underlying filesystem, in which case |
d9fe526a | 762 | * tmpfs should write out to swap only in response to memory pressure, |
48f170fb | 763 | * and not for the writeback threads or sync. |
d9fe526a | 764 | */ |
48f170fb HD |
765 | if (!wbc->for_reclaim) { |
766 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
767 | goto redirty; | |
768 | } | |
1635f6a7 HD |
769 | |
770 | /* | |
771 | * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC | |
772 | * value into swapfile.c, the only way we can correctly account for a | |
773 | * fallocated page arriving here is now to initialize it and write it. | |
1aac1400 HD |
774 | * |
775 | * That's okay for a page already fallocated earlier, but if we have | |
776 | * not yet completed the fallocation, then (a) we want to keep track | |
777 | * of this page in case we have to undo it, and (b) it may not be a | |
778 | * good idea to continue anyway, once we're pushing into swap. So | |
779 | * reactivate the page, and let shmem_fallocate() quit when too many. | |
1635f6a7 HD |
780 | */ |
781 | if (!PageUptodate(page)) { | |
1aac1400 HD |
782 | if (inode->i_private) { |
783 | struct shmem_falloc *shmem_falloc; | |
784 | spin_lock(&inode->i_lock); | |
785 | shmem_falloc = inode->i_private; | |
786 | if (shmem_falloc && | |
8e205f77 | 787 | !shmem_falloc->waitq && |
1aac1400 HD |
788 | index >= shmem_falloc->start && |
789 | index < shmem_falloc->next) | |
790 | shmem_falloc->nr_unswapped++; | |
791 | else | |
792 | shmem_falloc = NULL; | |
793 | spin_unlock(&inode->i_lock); | |
794 | if (shmem_falloc) | |
795 | goto redirty; | |
796 | } | |
1635f6a7 HD |
797 | clear_highpage(page); |
798 | flush_dcache_page(page); | |
799 | SetPageUptodate(page); | |
800 | } | |
801 | ||
48f170fb HD |
802 | swap = get_swap_page(); |
803 | if (!swap.val) | |
804 | goto redirty; | |
d9fe526a | 805 | |
b1dea800 HD |
806 | /* |
807 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
6922c0c7 HD |
808 | * if it's not already there. Do it now before the page is |
809 | * moved to swap cache, when its pagelock no longer protects | |
b1dea800 | 810 | * the inode from eviction. But don't unlock the mutex until |
6922c0c7 HD |
811 | * we've incremented swapped, because shmem_unuse_inode() will |
812 | * prune a !swapped inode from the swaplist under this mutex. | |
b1dea800 | 813 | */ |
48f170fb HD |
814 | mutex_lock(&shmem_swaplist_mutex); |
815 | if (list_empty(&info->swaplist)) | |
816 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 817 | |
48f170fb | 818 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
aaa46865 | 819 | swap_shmem_alloc(swap); |
6922c0c7 HD |
820 | shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); |
821 | ||
822 | spin_lock(&info->lock); | |
823 | info->swapped++; | |
824 | shmem_recalc_inode(inode); | |
826267cf | 825 | spin_unlock(&info->lock); |
6922c0c7 HD |
826 | |
827 | mutex_unlock(&shmem_swaplist_mutex); | |
d9fe526a | 828 | BUG_ON(page_mapped(page)); |
9fab5619 | 829 | swap_writepage(page, wbc); |
1da177e4 LT |
830 | return 0; |
831 | } | |
832 | ||
6922c0c7 | 833 | mutex_unlock(&shmem_swaplist_mutex); |
0a31bc97 | 834 | swapcache_free(swap); |
1da177e4 LT |
835 | redirty: |
836 | set_page_dirty(page); | |
d9fe526a HD |
837 | if (wbc->for_reclaim) |
838 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
839 | unlock_page(page); | |
840 | return 0; | |
1da177e4 LT |
841 | } |
842 | ||
843 | #ifdef CONFIG_NUMA | |
680d794b | 844 | #ifdef CONFIG_TMPFS |
71fe804b | 845 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 846 | { |
095f1fc4 | 847 | char buffer[64]; |
680d794b | 848 | |
71fe804b | 849 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 850 | return; /* show nothing */ |
680d794b | 851 | |
a7a88b23 | 852 | mpol_to_str(buffer, sizeof(buffer), mpol); |
095f1fc4 LS |
853 | |
854 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 855 | } |
71fe804b LS |
856 | |
857 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
858 | { | |
859 | struct mempolicy *mpol = NULL; | |
860 | if (sbinfo->mpol) { | |
861 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
862 | mpol = sbinfo->mpol; | |
863 | mpol_get(mpol); | |
864 | spin_unlock(&sbinfo->stat_lock); | |
865 | } | |
866 | return mpol; | |
867 | } | |
680d794b AM |
868 | #endif /* CONFIG_TMPFS */ |
869 | ||
41ffe5d5 HD |
870 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
871 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 872 | { |
1da177e4 | 873 | struct vm_area_struct pvma; |
18a2f371 | 874 | struct page *page; |
52cd3b07 | 875 | |
1da177e4 | 876 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 877 | pvma.vm_start = 0; |
09c231cb NZ |
878 | /* Bias interleave by inode number to distribute better across nodes */ |
879 | pvma.vm_pgoff = index + info->vfs_inode.i_ino; | |
c4cc6d07 | 880 | pvma.vm_ops = NULL; |
18a2f371 MG |
881 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
882 | ||
883 | page = swapin_readahead(swap, gfp, &pvma, 0); | |
884 | ||
885 | /* Drop reference taken by mpol_shared_policy_lookup() */ | |
886 | mpol_cond_put(pvma.vm_policy); | |
887 | ||
888 | return page; | |
1da177e4 LT |
889 | } |
890 | ||
02098fea | 891 | static struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 892 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 LT |
893 | { |
894 | struct vm_area_struct pvma; | |
18a2f371 | 895 | struct page *page; |
1da177e4 | 896 | |
c4cc6d07 HD |
897 | /* Create a pseudo vma that just contains the policy */ |
898 | pvma.vm_start = 0; | |
09c231cb NZ |
899 | /* Bias interleave by inode number to distribute better across nodes */ |
900 | pvma.vm_pgoff = index + info->vfs_inode.i_ino; | |
c4cc6d07 | 901 | pvma.vm_ops = NULL; |
41ffe5d5 | 902 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, index); |
52cd3b07 | 903 | |
18a2f371 MG |
904 | page = alloc_page_vma(gfp, &pvma, 0); |
905 | ||
906 | /* Drop reference taken by mpol_shared_policy_lookup() */ | |
907 | mpol_cond_put(pvma.vm_policy); | |
908 | ||
909 | return page; | |
1da177e4 | 910 | } |
680d794b AM |
911 | #else /* !CONFIG_NUMA */ |
912 | #ifdef CONFIG_TMPFS | |
41ffe5d5 | 913 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b AM |
914 | { |
915 | } | |
916 | #endif /* CONFIG_TMPFS */ | |
917 | ||
41ffe5d5 HD |
918 | static inline struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
919 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 920 | { |
41ffe5d5 | 921 | return swapin_readahead(swap, gfp, NULL, 0); |
1da177e4 LT |
922 | } |
923 | ||
02098fea | 924 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 925 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 926 | { |
e84e2e13 | 927 | return alloc_page(gfp); |
1da177e4 | 928 | } |
680d794b | 929 | #endif /* CONFIG_NUMA */ |
1da177e4 | 930 | |
71fe804b LS |
931 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
932 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
933 | { | |
934 | return NULL; | |
935 | } | |
936 | #endif | |
937 | ||
bde05d1c HD |
938 | /* |
939 | * When a page is moved from swapcache to shmem filecache (either by the | |
940 | * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of | |
941 | * shmem_unuse_inode()), it may have been read in earlier from swap, in | |
942 | * ignorance of the mapping it belongs to. If that mapping has special | |
943 | * constraints (like the gma500 GEM driver, which requires RAM below 4GB), | |
944 | * we may need to copy to a suitable page before moving to filecache. | |
945 | * | |
946 | * In a future release, this may well be extended to respect cpuset and | |
947 | * NUMA mempolicy, and applied also to anonymous pages in do_swap_page(); | |
948 | * but for now it is a simple matter of zone. | |
949 | */ | |
950 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp) | |
951 | { | |
952 | return page_zonenum(page) > gfp_zone(gfp); | |
953 | } | |
954 | ||
955 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
956 | struct shmem_inode_info *info, pgoff_t index) | |
957 | { | |
958 | struct page *oldpage, *newpage; | |
959 | struct address_space *swap_mapping; | |
960 | pgoff_t swap_index; | |
961 | int error; | |
962 | ||
963 | oldpage = *pagep; | |
964 | swap_index = page_private(oldpage); | |
965 | swap_mapping = page_mapping(oldpage); | |
966 | ||
967 | /* | |
968 | * We have arrived here because our zones are constrained, so don't | |
969 | * limit chance of success by further cpuset and node constraints. | |
970 | */ | |
971 | gfp &= ~GFP_CONSTRAINT_MASK; | |
972 | newpage = shmem_alloc_page(gfp, info, index); | |
973 | if (!newpage) | |
974 | return -ENOMEM; | |
bde05d1c | 975 | |
bde05d1c HD |
976 | page_cache_get(newpage); |
977 | copy_highpage(newpage, oldpage); | |
0142ef6c | 978 | flush_dcache_page(newpage); |
bde05d1c | 979 | |
bde05d1c | 980 | __set_page_locked(newpage); |
bde05d1c | 981 | SetPageUptodate(newpage); |
bde05d1c | 982 | SetPageSwapBacked(newpage); |
bde05d1c | 983 | set_page_private(newpage, swap_index); |
bde05d1c HD |
984 | SetPageSwapCache(newpage); |
985 | ||
986 | /* | |
987 | * Our caller will very soon move newpage out of swapcache, but it's | |
988 | * a nice clean interface for us to replace oldpage by newpage there. | |
989 | */ | |
990 | spin_lock_irq(&swap_mapping->tree_lock); | |
991 | error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage, | |
992 | newpage); | |
0142ef6c HD |
993 | if (!error) { |
994 | __inc_zone_page_state(newpage, NR_FILE_PAGES); | |
995 | __dec_zone_page_state(oldpage, NR_FILE_PAGES); | |
996 | } | |
bde05d1c | 997 | spin_unlock_irq(&swap_mapping->tree_lock); |
bde05d1c | 998 | |
0142ef6c HD |
999 | if (unlikely(error)) { |
1000 | /* | |
1001 | * Is this possible? I think not, now that our callers check | |
1002 | * both PageSwapCache and page_private after getting page lock; | |
1003 | * but be defensive. Reverse old to newpage for clear and free. | |
1004 | */ | |
1005 | oldpage = newpage; | |
1006 | } else { | |
0a31bc97 | 1007 | mem_cgroup_migrate(oldpage, newpage, false); |
0142ef6c HD |
1008 | lru_cache_add_anon(newpage); |
1009 | *pagep = newpage; | |
1010 | } | |
bde05d1c HD |
1011 | |
1012 | ClearPageSwapCache(oldpage); | |
1013 | set_page_private(oldpage, 0); | |
1014 | ||
1015 | unlock_page(oldpage); | |
1016 | page_cache_release(oldpage); | |
1017 | page_cache_release(oldpage); | |
0142ef6c | 1018 | return error; |
bde05d1c HD |
1019 | } |
1020 | ||
1da177e4 | 1021 | /* |
68da9f05 | 1022 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
1023 | * |
1024 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1025 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1026 | * entry since a page cannot live in both the swap and page cache | |
1027 | */ | |
41ffe5d5 | 1028 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
68da9f05 | 1029 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) |
1da177e4 LT |
1030 | { |
1031 | struct address_space *mapping = inode->i_mapping; | |
54af6042 | 1032 | struct shmem_inode_info *info; |
1da177e4 | 1033 | struct shmem_sb_info *sbinfo; |
00501b53 | 1034 | struct mem_cgroup *memcg; |
27ab7006 | 1035 | struct page *page; |
1da177e4 LT |
1036 | swp_entry_t swap; |
1037 | int error; | |
54af6042 | 1038 | int once = 0; |
1635f6a7 | 1039 | int alloced = 0; |
1da177e4 | 1040 | |
41ffe5d5 | 1041 | if (index > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
1da177e4 | 1042 | return -EFBIG; |
1da177e4 | 1043 | repeat: |
54af6042 | 1044 | swap.val = 0; |
0cd6144a | 1045 | page = find_lock_entry(mapping, index); |
54af6042 HD |
1046 | if (radix_tree_exceptional_entry(page)) { |
1047 | swap = radix_to_swp_entry(page); | |
1048 | page = NULL; | |
1049 | } | |
1050 | ||
1635f6a7 | 1051 | if (sgp != SGP_WRITE && sgp != SGP_FALLOC && |
54af6042 HD |
1052 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { |
1053 | error = -EINVAL; | |
1054 | goto failed; | |
1055 | } | |
1056 | ||
66d2f4d2 HD |
1057 | if (page && sgp == SGP_WRITE) |
1058 | mark_page_accessed(page); | |
1059 | ||
1635f6a7 HD |
1060 | /* fallocated page? */ |
1061 | if (page && !PageUptodate(page)) { | |
1062 | if (sgp != SGP_READ) | |
1063 | goto clear; | |
1064 | unlock_page(page); | |
1065 | page_cache_release(page); | |
1066 | page = NULL; | |
1067 | } | |
54af6042 | 1068 | if (page || (sgp == SGP_READ && !swap.val)) { |
54af6042 HD |
1069 | *pagep = page; |
1070 | return 0; | |
27ab7006 HD |
1071 | } |
1072 | ||
1073 | /* | |
54af6042 HD |
1074 | * Fast cache lookup did not find it: |
1075 | * bring it back from swap or allocate. | |
27ab7006 | 1076 | */ |
54af6042 HD |
1077 | info = SHMEM_I(inode); |
1078 | sbinfo = SHMEM_SB(inode->i_sb); | |
1da177e4 | 1079 | |
1da177e4 LT |
1080 | if (swap.val) { |
1081 | /* Look it up and read it in.. */ | |
27ab7006 HD |
1082 | page = lookup_swap_cache(swap); |
1083 | if (!page) { | |
1da177e4 | 1084 | /* here we actually do the io */ |
68da9f05 HD |
1085 | if (fault_type) |
1086 | *fault_type |= VM_FAULT_MAJOR; | |
41ffe5d5 | 1087 | page = shmem_swapin(swap, gfp, info, index); |
27ab7006 | 1088 | if (!page) { |
54af6042 HD |
1089 | error = -ENOMEM; |
1090 | goto failed; | |
1da177e4 | 1091 | } |
1da177e4 LT |
1092 | } |
1093 | ||
1094 | /* We have to do this with page locked to prevent races */ | |
54af6042 | 1095 | lock_page(page); |
0142ef6c | 1096 | if (!PageSwapCache(page) || page_private(page) != swap.val || |
d1899228 | 1097 | !shmem_confirm_swap(mapping, index, swap)) { |
bde05d1c | 1098 | error = -EEXIST; /* try again */ |
d1899228 | 1099 | goto unlock; |
bde05d1c | 1100 | } |
27ab7006 | 1101 | if (!PageUptodate(page)) { |
1da177e4 | 1102 | error = -EIO; |
54af6042 | 1103 | goto failed; |
1da177e4 | 1104 | } |
54af6042 HD |
1105 | wait_on_page_writeback(page); |
1106 | ||
bde05d1c HD |
1107 | if (shmem_should_replace_page(page, gfp)) { |
1108 | error = shmem_replace_page(&page, gfp, info, index); | |
1109 | if (error) | |
1110 | goto failed; | |
1da177e4 | 1111 | } |
27ab7006 | 1112 | |
00501b53 | 1113 | error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg); |
d1899228 | 1114 | if (!error) { |
aa3b1895 | 1115 | error = shmem_add_to_page_cache(page, mapping, index, |
fed400a1 | 1116 | swp_to_radix_entry(swap)); |
215c02bc HD |
1117 | /* |
1118 | * We already confirmed swap under page lock, and make | |
1119 | * no memory allocation here, so usually no possibility | |
1120 | * of error; but free_swap_and_cache() only trylocks a | |
1121 | * page, so it is just possible that the entry has been | |
1122 | * truncated or holepunched since swap was confirmed. | |
1123 | * shmem_undo_range() will have done some of the | |
1124 | * unaccounting, now delete_from_swap_cache() will do | |
1125 | * the rest (including mem_cgroup_uncharge_swapcache). | |
1126 | * Reset swap.val? No, leave it so "failed" goes back to | |
1127 | * "repeat": reading a hole and writing should succeed. | |
1128 | */ | |
00501b53 JW |
1129 | if (error) { |
1130 | mem_cgroup_cancel_charge(page, memcg); | |
215c02bc | 1131 | delete_from_swap_cache(page); |
00501b53 | 1132 | } |
d1899228 | 1133 | } |
54af6042 HD |
1134 | if (error) |
1135 | goto failed; | |
1136 | ||
00501b53 JW |
1137 | mem_cgroup_commit_charge(page, memcg, true); |
1138 | ||
54af6042 | 1139 | spin_lock(&info->lock); |
285b2c4f | 1140 | info->swapped--; |
54af6042 | 1141 | shmem_recalc_inode(inode); |
27ab7006 | 1142 | spin_unlock(&info->lock); |
54af6042 | 1143 | |
66d2f4d2 HD |
1144 | if (sgp == SGP_WRITE) |
1145 | mark_page_accessed(page); | |
1146 | ||
54af6042 | 1147 | delete_from_swap_cache(page); |
27ab7006 HD |
1148 | set_page_dirty(page); |
1149 | swap_free(swap); | |
1150 | ||
54af6042 HD |
1151 | } else { |
1152 | if (shmem_acct_block(info->flags)) { | |
1153 | error = -ENOSPC; | |
1154 | goto failed; | |
1da177e4 | 1155 | } |
0edd73b3 | 1156 | if (sbinfo->max_blocks) { |
fc5da22a | 1157 | if (percpu_counter_compare(&sbinfo->used_blocks, |
54af6042 HD |
1158 | sbinfo->max_blocks) >= 0) { |
1159 | error = -ENOSPC; | |
1160 | goto unacct; | |
1161 | } | |
7e496299 | 1162 | percpu_counter_inc(&sbinfo->used_blocks); |
54af6042 | 1163 | } |
1da177e4 | 1164 | |
54af6042 HD |
1165 | page = shmem_alloc_page(gfp, info, index); |
1166 | if (!page) { | |
1167 | error = -ENOMEM; | |
1168 | goto decused; | |
1da177e4 LT |
1169 | } |
1170 | ||
07a42788 | 1171 | __SetPageSwapBacked(page); |
54af6042 | 1172 | __set_page_locked(page); |
66d2f4d2 | 1173 | if (sgp == SGP_WRITE) |
eb39d618 | 1174 | __SetPageReferenced(page); |
66d2f4d2 | 1175 | |
00501b53 | 1176 | error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg); |
54af6042 HD |
1177 | if (error) |
1178 | goto decused; | |
5e4c0d97 | 1179 | error = radix_tree_maybe_preload(gfp & GFP_RECLAIM_MASK); |
b065b432 HD |
1180 | if (!error) { |
1181 | error = shmem_add_to_page_cache(page, mapping, index, | |
fed400a1 | 1182 | NULL); |
b065b432 HD |
1183 | radix_tree_preload_end(); |
1184 | } | |
1185 | if (error) { | |
00501b53 | 1186 | mem_cgroup_cancel_charge(page, memcg); |
b065b432 HD |
1187 | goto decused; |
1188 | } | |
00501b53 | 1189 | mem_cgroup_commit_charge(page, memcg, false); |
54af6042 HD |
1190 | lru_cache_add_anon(page); |
1191 | ||
1192 | spin_lock(&info->lock); | |
1da177e4 | 1193 | info->alloced++; |
54af6042 HD |
1194 | inode->i_blocks += BLOCKS_PER_PAGE; |
1195 | shmem_recalc_inode(inode); | |
1da177e4 | 1196 | spin_unlock(&info->lock); |
1635f6a7 | 1197 | alloced = true; |
54af6042 | 1198 | |
ec9516fb | 1199 | /* |
1635f6a7 HD |
1200 | * Let SGP_FALLOC use the SGP_WRITE optimization on a new page. |
1201 | */ | |
1202 | if (sgp == SGP_FALLOC) | |
1203 | sgp = SGP_WRITE; | |
1204 | clear: | |
1205 | /* | |
1206 | * Let SGP_WRITE caller clear ends if write does not fill page; | |
1207 | * but SGP_FALLOC on a page fallocated earlier must initialize | |
1208 | * it now, lest undo on failure cancel our earlier guarantee. | |
ec9516fb HD |
1209 | */ |
1210 | if (sgp != SGP_WRITE) { | |
1211 | clear_highpage(page); | |
1212 | flush_dcache_page(page); | |
1213 | SetPageUptodate(page); | |
1214 | } | |
a0ee5ec5 | 1215 | if (sgp == SGP_DIRTY) |
27ab7006 | 1216 | set_page_dirty(page); |
1da177e4 | 1217 | } |
bde05d1c | 1218 | |
54af6042 | 1219 | /* Perhaps the file has been truncated since we checked */ |
1635f6a7 | 1220 | if (sgp != SGP_WRITE && sgp != SGP_FALLOC && |
54af6042 HD |
1221 | ((loff_t)index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { |
1222 | error = -EINVAL; | |
1635f6a7 HD |
1223 | if (alloced) |
1224 | goto trunc; | |
1225 | else | |
1226 | goto failed; | |
e83c32e8 | 1227 | } |
54af6042 HD |
1228 | *pagep = page; |
1229 | return 0; | |
1da177e4 | 1230 | |
59a16ead | 1231 | /* |
54af6042 | 1232 | * Error recovery. |
59a16ead | 1233 | */ |
54af6042 | 1234 | trunc: |
1635f6a7 | 1235 | info = SHMEM_I(inode); |
54af6042 HD |
1236 | ClearPageDirty(page); |
1237 | delete_from_page_cache(page); | |
1238 | spin_lock(&info->lock); | |
1239 | info->alloced--; | |
1240 | inode->i_blocks -= BLOCKS_PER_PAGE; | |
59a16ead | 1241 | spin_unlock(&info->lock); |
54af6042 | 1242 | decused: |
1635f6a7 | 1243 | sbinfo = SHMEM_SB(inode->i_sb); |
54af6042 HD |
1244 | if (sbinfo->max_blocks) |
1245 | percpu_counter_add(&sbinfo->used_blocks, -1); | |
1246 | unacct: | |
1247 | shmem_unacct_blocks(info->flags, 1); | |
1248 | failed: | |
d1899228 HD |
1249 | if (swap.val && error != -EINVAL && |
1250 | !shmem_confirm_swap(mapping, index, swap)) | |
1251 | error = -EEXIST; | |
1252 | unlock: | |
27ab7006 | 1253 | if (page) { |
54af6042 | 1254 | unlock_page(page); |
27ab7006 | 1255 | page_cache_release(page); |
54af6042 HD |
1256 | } |
1257 | if (error == -ENOSPC && !once++) { | |
1258 | info = SHMEM_I(inode); | |
1259 | spin_lock(&info->lock); | |
1260 | shmem_recalc_inode(inode); | |
1261 | spin_unlock(&info->lock); | |
27ab7006 | 1262 | goto repeat; |
ff36b801 | 1263 | } |
d1899228 | 1264 | if (error == -EEXIST) /* from above or from radix_tree_insert */ |
54af6042 HD |
1265 | goto repeat; |
1266 | return error; | |
1da177e4 LT |
1267 | } |
1268 | ||
d0217ac0 | 1269 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1270 | { |
496ad9aa | 1271 | struct inode *inode = file_inode(vma->vm_file); |
1da177e4 | 1272 | int error; |
68da9f05 | 1273 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 1274 | |
f00cdc6d HD |
1275 | /* |
1276 | * Trinity finds that probing a hole which tmpfs is punching can | |
1277 | * prevent the hole-punch from ever completing: which in turn | |
1278 | * locks writers out with its hold on i_mutex. So refrain from | |
8e205f77 HD |
1279 | * faulting pages into the hole while it's being punched. Although |
1280 | * shmem_undo_range() does remove the additions, it may be unable to | |
1281 | * keep up, as each new page needs its own unmap_mapping_range() call, | |
1282 | * and the i_mmap tree grows ever slower to scan if new vmas are added. | |
1283 | * | |
1284 | * It does not matter if we sometimes reach this check just before the | |
1285 | * hole-punch begins, so that one fault then races with the punch: | |
1286 | * we just need to make racing faults a rare case. | |
1287 | * | |
1288 | * The implementation below would be much simpler if we just used a | |
1289 | * standard mutex or completion: but we cannot take i_mutex in fault, | |
1290 | * and bloating every shmem inode for this unlikely case would be sad. | |
f00cdc6d HD |
1291 | */ |
1292 | if (unlikely(inode->i_private)) { | |
1293 | struct shmem_falloc *shmem_falloc; | |
1294 | ||
1295 | spin_lock(&inode->i_lock); | |
1296 | shmem_falloc = inode->i_private; | |
8e205f77 HD |
1297 | if (shmem_falloc && |
1298 | shmem_falloc->waitq && | |
1299 | vmf->pgoff >= shmem_falloc->start && | |
1300 | vmf->pgoff < shmem_falloc->next) { | |
1301 | wait_queue_head_t *shmem_falloc_waitq; | |
1302 | DEFINE_WAIT(shmem_fault_wait); | |
1303 | ||
1304 | ret = VM_FAULT_NOPAGE; | |
f00cdc6d HD |
1305 | if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && |
1306 | !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { | |
8e205f77 | 1307 | /* It's polite to up mmap_sem if we can */ |
f00cdc6d | 1308 | up_read(&vma->vm_mm->mmap_sem); |
8e205f77 | 1309 | ret = VM_FAULT_RETRY; |
f00cdc6d | 1310 | } |
8e205f77 HD |
1311 | |
1312 | shmem_falloc_waitq = shmem_falloc->waitq; | |
1313 | prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, | |
1314 | TASK_UNINTERRUPTIBLE); | |
1315 | spin_unlock(&inode->i_lock); | |
1316 | schedule(); | |
1317 | ||
1318 | /* | |
1319 | * shmem_falloc_waitq points into the shmem_fallocate() | |
1320 | * stack of the hole-punching task: shmem_falloc_waitq | |
1321 | * is usually invalid by the time we reach here, but | |
1322 | * finish_wait() does not dereference it in that case; | |
1323 | * though i_lock needed lest racing with wake_up_all(). | |
1324 | */ | |
1325 | spin_lock(&inode->i_lock); | |
1326 | finish_wait(shmem_falloc_waitq, &shmem_fault_wait); | |
1327 | spin_unlock(&inode->i_lock); | |
1328 | return ret; | |
f00cdc6d | 1329 | } |
8e205f77 | 1330 | spin_unlock(&inode->i_lock); |
f00cdc6d HD |
1331 | } |
1332 | ||
27d54b39 | 1333 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1334 | if (error) |
1335 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 1336 | |
456f998e YH |
1337 | if (ret & VM_FAULT_MAJOR) { |
1338 | count_vm_event(PGMAJFAULT); | |
1339 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
1340 | } | |
68da9f05 | 1341 | return ret; |
1da177e4 LT |
1342 | } |
1343 | ||
1da177e4 | 1344 | #ifdef CONFIG_NUMA |
41ffe5d5 | 1345 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
1da177e4 | 1346 | { |
496ad9aa | 1347 | struct inode *inode = file_inode(vma->vm_file); |
41ffe5d5 | 1348 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); |
1da177e4 LT |
1349 | } |
1350 | ||
d8dc74f2 AB |
1351 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1352 | unsigned long addr) | |
1da177e4 | 1353 | { |
496ad9aa | 1354 | struct inode *inode = file_inode(vma->vm_file); |
41ffe5d5 | 1355 | pgoff_t index; |
1da177e4 | 1356 | |
41ffe5d5 HD |
1357 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
1358 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
1da177e4 LT |
1359 | } |
1360 | #endif | |
1361 | ||
1362 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1363 | { | |
496ad9aa | 1364 | struct inode *inode = file_inode(file); |
1da177e4 LT |
1365 | struct shmem_inode_info *info = SHMEM_I(inode); |
1366 | int retval = -ENOMEM; | |
1367 | ||
1368 | spin_lock(&info->lock); | |
1369 | if (lock && !(info->flags & VM_LOCKED)) { | |
1370 | if (!user_shm_lock(inode->i_size, user)) | |
1371 | goto out_nomem; | |
1372 | info->flags |= VM_LOCKED; | |
89e004ea | 1373 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1374 | } |
1375 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1376 | user_shm_unlock(inode->i_size, user); | |
1377 | info->flags &= ~VM_LOCKED; | |
89e004ea | 1378 | mapping_clear_unevictable(file->f_mapping); |
1da177e4 LT |
1379 | } |
1380 | retval = 0; | |
89e004ea | 1381 | |
1da177e4 LT |
1382 | out_nomem: |
1383 | spin_unlock(&info->lock); | |
1384 | return retval; | |
1385 | } | |
1386 | ||
9b83a6a8 | 1387 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1388 | { |
1389 | file_accessed(file); | |
1390 | vma->vm_ops = &shmem_vm_ops; | |
1391 | return 0; | |
1392 | } | |
1393 | ||
454abafe | 1394 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
09208d15 | 1395 | umode_t mode, dev_t dev, unsigned long flags) |
1da177e4 LT |
1396 | { |
1397 | struct inode *inode; | |
1398 | struct shmem_inode_info *info; | |
1399 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1400 | ||
5b04c689 PE |
1401 | if (shmem_reserve_inode(sb)) |
1402 | return NULL; | |
1da177e4 LT |
1403 | |
1404 | inode = new_inode(sb); | |
1405 | if (inode) { | |
85fe4025 | 1406 | inode->i_ino = get_next_ino(); |
454abafe | 1407 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1408 | inode->i_blocks = 0; |
1da177e4 LT |
1409 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1410 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1411 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1412 | info = SHMEM_I(inode); |
1413 | memset(info, 0, (char *)inode - (char *)info); | |
1414 | spin_lock_init(&info->lock); | |
0b0a0806 | 1415 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1416 | INIT_LIST_HEAD(&info->swaplist); |
38f38657 | 1417 | simple_xattrs_init(&info->xattrs); |
72c04902 | 1418 | cache_no_acl(inode); |
1da177e4 LT |
1419 | |
1420 | switch (mode & S_IFMT) { | |
1421 | default: | |
39f0247d | 1422 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1423 | init_special_inode(inode, mode, dev); |
1424 | break; | |
1425 | case S_IFREG: | |
14fcc23f | 1426 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1427 | inode->i_op = &shmem_inode_operations; |
1428 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1429 | mpol_shared_policy_init(&info->policy, |
1430 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1431 | break; |
1432 | case S_IFDIR: | |
d8c76e6f | 1433 | inc_nlink(inode); |
1da177e4 LT |
1434 | /* Some things misbehave if size == 0 on a directory */ |
1435 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1436 | inode->i_op = &shmem_dir_inode_operations; | |
1437 | inode->i_fop = &simple_dir_operations; | |
1438 | break; | |
1439 | case S_IFLNK: | |
1440 | /* | |
1441 | * Must not load anything in the rbtree, | |
1442 | * mpol_free_shared_policy will not be called. | |
1443 | */ | |
71fe804b | 1444 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1445 | break; |
1446 | } | |
5b04c689 PE |
1447 | } else |
1448 | shmem_free_inode(sb); | |
1da177e4 LT |
1449 | return inode; |
1450 | } | |
1451 | ||
0cd6144a JW |
1452 | bool shmem_mapping(struct address_space *mapping) |
1453 | { | |
1454 | return mapping->backing_dev_info == &shmem_backing_dev_info; | |
1455 | } | |
1456 | ||
1da177e4 | 1457 | #ifdef CONFIG_TMPFS |
92e1d5be | 1458 | static const struct inode_operations shmem_symlink_inode_operations; |
69f07ec9 | 1459 | static const struct inode_operations shmem_short_symlink_operations; |
1da177e4 | 1460 | |
6d9d88d0 JS |
1461 | #ifdef CONFIG_TMPFS_XATTR |
1462 | static int shmem_initxattrs(struct inode *, const struct xattr *, void *); | |
1463 | #else | |
1464 | #define shmem_initxattrs NULL | |
1465 | #endif | |
1466 | ||
1da177e4 | 1467 | static int |
800d15a5 NP |
1468 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1469 | loff_t pos, unsigned len, unsigned flags, | |
1470 | struct page **pagep, void **fsdata) | |
1da177e4 | 1471 | { |
800d15a5 NP |
1472 | struct inode *inode = mapping->host; |
1473 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
66d2f4d2 | 1474 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
800d15a5 NP |
1475 | } |
1476 | ||
1477 | static int | |
1478 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1479 | loff_t pos, unsigned len, unsigned copied, | |
1480 | struct page *page, void *fsdata) | |
1481 | { | |
1482 | struct inode *inode = mapping->host; | |
1483 | ||
d3602444 HD |
1484 | if (pos + copied > inode->i_size) |
1485 | i_size_write(inode, pos + copied); | |
1486 | ||
ec9516fb HD |
1487 | if (!PageUptodate(page)) { |
1488 | if (copied < PAGE_CACHE_SIZE) { | |
1489 | unsigned from = pos & (PAGE_CACHE_SIZE - 1); | |
1490 | zero_user_segments(page, 0, from, | |
1491 | from + copied, PAGE_CACHE_SIZE); | |
1492 | } | |
1493 | SetPageUptodate(page); | |
1494 | } | |
800d15a5 | 1495 | set_page_dirty(page); |
6746aff7 | 1496 | unlock_page(page); |
800d15a5 NP |
1497 | page_cache_release(page); |
1498 | ||
800d15a5 | 1499 | return copied; |
1da177e4 LT |
1500 | } |
1501 | ||
2ba5bbed | 1502 | static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) |
1da177e4 | 1503 | { |
6e58e79d AV |
1504 | struct file *file = iocb->ki_filp; |
1505 | struct inode *inode = file_inode(file); | |
1da177e4 | 1506 | struct address_space *mapping = inode->i_mapping; |
41ffe5d5 HD |
1507 | pgoff_t index; |
1508 | unsigned long offset; | |
a0ee5ec5 | 1509 | enum sgp_type sgp = SGP_READ; |
f7c1d074 | 1510 | int error = 0; |
cb66a7a1 | 1511 | ssize_t retval = 0; |
6e58e79d | 1512 | loff_t *ppos = &iocb->ki_pos; |
a0ee5ec5 HD |
1513 | |
1514 | /* | |
1515 | * Might this read be for a stacking filesystem? Then when reading | |
1516 | * holes of a sparse file, we actually need to allocate those pages, | |
1517 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1518 | */ | |
1519 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1520 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1521 | |
1522 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1523 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1524 | ||
1525 | for (;;) { | |
1526 | struct page *page = NULL; | |
41ffe5d5 HD |
1527 | pgoff_t end_index; |
1528 | unsigned long nr, ret; | |
1da177e4 LT |
1529 | loff_t i_size = i_size_read(inode); |
1530 | ||
1531 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1532 | if (index > end_index) | |
1533 | break; | |
1534 | if (index == end_index) { | |
1535 | nr = i_size & ~PAGE_CACHE_MASK; | |
1536 | if (nr <= offset) | |
1537 | break; | |
1538 | } | |
1539 | ||
6e58e79d AV |
1540 | error = shmem_getpage(inode, index, &page, sgp, NULL); |
1541 | if (error) { | |
1542 | if (error == -EINVAL) | |
1543 | error = 0; | |
1da177e4 LT |
1544 | break; |
1545 | } | |
d3602444 HD |
1546 | if (page) |
1547 | unlock_page(page); | |
1da177e4 LT |
1548 | |
1549 | /* | |
1550 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1551 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1552 | */ |
1553 | nr = PAGE_CACHE_SIZE; | |
1554 | i_size = i_size_read(inode); | |
1555 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1556 | if (index == end_index) { | |
1557 | nr = i_size & ~PAGE_CACHE_MASK; | |
1558 | if (nr <= offset) { | |
1559 | if (page) | |
1560 | page_cache_release(page); | |
1561 | break; | |
1562 | } | |
1563 | } | |
1564 | nr -= offset; | |
1565 | ||
1566 | if (page) { | |
1567 | /* | |
1568 | * If users can be writing to this page using arbitrary | |
1569 | * virtual addresses, take care about potential aliasing | |
1570 | * before reading the page on the kernel side. | |
1571 | */ | |
1572 | if (mapping_writably_mapped(mapping)) | |
1573 | flush_dcache_page(page); | |
1574 | /* | |
1575 | * Mark the page accessed if we read the beginning. | |
1576 | */ | |
1577 | if (!offset) | |
1578 | mark_page_accessed(page); | |
b5810039 | 1579 | } else { |
1da177e4 | 1580 | page = ZERO_PAGE(0); |
b5810039 NP |
1581 | page_cache_get(page); |
1582 | } | |
1da177e4 LT |
1583 | |
1584 | /* | |
1585 | * Ok, we have the page, and it's up-to-date, so | |
1586 | * now we can copy it to user space... | |
1da177e4 | 1587 | */ |
2ba5bbed | 1588 | ret = copy_page_to_iter(page, offset, nr, to); |
6e58e79d | 1589 | retval += ret; |
1da177e4 LT |
1590 | offset += ret; |
1591 | index += offset >> PAGE_CACHE_SHIFT; | |
1592 | offset &= ~PAGE_CACHE_MASK; | |
1593 | ||
1594 | page_cache_release(page); | |
2ba5bbed | 1595 | if (!iov_iter_count(to)) |
1da177e4 | 1596 | break; |
6e58e79d AV |
1597 | if (ret < nr) { |
1598 | error = -EFAULT; | |
1599 | break; | |
1600 | } | |
1da177e4 LT |
1601 | cond_resched(); |
1602 | } | |
1603 | ||
1604 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
6e58e79d AV |
1605 | file_accessed(file); |
1606 | return retval ? retval : error; | |
1da177e4 LT |
1607 | } |
1608 | ||
708e3508 HD |
1609 | static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
1610 | struct pipe_inode_info *pipe, size_t len, | |
1611 | unsigned int flags) | |
1612 | { | |
1613 | struct address_space *mapping = in->f_mapping; | |
71f0e07a | 1614 | struct inode *inode = mapping->host; |
708e3508 HD |
1615 | unsigned int loff, nr_pages, req_pages; |
1616 | struct page *pages[PIPE_DEF_BUFFERS]; | |
1617 | struct partial_page partial[PIPE_DEF_BUFFERS]; | |
1618 | struct page *page; | |
1619 | pgoff_t index, end_index; | |
1620 | loff_t isize, left; | |
1621 | int error, page_nr; | |
1622 | struct splice_pipe_desc spd = { | |
1623 | .pages = pages, | |
1624 | .partial = partial, | |
047fe360 | 1625 | .nr_pages_max = PIPE_DEF_BUFFERS, |
708e3508 HD |
1626 | .flags = flags, |
1627 | .ops = &page_cache_pipe_buf_ops, | |
1628 | .spd_release = spd_release_page, | |
1629 | }; | |
1630 | ||
71f0e07a | 1631 | isize = i_size_read(inode); |
708e3508 HD |
1632 | if (unlikely(*ppos >= isize)) |
1633 | return 0; | |
1634 | ||
1635 | left = isize - *ppos; | |
1636 | if (unlikely(left < len)) | |
1637 | len = left; | |
1638 | ||
1639 | if (splice_grow_spd(pipe, &spd)) | |
1640 | return -ENOMEM; | |
1641 | ||
1642 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1643 | loff = *ppos & ~PAGE_CACHE_MASK; | |
1644 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
a786c06d | 1645 | nr_pages = min(req_pages, spd.nr_pages_max); |
708e3508 | 1646 | |
708e3508 HD |
1647 | spd.nr_pages = find_get_pages_contig(mapping, index, |
1648 | nr_pages, spd.pages); | |
1649 | index += spd.nr_pages; | |
708e3508 | 1650 | error = 0; |
708e3508 | 1651 | |
71f0e07a | 1652 | while (spd.nr_pages < nr_pages) { |
71f0e07a HD |
1653 | error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
1654 | if (error) | |
1655 | break; | |
1656 | unlock_page(page); | |
708e3508 HD |
1657 | spd.pages[spd.nr_pages++] = page; |
1658 | index++; | |
1659 | } | |
1660 | ||
708e3508 HD |
1661 | index = *ppos >> PAGE_CACHE_SHIFT; |
1662 | nr_pages = spd.nr_pages; | |
1663 | spd.nr_pages = 0; | |
71f0e07a | 1664 | |
708e3508 HD |
1665 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
1666 | unsigned int this_len; | |
1667 | ||
1668 | if (!len) | |
1669 | break; | |
1670 | ||
708e3508 HD |
1671 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
1672 | page = spd.pages[page_nr]; | |
1673 | ||
71f0e07a | 1674 | if (!PageUptodate(page) || page->mapping != mapping) { |
71f0e07a HD |
1675 | error = shmem_getpage(inode, index, &page, |
1676 | SGP_CACHE, NULL); | |
1677 | if (error) | |
708e3508 | 1678 | break; |
71f0e07a HD |
1679 | unlock_page(page); |
1680 | page_cache_release(spd.pages[page_nr]); | |
1681 | spd.pages[page_nr] = page; | |
708e3508 | 1682 | } |
71f0e07a HD |
1683 | |
1684 | isize = i_size_read(inode); | |
708e3508 HD |
1685 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
1686 | if (unlikely(!isize || index > end_index)) | |
1687 | break; | |
1688 | ||
708e3508 HD |
1689 | if (end_index == index) { |
1690 | unsigned int plen; | |
1691 | ||
708e3508 HD |
1692 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
1693 | if (plen <= loff) | |
1694 | break; | |
1695 | ||
708e3508 HD |
1696 | this_len = min(this_len, plen - loff); |
1697 | len = this_len; | |
1698 | } | |
1699 | ||
1700 | spd.partial[page_nr].offset = loff; | |
1701 | spd.partial[page_nr].len = this_len; | |
1702 | len -= this_len; | |
1703 | loff = 0; | |
1704 | spd.nr_pages++; | |
1705 | index++; | |
1706 | } | |
1707 | ||
708e3508 HD |
1708 | while (page_nr < nr_pages) |
1709 | page_cache_release(spd.pages[page_nr++]); | |
708e3508 HD |
1710 | |
1711 | if (spd.nr_pages) | |
1712 | error = splice_to_pipe(pipe, &spd); | |
1713 | ||
047fe360 | 1714 | splice_shrink_spd(&spd); |
708e3508 HD |
1715 | |
1716 | if (error > 0) { | |
1717 | *ppos += error; | |
1718 | file_accessed(in); | |
1719 | } | |
1720 | return error; | |
1721 | } | |
1722 | ||
220f2ac9 HD |
1723 | /* |
1724 | * llseek SEEK_DATA or SEEK_HOLE through the radix_tree. | |
1725 | */ | |
1726 | static pgoff_t shmem_seek_hole_data(struct address_space *mapping, | |
965c8e59 | 1727 | pgoff_t index, pgoff_t end, int whence) |
220f2ac9 HD |
1728 | { |
1729 | struct page *page; | |
1730 | struct pagevec pvec; | |
1731 | pgoff_t indices[PAGEVEC_SIZE]; | |
1732 | bool done = false; | |
1733 | int i; | |
1734 | ||
1735 | pagevec_init(&pvec, 0); | |
1736 | pvec.nr = 1; /* start small: we may be there already */ | |
1737 | while (!done) { | |
0cd6144a | 1738 | pvec.nr = find_get_entries(mapping, index, |
220f2ac9 HD |
1739 | pvec.nr, pvec.pages, indices); |
1740 | if (!pvec.nr) { | |
965c8e59 | 1741 | if (whence == SEEK_DATA) |
220f2ac9 HD |
1742 | index = end; |
1743 | break; | |
1744 | } | |
1745 | for (i = 0; i < pvec.nr; i++, index++) { | |
1746 | if (index < indices[i]) { | |
965c8e59 | 1747 | if (whence == SEEK_HOLE) { |
220f2ac9 HD |
1748 | done = true; |
1749 | break; | |
1750 | } | |
1751 | index = indices[i]; | |
1752 | } | |
1753 | page = pvec.pages[i]; | |
1754 | if (page && !radix_tree_exceptional_entry(page)) { | |
1755 | if (!PageUptodate(page)) | |
1756 | page = NULL; | |
1757 | } | |
1758 | if (index >= end || | |
965c8e59 AM |
1759 | (page && whence == SEEK_DATA) || |
1760 | (!page && whence == SEEK_HOLE)) { | |
220f2ac9 HD |
1761 | done = true; |
1762 | break; | |
1763 | } | |
1764 | } | |
0cd6144a | 1765 | pagevec_remove_exceptionals(&pvec); |
220f2ac9 HD |
1766 | pagevec_release(&pvec); |
1767 | pvec.nr = PAGEVEC_SIZE; | |
1768 | cond_resched(); | |
1769 | } | |
1770 | return index; | |
1771 | } | |
1772 | ||
965c8e59 | 1773 | static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence) |
220f2ac9 HD |
1774 | { |
1775 | struct address_space *mapping = file->f_mapping; | |
1776 | struct inode *inode = mapping->host; | |
1777 | pgoff_t start, end; | |
1778 | loff_t new_offset; | |
1779 | ||
965c8e59 AM |
1780 | if (whence != SEEK_DATA && whence != SEEK_HOLE) |
1781 | return generic_file_llseek_size(file, offset, whence, | |
220f2ac9 HD |
1782 | MAX_LFS_FILESIZE, i_size_read(inode)); |
1783 | mutex_lock(&inode->i_mutex); | |
1784 | /* We're holding i_mutex so we can access i_size directly */ | |
1785 | ||
1786 | if (offset < 0) | |
1787 | offset = -EINVAL; | |
1788 | else if (offset >= inode->i_size) | |
1789 | offset = -ENXIO; | |
1790 | else { | |
1791 | start = offset >> PAGE_CACHE_SHIFT; | |
1792 | end = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
965c8e59 | 1793 | new_offset = shmem_seek_hole_data(mapping, start, end, whence); |
220f2ac9 HD |
1794 | new_offset <<= PAGE_CACHE_SHIFT; |
1795 | if (new_offset > offset) { | |
1796 | if (new_offset < inode->i_size) | |
1797 | offset = new_offset; | |
965c8e59 | 1798 | else if (whence == SEEK_DATA) |
220f2ac9 HD |
1799 | offset = -ENXIO; |
1800 | else | |
1801 | offset = inode->i_size; | |
1802 | } | |
1803 | } | |
1804 | ||
387aae6f HD |
1805 | if (offset >= 0) |
1806 | offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE); | |
220f2ac9 HD |
1807 | mutex_unlock(&inode->i_mutex); |
1808 | return offset; | |
1809 | } | |
1810 | ||
83e4fa9c HD |
1811 | static long shmem_fallocate(struct file *file, int mode, loff_t offset, |
1812 | loff_t len) | |
1813 | { | |
496ad9aa | 1814 | struct inode *inode = file_inode(file); |
e2d12e22 | 1815 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
1aac1400 | 1816 | struct shmem_falloc shmem_falloc; |
e2d12e22 HD |
1817 | pgoff_t start, index, end; |
1818 | int error; | |
83e4fa9c | 1819 | |
13ace4d0 HD |
1820 | if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) |
1821 | return -EOPNOTSUPP; | |
1822 | ||
83e4fa9c HD |
1823 | mutex_lock(&inode->i_mutex); |
1824 | ||
1825 | if (mode & FALLOC_FL_PUNCH_HOLE) { | |
1826 | struct address_space *mapping = file->f_mapping; | |
1827 | loff_t unmap_start = round_up(offset, PAGE_SIZE); | |
1828 | loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1; | |
8e205f77 | 1829 | DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq); |
83e4fa9c | 1830 | |
8e205f77 | 1831 | shmem_falloc.waitq = &shmem_falloc_waitq; |
f00cdc6d HD |
1832 | shmem_falloc.start = unmap_start >> PAGE_SHIFT; |
1833 | shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT; | |
1834 | spin_lock(&inode->i_lock); | |
1835 | inode->i_private = &shmem_falloc; | |
1836 | spin_unlock(&inode->i_lock); | |
1837 | ||
83e4fa9c HD |
1838 | if ((u64)unmap_end > (u64)unmap_start) |
1839 | unmap_mapping_range(mapping, unmap_start, | |
1840 | 1 + unmap_end - unmap_start, 0); | |
1841 | shmem_truncate_range(inode, offset, offset + len - 1); | |
1842 | /* No need to unmap again: hole-punching leaves COWed pages */ | |
8e205f77 HD |
1843 | |
1844 | spin_lock(&inode->i_lock); | |
1845 | inode->i_private = NULL; | |
1846 | wake_up_all(&shmem_falloc_waitq); | |
1847 | spin_unlock(&inode->i_lock); | |
83e4fa9c | 1848 | error = 0; |
8e205f77 | 1849 | goto out; |
e2d12e22 HD |
1850 | } |
1851 | ||
1852 | /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ | |
1853 | error = inode_newsize_ok(inode, offset + len); | |
1854 | if (error) | |
1855 | goto out; | |
1856 | ||
1857 | start = offset >> PAGE_CACHE_SHIFT; | |
1858 | end = (offset + len + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1859 | /* Try to avoid a swapstorm if len is impossible to satisfy */ | |
1860 | if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) { | |
1861 | error = -ENOSPC; | |
1862 | goto out; | |
83e4fa9c HD |
1863 | } |
1864 | ||
8e205f77 | 1865 | shmem_falloc.waitq = NULL; |
1aac1400 HD |
1866 | shmem_falloc.start = start; |
1867 | shmem_falloc.next = start; | |
1868 | shmem_falloc.nr_falloced = 0; | |
1869 | shmem_falloc.nr_unswapped = 0; | |
1870 | spin_lock(&inode->i_lock); | |
1871 | inode->i_private = &shmem_falloc; | |
1872 | spin_unlock(&inode->i_lock); | |
1873 | ||
e2d12e22 HD |
1874 | for (index = start; index < end; index++) { |
1875 | struct page *page; | |
1876 | ||
1877 | /* | |
1878 | * Good, the fallocate(2) manpage permits EINTR: we may have | |
1879 | * been interrupted because we are using up too much memory. | |
1880 | */ | |
1881 | if (signal_pending(current)) | |
1882 | error = -EINTR; | |
1aac1400 HD |
1883 | else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced) |
1884 | error = -ENOMEM; | |
e2d12e22 | 1885 | else |
1635f6a7 | 1886 | error = shmem_getpage(inode, index, &page, SGP_FALLOC, |
e2d12e22 HD |
1887 | NULL); |
1888 | if (error) { | |
1635f6a7 HD |
1889 | /* Remove the !PageUptodate pages we added */ |
1890 | shmem_undo_range(inode, | |
1891 | (loff_t)start << PAGE_CACHE_SHIFT, | |
1892 | (loff_t)index << PAGE_CACHE_SHIFT, true); | |
1aac1400 | 1893 | goto undone; |
e2d12e22 HD |
1894 | } |
1895 | ||
1aac1400 HD |
1896 | /* |
1897 | * Inform shmem_writepage() how far we have reached. | |
1898 | * No need for lock or barrier: we have the page lock. | |
1899 | */ | |
1900 | shmem_falloc.next++; | |
1901 | if (!PageUptodate(page)) | |
1902 | shmem_falloc.nr_falloced++; | |
1903 | ||
e2d12e22 | 1904 | /* |
1635f6a7 HD |
1905 | * If !PageUptodate, leave it that way so that freeable pages |
1906 | * can be recognized if we need to rollback on error later. | |
1907 | * But set_page_dirty so that memory pressure will swap rather | |
e2d12e22 HD |
1908 | * than free the pages we are allocating (and SGP_CACHE pages |
1909 | * might still be clean: we now need to mark those dirty too). | |
1910 | */ | |
1911 | set_page_dirty(page); | |
1912 | unlock_page(page); | |
1913 | page_cache_release(page); | |
1914 | cond_resched(); | |
1915 | } | |
1916 | ||
1917 | if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) | |
1918 | i_size_write(inode, offset + len); | |
e2d12e22 | 1919 | inode->i_ctime = CURRENT_TIME; |
1aac1400 HD |
1920 | undone: |
1921 | spin_lock(&inode->i_lock); | |
1922 | inode->i_private = NULL; | |
1923 | spin_unlock(&inode->i_lock); | |
e2d12e22 | 1924 | out: |
83e4fa9c HD |
1925 | mutex_unlock(&inode->i_mutex); |
1926 | return error; | |
1927 | } | |
1928 | ||
726c3342 | 1929 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1930 | { |
726c3342 | 1931 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1932 | |
1933 | buf->f_type = TMPFS_MAGIC; | |
1934 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1935 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1936 | if (sbinfo->max_blocks) { |
1da177e4 | 1937 | buf->f_blocks = sbinfo->max_blocks; |
41ffe5d5 HD |
1938 | buf->f_bavail = |
1939 | buf->f_bfree = sbinfo->max_blocks - | |
1940 | percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1941 | } |
1942 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1943 | buf->f_files = sbinfo->max_inodes; |
1944 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1945 | } |
1946 | /* else leave those fields 0 like simple_statfs */ | |
1947 | return 0; | |
1948 | } | |
1949 | ||
1950 | /* | |
1951 | * File creation. Allocate an inode, and we're done.. | |
1952 | */ | |
1953 | static int | |
1a67aafb | 1954 | shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 | 1955 | { |
0b0a0806 | 1956 | struct inode *inode; |
1da177e4 LT |
1957 | int error = -ENOSPC; |
1958 | ||
454abafe | 1959 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1960 | if (inode) { |
feda821e CH |
1961 | error = simple_acl_create(dir, inode); |
1962 | if (error) | |
1963 | goto out_iput; | |
2a7dba39 | 1964 | error = security_inode_init_security(inode, dir, |
9d8f13ba | 1965 | &dentry->d_name, |
6d9d88d0 | 1966 | shmem_initxattrs, NULL); |
feda821e CH |
1967 | if (error && error != -EOPNOTSUPP) |
1968 | goto out_iput; | |
37ec43cd | 1969 | |
718deb6b | 1970 | error = 0; |
1da177e4 LT |
1971 | dir->i_size += BOGO_DIRENT_SIZE; |
1972 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1973 | d_instantiate(dentry, inode); | |
1974 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1975 | } |
1976 | return error; | |
feda821e CH |
1977 | out_iput: |
1978 | iput(inode); | |
1979 | return error; | |
1da177e4 LT |
1980 | } |
1981 | ||
60545d0d AV |
1982 | static int |
1983 | shmem_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) | |
1984 | { | |
1985 | struct inode *inode; | |
1986 | int error = -ENOSPC; | |
1987 | ||
1988 | inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE); | |
1989 | if (inode) { | |
1990 | error = security_inode_init_security(inode, dir, | |
1991 | NULL, | |
1992 | shmem_initxattrs, NULL); | |
feda821e CH |
1993 | if (error && error != -EOPNOTSUPP) |
1994 | goto out_iput; | |
1995 | error = simple_acl_create(dir, inode); | |
1996 | if (error) | |
1997 | goto out_iput; | |
60545d0d AV |
1998 | d_tmpfile(dentry, inode); |
1999 | } | |
2000 | return error; | |
feda821e CH |
2001 | out_iput: |
2002 | iput(inode); | |
2003 | return error; | |
60545d0d AV |
2004 | } |
2005 | ||
18bb1db3 | 2006 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
2007 | { |
2008 | int error; | |
2009 | ||
2010 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
2011 | return error; | |
d8c76e6f | 2012 | inc_nlink(dir); |
1da177e4 LT |
2013 | return 0; |
2014 | } | |
2015 | ||
4acdaf27 | 2016 | static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
ebfc3b49 | 2017 | bool excl) |
1da177e4 LT |
2018 | { |
2019 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
2020 | } | |
2021 | ||
2022 | /* | |
2023 | * Link a file.. | |
2024 | */ | |
2025 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
2026 | { | |
2027 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 2028 | int ret; |
1da177e4 LT |
2029 | |
2030 | /* | |
2031 | * No ordinary (disk based) filesystem counts links as inodes; | |
2032 | * but each new link needs a new dentry, pinning lowmem, and | |
2033 | * tmpfs dentries cannot be pruned until they are unlinked. | |
2034 | */ | |
5b04c689 PE |
2035 | ret = shmem_reserve_inode(inode->i_sb); |
2036 | if (ret) | |
2037 | goto out; | |
1da177e4 LT |
2038 | |
2039 | dir->i_size += BOGO_DIRENT_SIZE; | |
2040 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 2041 | inc_nlink(inode); |
7de9c6ee | 2042 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
2043 | dget(dentry); /* Extra pinning count for the created dentry */ |
2044 | d_instantiate(dentry, inode); | |
5b04c689 PE |
2045 | out: |
2046 | return ret; | |
1da177e4 LT |
2047 | } |
2048 | ||
2049 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
2050 | { | |
2051 | struct inode *inode = dentry->d_inode; | |
2052 | ||
5b04c689 PE |
2053 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
2054 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
2055 | |
2056 | dir->i_size -= BOGO_DIRENT_SIZE; | |
2057 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 2058 | drop_nlink(inode); |
1da177e4 LT |
2059 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
2060 | return 0; | |
2061 | } | |
2062 | ||
2063 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
2064 | { | |
2065 | if (!simple_empty(dentry)) | |
2066 | return -ENOTEMPTY; | |
2067 | ||
9a53c3a7 DH |
2068 | drop_nlink(dentry->d_inode); |
2069 | drop_nlink(dir); | |
1da177e4 LT |
2070 | return shmem_unlink(dir, dentry); |
2071 | } | |
2072 | ||
2073 | /* | |
2074 | * The VFS layer already does all the dentry stuff for rename, | |
2075 | * we just have to decrement the usage count for the target if | |
2076 | * it exists so that the VFS layer correctly free's it when it | |
2077 | * gets overwritten. | |
2078 | */ | |
2079 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
2080 | { | |
2081 | struct inode *inode = old_dentry->d_inode; | |
2082 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
2083 | ||
2084 | if (!simple_empty(new_dentry)) | |
2085 | return -ENOTEMPTY; | |
2086 | ||
2087 | if (new_dentry->d_inode) { | |
2088 | (void) shmem_unlink(new_dir, new_dentry); | |
2089 | if (they_are_dirs) | |
9a53c3a7 | 2090 | drop_nlink(old_dir); |
1da177e4 | 2091 | } else if (they_are_dirs) { |
9a53c3a7 | 2092 | drop_nlink(old_dir); |
d8c76e6f | 2093 | inc_nlink(new_dir); |
1da177e4 LT |
2094 | } |
2095 | ||
2096 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
2097 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
2098 | old_dir->i_ctime = old_dir->i_mtime = | |
2099 | new_dir->i_ctime = new_dir->i_mtime = | |
2100 | inode->i_ctime = CURRENT_TIME; | |
2101 | return 0; | |
2102 | } | |
2103 | ||
2104 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
2105 | { | |
2106 | int error; | |
2107 | int len; | |
2108 | struct inode *inode; | |
9276aad6 | 2109 | struct page *page; |
1da177e4 LT |
2110 | char *kaddr; |
2111 | struct shmem_inode_info *info; | |
2112 | ||
2113 | len = strlen(symname) + 1; | |
2114 | if (len > PAGE_CACHE_SIZE) | |
2115 | return -ENAMETOOLONG; | |
2116 | ||
454abafe | 2117 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
2118 | if (!inode) |
2119 | return -ENOSPC; | |
2120 | ||
9d8f13ba | 2121 | error = security_inode_init_security(inode, dir, &dentry->d_name, |
6d9d88d0 | 2122 | shmem_initxattrs, NULL); |
570bc1c2 SS |
2123 | if (error) { |
2124 | if (error != -EOPNOTSUPP) { | |
2125 | iput(inode); | |
2126 | return error; | |
2127 | } | |
2128 | error = 0; | |
2129 | } | |
2130 | ||
1da177e4 LT |
2131 | info = SHMEM_I(inode); |
2132 | inode->i_size = len-1; | |
69f07ec9 HD |
2133 | if (len <= SHORT_SYMLINK_LEN) { |
2134 | info->symlink = kmemdup(symname, len, GFP_KERNEL); | |
2135 | if (!info->symlink) { | |
2136 | iput(inode); | |
2137 | return -ENOMEM; | |
2138 | } | |
2139 | inode->i_op = &shmem_short_symlink_operations; | |
1da177e4 LT |
2140 | } else { |
2141 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
2142 | if (error) { | |
2143 | iput(inode); | |
2144 | return error; | |
2145 | } | |
14fcc23f | 2146 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 | 2147 | inode->i_op = &shmem_symlink_inode_operations; |
9b04c5fe | 2148 | kaddr = kmap_atomic(page); |
1da177e4 | 2149 | memcpy(kaddr, symname, len); |
9b04c5fe | 2150 | kunmap_atomic(kaddr); |
ec9516fb | 2151 | SetPageUptodate(page); |
1da177e4 | 2152 | set_page_dirty(page); |
6746aff7 | 2153 | unlock_page(page); |
1da177e4 LT |
2154 | page_cache_release(page); |
2155 | } | |
1da177e4 LT |
2156 | dir->i_size += BOGO_DIRENT_SIZE; |
2157 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
2158 | d_instantiate(dentry, inode); | |
2159 | dget(dentry); | |
2160 | return 0; | |
2161 | } | |
2162 | ||
69f07ec9 | 2163 | static void *shmem_follow_short_symlink(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 2164 | { |
69f07ec9 | 2165 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->symlink); |
cc314eef | 2166 | return NULL; |
1da177e4 LT |
2167 | } |
2168 | ||
cc314eef | 2169 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
2170 | { |
2171 | struct page *page = NULL; | |
41ffe5d5 HD |
2172 | int error = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); |
2173 | nd_set_link(nd, error ? ERR_PTR(error) : kmap(page)); | |
d3602444 HD |
2174 | if (page) |
2175 | unlock_page(page); | |
cc314eef | 2176 | return page; |
1da177e4 LT |
2177 | } |
2178 | ||
cc314eef | 2179 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
2180 | { |
2181 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 2182 | struct page *page = cookie; |
1da177e4 LT |
2183 | kunmap(page); |
2184 | mark_page_accessed(page); | |
2185 | page_cache_release(page); | |
1da177e4 LT |
2186 | } |
2187 | } | |
2188 | ||
b09e0fa4 | 2189 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 2190 | /* |
b09e0fa4 EP |
2191 | * Superblocks without xattr inode operations may get some security.* xattr |
2192 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
2193 | * like ACLs, we also need to implement the security.* handlers at |
2194 | * filesystem level, though. | |
2195 | */ | |
2196 | ||
6d9d88d0 JS |
2197 | /* |
2198 | * Callback for security_inode_init_security() for acquiring xattrs. | |
2199 | */ | |
2200 | static int shmem_initxattrs(struct inode *inode, | |
2201 | const struct xattr *xattr_array, | |
2202 | void *fs_info) | |
2203 | { | |
2204 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2205 | const struct xattr *xattr; | |
38f38657 | 2206 | struct simple_xattr *new_xattr; |
6d9d88d0 JS |
2207 | size_t len; |
2208 | ||
2209 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { | |
38f38657 | 2210 | new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); |
6d9d88d0 JS |
2211 | if (!new_xattr) |
2212 | return -ENOMEM; | |
2213 | ||
2214 | len = strlen(xattr->name) + 1; | |
2215 | new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len, | |
2216 | GFP_KERNEL); | |
2217 | if (!new_xattr->name) { | |
2218 | kfree(new_xattr); | |
2219 | return -ENOMEM; | |
2220 | } | |
2221 | ||
2222 | memcpy(new_xattr->name, XATTR_SECURITY_PREFIX, | |
2223 | XATTR_SECURITY_PREFIX_LEN); | |
2224 | memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, | |
2225 | xattr->name, len); | |
2226 | ||
38f38657 | 2227 | simple_xattr_list_add(&info->xattrs, new_xattr); |
6d9d88d0 JS |
2228 | } |
2229 | ||
2230 | return 0; | |
2231 | } | |
2232 | ||
bb435453 | 2233 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 2234 | #ifdef CONFIG_TMPFS_POSIX_ACL |
feda821e CH |
2235 | &posix_acl_access_xattr_handler, |
2236 | &posix_acl_default_xattr_handler, | |
b09e0fa4 | 2237 | #endif |
39f0247d AG |
2238 | NULL |
2239 | }; | |
b09e0fa4 EP |
2240 | |
2241 | static int shmem_xattr_validate(const char *name) | |
2242 | { | |
2243 | struct { const char *prefix; size_t len; } arr[] = { | |
2244 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
2245 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
2246 | }; | |
2247 | int i; | |
2248 | ||
2249 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
2250 | size_t preflen = arr[i].len; | |
2251 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
2252 | if (!name[preflen]) | |
2253 | return -EINVAL; | |
2254 | return 0; | |
2255 | } | |
2256 | } | |
2257 | return -EOPNOTSUPP; | |
2258 | } | |
2259 | ||
2260 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
2261 | void *buffer, size_t size) | |
2262 | { | |
38f38657 | 2263 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
b09e0fa4 EP |
2264 | int err; |
2265 | ||
2266 | /* | |
2267 | * If this is a request for a synthetic attribute in the system.* | |
2268 | * namespace use the generic infrastructure to resolve a handler | |
2269 | * for it via sb->s_xattr. | |
2270 | */ | |
2271 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2272 | return generic_getxattr(dentry, name, buffer, size); | |
2273 | ||
2274 | err = shmem_xattr_validate(name); | |
2275 | if (err) | |
2276 | return err; | |
2277 | ||
38f38657 | 2278 | return simple_xattr_get(&info->xattrs, name, buffer, size); |
b09e0fa4 EP |
2279 | } |
2280 | ||
2281 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
2282 | const void *value, size_t size, int flags) | |
2283 | { | |
38f38657 | 2284 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
b09e0fa4 EP |
2285 | int err; |
2286 | ||
2287 | /* | |
2288 | * If this is a request for a synthetic attribute in the system.* | |
2289 | * namespace use the generic infrastructure to resolve a handler | |
2290 | * for it via sb->s_xattr. | |
2291 | */ | |
2292 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2293 | return generic_setxattr(dentry, name, value, size, flags); | |
2294 | ||
2295 | err = shmem_xattr_validate(name); | |
2296 | if (err) | |
2297 | return err; | |
2298 | ||
38f38657 | 2299 | return simple_xattr_set(&info->xattrs, name, value, size, flags); |
b09e0fa4 EP |
2300 | } |
2301 | ||
2302 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
2303 | { | |
38f38657 | 2304 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
b09e0fa4 EP |
2305 | int err; |
2306 | ||
2307 | /* | |
2308 | * If this is a request for a synthetic attribute in the system.* | |
2309 | * namespace use the generic infrastructure to resolve a handler | |
2310 | * for it via sb->s_xattr. | |
2311 | */ | |
2312 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2313 | return generic_removexattr(dentry, name); | |
2314 | ||
2315 | err = shmem_xattr_validate(name); | |
2316 | if (err) | |
2317 | return err; | |
2318 | ||
38f38657 | 2319 | return simple_xattr_remove(&info->xattrs, name); |
b09e0fa4 EP |
2320 | } |
2321 | ||
2322 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
2323 | { | |
38f38657 AR |
2324 | struct shmem_inode_info *info = SHMEM_I(dentry->d_inode); |
2325 | return simple_xattr_list(&info->xattrs, buffer, size); | |
b09e0fa4 EP |
2326 | } |
2327 | #endif /* CONFIG_TMPFS_XATTR */ | |
2328 | ||
69f07ec9 | 2329 | static const struct inode_operations shmem_short_symlink_operations = { |
b09e0fa4 | 2330 | .readlink = generic_readlink, |
69f07ec9 | 2331 | .follow_link = shmem_follow_short_symlink, |
b09e0fa4 EP |
2332 | #ifdef CONFIG_TMPFS_XATTR |
2333 | .setxattr = shmem_setxattr, | |
2334 | .getxattr = shmem_getxattr, | |
2335 | .listxattr = shmem_listxattr, | |
2336 | .removexattr = shmem_removexattr, | |
2337 | #endif | |
2338 | }; | |
2339 | ||
2340 | static const struct inode_operations shmem_symlink_inode_operations = { | |
2341 | .readlink = generic_readlink, | |
2342 | .follow_link = shmem_follow_link, | |
2343 | .put_link = shmem_put_link, | |
2344 | #ifdef CONFIG_TMPFS_XATTR | |
2345 | .setxattr = shmem_setxattr, | |
2346 | .getxattr = shmem_getxattr, | |
2347 | .listxattr = shmem_listxattr, | |
2348 | .removexattr = shmem_removexattr, | |
39f0247d | 2349 | #endif |
b09e0fa4 | 2350 | }; |
39f0247d | 2351 | |
91828a40 DG |
2352 | static struct dentry *shmem_get_parent(struct dentry *child) |
2353 | { | |
2354 | return ERR_PTR(-ESTALE); | |
2355 | } | |
2356 | ||
2357 | static int shmem_match(struct inode *ino, void *vfh) | |
2358 | { | |
2359 | __u32 *fh = vfh; | |
2360 | __u64 inum = fh[2]; | |
2361 | inum = (inum << 32) | fh[1]; | |
2362 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2363 | } | |
2364 | ||
480b116c CH |
2365 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2366 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2367 | { |
91828a40 | 2368 | struct inode *inode; |
480b116c | 2369 | struct dentry *dentry = NULL; |
35c2a7f4 | 2370 | u64 inum; |
480b116c CH |
2371 | |
2372 | if (fh_len < 3) | |
2373 | return NULL; | |
91828a40 | 2374 | |
35c2a7f4 HD |
2375 | inum = fid->raw[2]; |
2376 | inum = (inum << 32) | fid->raw[1]; | |
2377 | ||
480b116c CH |
2378 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2379 | shmem_match, fid->raw); | |
91828a40 | 2380 | if (inode) { |
480b116c | 2381 | dentry = d_find_alias(inode); |
91828a40 DG |
2382 | iput(inode); |
2383 | } | |
2384 | ||
480b116c | 2385 | return dentry; |
91828a40 DG |
2386 | } |
2387 | ||
b0b0382b AV |
2388 | static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len, |
2389 | struct inode *parent) | |
91828a40 | 2390 | { |
5fe0c237 AK |
2391 | if (*len < 3) { |
2392 | *len = 3; | |
94e07a75 | 2393 | return FILEID_INVALID; |
5fe0c237 | 2394 | } |
91828a40 | 2395 | |
1d3382cb | 2396 | if (inode_unhashed(inode)) { |
91828a40 DG |
2397 | /* Unfortunately insert_inode_hash is not idempotent, |
2398 | * so as we hash inodes here rather than at creation | |
2399 | * time, we need a lock to ensure we only try | |
2400 | * to do it once | |
2401 | */ | |
2402 | static DEFINE_SPINLOCK(lock); | |
2403 | spin_lock(&lock); | |
1d3382cb | 2404 | if (inode_unhashed(inode)) |
91828a40 DG |
2405 | __insert_inode_hash(inode, |
2406 | inode->i_ino + inode->i_generation); | |
2407 | spin_unlock(&lock); | |
2408 | } | |
2409 | ||
2410 | fh[0] = inode->i_generation; | |
2411 | fh[1] = inode->i_ino; | |
2412 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2413 | ||
2414 | *len = 3; | |
2415 | return 1; | |
2416 | } | |
2417 | ||
39655164 | 2418 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2419 | .get_parent = shmem_get_parent, |
91828a40 | 2420 | .encode_fh = shmem_encode_fh, |
480b116c | 2421 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2422 | }; |
2423 | ||
680d794b AM |
2424 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2425 | bool remount) | |
1da177e4 LT |
2426 | { |
2427 | char *this_char, *value, *rest; | |
49cd0a5c | 2428 | struct mempolicy *mpol = NULL; |
8751e039 EB |
2429 | uid_t uid; |
2430 | gid_t gid; | |
1da177e4 | 2431 | |
b00dc3ad HD |
2432 | while (options != NULL) { |
2433 | this_char = options; | |
2434 | for (;;) { | |
2435 | /* | |
2436 | * NUL-terminate this option: unfortunately, | |
2437 | * mount options form a comma-separated list, | |
2438 | * but mpol's nodelist may also contain commas. | |
2439 | */ | |
2440 | options = strchr(options, ','); | |
2441 | if (options == NULL) | |
2442 | break; | |
2443 | options++; | |
2444 | if (!isdigit(*options)) { | |
2445 | options[-1] = '\0'; | |
2446 | break; | |
2447 | } | |
2448 | } | |
1da177e4 LT |
2449 | if (!*this_char) |
2450 | continue; | |
2451 | if ((value = strchr(this_char,'=')) != NULL) { | |
2452 | *value++ = 0; | |
2453 | } else { | |
2454 | printk(KERN_ERR | |
2455 | "tmpfs: No value for mount option '%s'\n", | |
2456 | this_char); | |
49cd0a5c | 2457 | goto error; |
1da177e4 LT |
2458 | } |
2459 | ||
2460 | if (!strcmp(this_char,"size")) { | |
2461 | unsigned long long size; | |
2462 | size = memparse(value,&rest); | |
2463 | if (*rest == '%') { | |
2464 | size <<= PAGE_SHIFT; | |
2465 | size *= totalram_pages; | |
2466 | do_div(size, 100); | |
2467 | rest++; | |
2468 | } | |
2469 | if (*rest) | |
2470 | goto bad_val; | |
680d794b AM |
2471 | sbinfo->max_blocks = |
2472 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2473 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2474 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2475 | if (*rest) |
2476 | goto bad_val; | |
2477 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2478 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2479 | if (*rest) |
2480 | goto bad_val; | |
2481 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2482 | if (remount) |
1da177e4 | 2483 | continue; |
680d794b | 2484 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2485 | if (*rest) |
2486 | goto bad_val; | |
2487 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2488 | if (remount) |
1da177e4 | 2489 | continue; |
8751e039 | 2490 | uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2491 | if (*rest) |
2492 | goto bad_val; | |
8751e039 EB |
2493 | sbinfo->uid = make_kuid(current_user_ns(), uid); |
2494 | if (!uid_valid(sbinfo->uid)) | |
2495 | goto bad_val; | |
1da177e4 | 2496 | } else if (!strcmp(this_char,"gid")) { |
680d794b | 2497 | if (remount) |
1da177e4 | 2498 | continue; |
8751e039 | 2499 | gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2500 | if (*rest) |
2501 | goto bad_val; | |
8751e039 EB |
2502 | sbinfo->gid = make_kgid(current_user_ns(), gid); |
2503 | if (!gid_valid(sbinfo->gid)) | |
2504 | goto bad_val; | |
7339ff83 | 2505 | } else if (!strcmp(this_char,"mpol")) { |
49cd0a5c GT |
2506 | mpol_put(mpol); |
2507 | mpol = NULL; | |
2508 | if (mpol_parse_str(value, &mpol)) | |
7339ff83 | 2509 | goto bad_val; |
1da177e4 LT |
2510 | } else { |
2511 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2512 | this_char); | |
49cd0a5c | 2513 | goto error; |
1da177e4 LT |
2514 | } |
2515 | } | |
49cd0a5c | 2516 | sbinfo->mpol = mpol; |
1da177e4 LT |
2517 | return 0; |
2518 | ||
2519 | bad_val: | |
2520 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2521 | value, this_char); | |
49cd0a5c GT |
2522 | error: |
2523 | mpol_put(mpol); | |
1da177e4 LT |
2524 | return 1; |
2525 | ||
2526 | } | |
2527 | ||
2528 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2529 | { | |
2530 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2531 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2532 | unsigned long inodes; |
2533 | int error = -EINVAL; | |
2534 | ||
5f00110f | 2535 | config.mpol = NULL; |
680d794b | 2536 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2537 | return error; |
1da177e4 | 2538 | |
0edd73b3 | 2539 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2540 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2541 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2542 | goto out; |
680d794b | 2543 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2544 | goto out; |
2545 | /* | |
54af6042 | 2546 | * Those tests disallow limited->unlimited while any are in use; |
0edd73b3 HD |
2547 | * but we must separately disallow unlimited->limited, because |
2548 | * in that case we have no record of how much is already in use. | |
2549 | */ | |
680d794b | 2550 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2551 | goto out; |
680d794b | 2552 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2553 | goto out; |
2554 | ||
2555 | error = 0; | |
680d794b | 2556 | sbinfo->max_blocks = config.max_blocks; |
680d794b AM |
2557 | sbinfo->max_inodes = config.max_inodes; |
2558 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b | 2559 | |
5f00110f GT |
2560 | /* |
2561 | * Preserve previous mempolicy unless mpol remount option was specified. | |
2562 | */ | |
2563 | if (config.mpol) { | |
2564 | mpol_put(sbinfo->mpol); | |
2565 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
2566 | } | |
0edd73b3 HD |
2567 | out: |
2568 | spin_unlock(&sbinfo->stat_lock); | |
2569 | return error; | |
1da177e4 | 2570 | } |
680d794b | 2571 | |
34c80b1d | 2572 | static int shmem_show_options(struct seq_file *seq, struct dentry *root) |
680d794b | 2573 | { |
34c80b1d | 2574 | struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); |
680d794b AM |
2575 | |
2576 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2577 | seq_printf(seq, ",size=%luk", | |
2578 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2579 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2580 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2581 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
09208d15 | 2582 | seq_printf(seq, ",mode=%03ho", sbinfo->mode); |
8751e039 EB |
2583 | if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) |
2584 | seq_printf(seq, ",uid=%u", | |
2585 | from_kuid_munged(&init_user_ns, sbinfo->uid)); | |
2586 | if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) | |
2587 | seq_printf(seq, ",gid=%u", | |
2588 | from_kgid_munged(&init_user_ns, sbinfo->gid)); | |
71fe804b | 2589 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b AM |
2590 | return 0; |
2591 | } | |
2592 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2593 | |
2594 | static void shmem_put_super(struct super_block *sb) | |
2595 | { | |
602586a8 HD |
2596 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2597 | ||
2598 | percpu_counter_destroy(&sbinfo->used_blocks); | |
49cd0a5c | 2599 | mpol_put(sbinfo->mpol); |
602586a8 | 2600 | kfree(sbinfo); |
1da177e4 LT |
2601 | sb->s_fs_info = NULL; |
2602 | } | |
2603 | ||
2b2af54a | 2604 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2605 | { |
2606 | struct inode *inode; | |
0edd73b3 | 2607 | struct shmem_sb_info *sbinfo; |
680d794b AM |
2608 | int err = -ENOMEM; |
2609 | ||
2610 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2611 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b AM |
2612 | L1_CACHE_BYTES), GFP_KERNEL); |
2613 | if (!sbinfo) | |
2614 | return -ENOMEM; | |
2615 | ||
680d794b | 2616 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2617 | sbinfo->uid = current_fsuid(); |
2618 | sbinfo->gid = current_fsgid(); | |
680d794b | 2619 | sb->s_fs_info = sbinfo; |
1da177e4 | 2620 | |
0edd73b3 | 2621 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2622 | /* |
2623 | * Per default we only allow half of the physical ram per | |
2624 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2625 | * but the internal instance is left unlimited. | |
2626 | */ | |
ca4e0519 | 2627 | if (!(sb->s_flags & MS_KERNMOUNT)) { |
680d794b AM |
2628 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2629 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2630 | if (shmem_parse_options(data, sbinfo, false)) { | |
2631 | err = -EINVAL; | |
2632 | goto failed; | |
2633 | } | |
ca4e0519 AV |
2634 | } else { |
2635 | sb->s_flags |= MS_NOUSER; | |
1da177e4 | 2636 | } |
91828a40 | 2637 | sb->s_export_op = &shmem_export_ops; |
2f6e38f3 | 2638 | sb->s_flags |= MS_NOSEC; |
1da177e4 LT |
2639 | #else |
2640 | sb->s_flags |= MS_NOUSER; | |
2641 | #endif | |
2642 | ||
0edd73b3 | 2643 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2644 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2645 | goto failed; | |
680d794b | 2646 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2647 | |
285b2c4f | 2648 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 LT |
2649 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2650 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2651 | sb->s_magic = TMPFS_MAGIC; | |
2652 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2653 | sb->s_time_gran = 1; |
b09e0fa4 | 2654 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2655 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2656 | #endif |
2657 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2658 | sb->s_flags |= MS_POSIXACL; |
2659 | #endif | |
0edd73b3 | 2660 | |
454abafe | 2661 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2662 | if (!inode) |
2663 | goto failed; | |
680d794b AM |
2664 | inode->i_uid = sbinfo->uid; |
2665 | inode->i_gid = sbinfo->gid; | |
318ceed0 AV |
2666 | sb->s_root = d_make_root(inode); |
2667 | if (!sb->s_root) | |
48fde701 | 2668 | goto failed; |
1da177e4 LT |
2669 | return 0; |
2670 | ||
1da177e4 LT |
2671 | failed: |
2672 | shmem_put_super(sb); | |
2673 | return err; | |
2674 | } | |
2675 | ||
fcc234f8 | 2676 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2677 | |
2678 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2679 | { | |
41ffe5d5 HD |
2680 | struct shmem_inode_info *info; |
2681 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
2682 | if (!info) | |
1da177e4 | 2683 | return NULL; |
41ffe5d5 | 2684 | return &info->vfs_inode; |
1da177e4 LT |
2685 | } |
2686 | ||
41ffe5d5 | 2687 | static void shmem_destroy_callback(struct rcu_head *head) |
fa0d7e3d NP |
2688 | { |
2689 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
fa0d7e3d NP |
2690 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2691 | } | |
2692 | ||
1da177e4 LT |
2693 | static void shmem_destroy_inode(struct inode *inode) |
2694 | { | |
09208d15 | 2695 | if (S_ISREG(inode->i_mode)) |
1da177e4 | 2696 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
41ffe5d5 | 2697 | call_rcu(&inode->i_rcu, shmem_destroy_callback); |
1da177e4 LT |
2698 | } |
2699 | ||
41ffe5d5 | 2700 | static void shmem_init_inode(void *foo) |
1da177e4 | 2701 | { |
41ffe5d5 HD |
2702 | struct shmem_inode_info *info = foo; |
2703 | inode_init_once(&info->vfs_inode); | |
1da177e4 LT |
2704 | } |
2705 | ||
41ffe5d5 | 2706 | static int shmem_init_inodecache(void) |
1da177e4 LT |
2707 | { |
2708 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2709 | sizeof(struct shmem_inode_info), | |
41ffe5d5 | 2710 | 0, SLAB_PANIC, shmem_init_inode); |
1da177e4 LT |
2711 | return 0; |
2712 | } | |
2713 | ||
41ffe5d5 | 2714 | static void shmem_destroy_inodecache(void) |
1da177e4 | 2715 | { |
1a1d92c1 | 2716 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2717 | } |
2718 | ||
f5e54d6e | 2719 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2720 | .writepage = shmem_writepage, |
76719325 | 2721 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2722 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
2723 | .write_begin = shmem_write_begin, |
2724 | .write_end = shmem_write_end, | |
1da177e4 | 2725 | #endif |
304dbdb7 | 2726 | .migratepage = migrate_page, |
aa261f54 | 2727 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2728 | }; |
2729 | ||
15ad7cdc | 2730 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2731 | .mmap = shmem_mmap, |
2732 | #ifdef CONFIG_TMPFS | |
220f2ac9 | 2733 | .llseek = shmem_file_llseek, |
2ba5bbed | 2734 | .read = new_sync_read, |
8174202b | 2735 | .write = new_sync_write, |
2ba5bbed | 2736 | .read_iter = shmem_file_read_iter, |
8174202b | 2737 | .write_iter = generic_file_write_iter, |
1b061d92 | 2738 | .fsync = noop_fsync, |
708e3508 | 2739 | .splice_read = shmem_file_splice_read, |
f6cb85d0 | 2740 | .splice_write = iter_file_splice_write, |
83e4fa9c | 2741 | .fallocate = shmem_fallocate, |
1da177e4 LT |
2742 | #endif |
2743 | }; | |
2744 | ||
92e1d5be | 2745 | static const struct inode_operations shmem_inode_operations = { |
94c1e62d | 2746 | .setattr = shmem_setattr, |
b09e0fa4 EP |
2747 | #ifdef CONFIG_TMPFS_XATTR |
2748 | .setxattr = shmem_setxattr, | |
2749 | .getxattr = shmem_getxattr, | |
2750 | .listxattr = shmem_listxattr, | |
2751 | .removexattr = shmem_removexattr, | |
feda821e | 2752 | .set_acl = simple_set_acl, |
b09e0fa4 | 2753 | #endif |
1da177e4 LT |
2754 | }; |
2755 | ||
92e1d5be | 2756 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2757 | #ifdef CONFIG_TMPFS |
2758 | .create = shmem_create, | |
2759 | .lookup = simple_lookup, | |
2760 | .link = shmem_link, | |
2761 | .unlink = shmem_unlink, | |
2762 | .symlink = shmem_symlink, | |
2763 | .mkdir = shmem_mkdir, | |
2764 | .rmdir = shmem_rmdir, | |
2765 | .mknod = shmem_mknod, | |
2766 | .rename = shmem_rename, | |
60545d0d | 2767 | .tmpfile = shmem_tmpfile, |
1da177e4 | 2768 | #endif |
b09e0fa4 EP |
2769 | #ifdef CONFIG_TMPFS_XATTR |
2770 | .setxattr = shmem_setxattr, | |
2771 | .getxattr = shmem_getxattr, | |
2772 | .listxattr = shmem_listxattr, | |
2773 | .removexattr = shmem_removexattr, | |
2774 | #endif | |
39f0247d | 2775 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2776 | .setattr = shmem_setattr, |
feda821e | 2777 | .set_acl = simple_set_acl, |
39f0247d AG |
2778 | #endif |
2779 | }; | |
2780 | ||
92e1d5be | 2781 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2782 | #ifdef CONFIG_TMPFS_XATTR |
2783 | .setxattr = shmem_setxattr, | |
2784 | .getxattr = shmem_getxattr, | |
2785 | .listxattr = shmem_listxattr, | |
2786 | .removexattr = shmem_removexattr, | |
2787 | #endif | |
39f0247d | 2788 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2789 | .setattr = shmem_setattr, |
feda821e | 2790 | .set_acl = simple_set_acl, |
39f0247d | 2791 | #endif |
1da177e4 LT |
2792 | }; |
2793 | ||
759b9775 | 2794 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2795 | .alloc_inode = shmem_alloc_inode, |
2796 | .destroy_inode = shmem_destroy_inode, | |
2797 | #ifdef CONFIG_TMPFS | |
2798 | .statfs = shmem_statfs, | |
2799 | .remount_fs = shmem_remount_fs, | |
680d794b | 2800 | .show_options = shmem_show_options, |
1da177e4 | 2801 | #endif |
1f895f75 | 2802 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2803 | .drop_inode = generic_delete_inode, |
2804 | .put_super = shmem_put_super, | |
2805 | }; | |
2806 | ||
f0f37e2f | 2807 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2808 | .fault = shmem_fault, |
d7c17551 | 2809 | .map_pages = filemap_map_pages, |
1da177e4 LT |
2810 | #ifdef CONFIG_NUMA |
2811 | .set_policy = shmem_set_policy, | |
2812 | .get_policy = shmem_get_policy, | |
2813 | #endif | |
0b173bc4 | 2814 | .remap_pages = generic_file_remap_pages, |
1da177e4 LT |
2815 | }; |
2816 | ||
3c26ff6e AV |
2817 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2818 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2819 | { |
3c26ff6e | 2820 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2821 | } |
2822 | ||
41ffe5d5 | 2823 | static struct file_system_type shmem_fs_type = { |
1da177e4 LT |
2824 | .owner = THIS_MODULE, |
2825 | .name = "tmpfs", | |
3c26ff6e | 2826 | .mount = shmem_mount, |
1da177e4 | 2827 | .kill_sb = kill_litter_super, |
2b8576cb | 2828 | .fs_flags = FS_USERNS_MOUNT, |
1da177e4 | 2829 | }; |
1da177e4 | 2830 | |
41ffe5d5 | 2831 | int __init shmem_init(void) |
1da177e4 LT |
2832 | { |
2833 | int error; | |
2834 | ||
16203a7a RL |
2835 | /* If rootfs called this, don't re-init */ |
2836 | if (shmem_inode_cachep) | |
2837 | return 0; | |
2838 | ||
e0bf68dd PZ |
2839 | error = bdi_init(&shmem_backing_dev_info); |
2840 | if (error) | |
2841 | goto out4; | |
2842 | ||
41ffe5d5 | 2843 | error = shmem_init_inodecache(); |
1da177e4 LT |
2844 | if (error) |
2845 | goto out3; | |
2846 | ||
41ffe5d5 | 2847 | error = register_filesystem(&shmem_fs_type); |
1da177e4 LT |
2848 | if (error) { |
2849 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2850 | goto out2; | |
2851 | } | |
95dc112a | 2852 | |
ca4e0519 | 2853 | shm_mnt = kern_mount(&shmem_fs_type); |
1da177e4 LT |
2854 | if (IS_ERR(shm_mnt)) { |
2855 | error = PTR_ERR(shm_mnt); | |
2856 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2857 | goto out1; | |
2858 | } | |
2859 | return 0; | |
2860 | ||
2861 | out1: | |
41ffe5d5 | 2862 | unregister_filesystem(&shmem_fs_type); |
1da177e4 | 2863 | out2: |
41ffe5d5 | 2864 | shmem_destroy_inodecache(); |
1da177e4 | 2865 | out3: |
e0bf68dd PZ |
2866 | bdi_destroy(&shmem_backing_dev_info); |
2867 | out4: | |
1da177e4 LT |
2868 | shm_mnt = ERR_PTR(error); |
2869 | return error; | |
2870 | } | |
853ac43a MM |
2871 | |
2872 | #else /* !CONFIG_SHMEM */ | |
2873 | ||
2874 | /* | |
2875 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2876 | * | |
2877 | * This is intended for small system where the benefits of the full | |
2878 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2879 | * their complexity. On systems without swap this code should be | |
2880 | * effectively equivalent, but much lighter weight. | |
2881 | */ | |
2882 | ||
41ffe5d5 | 2883 | static struct file_system_type shmem_fs_type = { |
853ac43a | 2884 | .name = "tmpfs", |
3c26ff6e | 2885 | .mount = ramfs_mount, |
853ac43a | 2886 | .kill_sb = kill_litter_super, |
2b8576cb | 2887 | .fs_flags = FS_USERNS_MOUNT, |
853ac43a MM |
2888 | }; |
2889 | ||
41ffe5d5 | 2890 | int __init shmem_init(void) |
853ac43a | 2891 | { |
41ffe5d5 | 2892 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
853ac43a | 2893 | |
41ffe5d5 | 2894 | shm_mnt = kern_mount(&shmem_fs_type); |
853ac43a MM |
2895 | BUG_ON(IS_ERR(shm_mnt)); |
2896 | ||
2897 | return 0; | |
2898 | } | |
2899 | ||
41ffe5d5 | 2900 | int shmem_unuse(swp_entry_t swap, struct page *page) |
853ac43a MM |
2901 | { |
2902 | return 0; | |
2903 | } | |
2904 | ||
3f96b79a HD |
2905 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2906 | { | |
2907 | return 0; | |
2908 | } | |
2909 | ||
24513264 HD |
2910 | void shmem_unlock_mapping(struct address_space *mapping) |
2911 | { | |
2912 | } | |
2913 | ||
41ffe5d5 | 2914 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
94c1e62d | 2915 | { |
41ffe5d5 | 2916 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
94c1e62d HD |
2917 | } |
2918 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
2919 | ||
0b0a0806 HD |
2920 | #define shmem_vm_ops generic_file_vm_ops |
2921 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2922 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2923 | #define shmem_acct_size(flags, size) 0 |
2924 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
2925 | |
2926 | #endif /* CONFIG_SHMEM */ | |
2927 | ||
2928 | /* common code */ | |
1da177e4 | 2929 | |
3451538a | 2930 | static struct dentry_operations anon_ops = { |
118b2302 | 2931 | .d_dname = simple_dname |
3451538a AV |
2932 | }; |
2933 | ||
c7277090 EP |
2934 | static struct file *__shmem_file_setup(const char *name, loff_t size, |
2935 | unsigned long flags, unsigned int i_flags) | |
1da177e4 | 2936 | { |
6b4d0b27 | 2937 | struct file *res; |
1da177e4 | 2938 | struct inode *inode; |
2c48b9c4 | 2939 | struct path path; |
3451538a | 2940 | struct super_block *sb; |
1da177e4 LT |
2941 | struct qstr this; |
2942 | ||
2943 | if (IS_ERR(shm_mnt)) | |
6b4d0b27 | 2944 | return ERR_CAST(shm_mnt); |
1da177e4 | 2945 | |
285b2c4f | 2946 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
2947 | return ERR_PTR(-EINVAL); |
2948 | ||
2949 | if (shmem_acct_size(flags, size)) | |
2950 | return ERR_PTR(-ENOMEM); | |
2951 | ||
6b4d0b27 | 2952 | res = ERR_PTR(-ENOMEM); |
1da177e4 LT |
2953 | this.name = name; |
2954 | this.len = strlen(name); | |
2955 | this.hash = 0; /* will go */ | |
3451538a | 2956 | sb = shm_mnt->mnt_sb; |
66ee4b88 | 2957 | path.mnt = mntget(shm_mnt); |
3451538a | 2958 | path.dentry = d_alloc_pseudo(sb, &this); |
2c48b9c4 | 2959 | if (!path.dentry) |
1da177e4 | 2960 | goto put_memory; |
3451538a | 2961 | d_set_d_op(path.dentry, &anon_ops); |
1da177e4 | 2962 | |
6b4d0b27 | 2963 | res = ERR_PTR(-ENOSPC); |
3451538a | 2964 | inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2965 | if (!inode) |
66ee4b88 | 2966 | goto put_memory; |
1da177e4 | 2967 | |
c7277090 | 2968 | inode->i_flags |= i_flags; |
2c48b9c4 | 2969 | d_instantiate(path.dentry, inode); |
1da177e4 | 2970 | inode->i_size = size; |
6d6b77f1 | 2971 | clear_nlink(inode); /* It is unlinked */ |
26567cdb AV |
2972 | res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size)); |
2973 | if (IS_ERR(res)) | |
66ee4b88 | 2974 | goto put_path; |
4b42af81 | 2975 | |
6b4d0b27 | 2976 | res = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 | 2977 | &shmem_file_operations); |
6b4d0b27 | 2978 | if (IS_ERR(res)) |
66ee4b88 | 2979 | goto put_path; |
4b42af81 | 2980 | |
6b4d0b27 | 2981 | return res; |
1da177e4 | 2982 | |
1da177e4 LT |
2983 | put_memory: |
2984 | shmem_unacct_size(flags, size); | |
66ee4b88 KK |
2985 | put_path: |
2986 | path_put(&path); | |
6b4d0b27 | 2987 | return res; |
1da177e4 | 2988 | } |
c7277090 EP |
2989 | |
2990 | /** | |
2991 | * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be | |
2992 | * kernel internal. There will be NO LSM permission checks against the | |
2993 | * underlying inode. So users of this interface must do LSM checks at a | |
2994 | * higher layer. The one user is the big_key implementation. LSM checks | |
2995 | * are provided at the key level rather than the inode level. | |
2996 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2997 | * @size: size to be set for the file | |
2998 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
2999 | */ | |
3000 | struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags) | |
3001 | { | |
3002 | return __shmem_file_setup(name, size, flags, S_PRIVATE); | |
3003 | } | |
3004 | ||
3005 | /** | |
3006 | * shmem_file_setup - get an unlinked file living in tmpfs | |
3007 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
3008 | * @size: size to be set for the file | |
3009 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
3010 | */ | |
3011 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) | |
3012 | { | |
3013 | return __shmem_file_setup(name, size, flags, 0); | |
3014 | } | |
395e0ddc | 3015 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 3016 | |
46711810 | 3017 | /** |
1da177e4 | 3018 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
3019 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
3020 | */ | |
3021 | int shmem_zero_setup(struct vm_area_struct *vma) | |
3022 | { | |
3023 | struct file *file; | |
3024 | loff_t size = vma->vm_end - vma->vm_start; | |
3025 | ||
3026 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
3027 | if (IS_ERR(file)) | |
3028 | return PTR_ERR(file); | |
3029 | ||
3030 | if (vma->vm_file) | |
3031 | fput(vma->vm_file); | |
3032 | vma->vm_file = file; | |
3033 | vma->vm_ops = &shmem_vm_ops; | |
3034 | return 0; | |
3035 | } | |
d9d90e5e HD |
3036 | |
3037 | /** | |
3038 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
3039 | * @mapping: the page's address_space | |
3040 | * @index: the page index | |
3041 | * @gfp: the page allocator flags to use if allocating | |
3042 | * | |
3043 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
3044 | * with any new page allocations done using the specified allocation flags. | |
3045 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
3046 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
3047 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
3048 | * | |
68da9f05 HD |
3049 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
3050 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
3051 | */ |
3052 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
3053 | pgoff_t index, gfp_t gfp) | |
3054 | { | |
68da9f05 HD |
3055 | #ifdef CONFIG_SHMEM |
3056 | struct inode *inode = mapping->host; | |
9276aad6 | 3057 | struct page *page; |
68da9f05 HD |
3058 | int error; |
3059 | ||
3060 | BUG_ON(mapping->a_ops != &shmem_aops); | |
3061 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); | |
3062 | if (error) | |
3063 | page = ERR_PTR(error); | |
3064 | else | |
3065 | unlock_page(page); | |
3066 | return page; | |
3067 | #else | |
3068 | /* | |
3069 | * The tiny !SHMEM case uses ramfs without swap | |
3070 | */ | |
d9d90e5e | 3071 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 3072 | #endif |
d9d90e5e HD |
3073 | } |
3074 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |