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. | |
0edd73b3 HD |
9 | * Copyright (C) 2002-2005 Hugh Dickins. |
10 | * Copyright (C) 2002-2005 VERITAS Software Corporation. | |
1da177e4 LT |
11 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
12 | * | |
13 | * Extended attribute support for tmpfs: | |
14 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
15 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
16 | * | |
17 | * This file is released under the GPL. | |
18 | */ | |
19 | ||
20 | /* | |
21 | * This virtual memory filesystem is heavily based on the ramfs. It | |
22 | * extends ramfs by the ability to use swap and honor resource limits | |
23 | * which makes it a completely usable filesystem. | |
24 | */ | |
25 | ||
26 | #include <linux/config.h> | |
27 | #include <linux/module.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/devfs_fs_kernel.h> | |
30 | #include <linux/fs.h> | |
31 | #include <linux/mm.h> | |
32 | #include <linux/mman.h> | |
33 | #include <linux/file.h> | |
34 | #include <linux/swap.h> | |
35 | #include <linux/pagemap.h> | |
36 | #include <linux/string.h> | |
37 | #include <linux/slab.h> | |
38 | #include <linux/backing-dev.h> | |
39 | #include <linux/shmem_fs.h> | |
40 | #include <linux/mount.h> | |
41 | #include <linux/writeback.h> | |
42 | #include <linux/vfs.h> | |
43 | #include <linux/blkdev.h> | |
44 | #include <linux/security.h> | |
45 | #include <linux/swapops.h> | |
46 | #include <linux/mempolicy.h> | |
47 | #include <linux/namei.h> | |
1da177e4 LT |
48 | #include <asm/uaccess.h> |
49 | #include <asm/div64.h> | |
50 | #include <asm/pgtable.h> | |
51 | ||
52 | /* This magic number is used in glibc for posix shared memory */ | |
53 | #define TMPFS_MAGIC 0x01021994 | |
54 | ||
55 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) | |
56 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) | |
57 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
58 | ||
59 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) | |
60 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) | |
61 | ||
62 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) | |
63 | ||
64 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
65 | #define SHMEM_PAGEIN VM_READ | |
66 | #define SHMEM_TRUNCATE VM_WRITE | |
67 | ||
68 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
69 | #define LATENCY_LIMIT 64 | |
70 | ||
71 | /* Pretend that each entry is of this size in directory's i_size */ | |
72 | #define BOGO_DIRENT_SIZE 20 | |
73 | ||
74 | /* Keep swapped page count in private field of indirect struct page */ | |
75 | #define nr_swapped private | |
76 | ||
77 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ | |
78 | enum sgp_type { | |
79 | SGP_QUICK, /* don't try more than file page cache lookup */ | |
80 | SGP_READ, /* don't exceed i_size, don't allocate page */ | |
81 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
82 | SGP_WRITE, /* may exceed i_size, may allocate page */ | |
83 | }; | |
84 | ||
85 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
86 | struct page **pagep, enum sgp_type sgp, int *type); | |
87 | ||
88 | static inline struct page *shmem_dir_alloc(unsigned int gfp_mask) | |
89 | { | |
90 | /* | |
91 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
92 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
93 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
94 | */ | |
95 | return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
96 | } | |
97 | ||
98 | static inline void shmem_dir_free(struct page *page) | |
99 | { | |
100 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
101 | } | |
102 | ||
103 | static struct page **shmem_dir_map(struct page *page) | |
104 | { | |
105 | return (struct page **)kmap_atomic(page, KM_USER0); | |
106 | } | |
107 | ||
108 | static inline void shmem_dir_unmap(struct page **dir) | |
109 | { | |
110 | kunmap_atomic(dir, KM_USER0); | |
111 | } | |
112 | ||
113 | static swp_entry_t *shmem_swp_map(struct page *page) | |
114 | { | |
115 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
116 | } | |
117 | ||
118 | static inline void shmem_swp_balance_unmap(void) | |
119 | { | |
120 | /* | |
121 | * When passing a pointer to an i_direct entry, to code which | |
122 | * also handles indirect entries and so will shmem_swp_unmap, | |
123 | * we must arrange for the preempt count to remain in balance. | |
124 | * What kmap_atomic of a lowmem page does depends on config | |
125 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
126 | */ | |
127 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
128 | } | |
129 | ||
130 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
131 | { | |
132 | kunmap_atomic(entry, KM_USER1); | |
133 | } | |
134 | ||
135 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
136 | { | |
137 | return sb->s_fs_info; | |
138 | } | |
139 | ||
140 | /* | |
141 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
142 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
143 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
144 | * consistent with the pre-accounting of private mappings ... | |
145 | */ | |
146 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
147 | { | |
148 | return (flags & VM_ACCOUNT)? | |
149 | security_vm_enough_memory(VM_ACCT(size)): 0; | |
150 | } | |
151 | ||
152 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
153 | { | |
154 | if (flags & VM_ACCOUNT) | |
155 | vm_unacct_memory(VM_ACCT(size)); | |
156 | } | |
157 | ||
158 | /* | |
159 | * ... whereas tmpfs objects are accounted incrementally as | |
160 | * pages are allocated, in order to allow huge sparse files. | |
161 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
162 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
163 | */ | |
164 | static inline int shmem_acct_block(unsigned long flags) | |
165 | { | |
166 | return (flags & VM_ACCOUNT)? | |
167 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); | |
168 | } | |
169 | ||
170 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
171 | { | |
172 | if (!(flags & VM_ACCOUNT)) | |
173 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); | |
174 | } | |
175 | ||
176 | static struct super_operations shmem_ops; | |
177 | static struct address_space_operations shmem_aops; | |
178 | static struct file_operations shmem_file_operations; | |
179 | static struct inode_operations shmem_inode_operations; | |
180 | static struct inode_operations shmem_dir_inode_operations; | |
1da177e4 LT |
181 | static struct vm_operations_struct shmem_vm_ops; |
182 | ||
6c231b7b | 183 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 LT |
184 | .ra_pages = 0, /* No readahead */ |
185 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
186 | .unplug_io_fn = default_unplug_io_fn, | |
187 | }; | |
188 | ||
189 | static LIST_HEAD(shmem_swaplist); | |
190 | static DEFINE_SPINLOCK(shmem_swaplist_lock); | |
191 | ||
192 | static void shmem_free_blocks(struct inode *inode, long pages) | |
193 | { | |
194 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 195 | if (sbinfo->max_blocks) { |
1da177e4 LT |
196 | spin_lock(&sbinfo->stat_lock); |
197 | sbinfo->free_blocks += pages; | |
198 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
199 | spin_unlock(&sbinfo->stat_lock); | |
200 | } | |
201 | } | |
202 | ||
203 | /* | |
204 | * shmem_recalc_inode - recalculate the size of an inode | |
205 | * | |
206 | * @inode: inode to recalc | |
207 | * | |
208 | * We have to calculate the free blocks since the mm can drop | |
209 | * undirtied hole pages behind our back. | |
210 | * | |
211 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
212 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
213 | * | |
214 | * It has to be called with the spinlock held. | |
215 | */ | |
216 | static void shmem_recalc_inode(struct inode *inode) | |
217 | { | |
218 | struct shmem_inode_info *info = SHMEM_I(inode); | |
219 | long freed; | |
220 | ||
221 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
222 | if (freed > 0) { | |
223 | info->alloced -= freed; | |
224 | shmem_unacct_blocks(info->flags, freed); | |
225 | shmem_free_blocks(inode, freed); | |
226 | } | |
227 | } | |
228 | ||
229 | /* | |
230 | * shmem_swp_entry - find the swap vector position in the info structure | |
231 | * | |
232 | * @info: info structure for the inode | |
233 | * @index: index of the page to find | |
234 | * @page: optional page to add to the structure. Has to be preset to | |
235 | * all zeros | |
236 | * | |
237 | * If there is no space allocated yet it will return NULL when | |
238 | * page is NULL, else it will use the page for the needed block, | |
239 | * setting it to NULL on return to indicate that it has been used. | |
240 | * | |
241 | * The swap vector is organized the following way: | |
242 | * | |
243 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
244 | * shmem_inode_info structure. So small files do not need an addional | |
245 | * allocation. | |
246 | * | |
247 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
248 | * i_indirect which points to a page which holds in the first half | |
249 | * doubly indirect blocks, in the second half triple indirect blocks: | |
250 | * | |
251 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
252 | * following layout (for SHMEM_NR_DIRECT == 16): | |
253 | * | |
254 | * i_indirect -> dir --> 16-19 | |
255 | * | +-> 20-23 | |
256 | * | | |
257 | * +-->dir2 --> 24-27 | |
258 | * | +-> 28-31 | |
259 | * | +-> 32-35 | |
260 | * | +-> 36-39 | |
261 | * | | |
262 | * +-->dir3 --> 40-43 | |
263 | * +-> 44-47 | |
264 | * +-> 48-51 | |
265 | * +-> 52-55 | |
266 | */ | |
267 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
268 | { | |
269 | unsigned long offset; | |
270 | struct page **dir; | |
271 | struct page *subdir; | |
272 | ||
273 | if (index < SHMEM_NR_DIRECT) { | |
274 | shmem_swp_balance_unmap(); | |
275 | return info->i_direct+index; | |
276 | } | |
277 | if (!info->i_indirect) { | |
278 | if (page) { | |
279 | info->i_indirect = *page; | |
280 | *page = NULL; | |
281 | } | |
282 | return NULL; /* need another page */ | |
283 | } | |
284 | ||
285 | index -= SHMEM_NR_DIRECT; | |
286 | offset = index % ENTRIES_PER_PAGE; | |
287 | index /= ENTRIES_PER_PAGE; | |
288 | dir = shmem_dir_map(info->i_indirect); | |
289 | ||
290 | if (index >= ENTRIES_PER_PAGE/2) { | |
291 | index -= ENTRIES_PER_PAGE/2; | |
292 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
293 | index %= ENTRIES_PER_PAGE; | |
294 | subdir = *dir; | |
295 | if (!subdir) { | |
296 | if (page) { | |
297 | *dir = *page; | |
298 | *page = NULL; | |
299 | } | |
300 | shmem_dir_unmap(dir); | |
301 | return NULL; /* need another page */ | |
302 | } | |
303 | shmem_dir_unmap(dir); | |
304 | dir = shmem_dir_map(subdir); | |
305 | } | |
306 | ||
307 | dir += index; | |
308 | subdir = *dir; | |
309 | if (!subdir) { | |
310 | if (!page || !(subdir = *page)) { | |
311 | shmem_dir_unmap(dir); | |
312 | return NULL; /* need a page */ | |
313 | } | |
314 | *dir = subdir; | |
315 | *page = NULL; | |
316 | } | |
317 | shmem_dir_unmap(dir); | |
318 | return shmem_swp_map(subdir) + offset; | |
319 | } | |
320 | ||
321 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
322 | { | |
323 | long incdec = value? 1: -1; | |
324 | ||
325 | entry->val = value; | |
326 | info->swapped += incdec; | |
327 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) | |
328 | kmap_atomic_to_page(entry)->nr_swapped += incdec; | |
329 | } | |
330 | ||
331 | /* | |
332 | * shmem_swp_alloc - get the position of the swap entry for the page. | |
333 | * If it does not exist allocate the entry. | |
334 | * | |
335 | * @info: info structure for the inode | |
336 | * @index: index of the page to find | |
337 | * @sgp: check and recheck i_size? skip allocation? | |
338 | */ | |
339 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
340 | { | |
341 | struct inode *inode = &info->vfs_inode; | |
342 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
343 | struct page *page = NULL; | |
344 | swp_entry_t *entry; | |
345 | ||
346 | if (sgp != SGP_WRITE && | |
347 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
348 | return ERR_PTR(-EINVAL); | |
349 | ||
350 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
351 | if (sgp == SGP_READ) | |
352 | return shmem_swp_map(ZERO_PAGE(0)); | |
353 | /* | |
354 | * Test free_blocks against 1 not 0, since we have 1 data | |
355 | * page (and perhaps indirect index pages) yet to allocate: | |
356 | * a waste to allocate index if we cannot allocate data. | |
357 | */ | |
0edd73b3 | 358 | if (sbinfo->max_blocks) { |
1da177e4 LT |
359 | spin_lock(&sbinfo->stat_lock); |
360 | if (sbinfo->free_blocks <= 1) { | |
361 | spin_unlock(&sbinfo->stat_lock); | |
362 | return ERR_PTR(-ENOSPC); | |
363 | } | |
364 | sbinfo->free_blocks--; | |
365 | inode->i_blocks += BLOCKS_PER_PAGE; | |
366 | spin_unlock(&sbinfo->stat_lock); | |
367 | } | |
368 | ||
369 | spin_unlock(&info->lock); | |
370 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO); | |
371 | if (page) { | |
372 | page->nr_swapped = 0; | |
373 | } | |
374 | spin_lock(&info->lock); | |
375 | ||
376 | if (!page) { | |
377 | shmem_free_blocks(inode, 1); | |
378 | return ERR_PTR(-ENOMEM); | |
379 | } | |
380 | if (sgp != SGP_WRITE && | |
381 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
382 | entry = ERR_PTR(-EINVAL); | |
383 | break; | |
384 | } | |
385 | if (info->next_index <= index) | |
386 | info->next_index = index + 1; | |
387 | } | |
388 | if (page) { | |
389 | /* another task gave its page, or truncated the file */ | |
390 | shmem_free_blocks(inode, 1); | |
391 | shmem_dir_free(page); | |
392 | } | |
393 | if (info->next_index <= index && !IS_ERR(entry)) | |
394 | info->next_index = index + 1; | |
395 | return entry; | |
396 | } | |
397 | ||
398 | /* | |
399 | * shmem_free_swp - free some swap entries in a directory | |
400 | * | |
401 | * @dir: pointer to the directory | |
402 | * @edir: pointer after last entry of the directory | |
403 | */ | |
404 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir) | |
405 | { | |
406 | swp_entry_t *ptr; | |
407 | int freed = 0; | |
408 | ||
409 | for (ptr = dir; ptr < edir; ptr++) { | |
410 | if (ptr->val) { | |
411 | free_swap_and_cache(*ptr); | |
412 | *ptr = (swp_entry_t){0}; | |
413 | freed++; | |
414 | } | |
415 | } | |
416 | return freed; | |
417 | } | |
418 | ||
419 | static int shmem_map_and_free_swp(struct page *subdir, | |
420 | int offset, int limit, struct page ***dir) | |
421 | { | |
422 | swp_entry_t *ptr; | |
423 | int freed = 0; | |
424 | ||
425 | ptr = shmem_swp_map(subdir); | |
426 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
427 | int size = limit - offset; | |
428 | if (size > LATENCY_LIMIT) | |
429 | size = LATENCY_LIMIT; | |
430 | freed += shmem_free_swp(ptr+offset, ptr+offset+size); | |
431 | if (need_resched()) { | |
432 | shmem_swp_unmap(ptr); | |
433 | if (*dir) { | |
434 | shmem_dir_unmap(*dir); | |
435 | *dir = NULL; | |
436 | } | |
437 | cond_resched(); | |
438 | ptr = shmem_swp_map(subdir); | |
439 | } | |
440 | } | |
441 | shmem_swp_unmap(ptr); | |
442 | return freed; | |
443 | } | |
444 | ||
445 | static void shmem_free_pages(struct list_head *next) | |
446 | { | |
447 | struct page *page; | |
448 | int freed = 0; | |
449 | ||
450 | do { | |
451 | page = container_of(next, struct page, lru); | |
452 | next = next->next; | |
453 | shmem_dir_free(page); | |
454 | freed++; | |
455 | if (freed >= LATENCY_LIMIT) { | |
456 | cond_resched(); | |
457 | freed = 0; | |
458 | } | |
459 | } while (next); | |
460 | } | |
461 | ||
462 | static void shmem_truncate(struct inode *inode) | |
463 | { | |
464 | struct shmem_inode_info *info = SHMEM_I(inode); | |
465 | unsigned long idx; | |
466 | unsigned long size; | |
467 | unsigned long limit; | |
468 | unsigned long stage; | |
469 | unsigned long diroff; | |
470 | struct page **dir; | |
471 | struct page *topdir; | |
472 | struct page *middir; | |
473 | struct page *subdir; | |
474 | swp_entry_t *ptr; | |
475 | LIST_HEAD(pages_to_free); | |
476 | long nr_pages_to_free = 0; | |
477 | long nr_swaps_freed = 0; | |
478 | int offset; | |
479 | int freed; | |
480 | ||
481 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
482 | idx = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
483 | if (idx >= info->next_index) | |
484 | return; | |
485 | ||
486 | spin_lock(&info->lock); | |
487 | info->flags |= SHMEM_TRUNCATE; | |
488 | limit = info->next_index; | |
489 | info->next_index = idx; | |
490 | topdir = info->i_indirect; | |
491 | if (topdir && idx <= SHMEM_NR_DIRECT) { | |
492 | info->i_indirect = NULL; | |
493 | nr_pages_to_free++; | |
494 | list_add(&topdir->lru, &pages_to_free); | |
495 | } | |
496 | spin_unlock(&info->lock); | |
497 | ||
498 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
499 | ptr = info->i_direct; | |
500 | size = limit; | |
501 | if (size > SHMEM_NR_DIRECT) | |
502 | size = SHMEM_NR_DIRECT; | |
503 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size); | |
504 | } | |
505 | if (!topdir) | |
506 | goto done2; | |
507 | ||
508 | BUG_ON(limit <= SHMEM_NR_DIRECT); | |
509 | limit -= SHMEM_NR_DIRECT; | |
510 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
511 | offset = idx % ENTRIES_PER_PAGE; | |
512 | idx -= offset; | |
513 | ||
514 | dir = shmem_dir_map(topdir); | |
515 | stage = ENTRIES_PER_PAGEPAGE/2; | |
516 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
517 | middir = topdir; | |
518 | diroff = idx/ENTRIES_PER_PAGE; | |
519 | } else { | |
520 | dir += ENTRIES_PER_PAGE/2; | |
521 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
522 | while (stage <= idx) | |
523 | stage += ENTRIES_PER_PAGEPAGE; | |
524 | middir = *dir; | |
525 | if (*dir) { | |
526 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
527 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
528 | if (!diroff && !offset) { | |
529 | *dir = NULL; | |
530 | nr_pages_to_free++; | |
531 | list_add(&middir->lru, &pages_to_free); | |
532 | } | |
533 | shmem_dir_unmap(dir); | |
534 | dir = shmem_dir_map(middir); | |
535 | } else { | |
536 | diroff = 0; | |
537 | offset = 0; | |
538 | idx = stage; | |
539 | } | |
540 | } | |
541 | ||
542 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
543 | if (unlikely(idx == stage)) { | |
544 | shmem_dir_unmap(dir); | |
545 | dir = shmem_dir_map(topdir) + | |
546 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
547 | while (!*dir) { | |
548 | dir++; | |
549 | idx += ENTRIES_PER_PAGEPAGE; | |
550 | if (idx >= limit) | |
551 | goto done1; | |
552 | } | |
553 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
554 | middir = *dir; | |
555 | *dir = NULL; | |
556 | nr_pages_to_free++; | |
557 | list_add(&middir->lru, &pages_to_free); | |
558 | shmem_dir_unmap(dir); | |
559 | cond_resched(); | |
560 | dir = shmem_dir_map(middir); | |
561 | diroff = 0; | |
562 | } | |
563 | subdir = dir[diroff]; | |
564 | if (subdir && subdir->nr_swapped) { | |
565 | size = limit - idx; | |
566 | if (size > ENTRIES_PER_PAGE) | |
567 | size = ENTRIES_PER_PAGE; | |
568 | freed = shmem_map_and_free_swp(subdir, | |
569 | offset, size, &dir); | |
570 | if (!dir) | |
571 | dir = shmem_dir_map(middir); | |
572 | nr_swaps_freed += freed; | |
573 | if (offset) | |
574 | spin_lock(&info->lock); | |
575 | subdir->nr_swapped -= freed; | |
576 | if (offset) | |
577 | spin_unlock(&info->lock); | |
578 | BUG_ON(subdir->nr_swapped > offset); | |
579 | } | |
580 | if (offset) | |
581 | offset = 0; | |
582 | else if (subdir) { | |
583 | dir[diroff] = NULL; | |
584 | nr_pages_to_free++; | |
585 | list_add(&subdir->lru, &pages_to_free); | |
586 | } | |
587 | } | |
588 | done1: | |
589 | shmem_dir_unmap(dir); | |
590 | done2: | |
591 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
592 | /* | |
593 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
594 | * may have swizzled a page in from swap since vmtruncate or | |
595 | * generic_delete_inode did it, before we lowered next_index. | |
596 | * Also, though shmem_getpage checks i_size before adding to | |
597 | * cache, no recheck after: so fix the narrow window there too. | |
598 | */ | |
599 | truncate_inode_pages(inode->i_mapping, inode->i_size); | |
600 | } | |
601 | ||
602 | spin_lock(&info->lock); | |
603 | info->flags &= ~SHMEM_TRUNCATE; | |
604 | info->swapped -= nr_swaps_freed; | |
605 | if (nr_pages_to_free) | |
606 | shmem_free_blocks(inode, nr_pages_to_free); | |
607 | shmem_recalc_inode(inode); | |
608 | spin_unlock(&info->lock); | |
609 | ||
610 | /* | |
611 | * Empty swap vector directory pages to be freed? | |
612 | */ | |
613 | if (!list_empty(&pages_to_free)) { | |
614 | pages_to_free.prev->next = NULL; | |
615 | shmem_free_pages(pages_to_free.next); | |
616 | } | |
617 | } | |
618 | ||
619 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) | |
620 | { | |
621 | struct inode *inode = dentry->d_inode; | |
622 | struct page *page = NULL; | |
623 | int error; | |
624 | ||
625 | if (attr->ia_valid & ATTR_SIZE) { | |
626 | if (attr->ia_size < inode->i_size) { | |
627 | /* | |
628 | * If truncating down to a partial page, then | |
629 | * if that page is already allocated, hold it | |
630 | * in memory until the truncation is over, so | |
631 | * truncate_partial_page cannnot miss it were | |
632 | * it assigned to swap. | |
633 | */ | |
634 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
635 | (void) shmem_getpage(inode, | |
636 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
637 | &page, SGP_READ, NULL); | |
638 | } | |
639 | /* | |
640 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
641 | * detect if any pages might have been added to cache | |
642 | * after truncate_inode_pages. But we needn't bother | |
643 | * if it's being fully truncated to zero-length: the | |
644 | * nrpages check is efficient enough in that case. | |
645 | */ | |
646 | if (attr->ia_size) { | |
647 | struct shmem_inode_info *info = SHMEM_I(inode); | |
648 | spin_lock(&info->lock); | |
649 | info->flags &= ~SHMEM_PAGEIN; | |
650 | spin_unlock(&info->lock); | |
651 | } | |
652 | } | |
653 | } | |
654 | ||
655 | error = inode_change_ok(inode, attr); | |
656 | if (!error) | |
657 | error = inode_setattr(inode, attr); | |
658 | if (page) | |
659 | page_cache_release(page); | |
660 | return error; | |
661 | } | |
662 | ||
663 | static void shmem_delete_inode(struct inode *inode) | |
664 | { | |
665 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
666 | struct shmem_inode_info *info = SHMEM_I(inode); | |
667 | ||
668 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 669 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
670 | shmem_unacct_size(info->flags, inode->i_size); |
671 | inode->i_size = 0; | |
672 | shmem_truncate(inode); | |
673 | if (!list_empty(&info->swaplist)) { | |
674 | spin_lock(&shmem_swaplist_lock); | |
675 | list_del_init(&info->swaplist); | |
676 | spin_unlock(&shmem_swaplist_lock); | |
677 | } | |
678 | } | |
0edd73b3 HD |
679 | BUG_ON(inode->i_blocks); |
680 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
681 | spin_lock(&sbinfo->stat_lock); |
682 | sbinfo->free_inodes++; | |
683 | spin_unlock(&sbinfo->stat_lock); | |
684 | } | |
685 | clear_inode(inode); | |
686 | } | |
687 | ||
688 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
689 | { | |
690 | swp_entry_t *ptr; | |
691 | ||
692 | for (ptr = dir; ptr < edir; ptr++) { | |
693 | if (ptr->val == entry.val) | |
694 | return ptr - dir; | |
695 | } | |
696 | return -1; | |
697 | } | |
698 | ||
699 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
700 | { | |
701 | struct inode *inode; | |
702 | unsigned long idx; | |
703 | unsigned long size; | |
704 | unsigned long limit; | |
705 | unsigned long stage; | |
706 | struct page **dir; | |
707 | struct page *subdir; | |
708 | swp_entry_t *ptr; | |
709 | int offset; | |
710 | ||
711 | idx = 0; | |
712 | ptr = info->i_direct; | |
713 | spin_lock(&info->lock); | |
714 | limit = info->next_index; | |
715 | size = limit; | |
716 | if (size > SHMEM_NR_DIRECT) | |
717 | size = SHMEM_NR_DIRECT; | |
718 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
719 | if (offset >= 0) { | |
720 | shmem_swp_balance_unmap(); | |
721 | goto found; | |
722 | } | |
723 | if (!info->i_indirect) | |
724 | goto lost2; | |
725 | ||
726 | dir = shmem_dir_map(info->i_indirect); | |
727 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
728 | ||
729 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
730 | if (unlikely(idx == stage)) { | |
731 | shmem_dir_unmap(dir-1); | |
732 | dir = shmem_dir_map(info->i_indirect) + | |
733 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
734 | while (!*dir) { | |
735 | dir++; | |
736 | idx += ENTRIES_PER_PAGEPAGE; | |
737 | if (idx >= limit) | |
738 | goto lost1; | |
739 | } | |
740 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
741 | subdir = *dir; | |
742 | shmem_dir_unmap(dir); | |
743 | dir = shmem_dir_map(subdir); | |
744 | } | |
745 | subdir = *dir; | |
746 | if (subdir && subdir->nr_swapped) { | |
747 | ptr = shmem_swp_map(subdir); | |
748 | size = limit - idx; | |
749 | if (size > ENTRIES_PER_PAGE) | |
750 | size = ENTRIES_PER_PAGE; | |
751 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
752 | if (offset >= 0) { | |
753 | shmem_dir_unmap(dir); | |
754 | goto found; | |
755 | } | |
756 | shmem_swp_unmap(ptr); | |
757 | } | |
758 | } | |
759 | lost1: | |
760 | shmem_dir_unmap(dir-1); | |
761 | lost2: | |
762 | spin_unlock(&info->lock); | |
763 | return 0; | |
764 | found: | |
765 | idx += offset; | |
766 | inode = &info->vfs_inode; | |
767 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { | |
768 | info->flags |= SHMEM_PAGEIN; | |
769 | shmem_swp_set(info, ptr + offset, 0); | |
770 | } | |
771 | shmem_swp_unmap(ptr); | |
772 | spin_unlock(&info->lock); | |
773 | /* | |
774 | * Decrement swap count even when the entry is left behind: | |
775 | * try_to_unuse will skip over mms, then reincrement count. | |
776 | */ | |
777 | swap_free(entry); | |
778 | return 1; | |
779 | } | |
780 | ||
781 | /* | |
782 | * shmem_unuse() search for an eventually swapped out shmem page. | |
783 | */ | |
784 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
785 | { | |
786 | struct list_head *p, *next; | |
787 | struct shmem_inode_info *info; | |
788 | int found = 0; | |
789 | ||
790 | spin_lock(&shmem_swaplist_lock); | |
791 | list_for_each_safe(p, next, &shmem_swaplist) { | |
792 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
793 | if (!info->swapped) | |
794 | list_del_init(&info->swaplist); | |
795 | else if (shmem_unuse_inode(info, entry, page)) { | |
796 | /* move head to start search for next from here */ | |
797 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
798 | found = 1; | |
799 | break; | |
800 | } | |
801 | } | |
802 | spin_unlock(&shmem_swaplist_lock); | |
803 | return found; | |
804 | } | |
805 | ||
806 | /* | |
807 | * Move the page from the page cache to the swap cache. | |
808 | */ | |
809 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
810 | { | |
811 | struct shmem_inode_info *info; | |
812 | swp_entry_t *entry, swap; | |
813 | struct address_space *mapping; | |
814 | unsigned long index; | |
815 | struct inode *inode; | |
816 | ||
817 | BUG_ON(!PageLocked(page)); | |
818 | BUG_ON(page_mapped(page)); | |
819 | ||
820 | mapping = page->mapping; | |
821 | index = page->index; | |
822 | inode = mapping->host; | |
823 | info = SHMEM_I(inode); | |
824 | if (info->flags & VM_LOCKED) | |
825 | goto redirty; | |
826 | swap = get_swap_page(); | |
827 | if (!swap.val) | |
828 | goto redirty; | |
829 | ||
830 | spin_lock(&info->lock); | |
831 | shmem_recalc_inode(inode); | |
832 | if (index >= info->next_index) { | |
833 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
834 | goto unlock; | |
835 | } | |
836 | entry = shmem_swp_entry(info, index, NULL); | |
837 | BUG_ON(!entry); | |
838 | BUG_ON(entry->val); | |
839 | ||
840 | if (move_to_swap_cache(page, swap) == 0) { | |
841 | shmem_swp_set(info, entry, swap.val); | |
842 | shmem_swp_unmap(entry); | |
843 | spin_unlock(&info->lock); | |
844 | if (list_empty(&info->swaplist)) { | |
845 | spin_lock(&shmem_swaplist_lock); | |
846 | /* move instead of add in case we're racing */ | |
847 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
848 | spin_unlock(&shmem_swaplist_lock); | |
849 | } | |
850 | unlock_page(page); | |
851 | return 0; | |
852 | } | |
853 | ||
854 | shmem_swp_unmap(entry); | |
855 | unlock: | |
856 | spin_unlock(&info->lock); | |
857 | swap_free(swap); | |
858 | redirty: | |
859 | set_page_dirty(page); | |
860 | return WRITEPAGE_ACTIVATE; /* Return with the page locked */ | |
861 | } | |
862 | ||
863 | #ifdef CONFIG_NUMA | |
864 | static struct page *shmem_swapin_async(struct shared_policy *p, | |
865 | swp_entry_t entry, unsigned long idx) | |
866 | { | |
867 | struct page *page; | |
868 | struct vm_area_struct pvma; | |
869 | ||
870 | /* Create a pseudo vma that just contains the policy */ | |
871 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
872 | pvma.vm_end = PAGE_SIZE; | |
873 | pvma.vm_pgoff = idx; | |
874 | pvma.vm_policy = mpol_shared_policy_lookup(p, idx); | |
875 | page = read_swap_cache_async(entry, &pvma, 0); | |
876 | mpol_free(pvma.vm_policy); | |
877 | return page; | |
878 | } | |
879 | ||
880 | struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry, | |
881 | unsigned long idx) | |
882 | { | |
883 | struct shared_policy *p = &info->policy; | |
884 | int i, num; | |
885 | struct page *page; | |
886 | unsigned long offset; | |
887 | ||
888 | num = valid_swaphandles(entry, &offset); | |
889 | for (i = 0; i < num; offset++, i++) { | |
890 | page = shmem_swapin_async(p, | |
891 | swp_entry(swp_type(entry), offset), idx); | |
892 | if (!page) | |
893 | break; | |
894 | page_cache_release(page); | |
895 | } | |
896 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
897 | return shmem_swapin_async(p, entry, idx); | |
898 | } | |
899 | ||
900 | static struct page * | |
901 | shmem_alloc_page(unsigned long gfp, struct shmem_inode_info *info, | |
902 | unsigned long idx) | |
903 | { | |
904 | struct vm_area_struct pvma; | |
905 | struct page *page; | |
906 | ||
907 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
908 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
909 | pvma.vm_pgoff = idx; | |
910 | pvma.vm_end = PAGE_SIZE; | |
911 | page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0); | |
912 | mpol_free(pvma.vm_policy); | |
913 | return page; | |
914 | } | |
915 | #else | |
916 | static inline struct page * | |
917 | shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx) | |
918 | { | |
919 | swapin_readahead(entry, 0, NULL); | |
920 | return read_swap_cache_async(entry, NULL, 0); | |
921 | } | |
922 | ||
923 | static inline struct page * | |
924 | shmem_alloc_page(unsigned int __nocast gfp,struct shmem_inode_info *info, | |
925 | unsigned long idx) | |
926 | { | |
927 | return alloc_page(gfp | __GFP_ZERO); | |
928 | } | |
929 | #endif | |
930 | ||
931 | /* | |
932 | * shmem_getpage - either get the page from swap or allocate a new one | |
933 | * | |
934 | * If we allocate a new one we do not mark it dirty. That's up to the | |
935 | * vm. If we swap it in we mark it dirty since we also free the swap | |
936 | * entry since a page cannot live in both the swap and page cache | |
937 | */ | |
938 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
939 | struct page **pagep, enum sgp_type sgp, int *type) | |
940 | { | |
941 | struct address_space *mapping = inode->i_mapping; | |
942 | struct shmem_inode_info *info = SHMEM_I(inode); | |
943 | struct shmem_sb_info *sbinfo; | |
944 | struct page *filepage = *pagep; | |
945 | struct page *swappage; | |
946 | swp_entry_t *entry; | |
947 | swp_entry_t swap; | |
948 | int error; | |
949 | ||
950 | if (idx >= SHMEM_MAX_INDEX) | |
951 | return -EFBIG; | |
952 | /* | |
953 | * Normally, filepage is NULL on entry, and either found | |
954 | * uptodate immediately, or allocated and zeroed, or read | |
955 | * in under swappage, which is then assigned to filepage. | |
956 | * But shmem_prepare_write passes in a locked filepage, | |
957 | * which may be found not uptodate by other callers too, | |
958 | * and may need to be copied from the swappage read in. | |
959 | */ | |
960 | repeat: | |
961 | if (!filepage) | |
962 | filepage = find_lock_page(mapping, idx); | |
963 | if (filepage && PageUptodate(filepage)) | |
964 | goto done; | |
965 | error = 0; | |
966 | if (sgp == SGP_QUICK) | |
967 | goto failed; | |
968 | ||
969 | spin_lock(&info->lock); | |
970 | shmem_recalc_inode(inode); | |
971 | entry = shmem_swp_alloc(info, idx, sgp); | |
972 | if (IS_ERR(entry)) { | |
973 | spin_unlock(&info->lock); | |
974 | error = PTR_ERR(entry); | |
975 | goto failed; | |
976 | } | |
977 | swap = *entry; | |
978 | ||
979 | if (swap.val) { | |
980 | /* Look it up and read it in.. */ | |
981 | swappage = lookup_swap_cache(swap); | |
982 | if (!swappage) { | |
983 | shmem_swp_unmap(entry); | |
984 | spin_unlock(&info->lock); | |
985 | /* here we actually do the io */ | |
986 | if (type && *type == VM_FAULT_MINOR) { | |
987 | inc_page_state(pgmajfault); | |
988 | *type = VM_FAULT_MAJOR; | |
989 | } | |
990 | swappage = shmem_swapin(info, swap, idx); | |
991 | if (!swappage) { | |
992 | spin_lock(&info->lock); | |
993 | entry = shmem_swp_alloc(info, idx, sgp); | |
994 | if (IS_ERR(entry)) | |
995 | error = PTR_ERR(entry); | |
996 | else { | |
997 | if (entry->val == swap.val) | |
998 | error = -ENOMEM; | |
999 | shmem_swp_unmap(entry); | |
1000 | } | |
1001 | spin_unlock(&info->lock); | |
1002 | if (error) | |
1003 | goto failed; | |
1004 | goto repeat; | |
1005 | } | |
1006 | wait_on_page_locked(swappage); | |
1007 | page_cache_release(swappage); | |
1008 | goto repeat; | |
1009 | } | |
1010 | ||
1011 | /* We have to do this with page locked to prevent races */ | |
1012 | if (TestSetPageLocked(swappage)) { | |
1013 | shmem_swp_unmap(entry); | |
1014 | spin_unlock(&info->lock); | |
1015 | wait_on_page_locked(swappage); | |
1016 | page_cache_release(swappage); | |
1017 | goto repeat; | |
1018 | } | |
1019 | if (PageWriteback(swappage)) { | |
1020 | shmem_swp_unmap(entry); | |
1021 | spin_unlock(&info->lock); | |
1022 | wait_on_page_writeback(swappage); | |
1023 | unlock_page(swappage); | |
1024 | page_cache_release(swappage); | |
1025 | goto repeat; | |
1026 | } | |
1027 | if (!PageUptodate(swappage)) { | |
1028 | shmem_swp_unmap(entry); | |
1029 | spin_unlock(&info->lock); | |
1030 | unlock_page(swappage); | |
1031 | page_cache_release(swappage); | |
1032 | error = -EIO; | |
1033 | goto failed; | |
1034 | } | |
1035 | ||
1036 | if (filepage) { | |
1037 | shmem_swp_set(info, entry, 0); | |
1038 | shmem_swp_unmap(entry); | |
1039 | delete_from_swap_cache(swappage); | |
1040 | spin_unlock(&info->lock); | |
1041 | copy_highpage(filepage, swappage); | |
1042 | unlock_page(swappage); | |
1043 | page_cache_release(swappage); | |
1044 | flush_dcache_page(filepage); | |
1045 | SetPageUptodate(filepage); | |
1046 | set_page_dirty(filepage); | |
1047 | swap_free(swap); | |
1048 | } else if (!(error = move_from_swap_cache( | |
1049 | swappage, idx, mapping))) { | |
1050 | info->flags |= SHMEM_PAGEIN; | |
1051 | shmem_swp_set(info, entry, 0); | |
1052 | shmem_swp_unmap(entry); | |
1053 | spin_unlock(&info->lock); | |
1054 | filepage = swappage; | |
1055 | swap_free(swap); | |
1056 | } else { | |
1057 | shmem_swp_unmap(entry); | |
1058 | spin_unlock(&info->lock); | |
1059 | unlock_page(swappage); | |
1060 | page_cache_release(swappage); | |
1061 | if (error == -ENOMEM) { | |
1062 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
1063 | blk_congestion_wait(WRITE, HZ/50); | |
1064 | } | |
1065 | goto repeat; | |
1066 | } | |
1067 | } else if (sgp == SGP_READ && !filepage) { | |
1068 | shmem_swp_unmap(entry); | |
1069 | filepage = find_get_page(mapping, idx); | |
1070 | if (filepage && | |
1071 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1072 | spin_unlock(&info->lock); | |
1073 | wait_on_page_locked(filepage); | |
1074 | page_cache_release(filepage); | |
1075 | filepage = NULL; | |
1076 | goto repeat; | |
1077 | } | |
1078 | spin_unlock(&info->lock); | |
1079 | } else { | |
1080 | shmem_swp_unmap(entry); | |
1081 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1082 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1083 | spin_lock(&sbinfo->stat_lock); |
1084 | if (sbinfo->free_blocks == 0 || | |
1085 | shmem_acct_block(info->flags)) { | |
1086 | spin_unlock(&sbinfo->stat_lock); | |
1087 | spin_unlock(&info->lock); | |
1088 | error = -ENOSPC; | |
1089 | goto failed; | |
1090 | } | |
1091 | sbinfo->free_blocks--; | |
1092 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1093 | spin_unlock(&sbinfo->stat_lock); | |
1094 | } else if (shmem_acct_block(info->flags)) { | |
1095 | spin_unlock(&info->lock); | |
1096 | error = -ENOSPC; | |
1097 | goto failed; | |
1098 | } | |
1099 | ||
1100 | if (!filepage) { | |
1101 | spin_unlock(&info->lock); | |
1102 | filepage = shmem_alloc_page(mapping_gfp_mask(mapping), | |
1103 | info, | |
1104 | idx); | |
1105 | if (!filepage) { | |
1106 | shmem_unacct_blocks(info->flags, 1); | |
1107 | shmem_free_blocks(inode, 1); | |
1108 | error = -ENOMEM; | |
1109 | goto failed; | |
1110 | } | |
1111 | ||
1112 | spin_lock(&info->lock); | |
1113 | entry = shmem_swp_alloc(info, idx, sgp); | |
1114 | if (IS_ERR(entry)) | |
1115 | error = PTR_ERR(entry); | |
1116 | else { | |
1117 | swap = *entry; | |
1118 | shmem_swp_unmap(entry); | |
1119 | } | |
1120 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1121 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1122 | spin_unlock(&info->lock); | |
1123 | page_cache_release(filepage); | |
1124 | shmem_unacct_blocks(info->flags, 1); | |
1125 | shmem_free_blocks(inode, 1); | |
1126 | filepage = NULL; | |
1127 | if (error) | |
1128 | goto failed; | |
1129 | goto repeat; | |
1130 | } | |
1131 | info->flags |= SHMEM_PAGEIN; | |
1132 | } | |
1133 | ||
1134 | info->alloced++; | |
1135 | spin_unlock(&info->lock); | |
1136 | flush_dcache_page(filepage); | |
1137 | SetPageUptodate(filepage); | |
1138 | } | |
1139 | done: | |
1140 | if (*pagep != filepage) { | |
1141 | unlock_page(filepage); | |
1142 | *pagep = filepage; | |
1143 | } | |
1144 | return 0; | |
1145 | ||
1146 | failed: | |
1147 | if (*pagep != filepage) { | |
1148 | unlock_page(filepage); | |
1149 | page_cache_release(filepage); | |
1150 | } | |
1151 | return error; | |
1152 | } | |
1153 | ||
1154 | struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int *type) | |
1155 | { | |
1156 | struct inode *inode = vma->vm_file->f_dentry->d_inode; | |
1157 | struct page *page = NULL; | |
1158 | unsigned long idx; | |
1159 | int error; | |
1160 | ||
1161 | idx = (address - vma->vm_start) >> PAGE_SHIFT; | |
1162 | idx += vma->vm_pgoff; | |
1163 | idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT; | |
1164 | if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
1165 | return NOPAGE_SIGBUS; | |
1166 | ||
1167 | error = shmem_getpage(inode, idx, &page, SGP_CACHE, type); | |
1168 | if (error) | |
1169 | return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS; | |
1170 | ||
1171 | mark_page_accessed(page); | |
1172 | return page; | |
1173 | } | |
1174 | ||
1175 | static int shmem_populate(struct vm_area_struct *vma, | |
1176 | unsigned long addr, unsigned long len, | |
1177 | pgprot_t prot, unsigned long pgoff, int nonblock) | |
1178 | { | |
1179 | struct inode *inode = vma->vm_file->f_dentry->d_inode; | |
1180 | struct mm_struct *mm = vma->vm_mm; | |
1181 | enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE; | |
1182 | unsigned long size; | |
1183 | ||
1184 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1185 | if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size) | |
1186 | return -EINVAL; | |
1187 | ||
1188 | while ((long) len > 0) { | |
1189 | struct page *page = NULL; | |
1190 | int err; | |
1191 | /* | |
1192 | * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE | |
1193 | */ | |
1194 | err = shmem_getpage(inode, pgoff, &page, sgp, NULL); | |
1195 | if (err) | |
1196 | return err; | |
d44ed4f8 | 1197 | /* Page may still be null, but only if nonblock was set. */ |
1da177e4 LT |
1198 | if (page) { |
1199 | mark_page_accessed(page); | |
1200 | err = install_page(mm, vma, addr, page, prot); | |
1201 | if (err) { | |
1202 | page_cache_release(page); | |
1203 | return err; | |
1204 | } | |
d44ed4f8 PBG |
1205 | } else { |
1206 | /* No page was found just because we can't read it in | |
1207 | * now (being here implies nonblock != 0), but the page | |
1208 | * may exist, so set the PTE to fault it in later. */ | |
1da177e4 LT |
1209 | err = install_file_pte(mm, vma, addr, pgoff, prot); |
1210 | if (err) | |
1211 | return err; | |
1212 | } | |
1213 | ||
1214 | len -= PAGE_SIZE; | |
1215 | addr += PAGE_SIZE; | |
1216 | pgoff++; | |
1217 | } | |
1218 | return 0; | |
1219 | } | |
1220 | ||
1221 | #ifdef CONFIG_NUMA | |
1222 | int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) | |
1223 | { | |
1224 | struct inode *i = vma->vm_file->f_dentry->d_inode; | |
1225 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); | |
1226 | } | |
1227 | ||
1228 | struct mempolicy * | |
1229 | shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) | |
1230 | { | |
1231 | struct inode *i = vma->vm_file->f_dentry->d_inode; | |
1232 | unsigned long idx; | |
1233 | ||
1234 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1235 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1236 | } | |
1237 | #endif | |
1238 | ||
1239 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1240 | { | |
1241 | struct inode *inode = file->f_dentry->d_inode; | |
1242 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1243 | int retval = -ENOMEM; | |
1244 | ||
1245 | spin_lock(&info->lock); | |
1246 | if (lock && !(info->flags & VM_LOCKED)) { | |
1247 | if (!user_shm_lock(inode->i_size, user)) | |
1248 | goto out_nomem; | |
1249 | info->flags |= VM_LOCKED; | |
1250 | } | |
1251 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1252 | user_shm_unlock(inode->i_size, user); | |
1253 | info->flags &= ~VM_LOCKED; | |
1254 | } | |
1255 | retval = 0; | |
1256 | out_nomem: | |
1257 | spin_unlock(&info->lock); | |
1258 | return retval; | |
1259 | } | |
1260 | ||
1261 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) | |
1262 | { | |
1263 | file_accessed(file); | |
1264 | vma->vm_ops = &shmem_vm_ops; | |
1265 | return 0; | |
1266 | } | |
1267 | ||
1268 | static struct inode * | |
1269 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1270 | { | |
1271 | struct inode *inode; | |
1272 | struct shmem_inode_info *info; | |
1273 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1274 | ||
0edd73b3 | 1275 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1276 | spin_lock(&sbinfo->stat_lock); |
1277 | if (!sbinfo->free_inodes) { | |
1278 | spin_unlock(&sbinfo->stat_lock); | |
1279 | return NULL; | |
1280 | } | |
1281 | sbinfo->free_inodes--; | |
1282 | spin_unlock(&sbinfo->stat_lock); | |
1283 | } | |
1284 | ||
1285 | inode = new_inode(sb); | |
1286 | if (inode) { | |
1287 | inode->i_mode = mode; | |
1288 | inode->i_uid = current->fsuid; | |
1289 | inode->i_gid = current->fsgid; | |
1290 | inode->i_blksize = PAGE_CACHE_SIZE; | |
1291 | inode->i_blocks = 0; | |
1292 | inode->i_mapping->a_ops = &shmem_aops; | |
1293 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1294 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
1295 | info = SHMEM_I(inode); | |
1296 | memset(info, 0, (char *)inode - (char *)info); | |
1297 | spin_lock_init(&info->lock); | |
1298 | INIT_LIST_HEAD(&info->swaplist); | |
1299 | ||
1300 | switch (mode & S_IFMT) { | |
1301 | default: | |
1da177e4 LT |
1302 | init_special_inode(inode, mode, dev); |
1303 | break; | |
1304 | case S_IFREG: | |
1305 | inode->i_op = &shmem_inode_operations; | |
1306 | inode->i_fop = &shmem_file_operations; | |
1307 | mpol_shared_policy_init(&info->policy); | |
1308 | break; | |
1309 | case S_IFDIR: | |
1310 | inode->i_nlink++; | |
1311 | /* Some things misbehave if size == 0 on a directory */ | |
1312 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1313 | inode->i_op = &shmem_dir_inode_operations; | |
1314 | inode->i_fop = &simple_dir_operations; | |
1315 | break; | |
1316 | case S_IFLNK: | |
1317 | /* | |
1318 | * Must not load anything in the rbtree, | |
1319 | * mpol_free_shared_policy will not be called. | |
1320 | */ | |
1321 | mpol_shared_policy_init(&info->policy); | |
1322 | break; | |
1323 | } | |
0edd73b3 | 1324 | } else if (sbinfo->max_inodes) { |
1da177e4 LT |
1325 | spin_lock(&sbinfo->stat_lock); |
1326 | sbinfo->free_inodes++; | |
1327 | spin_unlock(&sbinfo->stat_lock); | |
1328 | } | |
1329 | return inode; | |
1330 | } | |
1331 | ||
1332 | #ifdef CONFIG_TMPFS | |
1da177e4 LT |
1333 | static struct inode_operations shmem_symlink_inode_operations; |
1334 | static struct inode_operations shmem_symlink_inline_operations; | |
1335 | ||
1336 | /* | |
1337 | * Normally tmpfs makes no use of shmem_prepare_write, but it | |
1338 | * lets a tmpfs file be used read-write below the loop driver. | |
1339 | */ | |
1340 | static int | |
1341 | shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) | |
1342 | { | |
1343 | struct inode *inode = page->mapping->host; | |
1344 | return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL); | |
1345 | } | |
1346 | ||
1347 | static ssize_t | |
1348 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
1349 | { | |
1350 | struct inode *inode = file->f_dentry->d_inode; | |
1351 | loff_t pos; | |
1352 | unsigned long written; | |
1353 | ssize_t err; | |
1354 | ||
1355 | if ((ssize_t) count < 0) | |
1356 | return -EINVAL; | |
1357 | ||
1358 | if (!access_ok(VERIFY_READ, buf, count)) | |
1359 | return -EFAULT; | |
1360 | ||
1361 | down(&inode->i_sem); | |
1362 | ||
1363 | pos = *ppos; | |
1364 | written = 0; | |
1365 | ||
1366 | err = generic_write_checks(file, &pos, &count, 0); | |
1367 | if (err || !count) | |
1368 | goto out; | |
1369 | ||
1370 | err = remove_suid(file->f_dentry); | |
1371 | if (err) | |
1372 | goto out; | |
1373 | ||
1374 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
1375 | ||
1376 | do { | |
1377 | struct page *page = NULL; | |
1378 | unsigned long bytes, index, offset; | |
1379 | char *kaddr; | |
1380 | int left; | |
1381 | ||
1382 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ | |
1383 | index = pos >> PAGE_CACHE_SHIFT; | |
1384 | bytes = PAGE_CACHE_SIZE - offset; | |
1385 | if (bytes > count) | |
1386 | bytes = count; | |
1387 | ||
1388 | /* | |
1389 | * We don't hold page lock across copy from user - | |
1390 | * what would it guard against? - so no deadlock here. | |
1391 | * But it still may be a good idea to prefault below. | |
1392 | */ | |
1393 | ||
1394 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); | |
1395 | if (err) | |
1396 | break; | |
1397 | ||
1398 | left = bytes; | |
1399 | if (PageHighMem(page)) { | |
1400 | volatile unsigned char dummy; | |
1401 | __get_user(dummy, buf); | |
1402 | __get_user(dummy, buf + bytes - 1); | |
1403 | ||
1404 | kaddr = kmap_atomic(page, KM_USER0); | |
1405 | left = __copy_from_user_inatomic(kaddr + offset, | |
1406 | buf, bytes); | |
1407 | kunmap_atomic(kaddr, KM_USER0); | |
1408 | } | |
1409 | if (left) { | |
1410 | kaddr = kmap(page); | |
1411 | left = __copy_from_user(kaddr + offset, buf, bytes); | |
1412 | kunmap(page); | |
1413 | } | |
1414 | ||
1415 | written += bytes; | |
1416 | count -= bytes; | |
1417 | pos += bytes; | |
1418 | buf += bytes; | |
1419 | if (pos > inode->i_size) | |
1420 | i_size_write(inode, pos); | |
1421 | ||
1422 | flush_dcache_page(page); | |
1423 | set_page_dirty(page); | |
1424 | mark_page_accessed(page); | |
1425 | page_cache_release(page); | |
1426 | ||
1427 | if (left) { | |
1428 | pos -= left; | |
1429 | written -= left; | |
1430 | err = -EFAULT; | |
1431 | break; | |
1432 | } | |
1433 | ||
1434 | /* | |
1435 | * Our dirty pages are not counted in nr_dirty, | |
1436 | * and we do not attempt to balance dirty pages. | |
1437 | */ | |
1438 | ||
1439 | cond_resched(); | |
1440 | } while (count); | |
1441 | ||
1442 | *ppos = pos; | |
1443 | if (written) | |
1444 | err = written; | |
1445 | out: | |
1446 | up(&inode->i_sem); | |
1447 | return err; | |
1448 | } | |
1449 | ||
1450 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) | |
1451 | { | |
1452 | struct inode *inode = filp->f_dentry->d_inode; | |
1453 | struct address_space *mapping = inode->i_mapping; | |
1454 | unsigned long index, offset; | |
1455 | ||
1456 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1457 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1458 | ||
1459 | for (;;) { | |
1460 | struct page *page = NULL; | |
1461 | unsigned long end_index, nr, ret; | |
1462 | loff_t i_size = i_size_read(inode); | |
1463 | ||
1464 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1465 | if (index > end_index) | |
1466 | break; | |
1467 | if (index == end_index) { | |
1468 | nr = i_size & ~PAGE_CACHE_MASK; | |
1469 | if (nr <= offset) | |
1470 | break; | |
1471 | } | |
1472 | ||
1473 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); | |
1474 | if (desc->error) { | |
1475 | if (desc->error == -EINVAL) | |
1476 | desc->error = 0; | |
1477 | break; | |
1478 | } | |
1479 | ||
1480 | /* | |
1481 | * We must evaluate after, since reads (unlike writes) | |
1482 | * are called without i_sem protection against truncate | |
1483 | */ | |
1484 | nr = PAGE_CACHE_SIZE; | |
1485 | i_size = i_size_read(inode); | |
1486 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1487 | if (index == end_index) { | |
1488 | nr = i_size & ~PAGE_CACHE_MASK; | |
1489 | if (nr <= offset) { | |
1490 | if (page) | |
1491 | page_cache_release(page); | |
1492 | break; | |
1493 | } | |
1494 | } | |
1495 | nr -= offset; | |
1496 | ||
1497 | if (page) { | |
1498 | /* | |
1499 | * If users can be writing to this page using arbitrary | |
1500 | * virtual addresses, take care about potential aliasing | |
1501 | * before reading the page on the kernel side. | |
1502 | */ | |
1503 | if (mapping_writably_mapped(mapping)) | |
1504 | flush_dcache_page(page); | |
1505 | /* | |
1506 | * Mark the page accessed if we read the beginning. | |
1507 | */ | |
1508 | if (!offset) | |
1509 | mark_page_accessed(page); | |
1510 | } else | |
1511 | page = ZERO_PAGE(0); | |
1512 | ||
1513 | /* | |
1514 | * Ok, we have the page, and it's up-to-date, so | |
1515 | * now we can copy it to user space... | |
1516 | * | |
1517 | * The actor routine returns how many bytes were actually used.. | |
1518 | * NOTE! This may not be the same as how much of a user buffer | |
1519 | * we filled up (we may be padding etc), so we can only update | |
1520 | * "pos" here (the actor routine has to update the user buffer | |
1521 | * pointers and the remaining count). | |
1522 | */ | |
1523 | ret = actor(desc, page, offset, nr); | |
1524 | offset += ret; | |
1525 | index += offset >> PAGE_CACHE_SHIFT; | |
1526 | offset &= ~PAGE_CACHE_MASK; | |
1527 | ||
1528 | page_cache_release(page); | |
1529 | if (ret != nr || !desc->count) | |
1530 | break; | |
1531 | ||
1532 | cond_resched(); | |
1533 | } | |
1534 | ||
1535 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1536 | file_accessed(filp); | |
1537 | } | |
1538 | ||
1539 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1540 | { | |
1541 | read_descriptor_t desc; | |
1542 | ||
1543 | if ((ssize_t) count < 0) | |
1544 | return -EINVAL; | |
1545 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1546 | return -EFAULT; | |
1547 | if (!count) | |
1548 | return 0; | |
1549 | ||
1550 | desc.written = 0; | |
1551 | desc.count = count; | |
1552 | desc.arg.buf = buf; | |
1553 | desc.error = 0; | |
1554 | ||
1555 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1556 | if (desc.written) | |
1557 | return desc.written; | |
1558 | return desc.error; | |
1559 | } | |
1560 | ||
1561 | static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos, | |
1562 | size_t count, read_actor_t actor, void *target) | |
1563 | { | |
1564 | read_descriptor_t desc; | |
1565 | ||
1566 | if (!count) | |
1567 | return 0; | |
1568 | ||
1569 | desc.written = 0; | |
1570 | desc.count = count; | |
1571 | desc.arg.data = target; | |
1572 | desc.error = 0; | |
1573 | ||
1574 | do_shmem_file_read(in_file, ppos, &desc, actor); | |
1575 | if (desc.written) | |
1576 | return desc.written; | |
1577 | return desc.error; | |
1578 | } | |
1579 | ||
1580 | static int shmem_statfs(struct super_block *sb, struct kstatfs *buf) | |
1581 | { | |
1582 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1583 | ||
1584 | buf->f_type = TMPFS_MAGIC; | |
1585 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1586 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1587 | spin_lock(&sbinfo->stat_lock); |
1588 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1589 | buf->f_blocks = sbinfo->max_blocks; |
1590 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1591 | } |
1592 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1593 | buf->f_files = sbinfo->max_inodes; |
1594 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1595 | } |
1596 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1597 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1598 | return 0; |
1599 | } | |
1600 | ||
1601 | /* | |
1602 | * File creation. Allocate an inode, and we're done.. | |
1603 | */ | |
1604 | static int | |
1605 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1606 | { | |
1607 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1608 | int error = -ENOSPC; | |
1609 | ||
1610 | if (inode) { | |
570bc1c2 SS |
1611 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1612 | NULL); | |
1613 | if (error) { | |
1614 | if (error != -EOPNOTSUPP) { | |
1615 | iput(inode); | |
1616 | return error; | |
1617 | } | |
1618 | error = 0; | |
1619 | } | |
1da177e4 LT |
1620 | if (dir->i_mode & S_ISGID) { |
1621 | inode->i_gid = dir->i_gid; | |
1622 | if (S_ISDIR(mode)) | |
1623 | inode->i_mode |= S_ISGID; | |
1624 | } | |
1625 | dir->i_size += BOGO_DIRENT_SIZE; | |
1626 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1627 | d_instantiate(dentry, inode); | |
1628 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1629 | } |
1630 | return error; | |
1631 | } | |
1632 | ||
1633 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1634 | { | |
1635 | int error; | |
1636 | ||
1637 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1638 | return error; | |
1639 | dir->i_nlink++; | |
1640 | return 0; | |
1641 | } | |
1642 | ||
1643 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1644 | struct nameidata *nd) | |
1645 | { | |
1646 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1647 | } | |
1648 | ||
1649 | /* | |
1650 | * Link a file.. | |
1651 | */ | |
1652 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1653 | { | |
1654 | struct inode *inode = old_dentry->d_inode; | |
1655 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
1656 | ||
1657 | /* | |
1658 | * No ordinary (disk based) filesystem counts links as inodes; | |
1659 | * but each new link needs a new dentry, pinning lowmem, and | |
1660 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1661 | */ | |
0edd73b3 | 1662 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1663 | spin_lock(&sbinfo->stat_lock); |
1664 | if (!sbinfo->free_inodes) { | |
1665 | spin_unlock(&sbinfo->stat_lock); | |
1666 | return -ENOSPC; | |
1667 | } | |
1668 | sbinfo->free_inodes--; | |
1669 | spin_unlock(&sbinfo->stat_lock); | |
1670 | } | |
1671 | ||
1672 | dir->i_size += BOGO_DIRENT_SIZE; | |
1673 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1674 | inode->i_nlink++; | |
1675 | atomic_inc(&inode->i_count); /* New dentry reference */ | |
1676 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1677 | d_instantiate(dentry, inode); | |
1678 | return 0; | |
1679 | } | |
1680 | ||
1681 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1682 | { | |
1683 | struct inode *inode = dentry->d_inode; | |
1684 | ||
1685 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { | |
1686 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1687 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1688 | spin_lock(&sbinfo->stat_lock); |
1689 | sbinfo->free_inodes++; | |
1690 | spin_unlock(&sbinfo->stat_lock); | |
1691 | } | |
1692 | } | |
1693 | ||
1694 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1695 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1696 | inode->i_nlink--; | |
1697 | dput(dentry); /* Undo the count from "create" - this does all the work */ | |
1698 | return 0; | |
1699 | } | |
1700 | ||
1701 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1702 | { | |
1703 | if (!simple_empty(dentry)) | |
1704 | return -ENOTEMPTY; | |
1705 | ||
1706 | dir->i_nlink--; | |
1707 | return shmem_unlink(dir, dentry); | |
1708 | } | |
1709 | ||
1710 | /* | |
1711 | * The VFS layer already does all the dentry stuff for rename, | |
1712 | * we just have to decrement the usage count for the target if | |
1713 | * it exists so that the VFS layer correctly free's it when it | |
1714 | * gets overwritten. | |
1715 | */ | |
1716 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1717 | { | |
1718 | struct inode *inode = old_dentry->d_inode; | |
1719 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1720 | ||
1721 | if (!simple_empty(new_dentry)) | |
1722 | return -ENOTEMPTY; | |
1723 | ||
1724 | if (new_dentry->d_inode) { | |
1725 | (void) shmem_unlink(new_dir, new_dentry); | |
1726 | if (they_are_dirs) | |
1727 | old_dir->i_nlink--; | |
1728 | } else if (they_are_dirs) { | |
1729 | old_dir->i_nlink--; | |
1730 | new_dir->i_nlink++; | |
1731 | } | |
1732 | ||
1733 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1734 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1735 | old_dir->i_ctime = old_dir->i_mtime = | |
1736 | new_dir->i_ctime = new_dir->i_mtime = | |
1737 | inode->i_ctime = CURRENT_TIME; | |
1738 | return 0; | |
1739 | } | |
1740 | ||
1741 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1742 | { | |
1743 | int error; | |
1744 | int len; | |
1745 | struct inode *inode; | |
1746 | struct page *page = NULL; | |
1747 | char *kaddr; | |
1748 | struct shmem_inode_info *info; | |
1749 | ||
1750 | len = strlen(symname) + 1; | |
1751 | if (len > PAGE_CACHE_SIZE) | |
1752 | return -ENAMETOOLONG; | |
1753 | ||
1754 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1755 | if (!inode) | |
1756 | return -ENOSPC; | |
1757 | ||
570bc1c2 SS |
1758 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1759 | NULL); | |
1760 | if (error) { | |
1761 | if (error != -EOPNOTSUPP) { | |
1762 | iput(inode); | |
1763 | return error; | |
1764 | } | |
1765 | error = 0; | |
1766 | } | |
1767 | ||
1da177e4 LT |
1768 | info = SHMEM_I(inode); |
1769 | inode->i_size = len-1; | |
1770 | if (len <= (char *)inode - (char *)info) { | |
1771 | /* do it inline */ | |
1772 | memcpy(info, symname, len); | |
1773 | inode->i_op = &shmem_symlink_inline_operations; | |
1774 | } else { | |
1775 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1776 | if (error) { | |
1777 | iput(inode); | |
1778 | return error; | |
1779 | } | |
1780 | inode->i_op = &shmem_symlink_inode_operations; | |
1781 | kaddr = kmap_atomic(page, KM_USER0); | |
1782 | memcpy(kaddr, symname, len); | |
1783 | kunmap_atomic(kaddr, KM_USER0); | |
1784 | set_page_dirty(page); | |
1785 | page_cache_release(page); | |
1786 | } | |
1787 | if (dir->i_mode & S_ISGID) | |
1788 | inode->i_gid = dir->i_gid; | |
1789 | dir->i_size += BOGO_DIRENT_SIZE; | |
1790 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1791 | d_instantiate(dentry, inode); | |
1792 | dget(dentry); | |
1793 | return 0; | |
1794 | } | |
1795 | ||
cc314eef | 1796 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1797 | { |
1798 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1799 | return NULL; |
1da177e4 LT |
1800 | } |
1801 | ||
cc314eef | 1802 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1803 | { |
1804 | struct page *page = NULL; | |
1805 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1806 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
cc314eef | 1807 | return page; |
1da177e4 LT |
1808 | } |
1809 | ||
cc314eef | 1810 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1811 | { |
1812 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1813 | struct page *page = cookie; |
1da177e4 LT |
1814 | kunmap(page); |
1815 | mark_page_accessed(page); | |
1816 | page_cache_release(page); | |
1da177e4 LT |
1817 | } |
1818 | } | |
1819 | ||
1820 | static struct inode_operations shmem_symlink_inline_operations = { | |
1821 | .readlink = generic_readlink, | |
1822 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1823 | }; |
1824 | ||
1825 | static struct inode_operations shmem_symlink_inode_operations = { | |
1826 | .truncate = shmem_truncate, | |
1827 | .readlink = generic_readlink, | |
1828 | .follow_link = shmem_follow_link, | |
1829 | .put_link = shmem_put_link, | |
1da177e4 LT |
1830 | }; |
1831 | ||
1832 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, gid_t *gid, unsigned long *blocks, unsigned long *inodes) | |
1833 | { | |
1834 | char *this_char, *value, *rest; | |
1835 | ||
1836 | while ((this_char = strsep(&options, ",")) != NULL) { | |
1837 | if (!*this_char) | |
1838 | continue; | |
1839 | if ((value = strchr(this_char,'=')) != NULL) { | |
1840 | *value++ = 0; | |
1841 | } else { | |
1842 | printk(KERN_ERR | |
1843 | "tmpfs: No value for mount option '%s'\n", | |
1844 | this_char); | |
1845 | return 1; | |
1846 | } | |
1847 | ||
1848 | if (!strcmp(this_char,"size")) { | |
1849 | unsigned long long size; | |
1850 | size = memparse(value,&rest); | |
1851 | if (*rest == '%') { | |
1852 | size <<= PAGE_SHIFT; | |
1853 | size *= totalram_pages; | |
1854 | do_div(size, 100); | |
1855 | rest++; | |
1856 | } | |
1857 | if (*rest) | |
1858 | goto bad_val; | |
1859 | *blocks = size >> PAGE_CACHE_SHIFT; | |
1860 | } else if (!strcmp(this_char,"nr_blocks")) { | |
1861 | *blocks = memparse(value,&rest); | |
1862 | if (*rest) | |
1863 | goto bad_val; | |
1864 | } else if (!strcmp(this_char,"nr_inodes")) { | |
1865 | *inodes = memparse(value,&rest); | |
1866 | if (*rest) | |
1867 | goto bad_val; | |
1868 | } else if (!strcmp(this_char,"mode")) { | |
1869 | if (!mode) | |
1870 | continue; | |
1871 | *mode = simple_strtoul(value,&rest,8); | |
1872 | if (*rest) | |
1873 | goto bad_val; | |
1874 | } else if (!strcmp(this_char,"uid")) { | |
1875 | if (!uid) | |
1876 | continue; | |
1877 | *uid = simple_strtoul(value,&rest,0); | |
1878 | if (*rest) | |
1879 | goto bad_val; | |
1880 | } else if (!strcmp(this_char,"gid")) { | |
1881 | if (!gid) | |
1882 | continue; | |
1883 | *gid = simple_strtoul(value,&rest,0); | |
1884 | if (*rest) | |
1885 | goto bad_val; | |
1886 | } else { | |
1887 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
1888 | this_char); | |
1889 | return 1; | |
1890 | } | |
1891 | } | |
1892 | return 0; | |
1893 | ||
1894 | bad_val: | |
1895 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
1896 | value, this_char); | |
1897 | return 1; | |
1898 | ||
1899 | } | |
1900 | ||
1901 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
1902 | { | |
1903 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
1904 | unsigned long max_blocks = sbinfo->max_blocks; |
1905 | unsigned long max_inodes = sbinfo->max_inodes; | |
1906 | unsigned long blocks; | |
1907 | unsigned long inodes; | |
1908 | int error = -EINVAL; | |
1909 | ||
1910 | if (shmem_parse_options(data, NULL, NULL, NULL, | |
1911 | &max_blocks, &max_inodes)) | |
1912 | return error; | |
1da177e4 | 1913 | |
0edd73b3 HD |
1914 | spin_lock(&sbinfo->stat_lock); |
1915 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
1916 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
1917 | if (max_blocks < blocks) | |
1918 | goto out; | |
1919 | if (max_inodes < inodes) | |
1920 | goto out; | |
1921 | /* | |
1922 | * Those tests also disallow limited->unlimited while any are in | |
1923 | * use, so i_blocks will always be zero when max_blocks is zero; | |
1924 | * but we must separately disallow unlimited->limited, because | |
1925 | * in that case we have no record of how much is already in use. | |
1926 | */ | |
1927 | if (max_blocks && !sbinfo->max_blocks) | |
1928 | goto out; | |
1929 | if (max_inodes && !sbinfo->max_inodes) | |
1930 | goto out; | |
1931 | ||
1932 | error = 0; | |
1933 | sbinfo->max_blocks = max_blocks; | |
1934 | sbinfo->free_blocks = max_blocks - blocks; | |
1935 | sbinfo->max_inodes = max_inodes; | |
1936 | sbinfo->free_inodes = max_inodes - inodes; | |
1937 | out: | |
1938 | spin_unlock(&sbinfo->stat_lock); | |
1939 | return error; | |
1da177e4 LT |
1940 | } |
1941 | #endif | |
1942 | ||
1943 | static void shmem_put_super(struct super_block *sb) | |
1944 | { | |
1945 | kfree(sb->s_fs_info); | |
1946 | sb->s_fs_info = NULL; | |
1947 | } | |
1948 | ||
1da177e4 LT |
1949 | static int shmem_fill_super(struct super_block *sb, |
1950 | void *data, int silent) | |
1951 | { | |
1952 | struct inode *inode; | |
1953 | struct dentry *root; | |
1954 | int mode = S_IRWXUGO | S_ISVTX; | |
1955 | uid_t uid = current->fsuid; | |
1956 | gid_t gid = current->fsgid; | |
1957 | int err = -ENOMEM; | |
0edd73b3 | 1958 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
1959 | unsigned long blocks = 0; |
1960 | unsigned long inodes = 0; | |
1961 | ||
0edd73b3 | 1962 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
1963 | /* |
1964 | * Per default we only allow half of the physical ram per | |
1965 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
1966 | * but the internal instance is left unlimited. | |
1967 | */ | |
1968 | if (!(sb->s_flags & MS_NOUSER)) { | |
1969 | blocks = totalram_pages / 2; | |
1970 | inodes = totalram_pages - totalhigh_pages; | |
1971 | if (inodes > blocks) | |
1972 | inodes = blocks; | |
0edd73b3 HD |
1973 | if (shmem_parse_options(data, &mode, &uid, &gid, |
1974 | &blocks, &inodes)) | |
1da177e4 LT |
1975 | return -EINVAL; |
1976 | } | |
1da177e4 LT |
1977 | #else |
1978 | sb->s_flags |= MS_NOUSER; | |
1979 | #endif | |
1980 | ||
0edd73b3 HD |
1981 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
1982 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
1983 | L1_CACHE_BYTES), GFP_KERNEL); | |
1984 | if (!sbinfo) | |
1985 | return -ENOMEM; | |
1986 | ||
1987 | spin_lock_init(&sbinfo->stat_lock); | |
1988 | sbinfo->max_blocks = blocks; | |
1989 | sbinfo->free_blocks = blocks; | |
1990 | sbinfo->max_inodes = inodes; | |
1991 | sbinfo->free_inodes = inodes; | |
1992 | ||
1993 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
1994 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
1995 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
1996 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
1997 | sb->s_magic = TMPFS_MAGIC; | |
1998 | sb->s_op = &shmem_ops; | |
0edd73b3 | 1999 | |
1da177e4 LT |
2000 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2001 | if (!inode) | |
2002 | goto failed; | |
2003 | inode->i_uid = uid; | |
2004 | inode->i_gid = gid; | |
2005 | root = d_alloc_root(inode); | |
2006 | if (!root) | |
2007 | goto failed_iput; | |
2008 | sb->s_root = root; | |
2009 | return 0; | |
2010 | ||
2011 | failed_iput: | |
2012 | iput(inode); | |
2013 | failed: | |
2014 | shmem_put_super(sb); | |
2015 | return err; | |
2016 | } | |
2017 | ||
2018 | static kmem_cache_t *shmem_inode_cachep; | |
2019 | ||
2020 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2021 | { | |
2022 | struct shmem_inode_info *p; | |
2023 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, SLAB_KERNEL); | |
2024 | if (!p) | |
2025 | return NULL; | |
2026 | return &p->vfs_inode; | |
2027 | } | |
2028 | ||
2029 | static void shmem_destroy_inode(struct inode *inode) | |
2030 | { | |
2031 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2032 | /* only struct inode is valid if it's an inline symlink */ | |
2033 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2034 | } | |
2035 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2036 | } | |
2037 | ||
2038 | static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) | |
2039 | { | |
2040 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2041 | ||
2042 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == | |
2043 | SLAB_CTOR_CONSTRUCTOR) { | |
2044 | inode_init_once(&p->vfs_inode); | |
2045 | } | |
2046 | } | |
2047 | ||
2048 | static int init_inodecache(void) | |
2049 | { | |
2050 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2051 | sizeof(struct shmem_inode_info), | |
2052 | 0, 0, init_once, NULL); | |
2053 | if (shmem_inode_cachep == NULL) | |
2054 | return -ENOMEM; | |
2055 | return 0; | |
2056 | } | |
2057 | ||
2058 | static void destroy_inodecache(void) | |
2059 | { | |
2060 | if (kmem_cache_destroy(shmem_inode_cachep)) | |
2061 | printk(KERN_INFO "shmem_inode_cache: not all structures were freed\n"); | |
2062 | } | |
2063 | ||
2064 | static struct address_space_operations shmem_aops = { | |
2065 | .writepage = shmem_writepage, | |
2066 | .set_page_dirty = __set_page_dirty_nobuffers, | |
2067 | #ifdef CONFIG_TMPFS | |
2068 | .prepare_write = shmem_prepare_write, | |
2069 | .commit_write = simple_commit_write, | |
2070 | #endif | |
2071 | }; | |
2072 | ||
2073 | static struct file_operations shmem_file_operations = { | |
2074 | .mmap = shmem_mmap, | |
2075 | #ifdef CONFIG_TMPFS | |
2076 | .llseek = generic_file_llseek, | |
2077 | .read = shmem_file_read, | |
2078 | .write = shmem_file_write, | |
2079 | .fsync = simple_sync_file, | |
2080 | .sendfile = shmem_file_sendfile, | |
2081 | #endif | |
2082 | }; | |
2083 | ||
2084 | static struct inode_operations shmem_inode_operations = { | |
2085 | .truncate = shmem_truncate, | |
2086 | .setattr = shmem_notify_change, | |
1da177e4 LT |
2087 | }; |
2088 | ||
2089 | static struct inode_operations shmem_dir_inode_operations = { | |
2090 | #ifdef CONFIG_TMPFS | |
2091 | .create = shmem_create, | |
2092 | .lookup = simple_lookup, | |
2093 | .link = shmem_link, | |
2094 | .unlink = shmem_unlink, | |
2095 | .symlink = shmem_symlink, | |
2096 | .mkdir = shmem_mkdir, | |
2097 | .rmdir = shmem_rmdir, | |
2098 | .mknod = shmem_mknod, | |
2099 | .rename = shmem_rename, | |
1da177e4 LT |
2100 | #endif |
2101 | }; | |
2102 | ||
2103 | static struct super_operations shmem_ops = { | |
2104 | .alloc_inode = shmem_alloc_inode, | |
2105 | .destroy_inode = shmem_destroy_inode, | |
2106 | #ifdef CONFIG_TMPFS | |
2107 | .statfs = shmem_statfs, | |
2108 | .remount_fs = shmem_remount_fs, | |
2109 | #endif | |
2110 | .delete_inode = shmem_delete_inode, | |
2111 | .drop_inode = generic_delete_inode, | |
2112 | .put_super = shmem_put_super, | |
2113 | }; | |
2114 | ||
2115 | static struct vm_operations_struct shmem_vm_ops = { | |
2116 | .nopage = shmem_nopage, | |
2117 | .populate = shmem_populate, | |
2118 | #ifdef CONFIG_NUMA | |
2119 | .set_policy = shmem_set_policy, | |
2120 | .get_policy = shmem_get_policy, | |
2121 | #endif | |
2122 | }; | |
2123 | ||
2124 | ||
1da177e4 LT |
2125 | static struct super_block *shmem_get_sb(struct file_system_type *fs_type, |
2126 | int flags, const char *dev_name, void *data) | |
2127 | { | |
2128 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super); | |
2129 | } | |
2130 | ||
2131 | static struct file_system_type tmpfs_fs_type = { | |
2132 | .owner = THIS_MODULE, | |
2133 | .name = "tmpfs", | |
2134 | .get_sb = shmem_get_sb, | |
2135 | .kill_sb = kill_litter_super, | |
2136 | }; | |
2137 | static struct vfsmount *shm_mnt; | |
2138 | ||
2139 | static int __init init_tmpfs(void) | |
2140 | { | |
2141 | int error; | |
2142 | ||
2143 | error = init_inodecache(); | |
2144 | if (error) | |
2145 | goto out3; | |
2146 | ||
2147 | error = register_filesystem(&tmpfs_fs_type); | |
2148 | if (error) { | |
2149 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2150 | goto out2; | |
2151 | } | |
2152 | #ifdef CONFIG_TMPFS | |
2153 | devfs_mk_dir("shm"); | |
2154 | #endif | |
2155 | shm_mnt = do_kern_mount(tmpfs_fs_type.name, MS_NOUSER, | |
2156 | tmpfs_fs_type.name, NULL); | |
2157 | if (IS_ERR(shm_mnt)) { | |
2158 | error = PTR_ERR(shm_mnt); | |
2159 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2160 | goto out1; | |
2161 | } | |
2162 | return 0; | |
2163 | ||
2164 | out1: | |
2165 | unregister_filesystem(&tmpfs_fs_type); | |
2166 | out2: | |
2167 | destroy_inodecache(); | |
2168 | out3: | |
2169 | shm_mnt = ERR_PTR(error); | |
2170 | return error; | |
2171 | } | |
2172 | module_init(init_tmpfs) | |
2173 | ||
2174 | /* | |
2175 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2176 | * | |
2177 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2178 | * @size: size to be set for the file | |
2179 | * | |
2180 | */ | |
2181 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2182 | { | |
2183 | int error; | |
2184 | struct file *file; | |
2185 | struct inode *inode; | |
2186 | struct dentry *dentry, *root; | |
2187 | struct qstr this; | |
2188 | ||
2189 | if (IS_ERR(shm_mnt)) | |
2190 | return (void *)shm_mnt; | |
2191 | ||
2192 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2193 | return ERR_PTR(-EINVAL); | |
2194 | ||
2195 | if (shmem_acct_size(flags, size)) | |
2196 | return ERR_PTR(-ENOMEM); | |
2197 | ||
2198 | error = -ENOMEM; | |
2199 | this.name = name; | |
2200 | this.len = strlen(name); | |
2201 | this.hash = 0; /* will go */ | |
2202 | root = shm_mnt->mnt_root; | |
2203 | dentry = d_alloc(root, &this); | |
2204 | if (!dentry) | |
2205 | goto put_memory; | |
2206 | ||
2207 | error = -ENFILE; | |
2208 | file = get_empty_filp(); | |
2209 | if (!file) | |
2210 | goto put_dentry; | |
2211 | ||
2212 | error = -ENOSPC; | |
2213 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2214 | if (!inode) | |
2215 | goto close_file; | |
2216 | ||
2217 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2218 | d_instantiate(dentry, inode); | |
2219 | inode->i_size = size; | |
2220 | inode->i_nlink = 0; /* It is unlinked */ | |
2221 | file->f_vfsmnt = mntget(shm_mnt); | |
2222 | file->f_dentry = dentry; | |
2223 | file->f_mapping = inode->i_mapping; | |
2224 | file->f_op = &shmem_file_operations; | |
2225 | file->f_mode = FMODE_WRITE | FMODE_READ; | |
2226 | return file; | |
2227 | ||
2228 | close_file: | |
2229 | put_filp(file); | |
2230 | put_dentry: | |
2231 | dput(dentry); | |
2232 | put_memory: | |
2233 | shmem_unacct_size(flags, size); | |
2234 | return ERR_PTR(error); | |
2235 | } | |
2236 | ||
2237 | /* | |
2238 | * shmem_zero_setup - setup a shared anonymous mapping | |
2239 | * | |
2240 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2241 | */ | |
2242 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2243 | { | |
2244 | struct file *file; | |
2245 | loff_t size = vma->vm_end - vma->vm_start; | |
2246 | ||
2247 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2248 | if (IS_ERR(file)) | |
2249 | return PTR_ERR(file); | |
2250 | ||
2251 | if (vma->vm_file) | |
2252 | fput(vma->vm_file); | |
2253 | vma->vm_file = file; | |
2254 | vma->vm_ops = &shmem_vm_ops; | |
2255 | return 0; | |
2256 | } |