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> | |
b00dc3ad | 48 | #include <linux/ctype.h> |
1da177e4 LT |
49 | #include <asm/uaccess.h> |
50 | #include <asm/div64.h> | |
51 | #include <asm/pgtable.h> | |
52 | ||
53 | /* This magic number is used in glibc for posix shared memory */ | |
54 | #define TMPFS_MAGIC 0x01021994 | |
55 | ||
56 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) | |
57 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) | |
58 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
59 | ||
60 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) | |
61 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) | |
62 | ||
63 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) | |
64 | ||
65 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
66 | #define SHMEM_PAGEIN VM_READ | |
67 | #define SHMEM_TRUNCATE VM_WRITE | |
68 | ||
69 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
70 | #define LATENCY_LIMIT 64 | |
71 | ||
72 | /* Pretend that each entry is of this size in directory's i_size */ | |
73 | #define BOGO_DIRENT_SIZE 20 | |
74 | ||
1da177e4 LT |
75 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
76 | enum sgp_type { | |
77 | SGP_QUICK, /* don't try more than file page cache lookup */ | |
78 | SGP_READ, /* don't exceed i_size, don't allocate page */ | |
79 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
80 | SGP_WRITE, /* may exceed i_size, may allocate page */ | |
81 | }; | |
82 | ||
83 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
84 | struct page **pagep, enum sgp_type sgp, int *type); | |
85 | ||
6daa0e28 | 86 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
87 | { |
88 | /* | |
89 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
90 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
91 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
92 | */ | |
93 | return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
94 | } | |
95 | ||
96 | static inline void shmem_dir_free(struct page *page) | |
97 | { | |
98 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
99 | } | |
100 | ||
101 | static struct page **shmem_dir_map(struct page *page) | |
102 | { | |
103 | return (struct page **)kmap_atomic(page, KM_USER0); | |
104 | } | |
105 | ||
106 | static inline void shmem_dir_unmap(struct page **dir) | |
107 | { | |
108 | kunmap_atomic(dir, KM_USER0); | |
109 | } | |
110 | ||
111 | static swp_entry_t *shmem_swp_map(struct page *page) | |
112 | { | |
113 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
114 | } | |
115 | ||
116 | static inline void shmem_swp_balance_unmap(void) | |
117 | { | |
118 | /* | |
119 | * When passing a pointer to an i_direct entry, to code which | |
120 | * also handles indirect entries and so will shmem_swp_unmap, | |
121 | * we must arrange for the preempt count to remain in balance. | |
122 | * What kmap_atomic of a lowmem page does depends on config | |
123 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
124 | */ | |
125 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
126 | } | |
127 | ||
128 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
129 | { | |
130 | kunmap_atomic(entry, KM_USER1); | |
131 | } | |
132 | ||
133 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
134 | { | |
135 | return sb->s_fs_info; | |
136 | } | |
137 | ||
138 | /* | |
139 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
140 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
141 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
142 | * consistent with the pre-accounting of private mappings ... | |
143 | */ | |
144 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
145 | { | |
146 | return (flags & VM_ACCOUNT)? | |
147 | security_vm_enough_memory(VM_ACCT(size)): 0; | |
148 | } | |
149 | ||
150 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
151 | { | |
152 | if (flags & VM_ACCOUNT) | |
153 | vm_unacct_memory(VM_ACCT(size)); | |
154 | } | |
155 | ||
156 | /* | |
157 | * ... whereas tmpfs objects are accounted incrementally as | |
158 | * pages are allocated, in order to allow huge sparse files. | |
159 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
160 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
161 | */ | |
162 | static inline int shmem_acct_block(unsigned long flags) | |
163 | { | |
164 | return (flags & VM_ACCOUNT)? | |
165 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); | |
166 | } | |
167 | ||
168 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
169 | { | |
170 | if (!(flags & VM_ACCOUNT)) | |
171 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); | |
172 | } | |
173 | ||
174 | static struct super_operations shmem_ops; | |
175 | static struct address_space_operations shmem_aops; | |
176 | static struct file_operations shmem_file_operations; | |
177 | static struct inode_operations shmem_inode_operations; | |
178 | static struct inode_operations shmem_dir_inode_operations; | |
1da177e4 LT |
179 | static struct vm_operations_struct shmem_vm_ops; |
180 | ||
6c231b7b | 181 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 LT |
182 | .ra_pages = 0, /* No readahead */ |
183 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
184 | .unplug_io_fn = default_unplug_io_fn, | |
185 | }; | |
186 | ||
187 | static LIST_HEAD(shmem_swaplist); | |
188 | static DEFINE_SPINLOCK(shmem_swaplist_lock); | |
189 | ||
190 | static void shmem_free_blocks(struct inode *inode, long pages) | |
191 | { | |
192 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 193 | if (sbinfo->max_blocks) { |
1da177e4 LT |
194 | spin_lock(&sbinfo->stat_lock); |
195 | sbinfo->free_blocks += pages; | |
196 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
197 | spin_unlock(&sbinfo->stat_lock); | |
198 | } | |
199 | } | |
200 | ||
201 | /* | |
202 | * shmem_recalc_inode - recalculate the size of an inode | |
203 | * | |
204 | * @inode: inode to recalc | |
205 | * | |
206 | * We have to calculate the free blocks since the mm can drop | |
207 | * undirtied hole pages behind our back. | |
208 | * | |
209 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
210 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
211 | * | |
212 | * It has to be called with the spinlock held. | |
213 | */ | |
214 | static void shmem_recalc_inode(struct inode *inode) | |
215 | { | |
216 | struct shmem_inode_info *info = SHMEM_I(inode); | |
217 | long freed; | |
218 | ||
219 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
220 | if (freed > 0) { | |
221 | info->alloced -= freed; | |
222 | shmem_unacct_blocks(info->flags, freed); | |
223 | shmem_free_blocks(inode, freed); | |
224 | } | |
225 | } | |
226 | ||
227 | /* | |
228 | * shmem_swp_entry - find the swap vector position in the info structure | |
229 | * | |
230 | * @info: info structure for the inode | |
231 | * @index: index of the page to find | |
232 | * @page: optional page to add to the structure. Has to be preset to | |
233 | * all zeros | |
234 | * | |
235 | * If there is no space allocated yet it will return NULL when | |
236 | * page is NULL, else it will use the page for the needed block, | |
237 | * setting it to NULL on return to indicate that it has been used. | |
238 | * | |
239 | * The swap vector is organized the following way: | |
240 | * | |
241 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
242 | * shmem_inode_info structure. So small files do not need an addional | |
243 | * allocation. | |
244 | * | |
245 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
246 | * i_indirect which points to a page which holds in the first half | |
247 | * doubly indirect blocks, in the second half triple indirect blocks: | |
248 | * | |
249 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
250 | * following layout (for SHMEM_NR_DIRECT == 16): | |
251 | * | |
252 | * i_indirect -> dir --> 16-19 | |
253 | * | +-> 20-23 | |
254 | * | | |
255 | * +-->dir2 --> 24-27 | |
256 | * | +-> 28-31 | |
257 | * | +-> 32-35 | |
258 | * | +-> 36-39 | |
259 | * | | |
260 | * +-->dir3 --> 40-43 | |
261 | * +-> 44-47 | |
262 | * +-> 48-51 | |
263 | * +-> 52-55 | |
264 | */ | |
265 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
266 | { | |
267 | unsigned long offset; | |
268 | struct page **dir; | |
269 | struct page *subdir; | |
270 | ||
271 | if (index < SHMEM_NR_DIRECT) { | |
272 | shmem_swp_balance_unmap(); | |
273 | return info->i_direct+index; | |
274 | } | |
275 | if (!info->i_indirect) { | |
276 | if (page) { | |
277 | info->i_indirect = *page; | |
278 | *page = NULL; | |
279 | } | |
280 | return NULL; /* need another page */ | |
281 | } | |
282 | ||
283 | index -= SHMEM_NR_DIRECT; | |
284 | offset = index % ENTRIES_PER_PAGE; | |
285 | index /= ENTRIES_PER_PAGE; | |
286 | dir = shmem_dir_map(info->i_indirect); | |
287 | ||
288 | if (index >= ENTRIES_PER_PAGE/2) { | |
289 | index -= ENTRIES_PER_PAGE/2; | |
290 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
291 | index %= ENTRIES_PER_PAGE; | |
292 | subdir = *dir; | |
293 | if (!subdir) { | |
294 | if (page) { | |
295 | *dir = *page; | |
296 | *page = NULL; | |
297 | } | |
298 | shmem_dir_unmap(dir); | |
299 | return NULL; /* need another page */ | |
300 | } | |
301 | shmem_dir_unmap(dir); | |
302 | dir = shmem_dir_map(subdir); | |
303 | } | |
304 | ||
305 | dir += index; | |
306 | subdir = *dir; | |
307 | if (!subdir) { | |
308 | if (!page || !(subdir = *page)) { | |
309 | shmem_dir_unmap(dir); | |
310 | return NULL; /* need a page */ | |
311 | } | |
312 | *dir = subdir; | |
313 | *page = NULL; | |
314 | } | |
315 | shmem_dir_unmap(dir); | |
316 | return shmem_swp_map(subdir) + offset; | |
317 | } | |
318 | ||
319 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
320 | { | |
321 | long incdec = value? 1: -1; | |
322 | ||
323 | entry->val = value; | |
324 | info->swapped += incdec; | |
4c21e2f2 HD |
325 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
326 | struct page *page = kmap_atomic_to_page(entry); | |
327 | set_page_private(page, page_private(page) + incdec); | |
328 | } | |
1da177e4 LT |
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); | |
4c21e2f2 HD |
371 | if (page) |
372 | set_page_private(page, 0); | |
1da177e4 LT |
373 | spin_lock(&info->lock); |
374 | ||
375 | if (!page) { | |
376 | shmem_free_blocks(inode, 1); | |
377 | return ERR_PTR(-ENOMEM); | |
378 | } | |
379 | if (sgp != SGP_WRITE && | |
380 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
381 | entry = ERR_PTR(-EINVAL); | |
382 | break; | |
383 | } | |
384 | if (info->next_index <= index) | |
385 | info->next_index = index + 1; | |
386 | } | |
387 | if (page) { | |
388 | /* another task gave its page, or truncated the file */ | |
389 | shmem_free_blocks(inode, 1); | |
390 | shmem_dir_free(page); | |
391 | } | |
392 | if (info->next_index <= index && !IS_ERR(entry)) | |
393 | info->next_index = index + 1; | |
394 | return entry; | |
395 | } | |
396 | ||
397 | /* | |
398 | * shmem_free_swp - free some swap entries in a directory | |
399 | * | |
400 | * @dir: pointer to the directory | |
401 | * @edir: pointer after last entry of the directory | |
402 | */ | |
403 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir) | |
404 | { | |
405 | swp_entry_t *ptr; | |
406 | int freed = 0; | |
407 | ||
408 | for (ptr = dir; ptr < edir; ptr++) { | |
409 | if (ptr->val) { | |
410 | free_swap_and_cache(*ptr); | |
411 | *ptr = (swp_entry_t){0}; | |
412 | freed++; | |
413 | } | |
414 | } | |
415 | return freed; | |
416 | } | |
417 | ||
418 | static int shmem_map_and_free_swp(struct page *subdir, | |
419 | int offset, int limit, struct page ***dir) | |
420 | { | |
421 | swp_entry_t *ptr; | |
422 | int freed = 0; | |
423 | ||
424 | ptr = shmem_swp_map(subdir); | |
425 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
426 | int size = limit - offset; | |
427 | if (size > LATENCY_LIMIT) | |
428 | size = LATENCY_LIMIT; | |
429 | freed += shmem_free_swp(ptr+offset, ptr+offset+size); | |
430 | if (need_resched()) { | |
431 | shmem_swp_unmap(ptr); | |
432 | if (*dir) { | |
433 | shmem_dir_unmap(*dir); | |
434 | *dir = NULL; | |
435 | } | |
436 | cond_resched(); | |
437 | ptr = shmem_swp_map(subdir); | |
438 | } | |
439 | } | |
440 | shmem_swp_unmap(ptr); | |
441 | return freed; | |
442 | } | |
443 | ||
444 | static void shmem_free_pages(struct list_head *next) | |
445 | { | |
446 | struct page *page; | |
447 | int freed = 0; | |
448 | ||
449 | do { | |
450 | page = container_of(next, struct page, lru); | |
451 | next = next->next; | |
452 | shmem_dir_free(page); | |
453 | freed++; | |
454 | if (freed >= LATENCY_LIMIT) { | |
455 | cond_resched(); | |
456 | freed = 0; | |
457 | } | |
458 | } while (next); | |
459 | } | |
460 | ||
f6b3ec23 | 461 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
462 | { |
463 | struct shmem_inode_info *info = SHMEM_I(inode); | |
464 | unsigned long idx; | |
465 | unsigned long size; | |
466 | unsigned long limit; | |
467 | unsigned long stage; | |
468 | unsigned long diroff; | |
469 | struct page **dir; | |
470 | struct page *topdir; | |
471 | struct page *middir; | |
472 | struct page *subdir; | |
473 | swp_entry_t *ptr; | |
474 | LIST_HEAD(pages_to_free); | |
475 | long nr_pages_to_free = 0; | |
476 | long nr_swaps_freed = 0; | |
477 | int offset; | |
478 | int freed; | |
f6b3ec23 | 479 | int punch_hole = 0; |
1da177e4 LT |
480 | |
481 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 482 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
483 | if (idx >= info->next_index) |
484 | return; | |
485 | ||
486 | spin_lock(&info->lock); | |
487 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
488 | if (likely(end == (loff_t) -1)) { |
489 | limit = info->next_index; | |
490 | info->next_index = idx; | |
491 | } else { | |
492 | limit = (end + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
493 | if (limit > info->next_index) | |
494 | limit = info->next_index; | |
495 | punch_hole = 1; | |
496 | } | |
497 | ||
1da177e4 | 498 | topdir = info->i_indirect; |
f6b3ec23 | 499 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
500 | info->i_indirect = NULL; |
501 | nr_pages_to_free++; | |
502 | list_add(&topdir->lru, &pages_to_free); | |
503 | } | |
504 | spin_unlock(&info->lock); | |
505 | ||
506 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
507 | ptr = info->i_direct; | |
508 | size = limit; | |
509 | if (size > SHMEM_NR_DIRECT) | |
510 | size = SHMEM_NR_DIRECT; | |
511 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size); | |
512 | } | |
513 | if (!topdir) | |
514 | goto done2; | |
515 | ||
516 | BUG_ON(limit <= SHMEM_NR_DIRECT); | |
517 | limit -= SHMEM_NR_DIRECT; | |
518 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
519 | offset = idx % ENTRIES_PER_PAGE; | |
520 | idx -= offset; | |
521 | ||
522 | dir = shmem_dir_map(topdir); | |
523 | stage = ENTRIES_PER_PAGEPAGE/2; | |
524 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
525 | middir = topdir; | |
526 | diroff = idx/ENTRIES_PER_PAGE; | |
527 | } else { | |
528 | dir += ENTRIES_PER_PAGE/2; | |
529 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
530 | while (stage <= idx) | |
531 | stage += ENTRIES_PER_PAGEPAGE; | |
532 | middir = *dir; | |
533 | if (*dir) { | |
534 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
535 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
536 | if (!diroff && !offset) { | |
537 | *dir = NULL; | |
538 | nr_pages_to_free++; | |
539 | list_add(&middir->lru, &pages_to_free); | |
540 | } | |
541 | shmem_dir_unmap(dir); | |
542 | dir = shmem_dir_map(middir); | |
543 | } else { | |
544 | diroff = 0; | |
545 | offset = 0; | |
546 | idx = stage; | |
547 | } | |
548 | } | |
549 | ||
550 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
551 | if (unlikely(idx == stage)) { | |
552 | shmem_dir_unmap(dir); | |
553 | dir = shmem_dir_map(topdir) + | |
554 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
555 | while (!*dir) { | |
556 | dir++; | |
557 | idx += ENTRIES_PER_PAGEPAGE; | |
558 | if (idx >= limit) | |
559 | goto done1; | |
560 | } | |
561 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
562 | middir = *dir; | |
563 | *dir = NULL; | |
564 | nr_pages_to_free++; | |
565 | list_add(&middir->lru, &pages_to_free); | |
566 | shmem_dir_unmap(dir); | |
567 | cond_resched(); | |
568 | dir = shmem_dir_map(middir); | |
569 | diroff = 0; | |
570 | } | |
571 | subdir = dir[diroff]; | |
4c21e2f2 | 572 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
573 | size = limit - idx; |
574 | if (size > ENTRIES_PER_PAGE) | |
575 | size = ENTRIES_PER_PAGE; | |
576 | freed = shmem_map_and_free_swp(subdir, | |
577 | offset, size, &dir); | |
578 | if (!dir) | |
579 | dir = shmem_dir_map(middir); | |
580 | nr_swaps_freed += freed; | |
581 | if (offset) | |
582 | spin_lock(&info->lock); | |
4c21e2f2 | 583 | set_page_private(subdir, page_private(subdir) - freed); |
1da177e4 LT |
584 | if (offset) |
585 | spin_unlock(&info->lock); | |
f6b3ec23 BP |
586 | if (!punch_hole) |
587 | BUG_ON(page_private(subdir) > offset); | |
1da177e4 LT |
588 | } |
589 | if (offset) | |
590 | offset = 0; | |
f6b3ec23 | 591 | else if (subdir && !page_private(subdir)) { |
1da177e4 LT |
592 | dir[diroff] = NULL; |
593 | nr_pages_to_free++; | |
594 | list_add(&subdir->lru, &pages_to_free); | |
595 | } | |
596 | } | |
597 | done1: | |
598 | shmem_dir_unmap(dir); | |
599 | done2: | |
600 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
601 | /* | |
602 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
603 | * may have swizzled a page in from swap since vmtruncate or | |
604 | * generic_delete_inode did it, before we lowered next_index. | |
605 | * Also, though shmem_getpage checks i_size before adding to | |
606 | * cache, no recheck after: so fix the narrow window there too. | |
607 | */ | |
f6b3ec23 | 608 | truncate_inode_pages_range(inode->i_mapping, start, end); |
1da177e4 LT |
609 | } |
610 | ||
611 | spin_lock(&info->lock); | |
612 | info->flags &= ~SHMEM_TRUNCATE; | |
613 | info->swapped -= nr_swaps_freed; | |
614 | if (nr_pages_to_free) | |
615 | shmem_free_blocks(inode, nr_pages_to_free); | |
616 | shmem_recalc_inode(inode); | |
617 | spin_unlock(&info->lock); | |
618 | ||
619 | /* | |
620 | * Empty swap vector directory pages to be freed? | |
621 | */ | |
622 | if (!list_empty(&pages_to_free)) { | |
623 | pages_to_free.prev->next = NULL; | |
624 | shmem_free_pages(pages_to_free.next); | |
625 | } | |
626 | } | |
627 | ||
f6b3ec23 BP |
628 | static void shmem_truncate(struct inode *inode) |
629 | { | |
630 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
631 | } | |
632 | ||
1da177e4 LT |
633 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
634 | { | |
635 | struct inode *inode = dentry->d_inode; | |
636 | struct page *page = NULL; | |
637 | int error; | |
638 | ||
639 | if (attr->ia_valid & ATTR_SIZE) { | |
640 | if (attr->ia_size < inode->i_size) { | |
641 | /* | |
642 | * If truncating down to a partial page, then | |
643 | * if that page is already allocated, hold it | |
644 | * in memory until the truncation is over, so | |
645 | * truncate_partial_page cannnot miss it were | |
646 | * it assigned to swap. | |
647 | */ | |
648 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
649 | (void) shmem_getpage(inode, | |
650 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
651 | &page, SGP_READ, NULL); | |
652 | } | |
653 | /* | |
654 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
655 | * detect if any pages might have been added to cache | |
656 | * after truncate_inode_pages. But we needn't bother | |
657 | * if it's being fully truncated to zero-length: the | |
658 | * nrpages check is efficient enough in that case. | |
659 | */ | |
660 | if (attr->ia_size) { | |
661 | struct shmem_inode_info *info = SHMEM_I(inode); | |
662 | spin_lock(&info->lock); | |
663 | info->flags &= ~SHMEM_PAGEIN; | |
664 | spin_unlock(&info->lock); | |
665 | } | |
666 | } | |
667 | } | |
668 | ||
669 | error = inode_change_ok(inode, attr); | |
670 | if (!error) | |
671 | error = inode_setattr(inode, attr); | |
672 | if (page) | |
673 | page_cache_release(page); | |
674 | return error; | |
675 | } | |
676 | ||
677 | static void shmem_delete_inode(struct inode *inode) | |
678 | { | |
679 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
680 | struct shmem_inode_info *info = SHMEM_I(inode); | |
681 | ||
682 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 683 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
684 | shmem_unacct_size(info->flags, inode->i_size); |
685 | inode->i_size = 0; | |
686 | shmem_truncate(inode); | |
687 | if (!list_empty(&info->swaplist)) { | |
688 | spin_lock(&shmem_swaplist_lock); | |
689 | list_del_init(&info->swaplist); | |
690 | spin_unlock(&shmem_swaplist_lock); | |
691 | } | |
692 | } | |
0edd73b3 HD |
693 | BUG_ON(inode->i_blocks); |
694 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
695 | spin_lock(&sbinfo->stat_lock); |
696 | sbinfo->free_inodes++; | |
697 | spin_unlock(&sbinfo->stat_lock); | |
698 | } | |
699 | clear_inode(inode); | |
700 | } | |
701 | ||
702 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
703 | { | |
704 | swp_entry_t *ptr; | |
705 | ||
706 | for (ptr = dir; ptr < edir; ptr++) { | |
707 | if (ptr->val == entry.val) | |
708 | return ptr - dir; | |
709 | } | |
710 | return -1; | |
711 | } | |
712 | ||
713 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
714 | { | |
715 | struct inode *inode; | |
716 | unsigned long idx; | |
717 | unsigned long size; | |
718 | unsigned long limit; | |
719 | unsigned long stage; | |
720 | struct page **dir; | |
721 | struct page *subdir; | |
722 | swp_entry_t *ptr; | |
723 | int offset; | |
724 | ||
725 | idx = 0; | |
726 | ptr = info->i_direct; | |
727 | spin_lock(&info->lock); | |
728 | limit = info->next_index; | |
729 | size = limit; | |
730 | if (size > SHMEM_NR_DIRECT) | |
731 | size = SHMEM_NR_DIRECT; | |
732 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
733 | if (offset >= 0) { | |
734 | shmem_swp_balance_unmap(); | |
735 | goto found; | |
736 | } | |
737 | if (!info->i_indirect) | |
738 | goto lost2; | |
739 | ||
740 | dir = shmem_dir_map(info->i_indirect); | |
741 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
742 | ||
743 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
744 | if (unlikely(idx == stage)) { | |
745 | shmem_dir_unmap(dir-1); | |
746 | dir = shmem_dir_map(info->i_indirect) + | |
747 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
748 | while (!*dir) { | |
749 | dir++; | |
750 | idx += ENTRIES_PER_PAGEPAGE; | |
751 | if (idx >= limit) | |
752 | goto lost1; | |
753 | } | |
754 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
755 | subdir = *dir; | |
756 | shmem_dir_unmap(dir); | |
757 | dir = shmem_dir_map(subdir); | |
758 | } | |
759 | subdir = *dir; | |
4c21e2f2 | 760 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
761 | ptr = shmem_swp_map(subdir); |
762 | size = limit - idx; | |
763 | if (size > ENTRIES_PER_PAGE) | |
764 | size = ENTRIES_PER_PAGE; | |
765 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
766 | if (offset >= 0) { | |
767 | shmem_dir_unmap(dir); | |
768 | goto found; | |
769 | } | |
770 | shmem_swp_unmap(ptr); | |
771 | } | |
772 | } | |
773 | lost1: | |
774 | shmem_dir_unmap(dir-1); | |
775 | lost2: | |
776 | spin_unlock(&info->lock); | |
777 | return 0; | |
778 | found: | |
779 | idx += offset; | |
780 | inode = &info->vfs_inode; | |
781 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { | |
782 | info->flags |= SHMEM_PAGEIN; | |
783 | shmem_swp_set(info, ptr + offset, 0); | |
784 | } | |
785 | shmem_swp_unmap(ptr); | |
786 | spin_unlock(&info->lock); | |
787 | /* | |
788 | * Decrement swap count even when the entry is left behind: | |
789 | * try_to_unuse will skip over mms, then reincrement count. | |
790 | */ | |
791 | swap_free(entry); | |
792 | return 1; | |
793 | } | |
794 | ||
795 | /* | |
796 | * shmem_unuse() search for an eventually swapped out shmem page. | |
797 | */ | |
798 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
799 | { | |
800 | struct list_head *p, *next; | |
801 | struct shmem_inode_info *info; | |
802 | int found = 0; | |
803 | ||
804 | spin_lock(&shmem_swaplist_lock); | |
805 | list_for_each_safe(p, next, &shmem_swaplist) { | |
806 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
807 | if (!info->swapped) | |
808 | list_del_init(&info->swaplist); | |
809 | else if (shmem_unuse_inode(info, entry, page)) { | |
810 | /* move head to start search for next from here */ | |
811 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
812 | found = 1; | |
813 | break; | |
814 | } | |
815 | } | |
816 | spin_unlock(&shmem_swaplist_lock); | |
817 | return found; | |
818 | } | |
819 | ||
820 | /* | |
821 | * Move the page from the page cache to the swap cache. | |
822 | */ | |
823 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
824 | { | |
825 | struct shmem_inode_info *info; | |
826 | swp_entry_t *entry, swap; | |
827 | struct address_space *mapping; | |
828 | unsigned long index; | |
829 | struct inode *inode; | |
830 | ||
831 | BUG_ON(!PageLocked(page)); | |
832 | BUG_ON(page_mapped(page)); | |
833 | ||
834 | mapping = page->mapping; | |
835 | index = page->index; | |
836 | inode = mapping->host; | |
837 | info = SHMEM_I(inode); | |
838 | if (info->flags & VM_LOCKED) | |
839 | goto redirty; | |
840 | swap = get_swap_page(); | |
841 | if (!swap.val) | |
842 | goto redirty; | |
843 | ||
844 | spin_lock(&info->lock); | |
845 | shmem_recalc_inode(inode); | |
846 | if (index >= info->next_index) { | |
847 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
848 | goto unlock; | |
849 | } | |
850 | entry = shmem_swp_entry(info, index, NULL); | |
851 | BUG_ON(!entry); | |
852 | BUG_ON(entry->val); | |
853 | ||
854 | if (move_to_swap_cache(page, swap) == 0) { | |
855 | shmem_swp_set(info, entry, swap.val); | |
856 | shmem_swp_unmap(entry); | |
857 | spin_unlock(&info->lock); | |
858 | if (list_empty(&info->swaplist)) { | |
859 | spin_lock(&shmem_swaplist_lock); | |
860 | /* move instead of add in case we're racing */ | |
861 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
862 | spin_unlock(&shmem_swaplist_lock); | |
863 | } | |
864 | unlock_page(page); | |
865 | return 0; | |
866 | } | |
867 | ||
868 | shmem_swp_unmap(entry); | |
869 | unlock: | |
870 | spin_unlock(&info->lock); | |
871 | swap_free(swap); | |
872 | redirty: | |
873 | set_page_dirty(page); | |
994fc28c | 874 | return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */ |
1da177e4 LT |
875 | } |
876 | ||
877 | #ifdef CONFIG_NUMA | |
b00dc3ad HD |
878 | static int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
879 | { | |
880 | char *nodelist = strchr(value, ':'); | |
881 | int err = 1; | |
882 | ||
883 | if (nodelist) { | |
884 | /* NUL-terminate policy string */ | |
885 | *nodelist++ = '\0'; | |
886 | if (nodelist_parse(nodelist, *policy_nodes)) | |
887 | goto out; | |
888 | } | |
889 | if (!strcmp(value, "default")) { | |
890 | *policy = MPOL_DEFAULT; | |
891 | /* Don't allow a nodelist */ | |
892 | if (!nodelist) | |
893 | err = 0; | |
894 | } else if (!strcmp(value, "prefer")) { | |
895 | *policy = MPOL_PREFERRED; | |
896 | /* Insist on a nodelist of one node only */ | |
897 | if (nodelist) { | |
898 | char *rest = nodelist; | |
899 | while (isdigit(*rest)) | |
900 | rest++; | |
901 | if (!*rest) | |
902 | err = 0; | |
903 | } | |
904 | } else if (!strcmp(value, "bind")) { | |
905 | *policy = MPOL_BIND; | |
906 | /* Insist on a nodelist */ | |
907 | if (nodelist) | |
908 | err = 0; | |
909 | } else if (!strcmp(value, "interleave")) { | |
910 | *policy = MPOL_INTERLEAVE; | |
911 | /* Default to nodes online if no nodelist */ | |
912 | if (!nodelist) | |
913 | *policy_nodes = node_online_map; | |
914 | err = 0; | |
915 | } | |
916 | out: | |
917 | /* Restore string for error message */ | |
918 | if (nodelist) | |
919 | *--nodelist = ':'; | |
920 | return err; | |
921 | } | |
922 | ||
1da177e4 LT |
923 | static struct page *shmem_swapin_async(struct shared_policy *p, |
924 | swp_entry_t entry, unsigned long idx) | |
925 | { | |
926 | struct page *page; | |
927 | struct vm_area_struct pvma; | |
928 | ||
929 | /* Create a pseudo vma that just contains the policy */ | |
930 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
931 | pvma.vm_end = PAGE_SIZE; | |
932 | pvma.vm_pgoff = idx; | |
933 | pvma.vm_policy = mpol_shared_policy_lookup(p, idx); | |
934 | page = read_swap_cache_async(entry, &pvma, 0); | |
935 | mpol_free(pvma.vm_policy); | |
936 | return page; | |
937 | } | |
938 | ||
939 | struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry, | |
940 | unsigned long idx) | |
941 | { | |
942 | struct shared_policy *p = &info->policy; | |
943 | int i, num; | |
944 | struct page *page; | |
945 | unsigned long offset; | |
946 | ||
947 | num = valid_swaphandles(entry, &offset); | |
948 | for (i = 0; i < num; offset++, i++) { | |
949 | page = shmem_swapin_async(p, | |
950 | swp_entry(swp_type(entry), offset), idx); | |
951 | if (!page) | |
952 | break; | |
953 | page_cache_release(page); | |
954 | } | |
955 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
956 | return shmem_swapin_async(p, entry, idx); | |
957 | } | |
958 | ||
959 | static struct page * | |
6daa0e28 | 960 | shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info, |
1da177e4 LT |
961 | unsigned long idx) |
962 | { | |
963 | struct vm_area_struct pvma; | |
964 | struct page *page; | |
965 | ||
966 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
967 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
968 | pvma.vm_pgoff = idx; | |
969 | pvma.vm_end = PAGE_SIZE; | |
970 | page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0); | |
971 | mpol_free(pvma.vm_policy); | |
972 | return page; | |
973 | } | |
974 | #else | |
b00dc3ad HD |
975 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
976 | { | |
977 | return 1; | |
978 | } | |
979 | ||
1da177e4 LT |
980 | static inline struct page * |
981 | shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx) | |
982 | { | |
983 | swapin_readahead(entry, 0, NULL); | |
984 | return read_swap_cache_async(entry, NULL, 0); | |
985 | } | |
986 | ||
987 | static inline struct page * | |
dd0fc66f | 988 | shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx) |
1da177e4 LT |
989 | { |
990 | return alloc_page(gfp | __GFP_ZERO); | |
991 | } | |
992 | #endif | |
993 | ||
994 | /* | |
995 | * shmem_getpage - either get the page from swap or allocate a new one | |
996 | * | |
997 | * If we allocate a new one we do not mark it dirty. That's up to the | |
998 | * vm. If we swap it in we mark it dirty since we also free the swap | |
999 | * entry since a page cannot live in both the swap and page cache | |
1000 | */ | |
1001 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1002 | struct page **pagep, enum sgp_type sgp, int *type) | |
1003 | { | |
1004 | struct address_space *mapping = inode->i_mapping; | |
1005 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1006 | struct shmem_sb_info *sbinfo; | |
1007 | struct page *filepage = *pagep; | |
1008 | struct page *swappage; | |
1009 | swp_entry_t *entry; | |
1010 | swp_entry_t swap; | |
1011 | int error; | |
1012 | ||
1013 | if (idx >= SHMEM_MAX_INDEX) | |
1014 | return -EFBIG; | |
1015 | /* | |
1016 | * Normally, filepage is NULL on entry, and either found | |
1017 | * uptodate immediately, or allocated and zeroed, or read | |
1018 | * in under swappage, which is then assigned to filepage. | |
1019 | * But shmem_prepare_write passes in a locked filepage, | |
1020 | * which may be found not uptodate by other callers too, | |
1021 | * and may need to be copied from the swappage read in. | |
1022 | */ | |
1023 | repeat: | |
1024 | if (!filepage) | |
1025 | filepage = find_lock_page(mapping, idx); | |
1026 | if (filepage && PageUptodate(filepage)) | |
1027 | goto done; | |
1028 | error = 0; | |
1029 | if (sgp == SGP_QUICK) | |
1030 | goto failed; | |
1031 | ||
1032 | spin_lock(&info->lock); | |
1033 | shmem_recalc_inode(inode); | |
1034 | entry = shmem_swp_alloc(info, idx, sgp); | |
1035 | if (IS_ERR(entry)) { | |
1036 | spin_unlock(&info->lock); | |
1037 | error = PTR_ERR(entry); | |
1038 | goto failed; | |
1039 | } | |
1040 | swap = *entry; | |
1041 | ||
1042 | if (swap.val) { | |
1043 | /* Look it up and read it in.. */ | |
1044 | swappage = lookup_swap_cache(swap); | |
1045 | if (!swappage) { | |
1046 | shmem_swp_unmap(entry); | |
1047 | spin_unlock(&info->lock); | |
1048 | /* here we actually do the io */ | |
1049 | if (type && *type == VM_FAULT_MINOR) { | |
1050 | inc_page_state(pgmajfault); | |
1051 | *type = VM_FAULT_MAJOR; | |
1052 | } | |
1053 | swappage = shmem_swapin(info, swap, idx); | |
1054 | if (!swappage) { | |
1055 | spin_lock(&info->lock); | |
1056 | entry = shmem_swp_alloc(info, idx, sgp); | |
1057 | if (IS_ERR(entry)) | |
1058 | error = PTR_ERR(entry); | |
1059 | else { | |
1060 | if (entry->val == swap.val) | |
1061 | error = -ENOMEM; | |
1062 | shmem_swp_unmap(entry); | |
1063 | } | |
1064 | spin_unlock(&info->lock); | |
1065 | if (error) | |
1066 | goto failed; | |
1067 | goto repeat; | |
1068 | } | |
1069 | wait_on_page_locked(swappage); | |
1070 | page_cache_release(swappage); | |
1071 | goto repeat; | |
1072 | } | |
1073 | ||
1074 | /* We have to do this with page locked to prevent races */ | |
1075 | if (TestSetPageLocked(swappage)) { | |
1076 | shmem_swp_unmap(entry); | |
1077 | spin_unlock(&info->lock); | |
1078 | wait_on_page_locked(swappage); | |
1079 | page_cache_release(swappage); | |
1080 | goto repeat; | |
1081 | } | |
b16664e4 CL |
1082 | if (!PageSwapCache(swappage)) { |
1083 | /* Page migration has occured */ | |
1084 | shmem_swp_unmap(entry); | |
1085 | spin_unlock(&info->lock); | |
1086 | unlock_page(swappage); | |
1087 | page_cache_release(swappage); | |
1088 | goto repeat; | |
1089 | } | |
1da177e4 LT |
1090 | if (PageWriteback(swappage)) { |
1091 | shmem_swp_unmap(entry); | |
1092 | spin_unlock(&info->lock); | |
1093 | wait_on_page_writeback(swappage); | |
1094 | unlock_page(swappage); | |
1095 | page_cache_release(swappage); | |
1096 | goto repeat; | |
1097 | } | |
1098 | if (!PageUptodate(swappage)) { | |
1099 | shmem_swp_unmap(entry); | |
1100 | spin_unlock(&info->lock); | |
1101 | unlock_page(swappage); | |
1102 | page_cache_release(swappage); | |
1103 | error = -EIO; | |
1104 | goto failed; | |
1105 | } | |
1106 | ||
1107 | if (filepage) { | |
1108 | shmem_swp_set(info, entry, 0); | |
1109 | shmem_swp_unmap(entry); | |
1110 | delete_from_swap_cache(swappage); | |
1111 | spin_unlock(&info->lock); | |
1112 | copy_highpage(filepage, swappage); | |
1113 | unlock_page(swappage); | |
1114 | page_cache_release(swappage); | |
1115 | flush_dcache_page(filepage); | |
1116 | SetPageUptodate(filepage); | |
1117 | set_page_dirty(filepage); | |
1118 | swap_free(swap); | |
1119 | } else if (!(error = move_from_swap_cache( | |
1120 | swappage, idx, mapping))) { | |
1121 | info->flags |= SHMEM_PAGEIN; | |
1122 | shmem_swp_set(info, entry, 0); | |
1123 | shmem_swp_unmap(entry); | |
1124 | spin_unlock(&info->lock); | |
1125 | filepage = swappage; | |
1126 | swap_free(swap); | |
1127 | } else { | |
1128 | shmem_swp_unmap(entry); | |
1129 | spin_unlock(&info->lock); | |
1130 | unlock_page(swappage); | |
1131 | page_cache_release(swappage); | |
1132 | if (error == -ENOMEM) { | |
1133 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
1134 | blk_congestion_wait(WRITE, HZ/50); | |
1135 | } | |
1136 | goto repeat; | |
1137 | } | |
1138 | } else if (sgp == SGP_READ && !filepage) { | |
1139 | shmem_swp_unmap(entry); | |
1140 | filepage = find_get_page(mapping, idx); | |
1141 | if (filepage && | |
1142 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1143 | spin_unlock(&info->lock); | |
1144 | wait_on_page_locked(filepage); | |
1145 | page_cache_release(filepage); | |
1146 | filepage = NULL; | |
1147 | goto repeat; | |
1148 | } | |
1149 | spin_unlock(&info->lock); | |
1150 | } else { | |
1151 | shmem_swp_unmap(entry); | |
1152 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1153 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1154 | spin_lock(&sbinfo->stat_lock); |
1155 | if (sbinfo->free_blocks == 0 || | |
1156 | shmem_acct_block(info->flags)) { | |
1157 | spin_unlock(&sbinfo->stat_lock); | |
1158 | spin_unlock(&info->lock); | |
1159 | error = -ENOSPC; | |
1160 | goto failed; | |
1161 | } | |
1162 | sbinfo->free_blocks--; | |
1163 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1164 | spin_unlock(&sbinfo->stat_lock); | |
1165 | } else if (shmem_acct_block(info->flags)) { | |
1166 | spin_unlock(&info->lock); | |
1167 | error = -ENOSPC; | |
1168 | goto failed; | |
1169 | } | |
1170 | ||
1171 | if (!filepage) { | |
1172 | spin_unlock(&info->lock); | |
1173 | filepage = shmem_alloc_page(mapping_gfp_mask(mapping), | |
1174 | info, | |
1175 | idx); | |
1176 | if (!filepage) { | |
1177 | shmem_unacct_blocks(info->flags, 1); | |
1178 | shmem_free_blocks(inode, 1); | |
1179 | error = -ENOMEM; | |
1180 | goto failed; | |
1181 | } | |
1182 | ||
1183 | spin_lock(&info->lock); | |
1184 | entry = shmem_swp_alloc(info, idx, sgp); | |
1185 | if (IS_ERR(entry)) | |
1186 | error = PTR_ERR(entry); | |
1187 | else { | |
1188 | swap = *entry; | |
1189 | shmem_swp_unmap(entry); | |
1190 | } | |
1191 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1192 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1193 | spin_unlock(&info->lock); | |
1194 | page_cache_release(filepage); | |
1195 | shmem_unacct_blocks(info->flags, 1); | |
1196 | shmem_free_blocks(inode, 1); | |
1197 | filepage = NULL; | |
1198 | if (error) | |
1199 | goto failed; | |
1200 | goto repeat; | |
1201 | } | |
1202 | info->flags |= SHMEM_PAGEIN; | |
1203 | } | |
1204 | ||
1205 | info->alloced++; | |
1206 | spin_unlock(&info->lock); | |
1207 | flush_dcache_page(filepage); | |
1208 | SetPageUptodate(filepage); | |
1209 | } | |
1210 | done: | |
1211 | if (*pagep != filepage) { | |
1212 | unlock_page(filepage); | |
1213 | *pagep = filepage; | |
1214 | } | |
1215 | return 0; | |
1216 | ||
1217 | failed: | |
1218 | if (*pagep != filepage) { | |
1219 | unlock_page(filepage); | |
1220 | page_cache_release(filepage); | |
1221 | } | |
1222 | return error; | |
1223 | } | |
1224 | ||
1225 | struct page *shmem_nopage(struct vm_area_struct *vma, unsigned long address, int *type) | |
1226 | { | |
1227 | struct inode *inode = vma->vm_file->f_dentry->d_inode; | |
1228 | struct page *page = NULL; | |
1229 | unsigned long idx; | |
1230 | int error; | |
1231 | ||
1232 | idx = (address - vma->vm_start) >> PAGE_SHIFT; | |
1233 | idx += vma->vm_pgoff; | |
1234 | idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT; | |
1235 | if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
1236 | return NOPAGE_SIGBUS; | |
1237 | ||
1238 | error = shmem_getpage(inode, idx, &page, SGP_CACHE, type); | |
1239 | if (error) | |
1240 | return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS; | |
1241 | ||
1242 | mark_page_accessed(page); | |
1243 | return page; | |
1244 | } | |
1245 | ||
1246 | static int shmem_populate(struct vm_area_struct *vma, | |
1247 | unsigned long addr, unsigned long len, | |
1248 | pgprot_t prot, unsigned long pgoff, int nonblock) | |
1249 | { | |
1250 | struct inode *inode = vma->vm_file->f_dentry->d_inode; | |
1251 | struct mm_struct *mm = vma->vm_mm; | |
1252 | enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE; | |
1253 | unsigned long size; | |
1254 | ||
1255 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1256 | if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size) | |
1257 | return -EINVAL; | |
1258 | ||
1259 | while ((long) len > 0) { | |
1260 | struct page *page = NULL; | |
1261 | int err; | |
1262 | /* | |
1263 | * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE | |
1264 | */ | |
1265 | err = shmem_getpage(inode, pgoff, &page, sgp, NULL); | |
1266 | if (err) | |
1267 | return err; | |
d44ed4f8 | 1268 | /* Page may still be null, but only if nonblock was set. */ |
1da177e4 LT |
1269 | if (page) { |
1270 | mark_page_accessed(page); | |
1271 | err = install_page(mm, vma, addr, page, prot); | |
1272 | if (err) { | |
1273 | page_cache_release(page); | |
1274 | return err; | |
1275 | } | |
65500d23 | 1276 | } else if (vma->vm_flags & VM_NONLINEAR) { |
d44ed4f8 PBG |
1277 | /* No page was found just because we can't read it in |
1278 | * now (being here implies nonblock != 0), but the page | |
1279 | * may exist, so set the PTE to fault it in later. */ | |
1da177e4 LT |
1280 | err = install_file_pte(mm, vma, addr, pgoff, prot); |
1281 | if (err) | |
1282 | return err; | |
1283 | } | |
1284 | ||
1285 | len -= PAGE_SIZE; | |
1286 | addr += PAGE_SIZE; | |
1287 | pgoff++; | |
1288 | } | |
1289 | return 0; | |
1290 | } | |
1291 | ||
1292 | #ifdef CONFIG_NUMA | |
1293 | int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) | |
1294 | { | |
1295 | struct inode *i = vma->vm_file->f_dentry->d_inode; | |
1296 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); | |
1297 | } | |
1298 | ||
1299 | struct mempolicy * | |
1300 | shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) | |
1301 | { | |
1302 | struct inode *i = vma->vm_file->f_dentry->d_inode; | |
1303 | unsigned long idx; | |
1304 | ||
1305 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1306 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1307 | } | |
1308 | #endif | |
1309 | ||
1310 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1311 | { | |
1312 | struct inode *inode = file->f_dentry->d_inode; | |
1313 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1314 | int retval = -ENOMEM; | |
1315 | ||
1316 | spin_lock(&info->lock); | |
1317 | if (lock && !(info->flags & VM_LOCKED)) { | |
1318 | if (!user_shm_lock(inode->i_size, user)) | |
1319 | goto out_nomem; | |
1320 | info->flags |= VM_LOCKED; | |
1321 | } | |
1322 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1323 | user_shm_unlock(inode->i_size, user); | |
1324 | info->flags &= ~VM_LOCKED; | |
1325 | } | |
1326 | retval = 0; | |
1327 | out_nomem: | |
1328 | spin_unlock(&info->lock); | |
1329 | return retval; | |
1330 | } | |
1331 | ||
b0e15190 | 1332 | int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1333 | { |
1334 | file_accessed(file); | |
1335 | vma->vm_ops = &shmem_vm_ops; | |
1336 | return 0; | |
1337 | } | |
1338 | ||
1339 | static struct inode * | |
1340 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1341 | { | |
1342 | struct inode *inode; | |
1343 | struct shmem_inode_info *info; | |
1344 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1345 | ||
0edd73b3 | 1346 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1347 | spin_lock(&sbinfo->stat_lock); |
1348 | if (!sbinfo->free_inodes) { | |
1349 | spin_unlock(&sbinfo->stat_lock); | |
1350 | return NULL; | |
1351 | } | |
1352 | sbinfo->free_inodes--; | |
1353 | spin_unlock(&sbinfo->stat_lock); | |
1354 | } | |
1355 | ||
1356 | inode = new_inode(sb); | |
1357 | if (inode) { | |
1358 | inode->i_mode = mode; | |
1359 | inode->i_uid = current->fsuid; | |
1360 | inode->i_gid = current->fsgid; | |
1361 | inode->i_blksize = PAGE_CACHE_SIZE; | |
1362 | inode->i_blocks = 0; | |
1363 | inode->i_mapping->a_ops = &shmem_aops; | |
1364 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1365 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
1366 | info = SHMEM_I(inode); | |
1367 | memset(info, 0, (char *)inode - (char *)info); | |
1368 | spin_lock_init(&info->lock); | |
1369 | INIT_LIST_HEAD(&info->swaplist); | |
1370 | ||
1371 | switch (mode & S_IFMT) { | |
1372 | default: | |
1da177e4 LT |
1373 | init_special_inode(inode, mode, dev); |
1374 | break; | |
1375 | case S_IFREG: | |
1376 | inode->i_op = &shmem_inode_operations; | |
1377 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1378 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1379 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1380 | break; |
1381 | case S_IFDIR: | |
1382 | inode->i_nlink++; | |
1383 | /* Some things misbehave if size == 0 on a directory */ | |
1384 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1385 | inode->i_op = &shmem_dir_inode_operations; | |
1386 | inode->i_fop = &simple_dir_operations; | |
1387 | break; | |
1388 | case S_IFLNK: | |
1389 | /* | |
1390 | * Must not load anything in the rbtree, | |
1391 | * mpol_free_shared_policy will not be called. | |
1392 | */ | |
7339ff83 RH |
1393 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1394 | NULL); | |
1da177e4 LT |
1395 | break; |
1396 | } | |
0edd73b3 | 1397 | } else if (sbinfo->max_inodes) { |
1da177e4 LT |
1398 | spin_lock(&sbinfo->stat_lock); |
1399 | sbinfo->free_inodes++; | |
1400 | spin_unlock(&sbinfo->stat_lock); | |
1401 | } | |
1402 | return inode; | |
1403 | } | |
1404 | ||
1405 | #ifdef CONFIG_TMPFS | |
1da177e4 LT |
1406 | static struct inode_operations shmem_symlink_inode_operations; |
1407 | static struct inode_operations shmem_symlink_inline_operations; | |
1408 | ||
1409 | /* | |
1410 | * Normally tmpfs makes no use of shmem_prepare_write, but it | |
1411 | * lets a tmpfs file be used read-write below the loop driver. | |
1412 | */ | |
1413 | static int | |
1414 | shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) | |
1415 | { | |
1416 | struct inode *inode = page->mapping->host; | |
1417 | return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL); | |
1418 | } | |
1419 | ||
1420 | static ssize_t | |
1421 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
1422 | { | |
1423 | struct inode *inode = file->f_dentry->d_inode; | |
1424 | loff_t pos; | |
1425 | unsigned long written; | |
1426 | ssize_t err; | |
1427 | ||
1428 | if ((ssize_t) count < 0) | |
1429 | return -EINVAL; | |
1430 | ||
1431 | if (!access_ok(VERIFY_READ, buf, count)) | |
1432 | return -EFAULT; | |
1433 | ||
1b1dcc1b | 1434 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1435 | |
1436 | pos = *ppos; | |
1437 | written = 0; | |
1438 | ||
1439 | err = generic_write_checks(file, &pos, &count, 0); | |
1440 | if (err || !count) | |
1441 | goto out; | |
1442 | ||
1443 | err = remove_suid(file->f_dentry); | |
1444 | if (err) | |
1445 | goto out; | |
1446 | ||
1447 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
1448 | ||
1449 | do { | |
1450 | struct page *page = NULL; | |
1451 | unsigned long bytes, index, offset; | |
1452 | char *kaddr; | |
1453 | int left; | |
1454 | ||
1455 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ | |
1456 | index = pos >> PAGE_CACHE_SHIFT; | |
1457 | bytes = PAGE_CACHE_SIZE - offset; | |
1458 | if (bytes > count) | |
1459 | bytes = count; | |
1460 | ||
1461 | /* | |
1462 | * We don't hold page lock across copy from user - | |
1463 | * what would it guard against? - so no deadlock here. | |
1464 | * But it still may be a good idea to prefault below. | |
1465 | */ | |
1466 | ||
1467 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); | |
1468 | if (err) | |
1469 | break; | |
1470 | ||
1471 | left = bytes; | |
1472 | if (PageHighMem(page)) { | |
1473 | volatile unsigned char dummy; | |
1474 | __get_user(dummy, buf); | |
1475 | __get_user(dummy, buf + bytes - 1); | |
1476 | ||
1477 | kaddr = kmap_atomic(page, KM_USER0); | |
1478 | left = __copy_from_user_inatomic(kaddr + offset, | |
1479 | buf, bytes); | |
1480 | kunmap_atomic(kaddr, KM_USER0); | |
1481 | } | |
1482 | if (left) { | |
1483 | kaddr = kmap(page); | |
1484 | left = __copy_from_user(kaddr + offset, buf, bytes); | |
1485 | kunmap(page); | |
1486 | } | |
1487 | ||
1488 | written += bytes; | |
1489 | count -= bytes; | |
1490 | pos += bytes; | |
1491 | buf += bytes; | |
1492 | if (pos > inode->i_size) | |
1493 | i_size_write(inode, pos); | |
1494 | ||
1495 | flush_dcache_page(page); | |
1496 | set_page_dirty(page); | |
1497 | mark_page_accessed(page); | |
1498 | page_cache_release(page); | |
1499 | ||
1500 | if (left) { | |
1501 | pos -= left; | |
1502 | written -= left; | |
1503 | err = -EFAULT; | |
1504 | break; | |
1505 | } | |
1506 | ||
1507 | /* | |
1508 | * Our dirty pages are not counted in nr_dirty, | |
1509 | * and we do not attempt to balance dirty pages. | |
1510 | */ | |
1511 | ||
1512 | cond_resched(); | |
1513 | } while (count); | |
1514 | ||
1515 | *ppos = pos; | |
1516 | if (written) | |
1517 | err = written; | |
1518 | out: | |
1b1dcc1b | 1519 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1520 | return err; |
1521 | } | |
1522 | ||
1523 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) | |
1524 | { | |
1525 | struct inode *inode = filp->f_dentry->d_inode; | |
1526 | struct address_space *mapping = inode->i_mapping; | |
1527 | unsigned long index, offset; | |
1528 | ||
1529 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1530 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1531 | ||
1532 | for (;;) { | |
1533 | struct page *page = NULL; | |
1534 | unsigned long end_index, nr, ret; | |
1535 | loff_t i_size = i_size_read(inode); | |
1536 | ||
1537 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1538 | if (index > end_index) | |
1539 | break; | |
1540 | if (index == end_index) { | |
1541 | nr = i_size & ~PAGE_CACHE_MASK; | |
1542 | if (nr <= offset) | |
1543 | break; | |
1544 | } | |
1545 | ||
1546 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); | |
1547 | if (desc->error) { | |
1548 | if (desc->error == -EINVAL) | |
1549 | desc->error = 0; | |
1550 | break; | |
1551 | } | |
1552 | ||
1553 | /* | |
1554 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1555 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1556 | */ |
1557 | nr = PAGE_CACHE_SIZE; | |
1558 | i_size = i_size_read(inode); | |
1559 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1560 | if (index == end_index) { | |
1561 | nr = i_size & ~PAGE_CACHE_MASK; | |
1562 | if (nr <= offset) { | |
1563 | if (page) | |
1564 | page_cache_release(page); | |
1565 | break; | |
1566 | } | |
1567 | } | |
1568 | nr -= offset; | |
1569 | ||
1570 | if (page) { | |
1571 | /* | |
1572 | * If users can be writing to this page using arbitrary | |
1573 | * virtual addresses, take care about potential aliasing | |
1574 | * before reading the page on the kernel side. | |
1575 | */ | |
1576 | if (mapping_writably_mapped(mapping)) | |
1577 | flush_dcache_page(page); | |
1578 | /* | |
1579 | * Mark the page accessed if we read the beginning. | |
1580 | */ | |
1581 | if (!offset) | |
1582 | mark_page_accessed(page); | |
b5810039 | 1583 | } else { |
1da177e4 | 1584 | page = ZERO_PAGE(0); |
b5810039 NP |
1585 | page_cache_get(page); |
1586 | } | |
1da177e4 LT |
1587 | |
1588 | /* | |
1589 | * Ok, we have the page, and it's up-to-date, so | |
1590 | * now we can copy it to user space... | |
1591 | * | |
1592 | * The actor routine returns how many bytes were actually used.. | |
1593 | * NOTE! This may not be the same as how much of a user buffer | |
1594 | * we filled up (we may be padding etc), so we can only update | |
1595 | * "pos" here (the actor routine has to update the user buffer | |
1596 | * pointers and the remaining count). | |
1597 | */ | |
1598 | ret = actor(desc, page, offset, nr); | |
1599 | offset += ret; | |
1600 | index += offset >> PAGE_CACHE_SHIFT; | |
1601 | offset &= ~PAGE_CACHE_MASK; | |
1602 | ||
1603 | page_cache_release(page); | |
1604 | if (ret != nr || !desc->count) | |
1605 | break; | |
1606 | ||
1607 | cond_resched(); | |
1608 | } | |
1609 | ||
1610 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1611 | file_accessed(filp); | |
1612 | } | |
1613 | ||
1614 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1615 | { | |
1616 | read_descriptor_t desc; | |
1617 | ||
1618 | if ((ssize_t) count < 0) | |
1619 | return -EINVAL; | |
1620 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1621 | return -EFAULT; | |
1622 | if (!count) | |
1623 | return 0; | |
1624 | ||
1625 | desc.written = 0; | |
1626 | desc.count = count; | |
1627 | desc.arg.buf = buf; | |
1628 | desc.error = 0; | |
1629 | ||
1630 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1631 | if (desc.written) | |
1632 | return desc.written; | |
1633 | return desc.error; | |
1634 | } | |
1635 | ||
1636 | static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos, | |
1637 | size_t count, read_actor_t actor, void *target) | |
1638 | { | |
1639 | read_descriptor_t desc; | |
1640 | ||
1641 | if (!count) | |
1642 | return 0; | |
1643 | ||
1644 | desc.written = 0; | |
1645 | desc.count = count; | |
1646 | desc.arg.data = target; | |
1647 | desc.error = 0; | |
1648 | ||
1649 | do_shmem_file_read(in_file, ppos, &desc, actor); | |
1650 | if (desc.written) | |
1651 | return desc.written; | |
1652 | return desc.error; | |
1653 | } | |
1654 | ||
1655 | static int shmem_statfs(struct super_block *sb, struct kstatfs *buf) | |
1656 | { | |
1657 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1658 | ||
1659 | buf->f_type = TMPFS_MAGIC; | |
1660 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1661 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1662 | spin_lock(&sbinfo->stat_lock); |
1663 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1664 | buf->f_blocks = sbinfo->max_blocks; |
1665 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1666 | } |
1667 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1668 | buf->f_files = sbinfo->max_inodes; |
1669 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1670 | } |
1671 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1672 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1673 | return 0; |
1674 | } | |
1675 | ||
1676 | /* | |
1677 | * File creation. Allocate an inode, and we're done.. | |
1678 | */ | |
1679 | static int | |
1680 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1681 | { | |
1682 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1683 | int error = -ENOSPC; | |
1684 | ||
1685 | if (inode) { | |
570bc1c2 SS |
1686 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1687 | NULL); | |
1688 | if (error) { | |
1689 | if (error != -EOPNOTSUPP) { | |
1690 | iput(inode); | |
1691 | return error; | |
1692 | } | |
1693 | error = 0; | |
1694 | } | |
1da177e4 LT |
1695 | if (dir->i_mode & S_ISGID) { |
1696 | inode->i_gid = dir->i_gid; | |
1697 | if (S_ISDIR(mode)) | |
1698 | inode->i_mode |= S_ISGID; | |
1699 | } | |
1700 | dir->i_size += BOGO_DIRENT_SIZE; | |
1701 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1702 | d_instantiate(dentry, inode); | |
1703 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1704 | } |
1705 | return error; | |
1706 | } | |
1707 | ||
1708 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1709 | { | |
1710 | int error; | |
1711 | ||
1712 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1713 | return error; | |
1714 | dir->i_nlink++; | |
1715 | return 0; | |
1716 | } | |
1717 | ||
1718 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1719 | struct nameidata *nd) | |
1720 | { | |
1721 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1722 | } | |
1723 | ||
1724 | /* | |
1725 | * Link a file.. | |
1726 | */ | |
1727 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1728 | { | |
1729 | struct inode *inode = old_dentry->d_inode; | |
1730 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
1731 | ||
1732 | /* | |
1733 | * No ordinary (disk based) filesystem counts links as inodes; | |
1734 | * but each new link needs a new dentry, pinning lowmem, and | |
1735 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1736 | */ | |
0edd73b3 | 1737 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1738 | spin_lock(&sbinfo->stat_lock); |
1739 | if (!sbinfo->free_inodes) { | |
1740 | spin_unlock(&sbinfo->stat_lock); | |
1741 | return -ENOSPC; | |
1742 | } | |
1743 | sbinfo->free_inodes--; | |
1744 | spin_unlock(&sbinfo->stat_lock); | |
1745 | } | |
1746 | ||
1747 | dir->i_size += BOGO_DIRENT_SIZE; | |
1748 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1749 | inode->i_nlink++; | |
1750 | atomic_inc(&inode->i_count); /* New dentry reference */ | |
1751 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1752 | d_instantiate(dentry, inode); | |
1753 | return 0; | |
1754 | } | |
1755 | ||
1756 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1757 | { | |
1758 | struct inode *inode = dentry->d_inode; | |
1759 | ||
1760 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { | |
1761 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1762 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1763 | spin_lock(&sbinfo->stat_lock); |
1764 | sbinfo->free_inodes++; | |
1765 | spin_unlock(&sbinfo->stat_lock); | |
1766 | } | |
1767 | } | |
1768 | ||
1769 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1770 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1771 | inode->i_nlink--; | |
1772 | dput(dentry); /* Undo the count from "create" - this does all the work */ | |
1773 | return 0; | |
1774 | } | |
1775 | ||
1776 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1777 | { | |
1778 | if (!simple_empty(dentry)) | |
1779 | return -ENOTEMPTY; | |
1780 | ||
1781 | dir->i_nlink--; | |
1782 | return shmem_unlink(dir, dentry); | |
1783 | } | |
1784 | ||
1785 | /* | |
1786 | * The VFS layer already does all the dentry stuff for rename, | |
1787 | * we just have to decrement the usage count for the target if | |
1788 | * it exists so that the VFS layer correctly free's it when it | |
1789 | * gets overwritten. | |
1790 | */ | |
1791 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1792 | { | |
1793 | struct inode *inode = old_dentry->d_inode; | |
1794 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1795 | ||
1796 | if (!simple_empty(new_dentry)) | |
1797 | return -ENOTEMPTY; | |
1798 | ||
1799 | if (new_dentry->d_inode) { | |
1800 | (void) shmem_unlink(new_dir, new_dentry); | |
1801 | if (they_are_dirs) | |
1802 | old_dir->i_nlink--; | |
1803 | } else if (they_are_dirs) { | |
1804 | old_dir->i_nlink--; | |
1805 | new_dir->i_nlink++; | |
1806 | } | |
1807 | ||
1808 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1809 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1810 | old_dir->i_ctime = old_dir->i_mtime = | |
1811 | new_dir->i_ctime = new_dir->i_mtime = | |
1812 | inode->i_ctime = CURRENT_TIME; | |
1813 | return 0; | |
1814 | } | |
1815 | ||
1816 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1817 | { | |
1818 | int error; | |
1819 | int len; | |
1820 | struct inode *inode; | |
1821 | struct page *page = NULL; | |
1822 | char *kaddr; | |
1823 | struct shmem_inode_info *info; | |
1824 | ||
1825 | len = strlen(symname) + 1; | |
1826 | if (len > PAGE_CACHE_SIZE) | |
1827 | return -ENAMETOOLONG; | |
1828 | ||
1829 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1830 | if (!inode) | |
1831 | return -ENOSPC; | |
1832 | ||
570bc1c2 SS |
1833 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1834 | NULL); | |
1835 | if (error) { | |
1836 | if (error != -EOPNOTSUPP) { | |
1837 | iput(inode); | |
1838 | return error; | |
1839 | } | |
1840 | error = 0; | |
1841 | } | |
1842 | ||
1da177e4 LT |
1843 | info = SHMEM_I(inode); |
1844 | inode->i_size = len-1; | |
1845 | if (len <= (char *)inode - (char *)info) { | |
1846 | /* do it inline */ | |
1847 | memcpy(info, symname, len); | |
1848 | inode->i_op = &shmem_symlink_inline_operations; | |
1849 | } else { | |
1850 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1851 | if (error) { | |
1852 | iput(inode); | |
1853 | return error; | |
1854 | } | |
1855 | inode->i_op = &shmem_symlink_inode_operations; | |
1856 | kaddr = kmap_atomic(page, KM_USER0); | |
1857 | memcpy(kaddr, symname, len); | |
1858 | kunmap_atomic(kaddr, KM_USER0); | |
1859 | set_page_dirty(page); | |
1860 | page_cache_release(page); | |
1861 | } | |
1862 | if (dir->i_mode & S_ISGID) | |
1863 | inode->i_gid = dir->i_gid; | |
1864 | dir->i_size += BOGO_DIRENT_SIZE; | |
1865 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1866 | d_instantiate(dentry, inode); | |
1867 | dget(dentry); | |
1868 | return 0; | |
1869 | } | |
1870 | ||
cc314eef | 1871 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1872 | { |
1873 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1874 | return NULL; |
1da177e4 LT |
1875 | } |
1876 | ||
cc314eef | 1877 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1878 | { |
1879 | struct page *page = NULL; | |
1880 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1881 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
cc314eef | 1882 | return page; |
1da177e4 LT |
1883 | } |
1884 | ||
cc314eef | 1885 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1886 | { |
1887 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1888 | struct page *page = cookie; |
1da177e4 LT |
1889 | kunmap(page); |
1890 | mark_page_accessed(page); | |
1891 | page_cache_release(page); | |
1da177e4 LT |
1892 | } |
1893 | } | |
1894 | ||
1895 | static struct inode_operations shmem_symlink_inline_operations = { | |
1896 | .readlink = generic_readlink, | |
1897 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1898 | }; |
1899 | ||
1900 | static struct inode_operations shmem_symlink_inode_operations = { | |
1901 | .truncate = shmem_truncate, | |
1902 | .readlink = generic_readlink, | |
1903 | .follow_link = shmem_follow_link, | |
1904 | .put_link = shmem_put_link, | |
1da177e4 LT |
1905 | }; |
1906 | ||
7339ff83 RH |
1907 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
1908 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, | |
1909 | int *policy, nodemask_t *policy_nodes) | |
1da177e4 LT |
1910 | { |
1911 | char *this_char, *value, *rest; | |
1912 | ||
b00dc3ad HD |
1913 | while (options != NULL) { |
1914 | this_char = options; | |
1915 | for (;;) { | |
1916 | /* | |
1917 | * NUL-terminate this option: unfortunately, | |
1918 | * mount options form a comma-separated list, | |
1919 | * but mpol's nodelist may also contain commas. | |
1920 | */ | |
1921 | options = strchr(options, ','); | |
1922 | if (options == NULL) | |
1923 | break; | |
1924 | options++; | |
1925 | if (!isdigit(*options)) { | |
1926 | options[-1] = '\0'; | |
1927 | break; | |
1928 | } | |
1929 | } | |
1da177e4 LT |
1930 | if (!*this_char) |
1931 | continue; | |
1932 | if ((value = strchr(this_char,'=')) != NULL) { | |
1933 | *value++ = 0; | |
1934 | } else { | |
1935 | printk(KERN_ERR | |
1936 | "tmpfs: No value for mount option '%s'\n", | |
1937 | this_char); | |
1938 | return 1; | |
1939 | } | |
1940 | ||
1941 | if (!strcmp(this_char,"size")) { | |
1942 | unsigned long long size; | |
1943 | size = memparse(value,&rest); | |
1944 | if (*rest == '%') { | |
1945 | size <<= PAGE_SHIFT; | |
1946 | size *= totalram_pages; | |
1947 | do_div(size, 100); | |
1948 | rest++; | |
1949 | } | |
1950 | if (*rest) | |
1951 | goto bad_val; | |
1952 | *blocks = size >> PAGE_CACHE_SHIFT; | |
1953 | } else if (!strcmp(this_char,"nr_blocks")) { | |
1954 | *blocks = memparse(value,&rest); | |
1955 | if (*rest) | |
1956 | goto bad_val; | |
1957 | } else if (!strcmp(this_char,"nr_inodes")) { | |
1958 | *inodes = memparse(value,&rest); | |
1959 | if (*rest) | |
1960 | goto bad_val; | |
1961 | } else if (!strcmp(this_char,"mode")) { | |
1962 | if (!mode) | |
1963 | continue; | |
1964 | *mode = simple_strtoul(value,&rest,8); | |
1965 | if (*rest) | |
1966 | goto bad_val; | |
1967 | } else if (!strcmp(this_char,"uid")) { | |
1968 | if (!uid) | |
1969 | continue; | |
1970 | *uid = simple_strtoul(value,&rest,0); | |
1971 | if (*rest) | |
1972 | goto bad_val; | |
1973 | } else if (!strcmp(this_char,"gid")) { | |
1974 | if (!gid) | |
1975 | continue; | |
1976 | *gid = simple_strtoul(value,&rest,0); | |
1977 | if (*rest) | |
1978 | goto bad_val; | |
7339ff83 | 1979 | } else if (!strcmp(this_char,"mpol")) { |
b00dc3ad | 1980 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
7339ff83 | 1981 | goto bad_val; |
1da177e4 LT |
1982 | } else { |
1983 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
1984 | this_char); | |
1985 | return 1; | |
1986 | } | |
1987 | } | |
1988 | return 0; | |
1989 | ||
1990 | bad_val: | |
1991 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
1992 | value, this_char); | |
1993 | return 1; | |
1994 | ||
1995 | } | |
1996 | ||
1997 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
1998 | { | |
1999 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
2000 | unsigned long max_blocks = sbinfo->max_blocks; |
2001 | unsigned long max_inodes = sbinfo->max_inodes; | |
7339ff83 RH |
2002 | int policy = sbinfo->policy; |
2003 | nodemask_t policy_nodes = sbinfo->policy_nodes; | |
0edd73b3 HD |
2004 | unsigned long blocks; |
2005 | unsigned long inodes; | |
2006 | int error = -EINVAL; | |
2007 | ||
7339ff83 RH |
2008 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
2009 | &max_inodes, &policy, &policy_nodes)) | |
0edd73b3 | 2010 | return error; |
1da177e4 | 2011 | |
0edd73b3 HD |
2012 | spin_lock(&sbinfo->stat_lock); |
2013 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2014 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
2015 | if (max_blocks < blocks) | |
2016 | goto out; | |
2017 | if (max_inodes < inodes) | |
2018 | goto out; | |
2019 | /* | |
2020 | * Those tests also disallow limited->unlimited while any are in | |
2021 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2022 | * but we must separately disallow unlimited->limited, because | |
2023 | * in that case we have no record of how much is already in use. | |
2024 | */ | |
2025 | if (max_blocks && !sbinfo->max_blocks) | |
2026 | goto out; | |
2027 | if (max_inodes && !sbinfo->max_inodes) | |
2028 | goto out; | |
2029 | ||
2030 | error = 0; | |
2031 | sbinfo->max_blocks = max_blocks; | |
2032 | sbinfo->free_blocks = max_blocks - blocks; | |
2033 | sbinfo->max_inodes = max_inodes; | |
2034 | sbinfo->free_inodes = max_inodes - inodes; | |
7339ff83 RH |
2035 | sbinfo->policy = policy; |
2036 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2037 | out: |
2038 | spin_unlock(&sbinfo->stat_lock); | |
2039 | return error; | |
1da177e4 LT |
2040 | } |
2041 | #endif | |
2042 | ||
2043 | static void shmem_put_super(struct super_block *sb) | |
2044 | { | |
2045 | kfree(sb->s_fs_info); | |
2046 | sb->s_fs_info = NULL; | |
2047 | } | |
2048 | ||
1da177e4 LT |
2049 | static int shmem_fill_super(struct super_block *sb, |
2050 | void *data, int silent) | |
2051 | { | |
2052 | struct inode *inode; | |
2053 | struct dentry *root; | |
2054 | int mode = S_IRWXUGO | S_ISVTX; | |
2055 | uid_t uid = current->fsuid; | |
2056 | gid_t gid = current->fsgid; | |
2057 | int err = -ENOMEM; | |
0edd73b3 | 2058 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
2059 | unsigned long blocks = 0; |
2060 | unsigned long inodes = 0; | |
7339ff83 RH |
2061 | int policy = MPOL_DEFAULT; |
2062 | nodemask_t policy_nodes = node_online_map; | |
1da177e4 | 2063 | |
0edd73b3 | 2064 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2065 | /* |
2066 | * Per default we only allow half of the physical ram per | |
2067 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2068 | * but the internal instance is left unlimited. | |
2069 | */ | |
2070 | if (!(sb->s_flags & MS_NOUSER)) { | |
2071 | blocks = totalram_pages / 2; | |
2072 | inodes = totalram_pages - totalhigh_pages; | |
2073 | if (inodes > blocks) | |
2074 | inodes = blocks; | |
7339ff83 RH |
2075 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
2076 | &inodes, &policy, &policy_nodes)) | |
1da177e4 LT |
2077 | return -EINVAL; |
2078 | } | |
1da177e4 LT |
2079 | #else |
2080 | sb->s_flags |= MS_NOUSER; | |
2081 | #endif | |
2082 | ||
0edd73b3 HD |
2083 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
2084 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2085 | L1_CACHE_BYTES), GFP_KERNEL); | |
2086 | if (!sbinfo) | |
2087 | return -ENOMEM; | |
2088 | ||
2089 | spin_lock_init(&sbinfo->stat_lock); | |
2090 | sbinfo->max_blocks = blocks; | |
2091 | sbinfo->free_blocks = blocks; | |
2092 | sbinfo->max_inodes = inodes; | |
2093 | sbinfo->free_inodes = inodes; | |
7339ff83 RH |
2094 | sbinfo->policy = policy; |
2095 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2096 | |
2097 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
2098 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2099 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2100 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2101 | sb->s_magic = TMPFS_MAGIC; | |
2102 | sb->s_op = &shmem_ops; | |
0edd73b3 | 2103 | |
1da177e4 LT |
2104 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2105 | if (!inode) | |
2106 | goto failed; | |
2107 | inode->i_uid = uid; | |
2108 | inode->i_gid = gid; | |
2109 | root = d_alloc_root(inode); | |
2110 | if (!root) | |
2111 | goto failed_iput; | |
2112 | sb->s_root = root; | |
2113 | return 0; | |
2114 | ||
2115 | failed_iput: | |
2116 | iput(inode); | |
2117 | failed: | |
2118 | shmem_put_super(sb); | |
2119 | return err; | |
2120 | } | |
2121 | ||
2122 | static kmem_cache_t *shmem_inode_cachep; | |
2123 | ||
2124 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2125 | { | |
2126 | struct shmem_inode_info *p; | |
2127 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, SLAB_KERNEL); | |
2128 | if (!p) | |
2129 | return NULL; | |
2130 | return &p->vfs_inode; | |
2131 | } | |
2132 | ||
2133 | static void shmem_destroy_inode(struct inode *inode) | |
2134 | { | |
2135 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2136 | /* only struct inode is valid if it's an inline symlink */ | |
2137 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2138 | } | |
2139 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2140 | } | |
2141 | ||
2142 | static void init_once(void *foo, kmem_cache_t *cachep, unsigned long flags) | |
2143 | { | |
2144 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2145 | ||
2146 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == | |
2147 | SLAB_CTOR_CONSTRUCTOR) { | |
2148 | inode_init_once(&p->vfs_inode); | |
2149 | } | |
2150 | } | |
2151 | ||
2152 | static int init_inodecache(void) | |
2153 | { | |
2154 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2155 | sizeof(struct shmem_inode_info), | |
2156 | 0, 0, init_once, NULL); | |
2157 | if (shmem_inode_cachep == NULL) | |
2158 | return -ENOMEM; | |
2159 | return 0; | |
2160 | } | |
2161 | ||
2162 | static void destroy_inodecache(void) | |
2163 | { | |
2164 | if (kmem_cache_destroy(shmem_inode_cachep)) | |
2165 | printk(KERN_INFO "shmem_inode_cache: not all structures were freed\n"); | |
2166 | } | |
2167 | ||
2168 | static struct address_space_operations shmem_aops = { | |
2169 | .writepage = shmem_writepage, | |
2170 | .set_page_dirty = __set_page_dirty_nobuffers, | |
2171 | #ifdef CONFIG_TMPFS | |
2172 | .prepare_write = shmem_prepare_write, | |
2173 | .commit_write = simple_commit_write, | |
2174 | #endif | |
2175 | }; | |
2176 | ||
2177 | static struct file_operations shmem_file_operations = { | |
2178 | .mmap = shmem_mmap, | |
2179 | #ifdef CONFIG_TMPFS | |
2180 | .llseek = generic_file_llseek, | |
2181 | .read = shmem_file_read, | |
2182 | .write = shmem_file_write, | |
2183 | .fsync = simple_sync_file, | |
2184 | .sendfile = shmem_file_sendfile, | |
2185 | #endif | |
2186 | }; | |
2187 | ||
2188 | static struct inode_operations shmem_inode_operations = { | |
2189 | .truncate = shmem_truncate, | |
2190 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2191 | .truncate_range = shmem_truncate_range, |
1da177e4 LT |
2192 | }; |
2193 | ||
2194 | static struct inode_operations shmem_dir_inode_operations = { | |
2195 | #ifdef CONFIG_TMPFS | |
2196 | .create = shmem_create, | |
2197 | .lookup = simple_lookup, | |
2198 | .link = shmem_link, | |
2199 | .unlink = shmem_unlink, | |
2200 | .symlink = shmem_symlink, | |
2201 | .mkdir = shmem_mkdir, | |
2202 | .rmdir = shmem_rmdir, | |
2203 | .mknod = shmem_mknod, | |
2204 | .rename = shmem_rename, | |
1da177e4 LT |
2205 | #endif |
2206 | }; | |
2207 | ||
2208 | static struct super_operations shmem_ops = { | |
2209 | .alloc_inode = shmem_alloc_inode, | |
2210 | .destroy_inode = shmem_destroy_inode, | |
2211 | #ifdef CONFIG_TMPFS | |
2212 | .statfs = shmem_statfs, | |
2213 | .remount_fs = shmem_remount_fs, | |
2214 | #endif | |
2215 | .delete_inode = shmem_delete_inode, | |
2216 | .drop_inode = generic_delete_inode, | |
2217 | .put_super = shmem_put_super, | |
2218 | }; | |
2219 | ||
2220 | static struct vm_operations_struct shmem_vm_ops = { | |
2221 | .nopage = shmem_nopage, | |
2222 | .populate = shmem_populate, | |
2223 | #ifdef CONFIG_NUMA | |
2224 | .set_policy = shmem_set_policy, | |
2225 | .get_policy = shmem_get_policy, | |
2226 | #endif | |
2227 | }; | |
2228 | ||
2229 | ||
1da177e4 LT |
2230 | static struct super_block *shmem_get_sb(struct file_system_type *fs_type, |
2231 | int flags, const char *dev_name, void *data) | |
2232 | { | |
2233 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super); | |
2234 | } | |
2235 | ||
2236 | static struct file_system_type tmpfs_fs_type = { | |
2237 | .owner = THIS_MODULE, | |
2238 | .name = "tmpfs", | |
2239 | .get_sb = shmem_get_sb, | |
2240 | .kill_sb = kill_litter_super, | |
2241 | }; | |
2242 | static struct vfsmount *shm_mnt; | |
2243 | ||
2244 | static int __init init_tmpfs(void) | |
2245 | { | |
2246 | int error; | |
2247 | ||
2248 | error = init_inodecache(); | |
2249 | if (error) | |
2250 | goto out3; | |
2251 | ||
2252 | error = register_filesystem(&tmpfs_fs_type); | |
2253 | if (error) { | |
2254 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2255 | goto out2; | |
2256 | } | |
2257 | #ifdef CONFIG_TMPFS | |
2258 | devfs_mk_dir("shm"); | |
2259 | #endif | |
2260 | shm_mnt = do_kern_mount(tmpfs_fs_type.name, MS_NOUSER, | |
2261 | tmpfs_fs_type.name, NULL); | |
2262 | if (IS_ERR(shm_mnt)) { | |
2263 | error = PTR_ERR(shm_mnt); | |
2264 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2265 | goto out1; | |
2266 | } | |
2267 | return 0; | |
2268 | ||
2269 | out1: | |
2270 | unregister_filesystem(&tmpfs_fs_type); | |
2271 | out2: | |
2272 | destroy_inodecache(); | |
2273 | out3: | |
2274 | shm_mnt = ERR_PTR(error); | |
2275 | return error; | |
2276 | } | |
2277 | module_init(init_tmpfs) | |
2278 | ||
2279 | /* | |
2280 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2281 | * | |
2282 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2283 | * @size: size to be set for the file | |
2284 | * | |
2285 | */ | |
2286 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2287 | { | |
2288 | int error; | |
2289 | struct file *file; | |
2290 | struct inode *inode; | |
2291 | struct dentry *dentry, *root; | |
2292 | struct qstr this; | |
2293 | ||
2294 | if (IS_ERR(shm_mnt)) | |
2295 | return (void *)shm_mnt; | |
2296 | ||
2297 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2298 | return ERR_PTR(-EINVAL); | |
2299 | ||
2300 | if (shmem_acct_size(flags, size)) | |
2301 | return ERR_PTR(-ENOMEM); | |
2302 | ||
2303 | error = -ENOMEM; | |
2304 | this.name = name; | |
2305 | this.len = strlen(name); | |
2306 | this.hash = 0; /* will go */ | |
2307 | root = shm_mnt->mnt_root; | |
2308 | dentry = d_alloc(root, &this); | |
2309 | if (!dentry) | |
2310 | goto put_memory; | |
2311 | ||
2312 | error = -ENFILE; | |
2313 | file = get_empty_filp(); | |
2314 | if (!file) | |
2315 | goto put_dentry; | |
2316 | ||
2317 | error = -ENOSPC; | |
2318 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2319 | if (!inode) | |
2320 | goto close_file; | |
2321 | ||
2322 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2323 | d_instantiate(dentry, inode); | |
2324 | inode->i_size = size; | |
2325 | inode->i_nlink = 0; /* It is unlinked */ | |
2326 | file->f_vfsmnt = mntget(shm_mnt); | |
2327 | file->f_dentry = dentry; | |
2328 | file->f_mapping = inode->i_mapping; | |
2329 | file->f_op = &shmem_file_operations; | |
2330 | file->f_mode = FMODE_WRITE | FMODE_READ; | |
2331 | return file; | |
2332 | ||
2333 | close_file: | |
2334 | put_filp(file); | |
2335 | put_dentry: | |
2336 | dput(dentry); | |
2337 | put_memory: | |
2338 | shmem_unacct_size(flags, size); | |
2339 | return ERR_PTR(error); | |
2340 | } | |
2341 | ||
2342 | /* | |
2343 | * shmem_zero_setup - setup a shared anonymous mapping | |
2344 | * | |
2345 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2346 | */ | |
2347 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2348 | { | |
2349 | struct file *file; | |
2350 | loff_t size = vma->vm_end - vma->vm_start; | |
2351 | ||
2352 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2353 | if (IS_ERR(file)) | |
2354 | return PTR_ERR(file); | |
2355 | ||
2356 | if (vma->vm_file) | |
2357 | fput(vma->vm_file); | |
2358 | vma->vm_file = file; | |
2359 | vma->vm_ops = &shmem_vm_ops; | |
2360 | return 0; | |
2361 | } |