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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
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 | ||
1da177e4 LT |
26 | #include <linux/module.h> |
27 | #include <linux/init.h> | |
1da177e4 | 28 | #include <linux/fs.h> |
39f0247d AG |
29 | #include <linux/xattr.h> |
30 | #include <linux/generic_acl.h> | |
1da177e4 LT |
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> |
304dbdb7 | 49 | #include <linux/migrate.h> |
c1f60a5a | 50 | #include <linux/highmem.h> |
3fcfab16 | 51 | #include <linux/backing-dev.h> |
304dbdb7 | 52 | |
1da177e4 LT |
53 | #include <asm/uaccess.h> |
54 | #include <asm/div64.h> | |
55 | #include <asm/pgtable.h> | |
56 | ||
57 | /* This magic number is used in glibc for posix shared memory */ | |
58 | #define TMPFS_MAGIC 0x01021994 | |
59 | ||
60 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) | |
61 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) | |
62 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
63 | ||
64 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) | |
65 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) | |
66 | ||
67 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) | |
68 | ||
69 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
70 | #define SHMEM_PAGEIN VM_READ | |
71 | #define SHMEM_TRUNCATE VM_WRITE | |
72 | ||
73 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
74 | #define LATENCY_LIMIT 64 | |
75 | ||
76 | /* Pretend that each entry is of this size in directory's i_size */ | |
77 | #define BOGO_DIRENT_SIZE 20 | |
78 | ||
1da177e4 LT |
79 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
80 | enum sgp_type { | |
81 | SGP_QUICK, /* don't try more than file page cache lookup */ | |
82 | SGP_READ, /* don't exceed i_size, don't allocate page */ | |
83 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
84 | SGP_WRITE, /* may exceed i_size, may allocate page */ | |
85 | }; | |
86 | ||
87 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
88 | struct page **pagep, enum sgp_type sgp, int *type); | |
89 | ||
6daa0e28 | 90 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
91 | { |
92 | /* | |
93 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
94 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
95 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
96 | */ | |
97 | return alloc_pages(gfp_mask, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
98 | } | |
99 | ||
100 | static inline void shmem_dir_free(struct page *page) | |
101 | { | |
102 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
103 | } | |
104 | ||
105 | static struct page **shmem_dir_map(struct page *page) | |
106 | { | |
107 | return (struct page **)kmap_atomic(page, KM_USER0); | |
108 | } | |
109 | ||
110 | static inline void shmem_dir_unmap(struct page **dir) | |
111 | { | |
112 | kunmap_atomic(dir, KM_USER0); | |
113 | } | |
114 | ||
115 | static swp_entry_t *shmem_swp_map(struct page *page) | |
116 | { | |
117 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
118 | } | |
119 | ||
120 | static inline void shmem_swp_balance_unmap(void) | |
121 | { | |
122 | /* | |
123 | * When passing a pointer to an i_direct entry, to code which | |
124 | * also handles indirect entries and so will shmem_swp_unmap, | |
125 | * we must arrange for the preempt count to remain in balance. | |
126 | * What kmap_atomic of a lowmem page does depends on config | |
127 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
128 | */ | |
129 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
130 | } | |
131 | ||
132 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
133 | { | |
134 | kunmap_atomic(entry, KM_USER1); | |
135 | } | |
136 | ||
137 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
138 | { | |
139 | return sb->s_fs_info; | |
140 | } | |
141 | ||
142 | /* | |
143 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
144 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
145 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
146 | * consistent with the pre-accounting of private mappings ... | |
147 | */ | |
148 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
149 | { | |
150 | return (flags & VM_ACCOUNT)? | |
151 | security_vm_enough_memory(VM_ACCT(size)): 0; | |
152 | } | |
153 | ||
154 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
155 | { | |
156 | if (flags & VM_ACCOUNT) | |
157 | vm_unacct_memory(VM_ACCT(size)); | |
158 | } | |
159 | ||
160 | /* | |
161 | * ... whereas tmpfs objects are accounted incrementally as | |
162 | * pages are allocated, in order to allow huge sparse files. | |
163 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
164 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
165 | */ | |
166 | static inline int shmem_acct_block(unsigned long flags) | |
167 | { | |
168 | return (flags & VM_ACCOUNT)? | |
169 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); | |
170 | } | |
171 | ||
172 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
173 | { | |
174 | if (!(flags & VM_ACCOUNT)) | |
175 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); | |
176 | } | |
177 | ||
759b9775 | 178 | static const struct super_operations shmem_ops; |
f5e54d6e | 179 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 180 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
181 | static const struct inode_operations shmem_inode_operations; |
182 | static const struct inode_operations shmem_dir_inode_operations; | |
183 | static const struct inode_operations shmem_special_inode_operations; | |
1da177e4 LT |
184 | static struct vm_operations_struct shmem_vm_ops; |
185 | ||
6c231b7b | 186 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 LT |
187 | .ra_pages = 0, /* No readahead */ |
188 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
189 | .unplug_io_fn = default_unplug_io_fn, | |
190 | }; | |
191 | ||
192 | static LIST_HEAD(shmem_swaplist); | |
193 | static DEFINE_SPINLOCK(shmem_swaplist_lock); | |
194 | ||
195 | static void shmem_free_blocks(struct inode *inode, long pages) | |
196 | { | |
197 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 198 | if (sbinfo->max_blocks) { |
1da177e4 LT |
199 | spin_lock(&sbinfo->stat_lock); |
200 | sbinfo->free_blocks += pages; | |
201 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
202 | spin_unlock(&sbinfo->stat_lock); | |
203 | } | |
204 | } | |
205 | ||
206 | /* | |
207 | * shmem_recalc_inode - recalculate the size of an inode | |
208 | * | |
209 | * @inode: inode to recalc | |
210 | * | |
211 | * We have to calculate the free blocks since the mm can drop | |
212 | * undirtied hole pages behind our back. | |
213 | * | |
214 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
215 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
216 | * | |
217 | * It has to be called with the spinlock held. | |
218 | */ | |
219 | static void shmem_recalc_inode(struct inode *inode) | |
220 | { | |
221 | struct shmem_inode_info *info = SHMEM_I(inode); | |
222 | long freed; | |
223 | ||
224 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
225 | if (freed > 0) { | |
226 | info->alloced -= freed; | |
227 | shmem_unacct_blocks(info->flags, freed); | |
228 | shmem_free_blocks(inode, freed); | |
229 | } | |
230 | } | |
231 | ||
232 | /* | |
233 | * shmem_swp_entry - find the swap vector position in the info structure | |
234 | * | |
235 | * @info: info structure for the inode | |
236 | * @index: index of the page to find | |
237 | * @page: optional page to add to the structure. Has to be preset to | |
238 | * all zeros | |
239 | * | |
240 | * If there is no space allocated yet it will return NULL when | |
241 | * page is NULL, else it will use the page for the needed block, | |
242 | * setting it to NULL on return to indicate that it has been used. | |
243 | * | |
244 | * The swap vector is organized the following way: | |
245 | * | |
246 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
247 | * shmem_inode_info structure. So small files do not need an addional | |
248 | * allocation. | |
249 | * | |
250 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
251 | * i_indirect which points to a page which holds in the first half | |
252 | * doubly indirect blocks, in the second half triple indirect blocks: | |
253 | * | |
254 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
255 | * following layout (for SHMEM_NR_DIRECT == 16): | |
256 | * | |
257 | * i_indirect -> dir --> 16-19 | |
258 | * | +-> 20-23 | |
259 | * | | |
260 | * +-->dir2 --> 24-27 | |
261 | * | +-> 28-31 | |
262 | * | +-> 32-35 | |
263 | * | +-> 36-39 | |
264 | * | | |
265 | * +-->dir3 --> 40-43 | |
266 | * +-> 44-47 | |
267 | * +-> 48-51 | |
268 | * +-> 52-55 | |
269 | */ | |
270 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
271 | { | |
272 | unsigned long offset; | |
273 | struct page **dir; | |
274 | struct page *subdir; | |
275 | ||
276 | if (index < SHMEM_NR_DIRECT) { | |
277 | shmem_swp_balance_unmap(); | |
278 | return info->i_direct+index; | |
279 | } | |
280 | if (!info->i_indirect) { | |
281 | if (page) { | |
282 | info->i_indirect = *page; | |
283 | *page = NULL; | |
284 | } | |
285 | return NULL; /* need another page */ | |
286 | } | |
287 | ||
288 | index -= SHMEM_NR_DIRECT; | |
289 | offset = index % ENTRIES_PER_PAGE; | |
290 | index /= ENTRIES_PER_PAGE; | |
291 | dir = shmem_dir_map(info->i_indirect); | |
292 | ||
293 | if (index >= ENTRIES_PER_PAGE/2) { | |
294 | index -= ENTRIES_PER_PAGE/2; | |
295 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
296 | index %= ENTRIES_PER_PAGE; | |
297 | subdir = *dir; | |
298 | if (!subdir) { | |
299 | if (page) { | |
300 | *dir = *page; | |
301 | *page = NULL; | |
302 | } | |
303 | shmem_dir_unmap(dir); | |
304 | return NULL; /* need another page */ | |
305 | } | |
306 | shmem_dir_unmap(dir); | |
307 | dir = shmem_dir_map(subdir); | |
308 | } | |
309 | ||
310 | dir += index; | |
311 | subdir = *dir; | |
312 | if (!subdir) { | |
313 | if (!page || !(subdir = *page)) { | |
314 | shmem_dir_unmap(dir); | |
315 | return NULL; /* need a page */ | |
316 | } | |
317 | *dir = subdir; | |
318 | *page = NULL; | |
319 | } | |
320 | shmem_dir_unmap(dir); | |
321 | return shmem_swp_map(subdir) + offset; | |
322 | } | |
323 | ||
324 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
325 | { | |
326 | long incdec = value? 1: -1; | |
327 | ||
328 | entry->val = value; | |
329 | info->swapped += incdec; | |
4c21e2f2 HD |
330 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
331 | struct page *page = kmap_atomic_to_page(entry); | |
332 | set_page_private(page, page_private(page) + incdec); | |
333 | } | |
1da177e4 LT |
334 | } |
335 | ||
336 | /* | |
337 | * shmem_swp_alloc - get the position of the swap entry for the page. | |
338 | * If it does not exist allocate the entry. | |
339 | * | |
340 | * @info: info structure for the inode | |
341 | * @index: index of the page to find | |
342 | * @sgp: check and recheck i_size? skip allocation? | |
343 | */ | |
344 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
345 | { | |
346 | struct inode *inode = &info->vfs_inode; | |
347 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
348 | struct page *page = NULL; | |
349 | swp_entry_t *entry; | |
350 | ||
351 | if (sgp != SGP_WRITE && | |
352 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
353 | return ERR_PTR(-EINVAL); | |
354 | ||
355 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
356 | if (sgp == SGP_READ) | |
357 | return shmem_swp_map(ZERO_PAGE(0)); | |
358 | /* | |
359 | * Test free_blocks against 1 not 0, since we have 1 data | |
360 | * page (and perhaps indirect index pages) yet to allocate: | |
361 | * a waste to allocate index if we cannot allocate data. | |
362 | */ | |
0edd73b3 | 363 | if (sbinfo->max_blocks) { |
1da177e4 LT |
364 | spin_lock(&sbinfo->stat_lock); |
365 | if (sbinfo->free_blocks <= 1) { | |
366 | spin_unlock(&sbinfo->stat_lock); | |
367 | return ERR_PTR(-ENOSPC); | |
368 | } | |
369 | sbinfo->free_blocks--; | |
370 | inode->i_blocks += BLOCKS_PER_PAGE; | |
371 | spin_unlock(&sbinfo->stat_lock); | |
372 | } | |
373 | ||
374 | spin_unlock(&info->lock); | |
375 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping) | __GFP_ZERO); | |
4c21e2f2 HD |
376 | if (page) |
377 | set_page_private(page, 0); | |
1da177e4 LT |
378 | spin_lock(&info->lock); |
379 | ||
380 | if (!page) { | |
381 | shmem_free_blocks(inode, 1); | |
382 | return ERR_PTR(-ENOMEM); | |
383 | } | |
384 | if (sgp != SGP_WRITE && | |
385 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
386 | entry = ERR_PTR(-EINVAL); | |
387 | break; | |
388 | } | |
389 | if (info->next_index <= index) | |
390 | info->next_index = index + 1; | |
391 | } | |
392 | if (page) { | |
393 | /* another task gave its page, or truncated the file */ | |
394 | shmem_free_blocks(inode, 1); | |
395 | shmem_dir_free(page); | |
396 | } | |
397 | if (info->next_index <= index && !IS_ERR(entry)) | |
398 | info->next_index = index + 1; | |
399 | return entry; | |
400 | } | |
401 | ||
402 | /* | |
403 | * shmem_free_swp - free some swap entries in a directory | |
404 | * | |
405 | * @dir: pointer to the directory | |
406 | * @edir: pointer after last entry of the directory | |
407 | */ | |
408 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir) | |
409 | { | |
410 | swp_entry_t *ptr; | |
411 | int freed = 0; | |
412 | ||
413 | for (ptr = dir; ptr < edir; ptr++) { | |
414 | if (ptr->val) { | |
415 | free_swap_and_cache(*ptr); | |
416 | *ptr = (swp_entry_t){0}; | |
417 | freed++; | |
418 | } | |
419 | } | |
420 | return freed; | |
421 | } | |
422 | ||
423 | static int shmem_map_and_free_swp(struct page *subdir, | |
424 | int offset, int limit, struct page ***dir) | |
425 | { | |
426 | swp_entry_t *ptr; | |
427 | int freed = 0; | |
428 | ||
429 | ptr = shmem_swp_map(subdir); | |
430 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
431 | int size = limit - offset; | |
432 | if (size > LATENCY_LIMIT) | |
433 | size = LATENCY_LIMIT; | |
434 | freed += shmem_free_swp(ptr+offset, ptr+offset+size); | |
435 | if (need_resched()) { | |
436 | shmem_swp_unmap(ptr); | |
437 | if (*dir) { | |
438 | shmem_dir_unmap(*dir); | |
439 | *dir = NULL; | |
440 | } | |
441 | cond_resched(); | |
442 | ptr = shmem_swp_map(subdir); | |
443 | } | |
444 | } | |
445 | shmem_swp_unmap(ptr); | |
446 | return freed; | |
447 | } | |
448 | ||
449 | static void shmem_free_pages(struct list_head *next) | |
450 | { | |
451 | struct page *page; | |
452 | int freed = 0; | |
453 | ||
454 | do { | |
455 | page = container_of(next, struct page, lru); | |
456 | next = next->next; | |
457 | shmem_dir_free(page); | |
458 | freed++; | |
459 | if (freed >= LATENCY_LIMIT) { | |
460 | cond_resched(); | |
461 | freed = 0; | |
462 | } | |
463 | } while (next); | |
464 | } | |
465 | ||
f6b3ec23 | 466 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
467 | { |
468 | struct shmem_inode_info *info = SHMEM_I(inode); | |
469 | unsigned long idx; | |
470 | unsigned long size; | |
471 | unsigned long limit; | |
472 | unsigned long stage; | |
473 | unsigned long diroff; | |
474 | struct page **dir; | |
475 | struct page *topdir; | |
476 | struct page *middir; | |
477 | struct page *subdir; | |
478 | swp_entry_t *ptr; | |
479 | LIST_HEAD(pages_to_free); | |
480 | long nr_pages_to_free = 0; | |
481 | long nr_swaps_freed = 0; | |
482 | int offset; | |
483 | int freed; | |
a2646d1e HD |
484 | int punch_hole; |
485 | unsigned long upper_limit; | |
1da177e4 LT |
486 | |
487 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 488 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
489 | if (idx >= info->next_index) |
490 | return; | |
491 | ||
492 | spin_lock(&info->lock); | |
493 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
494 | if (likely(end == (loff_t) -1)) { |
495 | limit = info->next_index; | |
a2646d1e | 496 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 497 | info->next_index = idx; |
a2646d1e | 498 | punch_hole = 0; |
f6b3ec23 | 499 | } else { |
a2646d1e HD |
500 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
501 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
502 | PAGE_CACHE_SHIFT; | |
503 | upper_limit = SHMEM_MAX_INDEX; | |
504 | } else { | |
505 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
506 | upper_limit = limit; | |
507 | } | |
f6b3ec23 BP |
508 | punch_hole = 1; |
509 | } | |
510 | ||
1da177e4 | 511 | topdir = info->i_indirect; |
f6b3ec23 | 512 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
513 | info->i_indirect = NULL; |
514 | nr_pages_to_free++; | |
515 | list_add(&topdir->lru, &pages_to_free); | |
516 | } | |
517 | spin_unlock(&info->lock); | |
518 | ||
519 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
520 | ptr = info->i_direct; | |
521 | size = limit; | |
522 | if (size > SHMEM_NR_DIRECT) | |
523 | size = SHMEM_NR_DIRECT; | |
524 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size); | |
525 | } | |
92a3d03a BP |
526 | |
527 | /* | |
528 | * If there are no indirect blocks or we are punching a hole | |
529 | * below indirect blocks, nothing to be done. | |
530 | */ | |
a2646d1e | 531 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
532 | goto done2; |
533 | ||
a2646d1e | 534 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
535 | limit -= SHMEM_NR_DIRECT; |
536 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
537 | offset = idx % ENTRIES_PER_PAGE; | |
538 | idx -= offset; | |
539 | ||
540 | dir = shmem_dir_map(topdir); | |
541 | stage = ENTRIES_PER_PAGEPAGE/2; | |
542 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
543 | middir = topdir; | |
544 | diroff = idx/ENTRIES_PER_PAGE; | |
545 | } else { | |
546 | dir += ENTRIES_PER_PAGE/2; | |
547 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
548 | while (stage <= idx) | |
549 | stage += ENTRIES_PER_PAGEPAGE; | |
550 | middir = *dir; | |
551 | if (*dir) { | |
552 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
553 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 554 | if (!diroff && !offset && upper_limit >= stage) { |
1da177e4 LT |
555 | *dir = NULL; |
556 | nr_pages_to_free++; | |
557 | list_add(&middir->lru, &pages_to_free); | |
558 | } | |
559 | shmem_dir_unmap(dir); | |
560 | dir = shmem_dir_map(middir); | |
561 | } else { | |
562 | diroff = 0; | |
563 | offset = 0; | |
564 | idx = stage; | |
565 | } | |
566 | } | |
567 | ||
568 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
569 | if (unlikely(idx == stage)) { | |
570 | shmem_dir_unmap(dir); | |
571 | dir = shmem_dir_map(topdir) + | |
572 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
573 | while (!*dir) { | |
574 | dir++; | |
575 | idx += ENTRIES_PER_PAGEPAGE; | |
576 | if (idx >= limit) | |
577 | goto done1; | |
578 | } | |
579 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
580 | middir = *dir; | |
a2646d1e HD |
581 | if (upper_limit >= stage) { |
582 | *dir = NULL; | |
583 | nr_pages_to_free++; | |
584 | list_add(&middir->lru, &pages_to_free); | |
585 | } | |
1da177e4 LT |
586 | shmem_dir_unmap(dir); |
587 | cond_resched(); | |
588 | dir = shmem_dir_map(middir); | |
589 | diroff = 0; | |
590 | } | |
591 | subdir = dir[diroff]; | |
4c21e2f2 | 592 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
593 | size = limit - idx; |
594 | if (size > ENTRIES_PER_PAGE) | |
595 | size = ENTRIES_PER_PAGE; | |
596 | freed = shmem_map_and_free_swp(subdir, | |
597 | offset, size, &dir); | |
598 | if (!dir) | |
599 | dir = shmem_dir_map(middir); | |
600 | nr_swaps_freed += freed; | |
601 | if (offset) | |
602 | spin_lock(&info->lock); | |
4c21e2f2 | 603 | set_page_private(subdir, page_private(subdir) - freed); |
1da177e4 LT |
604 | if (offset) |
605 | spin_unlock(&info->lock); | |
f6b3ec23 BP |
606 | if (!punch_hole) |
607 | BUG_ON(page_private(subdir) > offset); | |
1da177e4 LT |
608 | } |
609 | if (offset) | |
610 | offset = 0; | |
a2646d1e | 611 | else if (subdir && upper_limit - idx >= ENTRIES_PER_PAGE) { |
1da177e4 LT |
612 | dir[diroff] = NULL; |
613 | nr_pages_to_free++; | |
614 | list_add(&subdir->lru, &pages_to_free); | |
615 | } | |
616 | } | |
617 | done1: | |
618 | shmem_dir_unmap(dir); | |
619 | done2: | |
620 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
621 | /* | |
622 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
623 | * may have swizzled a page in from swap since vmtruncate or | |
624 | * generic_delete_inode did it, before we lowered next_index. | |
625 | * Also, though shmem_getpage checks i_size before adding to | |
626 | * cache, no recheck after: so fix the narrow window there too. | |
627 | */ | |
f6b3ec23 | 628 | truncate_inode_pages_range(inode->i_mapping, start, end); |
1da177e4 LT |
629 | } |
630 | ||
631 | spin_lock(&info->lock); | |
632 | info->flags &= ~SHMEM_TRUNCATE; | |
633 | info->swapped -= nr_swaps_freed; | |
634 | if (nr_pages_to_free) | |
635 | shmem_free_blocks(inode, nr_pages_to_free); | |
636 | shmem_recalc_inode(inode); | |
637 | spin_unlock(&info->lock); | |
638 | ||
639 | /* | |
640 | * Empty swap vector directory pages to be freed? | |
641 | */ | |
642 | if (!list_empty(&pages_to_free)) { | |
643 | pages_to_free.prev->next = NULL; | |
644 | shmem_free_pages(pages_to_free.next); | |
645 | } | |
646 | } | |
647 | ||
f6b3ec23 BP |
648 | static void shmem_truncate(struct inode *inode) |
649 | { | |
650 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
651 | } | |
652 | ||
1da177e4 LT |
653 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
654 | { | |
655 | struct inode *inode = dentry->d_inode; | |
656 | struct page *page = NULL; | |
657 | int error; | |
658 | ||
39f0247d | 659 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
660 | if (attr->ia_size < inode->i_size) { |
661 | /* | |
662 | * If truncating down to a partial page, then | |
663 | * if that page is already allocated, hold it | |
664 | * in memory until the truncation is over, so | |
665 | * truncate_partial_page cannnot miss it were | |
666 | * it assigned to swap. | |
667 | */ | |
668 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
669 | (void) shmem_getpage(inode, | |
670 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
671 | &page, SGP_READ, NULL); | |
672 | } | |
673 | /* | |
674 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
675 | * detect if any pages might have been added to cache | |
676 | * after truncate_inode_pages. But we needn't bother | |
677 | * if it's being fully truncated to zero-length: the | |
678 | * nrpages check is efficient enough in that case. | |
679 | */ | |
680 | if (attr->ia_size) { | |
681 | struct shmem_inode_info *info = SHMEM_I(inode); | |
682 | spin_lock(&info->lock); | |
683 | info->flags &= ~SHMEM_PAGEIN; | |
684 | spin_unlock(&info->lock); | |
685 | } | |
686 | } | |
687 | } | |
688 | ||
689 | error = inode_change_ok(inode, attr); | |
690 | if (!error) | |
691 | error = inode_setattr(inode, attr); | |
39f0247d AG |
692 | #ifdef CONFIG_TMPFS_POSIX_ACL |
693 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
694 | error = generic_acl_chmod(inode, &shmem_acl_ops); | |
695 | #endif | |
1da177e4 LT |
696 | if (page) |
697 | page_cache_release(page); | |
698 | return error; | |
699 | } | |
700 | ||
701 | static void shmem_delete_inode(struct inode *inode) | |
702 | { | |
703 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
704 | struct shmem_inode_info *info = SHMEM_I(inode); | |
705 | ||
706 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 707 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
708 | shmem_unacct_size(info->flags, inode->i_size); |
709 | inode->i_size = 0; | |
710 | shmem_truncate(inode); | |
711 | if (!list_empty(&info->swaplist)) { | |
712 | spin_lock(&shmem_swaplist_lock); | |
713 | list_del_init(&info->swaplist); | |
714 | spin_unlock(&shmem_swaplist_lock); | |
715 | } | |
716 | } | |
0edd73b3 HD |
717 | BUG_ON(inode->i_blocks); |
718 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
719 | spin_lock(&sbinfo->stat_lock); |
720 | sbinfo->free_inodes++; | |
721 | spin_unlock(&sbinfo->stat_lock); | |
722 | } | |
723 | clear_inode(inode); | |
724 | } | |
725 | ||
726 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
727 | { | |
728 | swp_entry_t *ptr; | |
729 | ||
730 | for (ptr = dir; ptr < edir; ptr++) { | |
731 | if (ptr->val == entry.val) | |
732 | return ptr - dir; | |
733 | } | |
734 | return -1; | |
735 | } | |
736 | ||
737 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
738 | { | |
739 | struct inode *inode; | |
740 | unsigned long idx; | |
741 | unsigned long size; | |
742 | unsigned long limit; | |
743 | unsigned long stage; | |
744 | struct page **dir; | |
745 | struct page *subdir; | |
746 | swp_entry_t *ptr; | |
747 | int offset; | |
748 | ||
749 | idx = 0; | |
750 | ptr = info->i_direct; | |
751 | spin_lock(&info->lock); | |
752 | limit = info->next_index; | |
753 | size = limit; | |
754 | if (size > SHMEM_NR_DIRECT) | |
755 | size = SHMEM_NR_DIRECT; | |
756 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
757 | if (offset >= 0) { | |
758 | shmem_swp_balance_unmap(); | |
759 | goto found; | |
760 | } | |
761 | if (!info->i_indirect) | |
762 | goto lost2; | |
763 | ||
764 | dir = shmem_dir_map(info->i_indirect); | |
765 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
766 | ||
767 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
768 | if (unlikely(idx == stage)) { | |
769 | shmem_dir_unmap(dir-1); | |
770 | dir = shmem_dir_map(info->i_indirect) + | |
771 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
772 | while (!*dir) { | |
773 | dir++; | |
774 | idx += ENTRIES_PER_PAGEPAGE; | |
775 | if (idx >= limit) | |
776 | goto lost1; | |
777 | } | |
778 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
779 | subdir = *dir; | |
780 | shmem_dir_unmap(dir); | |
781 | dir = shmem_dir_map(subdir); | |
782 | } | |
783 | subdir = *dir; | |
4c21e2f2 | 784 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
785 | ptr = shmem_swp_map(subdir); |
786 | size = limit - idx; | |
787 | if (size > ENTRIES_PER_PAGE) | |
788 | size = ENTRIES_PER_PAGE; | |
789 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
790 | if (offset >= 0) { | |
791 | shmem_dir_unmap(dir); | |
792 | goto found; | |
793 | } | |
794 | shmem_swp_unmap(ptr); | |
795 | } | |
796 | } | |
797 | lost1: | |
798 | shmem_dir_unmap(dir-1); | |
799 | lost2: | |
800 | spin_unlock(&info->lock); | |
801 | return 0; | |
802 | found: | |
803 | idx += offset; | |
804 | inode = &info->vfs_inode; | |
805 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { | |
806 | info->flags |= SHMEM_PAGEIN; | |
807 | shmem_swp_set(info, ptr + offset, 0); | |
808 | } | |
809 | shmem_swp_unmap(ptr); | |
810 | spin_unlock(&info->lock); | |
811 | /* | |
812 | * Decrement swap count even when the entry is left behind: | |
813 | * try_to_unuse will skip over mms, then reincrement count. | |
814 | */ | |
815 | swap_free(entry); | |
816 | return 1; | |
817 | } | |
818 | ||
819 | /* | |
820 | * shmem_unuse() search for an eventually swapped out shmem page. | |
821 | */ | |
822 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
823 | { | |
824 | struct list_head *p, *next; | |
825 | struct shmem_inode_info *info; | |
826 | int found = 0; | |
827 | ||
828 | spin_lock(&shmem_swaplist_lock); | |
829 | list_for_each_safe(p, next, &shmem_swaplist) { | |
830 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
831 | if (!info->swapped) | |
832 | list_del_init(&info->swaplist); | |
833 | else if (shmem_unuse_inode(info, entry, page)) { | |
834 | /* move head to start search for next from here */ | |
835 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
836 | found = 1; | |
837 | break; | |
838 | } | |
839 | } | |
840 | spin_unlock(&shmem_swaplist_lock); | |
841 | return found; | |
842 | } | |
843 | ||
844 | /* | |
845 | * Move the page from the page cache to the swap cache. | |
846 | */ | |
847 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
848 | { | |
849 | struct shmem_inode_info *info; | |
850 | swp_entry_t *entry, swap; | |
851 | struct address_space *mapping; | |
852 | unsigned long index; | |
853 | struct inode *inode; | |
854 | ||
855 | BUG_ON(!PageLocked(page)); | |
856 | BUG_ON(page_mapped(page)); | |
857 | ||
858 | mapping = page->mapping; | |
859 | index = page->index; | |
860 | inode = mapping->host; | |
861 | info = SHMEM_I(inode); | |
862 | if (info->flags & VM_LOCKED) | |
863 | goto redirty; | |
864 | swap = get_swap_page(); | |
865 | if (!swap.val) | |
866 | goto redirty; | |
867 | ||
868 | spin_lock(&info->lock); | |
869 | shmem_recalc_inode(inode); | |
870 | if (index >= info->next_index) { | |
871 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
872 | goto unlock; | |
873 | } | |
874 | entry = shmem_swp_entry(info, index, NULL); | |
875 | BUG_ON(!entry); | |
876 | BUG_ON(entry->val); | |
877 | ||
878 | if (move_to_swap_cache(page, swap) == 0) { | |
879 | shmem_swp_set(info, entry, swap.val); | |
880 | shmem_swp_unmap(entry); | |
881 | spin_unlock(&info->lock); | |
882 | if (list_empty(&info->swaplist)) { | |
883 | spin_lock(&shmem_swaplist_lock); | |
884 | /* move instead of add in case we're racing */ | |
885 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
886 | spin_unlock(&shmem_swaplist_lock); | |
887 | } | |
888 | unlock_page(page); | |
889 | return 0; | |
890 | } | |
891 | ||
892 | shmem_swp_unmap(entry); | |
893 | unlock: | |
894 | spin_unlock(&info->lock); | |
895 | swap_free(swap); | |
896 | redirty: | |
897 | set_page_dirty(page); | |
994fc28c | 898 | return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */ |
1da177e4 LT |
899 | } |
900 | ||
901 | #ifdef CONFIG_NUMA | |
d15c023b | 902 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
b00dc3ad HD |
903 | { |
904 | char *nodelist = strchr(value, ':'); | |
905 | int err = 1; | |
906 | ||
907 | if (nodelist) { | |
908 | /* NUL-terminate policy string */ | |
909 | *nodelist++ = '\0'; | |
910 | if (nodelist_parse(nodelist, *policy_nodes)) | |
911 | goto out; | |
912 | } | |
913 | if (!strcmp(value, "default")) { | |
914 | *policy = MPOL_DEFAULT; | |
915 | /* Don't allow a nodelist */ | |
916 | if (!nodelist) | |
917 | err = 0; | |
918 | } else if (!strcmp(value, "prefer")) { | |
919 | *policy = MPOL_PREFERRED; | |
920 | /* Insist on a nodelist of one node only */ | |
921 | if (nodelist) { | |
922 | char *rest = nodelist; | |
923 | while (isdigit(*rest)) | |
924 | rest++; | |
925 | if (!*rest) | |
926 | err = 0; | |
927 | } | |
928 | } else if (!strcmp(value, "bind")) { | |
929 | *policy = MPOL_BIND; | |
930 | /* Insist on a nodelist */ | |
931 | if (nodelist) | |
932 | err = 0; | |
933 | } else if (!strcmp(value, "interleave")) { | |
934 | *policy = MPOL_INTERLEAVE; | |
935 | /* Default to nodes online if no nodelist */ | |
936 | if (!nodelist) | |
937 | *policy_nodes = node_online_map; | |
938 | err = 0; | |
939 | } | |
940 | out: | |
941 | /* Restore string for error message */ | |
942 | if (nodelist) | |
943 | *--nodelist = ':'; | |
944 | return err; | |
945 | } | |
946 | ||
1da177e4 LT |
947 | static struct page *shmem_swapin_async(struct shared_policy *p, |
948 | swp_entry_t entry, unsigned long idx) | |
949 | { | |
950 | struct page *page; | |
951 | struct vm_area_struct pvma; | |
952 | ||
953 | /* Create a pseudo vma that just contains the policy */ | |
954 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
955 | pvma.vm_end = PAGE_SIZE; | |
956 | pvma.vm_pgoff = idx; | |
957 | pvma.vm_policy = mpol_shared_policy_lookup(p, idx); | |
958 | page = read_swap_cache_async(entry, &pvma, 0); | |
959 | mpol_free(pvma.vm_policy); | |
960 | return page; | |
961 | } | |
962 | ||
963 | struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry, | |
964 | unsigned long idx) | |
965 | { | |
966 | struct shared_policy *p = &info->policy; | |
967 | int i, num; | |
968 | struct page *page; | |
969 | unsigned long offset; | |
970 | ||
971 | num = valid_swaphandles(entry, &offset); | |
972 | for (i = 0; i < num; offset++, i++) { | |
973 | page = shmem_swapin_async(p, | |
974 | swp_entry(swp_type(entry), offset), idx); | |
975 | if (!page) | |
976 | break; | |
977 | page_cache_release(page); | |
978 | } | |
979 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
980 | return shmem_swapin_async(p, entry, idx); | |
981 | } | |
982 | ||
983 | static struct page * | |
6daa0e28 | 984 | shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info, |
1da177e4 LT |
985 | unsigned long idx) |
986 | { | |
987 | struct vm_area_struct pvma; | |
988 | struct page *page; | |
989 | ||
990 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
991 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
992 | pvma.vm_pgoff = idx; | |
993 | pvma.vm_end = PAGE_SIZE; | |
994 | page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0); | |
995 | mpol_free(pvma.vm_policy); | |
996 | return page; | |
997 | } | |
998 | #else | |
b00dc3ad HD |
999 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
1000 | { | |
1001 | return 1; | |
1002 | } | |
1003 | ||
1da177e4 LT |
1004 | static inline struct page * |
1005 | shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx) | |
1006 | { | |
1007 | swapin_readahead(entry, 0, NULL); | |
1008 | return read_swap_cache_async(entry, NULL, 0); | |
1009 | } | |
1010 | ||
1011 | static inline struct page * | |
dd0fc66f | 1012 | shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx) |
1da177e4 LT |
1013 | { |
1014 | return alloc_page(gfp | __GFP_ZERO); | |
1015 | } | |
1016 | #endif | |
1017 | ||
1018 | /* | |
1019 | * shmem_getpage - either get the page from swap or allocate a new one | |
1020 | * | |
1021 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1022 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1023 | * entry since a page cannot live in both the swap and page cache | |
1024 | */ | |
1025 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1026 | struct page **pagep, enum sgp_type sgp, int *type) | |
1027 | { | |
1028 | struct address_space *mapping = inode->i_mapping; | |
1029 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1030 | struct shmem_sb_info *sbinfo; | |
1031 | struct page *filepage = *pagep; | |
1032 | struct page *swappage; | |
1033 | swp_entry_t *entry; | |
1034 | swp_entry_t swap; | |
1035 | int error; | |
1036 | ||
1037 | if (idx >= SHMEM_MAX_INDEX) | |
1038 | return -EFBIG; | |
1039 | /* | |
1040 | * Normally, filepage is NULL on entry, and either found | |
1041 | * uptodate immediately, or allocated and zeroed, or read | |
1042 | * in under swappage, which is then assigned to filepage. | |
1043 | * But shmem_prepare_write passes in a locked filepage, | |
1044 | * which may be found not uptodate by other callers too, | |
1045 | * and may need to be copied from the swappage read in. | |
1046 | */ | |
1047 | repeat: | |
1048 | if (!filepage) | |
1049 | filepage = find_lock_page(mapping, idx); | |
1050 | if (filepage && PageUptodate(filepage)) | |
1051 | goto done; | |
1052 | error = 0; | |
1053 | if (sgp == SGP_QUICK) | |
1054 | goto failed; | |
1055 | ||
1056 | spin_lock(&info->lock); | |
1057 | shmem_recalc_inode(inode); | |
1058 | entry = shmem_swp_alloc(info, idx, sgp); | |
1059 | if (IS_ERR(entry)) { | |
1060 | spin_unlock(&info->lock); | |
1061 | error = PTR_ERR(entry); | |
1062 | goto failed; | |
1063 | } | |
1064 | swap = *entry; | |
1065 | ||
1066 | if (swap.val) { | |
1067 | /* Look it up and read it in.. */ | |
1068 | swappage = lookup_swap_cache(swap); | |
1069 | if (!swappage) { | |
1070 | shmem_swp_unmap(entry); | |
1da177e4 LT |
1071 | /* here we actually do the io */ |
1072 | if (type && *type == VM_FAULT_MINOR) { | |
f8891e5e | 1073 | __count_vm_event(PGMAJFAULT); |
1da177e4 LT |
1074 | *type = VM_FAULT_MAJOR; |
1075 | } | |
f8891e5e | 1076 | spin_unlock(&info->lock); |
1da177e4 LT |
1077 | swappage = shmem_swapin(info, swap, idx); |
1078 | if (!swappage) { | |
1079 | spin_lock(&info->lock); | |
1080 | entry = shmem_swp_alloc(info, idx, sgp); | |
1081 | if (IS_ERR(entry)) | |
1082 | error = PTR_ERR(entry); | |
1083 | else { | |
1084 | if (entry->val == swap.val) | |
1085 | error = -ENOMEM; | |
1086 | shmem_swp_unmap(entry); | |
1087 | } | |
1088 | spin_unlock(&info->lock); | |
1089 | if (error) | |
1090 | goto failed; | |
1091 | goto repeat; | |
1092 | } | |
1093 | wait_on_page_locked(swappage); | |
1094 | page_cache_release(swappage); | |
1095 | goto repeat; | |
1096 | } | |
1097 | ||
1098 | /* We have to do this with page locked to prevent races */ | |
1099 | if (TestSetPageLocked(swappage)) { | |
1100 | shmem_swp_unmap(entry); | |
1101 | spin_unlock(&info->lock); | |
1102 | wait_on_page_locked(swappage); | |
1103 | page_cache_release(swappage); | |
1104 | goto repeat; | |
1105 | } | |
1106 | if (PageWriteback(swappage)) { | |
1107 | shmem_swp_unmap(entry); | |
1108 | spin_unlock(&info->lock); | |
1109 | wait_on_page_writeback(swappage); | |
1110 | unlock_page(swappage); | |
1111 | page_cache_release(swappage); | |
1112 | goto repeat; | |
1113 | } | |
1114 | if (!PageUptodate(swappage)) { | |
1115 | shmem_swp_unmap(entry); | |
1116 | spin_unlock(&info->lock); | |
1117 | unlock_page(swappage); | |
1118 | page_cache_release(swappage); | |
1119 | error = -EIO; | |
1120 | goto failed; | |
1121 | } | |
1122 | ||
1123 | if (filepage) { | |
1124 | shmem_swp_set(info, entry, 0); | |
1125 | shmem_swp_unmap(entry); | |
1126 | delete_from_swap_cache(swappage); | |
1127 | spin_unlock(&info->lock); | |
1128 | copy_highpage(filepage, swappage); | |
1129 | unlock_page(swappage); | |
1130 | page_cache_release(swappage); | |
1131 | flush_dcache_page(filepage); | |
1132 | SetPageUptodate(filepage); | |
1133 | set_page_dirty(filepage); | |
1134 | swap_free(swap); | |
1135 | } else if (!(error = move_from_swap_cache( | |
1136 | swappage, idx, mapping))) { | |
1137 | info->flags |= SHMEM_PAGEIN; | |
1138 | shmem_swp_set(info, entry, 0); | |
1139 | shmem_swp_unmap(entry); | |
1140 | spin_unlock(&info->lock); | |
1141 | filepage = swappage; | |
1142 | swap_free(swap); | |
1143 | } else { | |
1144 | shmem_swp_unmap(entry); | |
1145 | spin_unlock(&info->lock); | |
1146 | unlock_page(swappage); | |
1147 | page_cache_release(swappage); | |
1148 | if (error == -ENOMEM) { | |
1149 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
3fcfab16 | 1150 | congestion_wait(WRITE, HZ/50); |
1da177e4 LT |
1151 | } |
1152 | goto repeat; | |
1153 | } | |
1154 | } else if (sgp == SGP_READ && !filepage) { | |
1155 | shmem_swp_unmap(entry); | |
1156 | filepage = find_get_page(mapping, idx); | |
1157 | if (filepage && | |
1158 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1159 | spin_unlock(&info->lock); | |
1160 | wait_on_page_locked(filepage); | |
1161 | page_cache_release(filepage); | |
1162 | filepage = NULL; | |
1163 | goto repeat; | |
1164 | } | |
1165 | spin_unlock(&info->lock); | |
1166 | } else { | |
1167 | shmem_swp_unmap(entry); | |
1168 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1169 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1170 | spin_lock(&sbinfo->stat_lock); |
1171 | if (sbinfo->free_blocks == 0 || | |
1172 | shmem_acct_block(info->flags)) { | |
1173 | spin_unlock(&sbinfo->stat_lock); | |
1174 | spin_unlock(&info->lock); | |
1175 | error = -ENOSPC; | |
1176 | goto failed; | |
1177 | } | |
1178 | sbinfo->free_blocks--; | |
1179 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1180 | spin_unlock(&sbinfo->stat_lock); | |
1181 | } else if (shmem_acct_block(info->flags)) { | |
1182 | spin_unlock(&info->lock); | |
1183 | error = -ENOSPC; | |
1184 | goto failed; | |
1185 | } | |
1186 | ||
1187 | if (!filepage) { | |
1188 | spin_unlock(&info->lock); | |
1189 | filepage = shmem_alloc_page(mapping_gfp_mask(mapping), | |
1190 | info, | |
1191 | idx); | |
1192 | if (!filepage) { | |
1193 | shmem_unacct_blocks(info->flags, 1); | |
1194 | shmem_free_blocks(inode, 1); | |
1195 | error = -ENOMEM; | |
1196 | goto failed; | |
1197 | } | |
1198 | ||
1199 | spin_lock(&info->lock); | |
1200 | entry = shmem_swp_alloc(info, idx, sgp); | |
1201 | if (IS_ERR(entry)) | |
1202 | error = PTR_ERR(entry); | |
1203 | else { | |
1204 | swap = *entry; | |
1205 | shmem_swp_unmap(entry); | |
1206 | } | |
1207 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1208 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1209 | spin_unlock(&info->lock); | |
1210 | page_cache_release(filepage); | |
1211 | shmem_unacct_blocks(info->flags, 1); | |
1212 | shmem_free_blocks(inode, 1); | |
1213 | filepage = NULL; | |
1214 | if (error) | |
1215 | goto failed; | |
1216 | goto repeat; | |
1217 | } | |
1218 | info->flags |= SHMEM_PAGEIN; | |
1219 | } | |
1220 | ||
1221 | info->alloced++; | |
1222 | spin_unlock(&info->lock); | |
1223 | flush_dcache_page(filepage); | |
1224 | SetPageUptodate(filepage); | |
1225 | } | |
1226 | done: | |
1227 | if (*pagep != filepage) { | |
1228 | unlock_page(filepage); | |
1229 | *pagep = filepage; | |
1230 | } | |
1231 | return 0; | |
1232 | ||
1233 | failed: | |
1234 | if (*pagep != filepage) { | |
1235 | unlock_page(filepage); | |
1236 | page_cache_release(filepage); | |
1237 | } | |
1238 | return error; | |
1239 | } | |
1240 | ||
9b83a6a8 AB |
1241 | static struct page *shmem_nopage(struct vm_area_struct *vma, |
1242 | unsigned long address, int *type) | |
1da177e4 | 1243 | { |
d3ac7f89 | 1244 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1245 | struct page *page = NULL; |
1246 | unsigned long idx; | |
1247 | int error; | |
1248 | ||
1249 | idx = (address - vma->vm_start) >> PAGE_SHIFT; | |
1250 | idx += vma->vm_pgoff; | |
1251 | idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT; | |
1252 | if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
1253 | return NOPAGE_SIGBUS; | |
1254 | ||
1255 | error = shmem_getpage(inode, idx, &page, SGP_CACHE, type); | |
1256 | if (error) | |
1257 | return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS; | |
1258 | ||
1259 | mark_page_accessed(page); | |
1260 | return page; | |
1261 | } | |
1262 | ||
1263 | static int shmem_populate(struct vm_area_struct *vma, | |
1264 | unsigned long addr, unsigned long len, | |
1265 | pgprot_t prot, unsigned long pgoff, int nonblock) | |
1266 | { | |
d3ac7f89 | 1267 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1268 | struct mm_struct *mm = vma->vm_mm; |
1269 | enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE; | |
1270 | unsigned long size; | |
1271 | ||
1272 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1273 | if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size) | |
1274 | return -EINVAL; | |
1275 | ||
1276 | while ((long) len > 0) { | |
1277 | struct page *page = NULL; | |
1278 | int err; | |
1279 | /* | |
1280 | * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE | |
1281 | */ | |
1282 | err = shmem_getpage(inode, pgoff, &page, sgp, NULL); | |
1283 | if (err) | |
1284 | return err; | |
d44ed4f8 | 1285 | /* Page may still be null, but only if nonblock was set. */ |
1da177e4 LT |
1286 | if (page) { |
1287 | mark_page_accessed(page); | |
1288 | err = install_page(mm, vma, addr, page, prot); | |
1289 | if (err) { | |
1290 | page_cache_release(page); | |
1291 | return err; | |
1292 | } | |
65500d23 | 1293 | } else if (vma->vm_flags & VM_NONLINEAR) { |
d44ed4f8 PBG |
1294 | /* No page was found just because we can't read it in |
1295 | * now (being here implies nonblock != 0), but the page | |
1296 | * may exist, so set the PTE to fault it in later. */ | |
1da177e4 LT |
1297 | err = install_file_pte(mm, vma, addr, pgoff, prot); |
1298 | if (err) | |
1299 | return err; | |
1300 | } | |
1301 | ||
1302 | len -= PAGE_SIZE; | |
1303 | addr += PAGE_SIZE; | |
1304 | pgoff++; | |
1305 | } | |
1306 | return 0; | |
1307 | } | |
1308 | ||
1309 | #ifdef CONFIG_NUMA | |
1310 | int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) | |
1311 | { | |
d3ac7f89 | 1312 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1313 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1314 | } | |
1315 | ||
1316 | struct mempolicy * | |
1317 | shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) | |
1318 | { | |
d3ac7f89 | 1319 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1320 | unsigned long idx; |
1321 | ||
1322 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1323 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1324 | } | |
1325 | #endif | |
1326 | ||
1327 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1328 | { | |
d3ac7f89 | 1329 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1330 | struct shmem_inode_info *info = SHMEM_I(inode); |
1331 | int retval = -ENOMEM; | |
1332 | ||
1333 | spin_lock(&info->lock); | |
1334 | if (lock && !(info->flags & VM_LOCKED)) { | |
1335 | if (!user_shm_lock(inode->i_size, user)) | |
1336 | goto out_nomem; | |
1337 | info->flags |= VM_LOCKED; | |
1338 | } | |
1339 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1340 | user_shm_unlock(inode->i_size, user); | |
1341 | info->flags &= ~VM_LOCKED; | |
1342 | } | |
1343 | retval = 0; | |
1344 | out_nomem: | |
1345 | spin_unlock(&info->lock); | |
1346 | return retval; | |
1347 | } | |
1348 | ||
9b83a6a8 | 1349 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1350 | { |
1351 | file_accessed(file); | |
1352 | vma->vm_ops = &shmem_vm_ops; | |
1353 | return 0; | |
1354 | } | |
1355 | ||
1356 | static struct inode * | |
1357 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1358 | { | |
1359 | struct inode *inode; | |
1360 | struct shmem_inode_info *info; | |
1361 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1362 | ||
0edd73b3 | 1363 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1364 | spin_lock(&sbinfo->stat_lock); |
1365 | if (!sbinfo->free_inodes) { | |
1366 | spin_unlock(&sbinfo->stat_lock); | |
1367 | return NULL; | |
1368 | } | |
1369 | sbinfo->free_inodes--; | |
1370 | spin_unlock(&sbinfo->stat_lock); | |
1371 | } | |
1372 | ||
1373 | inode = new_inode(sb); | |
1374 | if (inode) { | |
1375 | inode->i_mode = mode; | |
1376 | inode->i_uid = current->fsuid; | |
1377 | inode->i_gid = current->fsgid; | |
1da177e4 LT |
1378 | inode->i_blocks = 0; |
1379 | inode->i_mapping->a_ops = &shmem_aops; | |
1380 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1381 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1382 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1383 | info = SHMEM_I(inode); |
1384 | memset(info, 0, (char *)inode - (char *)info); | |
1385 | spin_lock_init(&info->lock); | |
1386 | INIT_LIST_HEAD(&info->swaplist); | |
1387 | ||
1388 | switch (mode & S_IFMT) { | |
1389 | default: | |
39f0247d | 1390 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1391 | init_special_inode(inode, mode, dev); |
1392 | break; | |
1393 | case S_IFREG: | |
1394 | inode->i_op = &shmem_inode_operations; | |
1395 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1396 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1397 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1398 | break; |
1399 | case S_IFDIR: | |
d8c76e6f | 1400 | inc_nlink(inode); |
1da177e4 LT |
1401 | /* Some things misbehave if size == 0 on a directory */ |
1402 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1403 | inode->i_op = &shmem_dir_inode_operations; | |
1404 | inode->i_fop = &simple_dir_operations; | |
1405 | break; | |
1406 | case S_IFLNK: | |
1407 | /* | |
1408 | * Must not load anything in the rbtree, | |
1409 | * mpol_free_shared_policy will not be called. | |
1410 | */ | |
7339ff83 RH |
1411 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1412 | NULL); | |
1da177e4 LT |
1413 | break; |
1414 | } | |
0edd73b3 | 1415 | } else if (sbinfo->max_inodes) { |
1da177e4 LT |
1416 | spin_lock(&sbinfo->stat_lock); |
1417 | sbinfo->free_inodes++; | |
1418 | spin_unlock(&sbinfo->stat_lock); | |
1419 | } | |
1420 | return inode; | |
1421 | } | |
1422 | ||
1423 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1424 | static const struct inode_operations shmem_symlink_inode_operations; |
1425 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1426 | |
1427 | /* | |
1428 | * Normally tmpfs makes no use of shmem_prepare_write, but it | |
1429 | * lets a tmpfs file be used read-write below the loop driver. | |
1430 | */ | |
1431 | static int | |
1432 | shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) | |
1433 | { | |
1434 | struct inode *inode = page->mapping->host; | |
1435 | return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL); | |
1436 | } | |
1437 | ||
1438 | static ssize_t | |
1439 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
1440 | { | |
d3ac7f89 | 1441 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1442 | loff_t pos; |
1443 | unsigned long written; | |
1444 | ssize_t err; | |
1445 | ||
1446 | if ((ssize_t) count < 0) | |
1447 | return -EINVAL; | |
1448 | ||
1449 | if (!access_ok(VERIFY_READ, buf, count)) | |
1450 | return -EFAULT; | |
1451 | ||
1b1dcc1b | 1452 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1453 | |
1454 | pos = *ppos; | |
1455 | written = 0; | |
1456 | ||
1457 | err = generic_write_checks(file, &pos, &count, 0); | |
1458 | if (err || !count) | |
1459 | goto out; | |
1460 | ||
d3ac7f89 | 1461 | err = remove_suid(file->f_path.dentry); |
1da177e4 LT |
1462 | if (err) |
1463 | goto out; | |
1464 | ||
1465 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
1466 | ||
1467 | do { | |
1468 | struct page *page = NULL; | |
1469 | unsigned long bytes, index, offset; | |
1470 | char *kaddr; | |
1471 | int left; | |
1472 | ||
1473 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ | |
1474 | index = pos >> PAGE_CACHE_SHIFT; | |
1475 | bytes = PAGE_CACHE_SIZE - offset; | |
1476 | if (bytes > count) | |
1477 | bytes = count; | |
1478 | ||
1479 | /* | |
1480 | * We don't hold page lock across copy from user - | |
1481 | * what would it guard against? - so no deadlock here. | |
1482 | * But it still may be a good idea to prefault below. | |
1483 | */ | |
1484 | ||
1485 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); | |
1486 | if (err) | |
1487 | break; | |
1488 | ||
1489 | left = bytes; | |
1490 | if (PageHighMem(page)) { | |
1491 | volatile unsigned char dummy; | |
1492 | __get_user(dummy, buf); | |
1493 | __get_user(dummy, buf + bytes - 1); | |
1494 | ||
1495 | kaddr = kmap_atomic(page, KM_USER0); | |
1496 | left = __copy_from_user_inatomic(kaddr + offset, | |
1497 | buf, bytes); | |
1498 | kunmap_atomic(kaddr, KM_USER0); | |
1499 | } | |
1500 | if (left) { | |
1501 | kaddr = kmap(page); | |
1502 | left = __copy_from_user(kaddr + offset, buf, bytes); | |
1503 | kunmap(page); | |
1504 | } | |
1505 | ||
1506 | written += bytes; | |
1507 | count -= bytes; | |
1508 | pos += bytes; | |
1509 | buf += bytes; | |
1510 | if (pos > inode->i_size) | |
1511 | i_size_write(inode, pos); | |
1512 | ||
1513 | flush_dcache_page(page); | |
1514 | set_page_dirty(page); | |
1515 | mark_page_accessed(page); | |
1516 | page_cache_release(page); | |
1517 | ||
1518 | if (left) { | |
1519 | pos -= left; | |
1520 | written -= left; | |
1521 | err = -EFAULT; | |
1522 | break; | |
1523 | } | |
1524 | ||
1525 | /* | |
1526 | * Our dirty pages are not counted in nr_dirty, | |
1527 | * and we do not attempt to balance dirty pages. | |
1528 | */ | |
1529 | ||
1530 | cond_resched(); | |
1531 | } while (count); | |
1532 | ||
1533 | *ppos = pos; | |
1534 | if (written) | |
1535 | err = written; | |
1536 | out: | |
1b1dcc1b | 1537 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1538 | return err; |
1539 | } | |
1540 | ||
1541 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) | |
1542 | { | |
d3ac7f89 | 1543 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1544 | struct address_space *mapping = inode->i_mapping; |
1545 | unsigned long index, offset; | |
1546 | ||
1547 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1548 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1549 | ||
1550 | for (;;) { | |
1551 | struct page *page = NULL; | |
1552 | unsigned long end_index, nr, ret; | |
1553 | loff_t i_size = i_size_read(inode); | |
1554 | ||
1555 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1556 | if (index > end_index) | |
1557 | break; | |
1558 | if (index == end_index) { | |
1559 | nr = i_size & ~PAGE_CACHE_MASK; | |
1560 | if (nr <= offset) | |
1561 | break; | |
1562 | } | |
1563 | ||
1564 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); | |
1565 | if (desc->error) { | |
1566 | if (desc->error == -EINVAL) | |
1567 | desc->error = 0; | |
1568 | break; | |
1569 | } | |
1570 | ||
1571 | /* | |
1572 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1573 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1574 | */ |
1575 | nr = PAGE_CACHE_SIZE; | |
1576 | i_size = i_size_read(inode); | |
1577 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1578 | if (index == end_index) { | |
1579 | nr = i_size & ~PAGE_CACHE_MASK; | |
1580 | if (nr <= offset) { | |
1581 | if (page) | |
1582 | page_cache_release(page); | |
1583 | break; | |
1584 | } | |
1585 | } | |
1586 | nr -= offset; | |
1587 | ||
1588 | if (page) { | |
1589 | /* | |
1590 | * If users can be writing to this page using arbitrary | |
1591 | * virtual addresses, take care about potential aliasing | |
1592 | * before reading the page on the kernel side. | |
1593 | */ | |
1594 | if (mapping_writably_mapped(mapping)) | |
1595 | flush_dcache_page(page); | |
1596 | /* | |
1597 | * Mark the page accessed if we read the beginning. | |
1598 | */ | |
1599 | if (!offset) | |
1600 | mark_page_accessed(page); | |
b5810039 | 1601 | } else { |
1da177e4 | 1602 | page = ZERO_PAGE(0); |
b5810039 NP |
1603 | page_cache_get(page); |
1604 | } | |
1da177e4 LT |
1605 | |
1606 | /* | |
1607 | * Ok, we have the page, and it's up-to-date, so | |
1608 | * now we can copy it to user space... | |
1609 | * | |
1610 | * The actor routine returns how many bytes were actually used.. | |
1611 | * NOTE! This may not be the same as how much of a user buffer | |
1612 | * we filled up (we may be padding etc), so we can only update | |
1613 | * "pos" here (the actor routine has to update the user buffer | |
1614 | * pointers and the remaining count). | |
1615 | */ | |
1616 | ret = actor(desc, page, offset, nr); | |
1617 | offset += ret; | |
1618 | index += offset >> PAGE_CACHE_SHIFT; | |
1619 | offset &= ~PAGE_CACHE_MASK; | |
1620 | ||
1621 | page_cache_release(page); | |
1622 | if (ret != nr || !desc->count) | |
1623 | break; | |
1624 | ||
1625 | cond_resched(); | |
1626 | } | |
1627 | ||
1628 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1629 | file_accessed(filp); | |
1630 | } | |
1631 | ||
1632 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1633 | { | |
1634 | read_descriptor_t desc; | |
1635 | ||
1636 | if ((ssize_t) count < 0) | |
1637 | return -EINVAL; | |
1638 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1639 | return -EFAULT; | |
1640 | if (!count) | |
1641 | return 0; | |
1642 | ||
1643 | desc.written = 0; | |
1644 | desc.count = count; | |
1645 | desc.arg.buf = buf; | |
1646 | desc.error = 0; | |
1647 | ||
1648 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1649 | if (desc.written) | |
1650 | return desc.written; | |
1651 | return desc.error; | |
1652 | } | |
1653 | ||
1654 | static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos, | |
1655 | size_t count, read_actor_t actor, void *target) | |
1656 | { | |
1657 | read_descriptor_t desc; | |
1658 | ||
1659 | if (!count) | |
1660 | return 0; | |
1661 | ||
1662 | desc.written = 0; | |
1663 | desc.count = count; | |
1664 | desc.arg.data = target; | |
1665 | desc.error = 0; | |
1666 | ||
1667 | do_shmem_file_read(in_file, ppos, &desc, actor); | |
1668 | if (desc.written) | |
1669 | return desc.written; | |
1670 | return desc.error; | |
1671 | } | |
1672 | ||
726c3342 | 1673 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1674 | { |
726c3342 | 1675 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1676 | |
1677 | buf->f_type = TMPFS_MAGIC; | |
1678 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1679 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1680 | spin_lock(&sbinfo->stat_lock); |
1681 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1682 | buf->f_blocks = sbinfo->max_blocks; |
1683 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1684 | } |
1685 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1686 | buf->f_files = sbinfo->max_inodes; |
1687 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1688 | } |
1689 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1690 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1691 | return 0; |
1692 | } | |
1693 | ||
1694 | /* | |
1695 | * File creation. Allocate an inode, and we're done.. | |
1696 | */ | |
1697 | static int | |
1698 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1699 | { | |
1700 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1701 | int error = -ENOSPC; | |
1702 | ||
1703 | if (inode) { | |
570bc1c2 SS |
1704 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1705 | NULL); | |
1706 | if (error) { | |
1707 | if (error != -EOPNOTSUPP) { | |
1708 | iput(inode); | |
1709 | return error; | |
1710 | } | |
39f0247d AG |
1711 | } |
1712 | error = shmem_acl_init(inode, dir); | |
1713 | if (error) { | |
1714 | iput(inode); | |
1715 | return error; | |
570bc1c2 | 1716 | } |
1da177e4 LT |
1717 | if (dir->i_mode & S_ISGID) { |
1718 | inode->i_gid = dir->i_gid; | |
1719 | if (S_ISDIR(mode)) | |
1720 | inode->i_mode |= S_ISGID; | |
1721 | } | |
1722 | dir->i_size += BOGO_DIRENT_SIZE; | |
1723 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1724 | d_instantiate(dentry, inode); | |
1725 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1726 | } |
1727 | return error; | |
1728 | } | |
1729 | ||
1730 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1731 | { | |
1732 | int error; | |
1733 | ||
1734 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1735 | return error; | |
d8c76e6f | 1736 | inc_nlink(dir); |
1da177e4 LT |
1737 | return 0; |
1738 | } | |
1739 | ||
1740 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1741 | struct nameidata *nd) | |
1742 | { | |
1743 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1744 | } | |
1745 | ||
1746 | /* | |
1747 | * Link a file.. | |
1748 | */ | |
1749 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1750 | { | |
1751 | struct inode *inode = old_dentry->d_inode; | |
1752 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
1753 | ||
1754 | /* | |
1755 | * No ordinary (disk based) filesystem counts links as inodes; | |
1756 | * but each new link needs a new dentry, pinning lowmem, and | |
1757 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1758 | */ | |
0edd73b3 | 1759 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1760 | spin_lock(&sbinfo->stat_lock); |
1761 | if (!sbinfo->free_inodes) { | |
1762 | spin_unlock(&sbinfo->stat_lock); | |
1763 | return -ENOSPC; | |
1764 | } | |
1765 | sbinfo->free_inodes--; | |
1766 | spin_unlock(&sbinfo->stat_lock); | |
1767 | } | |
1768 | ||
1769 | dir->i_size += BOGO_DIRENT_SIZE; | |
1770 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1771 | inc_nlink(inode); |
1da177e4 LT |
1772 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1773 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1774 | d_instantiate(dentry, inode); | |
1775 | return 0; | |
1776 | } | |
1777 | ||
1778 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1779 | { | |
1780 | struct inode *inode = dentry->d_inode; | |
1781 | ||
1782 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { | |
1783 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1784 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1785 | spin_lock(&sbinfo->stat_lock); |
1786 | sbinfo->free_inodes++; | |
1787 | spin_unlock(&sbinfo->stat_lock); | |
1788 | } | |
1789 | } | |
1790 | ||
1791 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1792 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1793 | drop_nlink(inode); |
1da177e4 LT |
1794 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1795 | return 0; | |
1796 | } | |
1797 | ||
1798 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1799 | { | |
1800 | if (!simple_empty(dentry)) | |
1801 | return -ENOTEMPTY; | |
1802 | ||
9a53c3a7 DH |
1803 | drop_nlink(dentry->d_inode); |
1804 | drop_nlink(dir); | |
1da177e4 LT |
1805 | return shmem_unlink(dir, dentry); |
1806 | } | |
1807 | ||
1808 | /* | |
1809 | * The VFS layer already does all the dentry stuff for rename, | |
1810 | * we just have to decrement the usage count for the target if | |
1811 | * it exists so that the VFS layer correctly free's it when it | |
1812 | * gets overwritten. | |
1813 | */ | |
1814 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1815 | { | |
1816 | struct inode *inode = old_dentry->d_inode; | |
1817 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1818 | ||
1819 | if (!simple_empty(new_dentry)) | |
1820 | return -ENOTEMPTY; | |
1821 | ||
1822 | if (new_dentry->d_inode) { | |
1823 | (void) shmem_unlink(new_dir, new_dentry); | |
1824 | if (they_are_dirs) | |
9a53c3a7 | 1825 | drop_nlink(old_dir); |
1da177e4 | 1826 | } else if (they_are_dirs) { |
9a53c3a7 | 1827 | drop_nlink(old_dir); |
d8c76e6f | 1828 | inc_nlink(new_dir); |
1da177e4 LT |
1829 | } |
1830 | ||
1831 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1832 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1833 | old_dir->i_ctime = old_dir->i_mtime = | |
1834 | new_dir->i_ctime = new_dir->i_mtime = | |
1835 | inode->i_ctime = CURRENT_TIME; | |
1836 | return 0; | |
1837 | } | |
1838 | ||
1839 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1840 | { | |
1841 | int error; | |
1842 | int len; | |
1843 | struct inode *inode; | |
1844 | struct page *page = NULL; | |
1845 | char *kaddr; | |
1846 | struct shmem_inode_info *info; | |
1847 | ||
1848 | len = strlen(symname) + 1; | |
1849 | if (len > PAGE_CACHE_SIZE) | |
1850 | return -ENAMETOOLONG; | |
1851 | ||
1852 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1853 | if (!inode) | |
1854 | return -ENOSPC; | |
1855 | ||
570bc1c2 SS |
1856 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1857 | NULL); | |
1858 | if (error) { | |
1859 | if (error != -EOPNOTSUPP) { | |
1860 | iput(inode); | |
1861 | return error; | |
1862 | } | |
1863 | error = 0; | |
1864 | } | |
1865 | ||
1da177e4 LT |
1866 | info = SHMEM_I(inode); |
1867 | inode->i_size = len-1; | |
1868 | if (len <= (char *)inode - (char *)info) { | |
1869 | /* do it inline */ | |
1870 | memcpy(info, symname, len); | |
1871 | inode->i_op = &shmem_symlink_inline_operations; | |
1872 | } else { | |
1873 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1874 | if (error) { | |
1875 | iput(inode); | |
1876 | return error; | |
1877 | } | |
1878 | inode->i_op = &shmem_symlink_inode_operations; | |
1879 | kaddr = kmap_atomic(page, KM_USER0); | |
1880 | memcpy(kaddr, symname, len); | |
1881 | kunmap_atomic(kaddr, KM_USER0); | |
1882 | set_page_dirty(page); | |
1883 | page_cache_release(page); | |
1884 | } | |
1885 | if (dir->i_mode & S_ISGID) | |
1886 | inode->i_gid = dir->i_gid; | |
1887 | dir->i_size += BOGO_DIRENT_SIZE; | |
1888 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1889 | d_instantiate(dentry, inode); | |
1890 | dget(dentry); | |
1891 | return 0; | |
1892 | } | |
1893 | ||
cc314eef | 1894 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1895 | { |
1896 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1897 | return NULL; |
1da177e4 LT |
1898 | } |
1899 | ||
cc314eef | 1900 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1901 | { |
1902 | struct page *page = NULL; | |
1903 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1904 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
cc314eef | 1905 | return page; |
1da177e4 LT |
1906 | } |
1907 | ||
cc314eef | 1908 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1909 | { |
1910 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1911 | struct page *page = cookie; |
1da177e4 LT |
1912 | kunmap(page); |
1913 | mark_page_accessed(page); | |
1914 | page_cache_release(page); | |
1da177e4 LT |
1915 | } |
1916 | } | |
1917 | ||
92e1d5be | 1918 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
1919 | .readlink = generic_readlink, |
1920 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1921 | }; |
1922 | ||
92e1d5be | 1923 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
1924 | .truncate = shmem_truncate, |
1925 | .readlink = generic_readlink, | |
1926 | .follow_link = shmem_follow_link, | |
1927 | .put_link = shmem_put_link, | |
1da177e4 LT |
1928 | }; |
1929 | ||
39f0247d AG |
1930 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1931 | /** | |
1932 | * Superblocks without xattr inode operations will get security.* xattr | |
1933 | * support from the VFS "for free". As soon as we have any other xattrs | |
1934 | * like ACLs, we also need to implement the security.* handlers at | |
1935 | * filesystem level, though. | |
1936 | */ | |
1937 | ||
1938 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
1939 | size_t list_len, const char *name, | |
1940 | size_t name_len) | |
1941 | { | |
1942 | return security_inode_listsecurity(inode, list, list_len); | |
1943 | } | |
1944 | ||
1945 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
1946 | void *buffer, size_t size) | |
1947 | { | |
1948 | if (strcmp(name, "") == 0) | |
1949 | return -EINVAL; | |
1950 | return security_inode_getsecurity(inode, name, buffer, size, | |
1951 | -EOPNOTSUPP); | |
1952 | } | |
1953 | ||
1954 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
1955 | const void *value, size_t size, int flags) | |
1956 | { | |
1957 | if (strcmp(name, "") == 0) | |
1958 | return -EINVAL; | |
1959 | return security_inode_setsecurity(inode, name, value, size, flags); | |
1960 | } | |
1961 | ||
1f370a23 | 1962 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
1963 | .prefix = XATTR_SECURITY_PREFIX, |
1964 | .list = shmem_xattr_security_list, | |
1965 | .get = shmem_xattr_security_get, | |
1966 | .set = shmem_xattr_security_set, | |
1967 | }; | |
1968 | ||
1969 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
1970 | &shmem_xattr_acl_access_handler, | |
1971 | &shmem_xattr_acl_default_handler, | |
1972 | &shmem_xattr_security_handler, | |
1973 | NULL | |
1974 | }; | |
1975 | #endif | |
1976 | ||
91828a40 DG |
1977 | static struct dentry *shmem_get_parent(struct dentry *child) |
1978 | { | |
1979 | return ERR_PTR(-ESTALE); | |
1980 | } | |
1981 | ||
1982 | static int shmem_match(struct inode *ino, void *vfh) | |
1983 | { | |
1984 | __u32 *fh = vfh; | |
1985 | __u64 inum = fh[2]; | |
1986 | inum = (inum << 32) | fh[1]; | |
1987 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1988 | } | |
1989 | ||
1990 | static struct dentry *shmem_get_dentry(struct super_block *sb, void *vfh) | |
1991 | { | |
1992 | struct dentry *de = NULL; | |
1993 | struct inode *inode; | |
1994 | __u32 *fh = vfh; | |
1995 | __u64 inum = fh[2]; | |
1996 | inum = (inum << 32) | fh[1]; | |
1997 | ||
1998 | inode = ilookup5(sb, (unsigned long)(inum+fh[0]), shmem_match, vfh); | |
1999 | if (inode) { | |
2000 | de = d_find_alias(inode); | |
2001 | iput(inode); | |
2002 | } | |
2003 | ||
2004 | return de? de: ERR_PTR(-ESTALE); | |
2005 | } | |
2006 | ||
2007 | static struct dentry *shmem_decode_fh(struct super_block *sb, __u32 *fh, | |
2008 | int len, int type, | |
2009 | int (*acceptable)(void *context, struct dentry *de), | |
2010 | void *context) | |
2011 | { | |
2012 | if (len < 3) | |
2013 | return ERR_PTR(-ESTALE); | |
2014 | ||
2015 | return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, | |
2016 | context); | |
2017 | } | |
2018 | ||
2019 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2020 | int connectable) | |
2021 | { | |
2022 | struct inode *inode = dentry->d_inode; | |
2023 | ||
2024 | if (*len < 3) | |
2025 | return 255; | |
2026 | ||
2027 | if (hlist_unhashed(&inode->i_hash)) { | |
2028 | /* Unfortunately insert_inode_hash is not idempotent, | |
2029 | * so as we hash inodes here rather than at creation | |
2030 | * time, we need a lock to ensure we only try | |
2031 | * to do it once | |
2032 | */ | |
2033 | static DEFINE_SPINLOCK(lock); | |
2034 | spin_lock(&lock); | |
2035 | if (hlist_unhashed(&inode->i_hash)) | |
2036 | __insert_inode_hash(inode, | |
2037 | inode->i_ino + inode->i_generation); | |
2038 | spin_unlock(&lock); | |
2039 | } | |
2040 | ||
2041 | fh[0] = inode->i_generation; | |
2042 | fh[1] = inode->i_ino; | |
2043 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2044 | ||
2045 | *len = 3; | |
2046 | return 1; | |
2047 | } | |
2048 | ||
2049 | static struct export_operations shmem_export_ops = { | |
2050 | .get_parent = shmem_get_parent, | |
2051 | .get_dentry = shmem_get_dentry, | |
2052 | .encode_fh = shmem_encode_fh, | |
2053 | .decode_fh = shmem_decode_fh, | |
2054 | }; | |
2055 | ||
7339ff83 RH |
2056 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
2057 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, | |
2058 | int *policy, nodemask_t *policy_nodes) | |
1da177e4 LT |
2059 | { |
2060 | char *this_char, *value, *rest; | |
2061 | ||
b00dc3ad HD |
2062 | while (options != NULL) { |
2063 | this_char = options; | |
2064 | for (;;) { | |
2065 | /* | |
2066 | * NUL-terminate this option: unfortunately, | |
2067 | * mount options form a comma-separated list, | |
2068 | * but mpol's nodelist may also contain commas. | |
2069 | */ | |
2070 | options = strchr(options, ','); | |
2071 | if (options == NULL) | |
2072 | break; | |
2073 | options++; | |
2074 | if (!isdigit(*options)) { | |
2075 | options[-1] = '\0'; | |
2076 | break; | |
2077 | } | |
2078 | } | |
1da177e4 LT |
2079 | if (!*this_char) |
2080 | continue; | |
2081 | if ((value = strchr(this_char,'=')) != NULL) { | |
2082 | *value++ = 0; | |
2083 | } else { | |
2084 | printk(KERN_ERR | |
2085 | "tmpfs: No value for mount option '%s'\n", | |
2086 | this_char); | |
2087 | return 1; | |
2088 | } | |
2089 | ||
2090 | if (!strcmp(this_char,"size")) { | |
2091 | unsigned long long size; | |
2092 | size = memparse(value,&rest); | |
2093 | if (*rest == '%') { | |
2094 | size <<= PAGE_SHIFT; | |
2095 | size *= totalram_pages; | |
2096 | do_div(size, 100); | |
2097 | rest++; | |
2098 | } | |
2099 | if (*rest) | |
2100 | goto bad_val; | |
2101 | *blocks = size >> PAGE_CACHE_SHIFT; | |
2102 | } else if (!strcmp(this_char,"nr_blocks")) { | |
2103 | *blocks = memparse(value,&rest); | |
2104 | if (*rest) | |
2105 | goto bad_val; | |
2106 | } else if (!strcmp(this_char,"nr_inodes")) { | |
2107 | *inodes = memparse(value,&rest); | |
2108 | if (*rest) | |
2109 | goto bad_val; | |
2110 | } else if (!strcmp(this_char,"mode")) { | |
2111 | if (!mode) | |
2112 | continue; | |
2113 | *mode = simple_strtoul(value,&rest,8); | |
2114 | if (*rest) | |
2115 | goto bad_val; | |
2116 | } else if (!strcmp(this_char,"uid")) { | |
2117 | if (!uid) | |
2118 | continue; | |
2119 | *uid = simple_strtoul(value,&rest,0); | |
2120 | if (*rest) | |
2121 | goto bad_val; | |
2122 | } else if (!strcmp(this_char,"gid")) { | |
2123 | if (!gid) | |
2124 | continue; | |
2125 | *gid = simple_strtoul(value,&rest,0); | |
2126 | if (*rest) | |
2127 | goto bad_val; | |
7339ff83 | 2128 | } else if (!strcmp(this_char,"mpol")) { |
b00dc3ad | 2129 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
7339ff83 | 2130 | goto bad_val; |
1da177e4 LT |
2131 | } else { |
2132 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2133 | this_char); | |
2134 | return 1; | |
2135 | } | |
2136 | } | |
2137 | return 0; | |
2138 | ||
2139 | bad_val: | |
2140 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2141 | value, this_char); | |
2142 | return 1; | |
2143 | ||
2144 | } | |
2145 | ||
2146 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2147 | { | |
2148 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
2149 | unsigned long max_blocks = sbinfo->max_blocks; |
2150 | unsigned long max_inodes = sbinfo->max_inodes; | |
7339ff83 RH |
2151 | int policy = sbinfo->policy; |
2152 | nodemask_t policy_nodes = sbinfo->policy_nodes; | |
0edd73b3 HD |
2153 | unsigned long blocks; |
2154 | unsigned long inodes; | |
2155 | int error = -EINVAL; | |
2156 | ||
7339ff83 RH |
2157 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
2158 | &max_inodes, &policy, &policy_nodes)) | |
0edd73b3 | 2159 | return error; |
1da177e4 | 2160 | |
0edd73b3 HD |
2161 | spin_lock(&sbinfo->stat_lock); |
2162 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2163 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
2164 | if (max_blocks < blocks) | |
2165 | goto out; | |
2166 | if (max_inodes < inodes) | |
2167 | goto out; | |
2168 | /* | |
2169 | * Those tests also disallow limited->unlimited while any are in | |
2170 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2171 | * but we must separately disallow unlimited->limited, because | |
2172 | * in that case we have no record of how much is already in use. | |
2173 | */ | |
2174 | if (max_blocks && !sbinfo->max_blocks) | |
2175 | goto out; | |
2176 | if (max_inodes && !sbinfo->max_inodes) | |
2177 | goto out; | |
2178 | ||
2179 | error = 0; | |
2180 | sbinfo->max_blocks = max_blocks; | |
2181 | sbinfo->free_blocks = max_blocks - blocks; | |
2182 | sbinfo->max_inodes = max_inodes; | |
2183 | sbinfo->free_inodes = max_inodes - inodes; | |
7339ff83 RH |
2184 | sbinfo->policy = policy; |
2185 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2186 | out: |
2187 | spin_unlock(&sbinfo->stat_lock); | |
2188 | return error; | |
1da177e4 LT |
2189 | } |
2190 | #endif | |
2191 | ||
2192 | static void shmem_put_super(struct super_block *sb) | |
2193 | { | |
2194 | kfree(sb->s_fs_info); | |
2195 | sb->s_fs_info = NULL; | |
2196 | } | |
2197 | ||
1da177e4 LT |
2198 | static int shmem_fill_super(struct super_block *sb, |
2199 | void *data, int silent) | |
2200 | { | |
2201 | struct inode *inode; | |
2202 | struct dentry *root; | |
2203 | int mode = S_IRWXUGO | S_ISVTX; | |
2204 | uid_t uid = current->fsuid; | |
2205 | gid_t gid = current->fsgid; | |
2206 | int err = -ENOMEM; | |
0edd73b3 | 2207 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
2208 | unsigned long blocks = 0; |
2209 | unsigned long inodes = 0; | |
7339ff83 RH |
2210 | int policy = MPOL_DEFAULT; |
2211 | nodemask_t policy_nodes = node_online_map; | |
1da177e4 | 2212 | |
0edd73b3 | 2213 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2214 | /* |
2215 | * Per default we only allow half of the physical ram per | |
2216 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2217 | * but the internal instance is left unlimited. | |
2218 | */ | |
2219 | if (!(sb->s_flags & MS_NOUSER)) { | |
2220 | blocks = totalram_pages / 2; | |
2221 | inodes = totalram_pages - totalhigh_pages; | |
2222 | if (inodes > blocks) | |
2223 | inodes = blocks; | |
7339ff83 RH |
2224 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
2225 | &inodes, &policy, &policy_nodes)) | |
1da177e4 LT |
2226 | return -EINVAL; |
2227 | } | |
91828a40 | 2228 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2229 | #else |
2230 | sb->s_flags |= MS_NOUSER; | |
2231 | #endif | |
2232 | ||
0edd73b3 HD |
2233 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
2234 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2235 | L1_CACHE_BYTES), GFP_KERNEL); | |
2236 | if (!sbinfo) | |
2237 | return -ENOMEM; | |
2238 | ||
2239 | spin_lock_init(&sbinfo->stat_lock); | |
2240 | sbinfo->max_blocks = blocks; | |
2241 | sbinfo->free_blocks = blocks; | |
2242 | sbinfo->max_inodes = inodes; | |
2243 | sbinfo->free_inodes = inodes; | |
7339ff83 RH |
2244 | sbinfo->policy = policy; |
2245 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2246 | |
2247 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
2248 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2249 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2250 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2251 | sb->s_magic = TMPFS_MAGIC; | |
2252 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2253 | sb->s_time_gran = 1; |
39f0247d AG |
2254 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2255 | sb->s_xattr = shmem_xattr_handlers; | |
2256 | sb->s_flags |= MS_POSIXACL; | |
2257 | #endif | |
0edd73b3 | 2258 | |
1da177e4 LT |
2259 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2260 | if (!inode) | |
2261 | goto failed; | |
2262 | inode->i_uid = uid; | |
2263 | inode->i_gid = gid; | |
2264 | root = d_alloc_root(inode); | |
2265 | if (!root) | |
2266 | goto failed_iput; | |
2267 | sb->s_root = root; | |
2268 | return 0; | |
2269 | ||
2270 | failed_iput: | |
2271 | iput(inode); | |
2272 | failed: | |
2273 | shmem_put_super(sb); | |
2274 | return err; | |
2275 | } | |
2276 | ||
fcc234f8 | 2277 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2278 | |
2279 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2280 | { | |
2281 | struct shmem_inode_info *p; | |
e94b1766 | 2282 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2283 | if (!p) |
2284 | return NULL; | |
2285 | return &p->vfs_inode; | |
2286 | } | |
2287 | ||
2288 | static void shmem_destroy_inode(struct inode *inode) | |
2289 | { | |
2290 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2291 | /* only struct inode is valid if it's an inline symlink */ | |
2292 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2293 | } | |
39f0247d | 2294 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2295 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2296 | } | |
2297 | ||
fcc234f8 PE |
2298 | static void init_once(void *foo, struct kmem_cache *cachep, |
2299 | unsigned long flags) | |
1da177e4 LT |
2300 | { |
2301 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2302 | ||
2303 | if ((flags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == | |
2304 | SLAB_CTOR_CONSTRUCTOR) { | |
2305 | inode_init_once(&p->vfs_inode); | |
39f0247d AG |
2306 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2307 | p->i_acl = NULL; | |
2308 | p->i_default_acl = NULL; | |
2309 | #endif | |
1da177e4 LT |
2310 | } |
2311 | } | |
2312 | ||
2313 | static int init_inodecache(void) | |
2314 | { | |
2315 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2316 | sizeof(struct shmem_inode_info), | |
2317 | 0, 0, init_once, NULL); | |
2318 | if (shmem_inode_cachep == NULL) | |
2319 | return -ENOMEM; | |
2320 | return 0; | |
2321 | } | |
2322 | ||
2323 | static void destroy_inodecache(void) | |
2324 | { | |
1a1d92c1 | 2325 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2326 | } |
2327 | ||
f5e54d6e | 2328 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2329 | .writepage = shmem_writepage, |
76719325 | 2330 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 LT |
2331 | #ifdef CONFIG_TMPFS |
2332 | .prepare_write = shmem_prepare_write, | |
2333 | .commit_write = simple_commit_write, | |
2334 | #endif | |
304dbdb7 | 2335 | .migratepage = migrate_page, |
1da177e4 LT |
2336 | }; |
2337 | ||
15ad7cdc | 2338 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2339 | .mmap = shmem_mmap, |
2340 | #ifdef CONFIG_TMPFS | |
2341 | .llseek = generic_file_llseek, | |
2342 | .read = shmem_file_read, | |
2343 | .write = shmem_file_write, | |
2344 | .fsync = simple_sync_file, | |
2345 | .sendfile = shmem_file_sendfile, | |
2346 | #endif | |
2347 | }; | |
2348 | ||
92e1d5be | 2349 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2350 | .truncate = shmem_truncate, |
2351 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2352 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2353 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2354 | .setxattr = generic_setxattr, | |
2355 | .getxattr = generic_getxattr, | |
2356 | .listxattr = generic_listxattr, | |
2357 | .removexattr = generic_removexattr, | |
2358 | .permission = shmem_permission, | |
2359 | #endif | |
2360 | ||
1da177e4 LT |
2361 | }; |
2362 | ||
92e1d5be | 2363 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2364 | #ifdef CONFIG_TMPFS |
2365 | .create = shmem_create, | |
2366 | .lookup = simple_lookup, | |
2367 | .link = shmem_link, | |
2368 | .unlink = shmem_unlink, | |
2369 | .symlink = shmem_symlink, | |
2370 | .mkdir = shmem_mkdir, | |
2371 | .rmdir = shmem_rmdir, | |
2372 | .mknod = shmem_mknod, | |
2373 | .rename = shmem_rename, | |
1da177e4 | 2374 | #endif |
39f0247d AG |
2375 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2376 | .setattr = shmem_notify_change, | |
2377 | .setxattr = generic_setxattr, | |
2378 | .getxattr = generic_getxattr, | |
2379 | .listxattr = generic_listxattr, | |
2380 | .removexattr = generic_removexattr, | |
2381 | .permission = shmem_permission, | |
2382 | #endif | |
2383 | }; | |
2384 | ||
92e1d5be | 2385 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2386 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2387 | .setattr = shmem_notify_change, | |
2388 | .setxattr = generic_setxattr, | |
2389 | .getxattr = generic_getxattr, | |
2390 | .listxattr = generic_listxattr, | |
2391 | .removexattr = generic_removexattr, | |
2392 | .permission = shmem_permission, | |
2393 | #endif | |
1da177e4 LT |
2394 | }; |
2395 | ||
759b9775 | 2396 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2397 | .alloc_inode = shmem_alloc_inode, |
2398 | .destroy_inode = shmem_destroy_inode, | |
2399 | #ifdef CONFIG_TMPFS | |
2400 | .statfs = shmem_statfs, | |
2401 | .remount_fs = shmem_remount_fs, | |
2402 | #endif | |
2403 | .delete_inode = shmem_delete_inode, | |
2404 | .drop_inode = generic_delete_inode, | |
2405 | .put_super = shmem_put_super, | |
2406 | }; | |
2407 | ||
2408 | static struct vm_operations_struct shmem_vm_ops = { | |
2409 | .nopage = shmem_nopage, | |
2410 | .populate = shmem_populate, | |
2411 | #ifdef CONFIG_NUMA | |
2412 | .set_policy = shmem_set_policy, | |
2413 | .get_policy = shmem_get_policy, | |
2414 | #endif | |
2415 | }; | |
2416 | ||
2417 | ||
454e2398 DH |
2418 | static int shmem_get_sb(struct file_system_type *fs_type, |
2419 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2420 | { |
454e2398 | 2421 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2422 | } |
2423 | ||
2424 | static struct file_system_type tmpfs_fs_type = { | |
2425 | .owner = THIS_MODULE, | |
2426 | .name = "tmpfs", | |
2427 | .get_sb = shmem_get_sb, | |
2428 | .kill_sb = kill_litter_super, | |
2429 | }; | |
2430 | static struct vfsmount *shm_mnt; | |
2431 | ||
2432 | static int __init init_tmpfs(void) | |
2433 | { | |
2434 | int error; | |
2435 | ||
2436 | error = init_inodecache(); | |
2437 | if (error) | |
2438 | goto out3; | |
2439 | ||
2440 | error = register_filesystem(&tmpfs_fs_type); | |
2441 | if (error) { | |
2442 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2443 | goto out2; | |
2444 | } | |
95dc112a | 2445 | |
1f5ce9e9 | 2446 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2447 | tmpfs_fs_type.name, NULL); |
2448 | if (IS_ERR(shm_mnt)) { | |
2449 | error = PTR_ERR(shm_mnt); | |
2450 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2451 | goto out1; | |
2452 | } | |
2453 | return 0; | |
2454 | ||
2455 | out1: | |
2456 | unregister_filesystem(&tmpfs_fs_type); | |
2457 | out2: | |
2458 | destroy_inodecache(); | |
2459 | out3: | |
2460 | shm_mnt = ERR_PTR(error); | |
2461 | return error; | |
2462 | } | |
2463 | module_init(init_tmpfs) | |
2464 | ||
2465 | /* | |
2466 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2467 | * | |
2468 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2469 | * @size: size to be set for the file | |
2470 | * | |
2471 | */ | |
2472 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2473 | { | |
2474 | int error; | |
2475 | struct file *file; | |
2476 | struct inode *inode; | |
2477 | struct dentry *dentry, *root; | |
2478 | struct qstr this; | |
2479 | ||
2480 | if (IS_ERR(shm_mnt)) | |
2481 | return (void *)shm_mnt; | |
2482 | ||
2483 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2484 | return ERR_PTR(-EINVAL); | |
2485 | ||
2486 | if (shmem_acct_size(flags, size)) | |
2487 | return ERR_PTR(-ENOMEM); | |
2488 | ||
2489 | error = -ENOMEM; | |
2490 | this.name = name; | |
2491 | this.len = strlen(name); | |
2492 | this.hash = 0; /* will go */ | |
2493 | root = shm_mnt->mnt_root; | |
2494 | dentry = d_alloc(root, &this); | |
2495 | if (!dentry) | |
2496 | goto put_memory; | |
2497 | ||
2498 | error = -ENFILE; | |
2499 | file = get_empty_filp(); | |
2500 | if (!file) | |
2501 | goto put_dentry; | |
2502 | ||
2503 | error = -ENOSPC; | |
2504 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2505 | if (!inode) | |
2506 | goto close_file; | |
2507 | ||
2508 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2509 | d_instantiate(dentry, inode); | |
2510 | inode->i_size = size; | |
2511 | inode->i_nlink = 0; /* It is unlinked */ | |
d3ac7f89 JJS |
2512 | file->f_path.mnt = mntget(shm_mnt); |
2513 | file->f_path.dentry = dentry; | |
1da177e4 LT |
2514 | file->f_mapping = inode->i_mapping; |
2515 | file->f_op = &shmem_file_operations; | |
2516 | file->f_mode = FMODE_WRITE | FMODE_READ; | |
2517 | return file; | |
2518 | ||
2519 | close_file: | |
2520 | put_filp(file); | |
2521 | put_dentry: | |
2522 | dput(dentry); | |
2523 | put_memory: | |
2524 | shmem_unacct_size(flags, size); | |
2525 | return ERR_PTR(error); | |
2526 | } | |
2527 | ||
2528 | /* | |
2529 | * shmem_zero_setup - setup a shared anonymous mapping | |
2530 | * | |
2531 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2532 | */ | |
2533 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2534 | { | |
2535 | struct file *file; | |
2536 | loff_t size = vma->vm_end - vma->vm_start; | |
2537 | ||
2538 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2539 | if (IS_ERR(file)) | |
2540 | return PTR_ERR(file); | |
2541 | ||
2542 | if (vma->vm_file) | |
2543 | fput(vma->vm_file); | |
2544 | vma->vm_file = file; | |
2545 | vma->vm_ops = &shmem_vm_ops; | |
2546 | return 0; | |
2547 | } |