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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 | * | |
1ae70006 HD |
405 | * @dir: pointer to the directory |
406 | * @edir: pointer after last entry of the directory | |
407 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 408 | */ |
1ae70006 HD |
409 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
410 | spinlock_t *punch_lock) | |
1da177e4 | 411 | { |
1ae70006 | 412 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
413 | swp_entry_t *ptr; |
414 | int freed = 0; | |
415 | ||
416 | for (ptr = dir; ptr < edir; ptr++) { | |
417 | if (ptr->val) { | |
1ae70006 HD |
418 | if (unlikely(punch_lock)) { |
419 | punch_unlock = punch_lock; | |
420 | punch_lock = NULL; | |
421 | spin_lock(punch_unlock); | |
422 | if (!ptr->val) | |
423 | continue; | |
424 | } | |
1da177e4 LT |
425 | free_swap_and_cache(*ptr); |
426 | *ptr = (swp_entry_t){0}; | |
427 | freed++; | |
428 | } | |
429 | } | |
1ae70006 HD |
430 | if (punch_unlock) |
431 | spin_unlock(punch_unlock); | |
1da177e4 LT |
432 | return freed; |
433 | } | |
434 | ||
1ae70006 HD |
435 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
436 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
437 | { |
438 | swp_entry_t *ptr; | |
439 | int freed = 0; | |
440 | ||
441 | ptr = shmem_swp_map(subdir); | |
442 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
443 | int size = limit - offset; | |
444 | if (size > LATENCY_LIMIT) | |
445 | size = LATENCY_LIMIT; | |
1ae70006 HD |
446 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
447 | punch_lock); | |
1da177e4 LT |
448 | if (need_resched()) { |
449 | shmem_swp_unmap(ptr); | |
450 | if (*dir) { | |
451 | shmem_dir_unmap(*dir); | |
452 | *dir = NULL; | |
453 | } | |
454 | cond_resched(); | |
455 | ptr = shmem_swp_map(subdir); | |
456 | } | |
457 | } | |
458 | shmem_swp_unmap(ptr); | |
459 | return freed; | |
460 | } | |
461 | ||
462 | static void shmem_free_pages(struct list_head *next) | |
463 | { | |
464 | struct page *page; | |
465 | int freed = 0; | |
466 | ||
467 | do { | |
468 | page = container_of(next, struct page, lru); | |
469 | next = next->next; | |
470 | shmem_dir_free(page); | |
471 | freed++; | |
472 | if (freed >= LATENCY_LIMIT) { | |
473 | cond_resched(); | |
474 | freed = 0; | |
475 | } | |
476 | } while (next); | |
477 | } | |
478 | ||
f6b3ec23 | 479 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
480 | { |
481 | struct shmem_inode_info *info = SHMEM_I(inode); | |
482 | unsigned long idx; | |
483 | unsigned long size; | |
484 | unsigned long limit; | |
485 | unsigned long stage; | |
486 | unsigned long diroff; | |
487 | struct page **dir; | |
488 | struct page *topdir; | |
489 | struct page *middir; | |
490 | struct page *subdir; | |
491 | swp_entry_t *ptr; | |
492 | LIST_HEAD(pages_to_free); | |
493 | long nr_pages_to_free = 0; | |
494 | long nr_swaps_freed = 0; | |
495 | int offset; | |
496 | int freed; | |
a2646d1e | 497 | int punch_hole; |
1ae70006 HD |
498 | spinlock_t *needs_lock; |
499 | spinlock_t *punch_lock; | |
a2646d1e | 500 | unsigned long upper_limit; |
1da177e4 LT |
501 | |
502 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 503 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
504 | if (idx >= info->next_index) |
505 | return; | |
506 | ||
507 | spin_lock(&info->lock); | |
508 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
509 | if (likely(end == (loff_t) -1)) { |
510 | limit = info->next_index; | |
a2646d1e | 511 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 512 | info->next_index = idx; |
1ae70006 | 513 | needs_lock = NULL; |
a2646d1e | 514 | punch_hole = 0; |
f6b3ec23 | 515 | } else { |
a2646d1e HD |
516 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
517 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
518 | PAGE_CACHE_SHIFT; | |
519 | upper_limit = SHMEM_MAX_INDEX; | |
520 | } else { | |
521 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
522 | upper_limit = limit; | |
523 | } | |
1ae70006 | 524 | needs_lock = &info->lock; |
f6b3ec23 BP |
525 | punch_hole = 1; |
526 | } | |
527 | ||
1da177e4 | 528 | topdir = info->i_indirect; |
f6b3ec23 | 529 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
530 | info->i_indirect = NULL; |
531 | nr_pages_to_free++; | |
532 | list_add(&topdir->lru, &pages_to_free); | |
533 | } | |
534 | spin_unlock(&info->lock); | |
535 | ||
536 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
537 | ptr = info->i_direct; | |
538 | size = limit; | |
539 | if (size > SHMEM_NR_DIRECT) | |
540 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 541 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 542 | } |
92a3d03a BP |
543 | |
544 | /* | |
545 | * If there are no indirect blocks or we are punching a hole | |
546 | * below indirect blocks, nothing to be done. | |
547 | */ | |
a2646d1e | 548 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
549 | goto done2; |
550 | ||
1ae70006 HD |
551 | /* |
552 | * The truncation case has already dropped info->lock, and we're safe | |
553 | * because i_size and next_index have already been lowered, preventing | |
554 | * access beyond. But in the punch_hole case, we still need to take | |
555 | * the lock when updating the swap directory, because there might be | |
556 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
557 | * shmem_writepage. However, whenever we find we can remove a whole | |
558 | * directory page (not at the misaligned start or end of the range), | |
559 | * we first NULLify its pointer in the level above, and then have no | |
560 | * need to take the lock when updating its contents: needs_lock and | |
561 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
562 | */ | |
563 | ||
a2646d1e | 564 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
565 | limit -= SHMEM_NR_DIRECT; |
566 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
567 | offset = idx % ENTRIES_PER_PAGE; | |
568 | idx -= offset; | |
569 | ||
570 | dir = shmem_dir_map(topdir); | |
571 | stage = ENTRIES_PER_PAGEPAGE/2; | |
572 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
573 | middir = topdir; | |
574 | diroff = idx/ENTRIES_PER_PAGE; | |
575 | } else { | |
576 | dir += ENTRIES_PER_PAGE/2; | |
577 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
578 | while (stage <= idx) | |
579 | stage += ENTRIES_PER_PAGEPAGE; | |
580 | middir = *dir; | |
581 | if (*dir) { | |
582 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
583 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 584 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
585 | if (needs_lock) { |
586 | spin_lock(needs_lock); | |
587 | *dir = NULL; | |
588 | spin_unlock(needs_lock); | |
589 | needs_lock = NULL; | |
590 | } else | |
591 | *dir = NULL; | |
1da177e4 LT |
592 | nr_pages_to_free++; |
593 | list_add(&middir->lru, &pages_to_free); | |
594 | } | |
595 | shmem_dir_unmap(dir); | |
596 | dir = shmem_dir_map(middir); | |
597 | } else { | |
598 | diroff = 0; | |
599 | offset = 0; | |
600 | idx = stage; | |
601 | } | |
602 | } | |
603 | ||
604 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
605 | if (unlikely(idx == stage)) { | |
606 | shmem_dir_unmap(dir); | |
607 | dir = shmem_dir_map(topdir) + | |
608 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
609 | while (!*dir) { | |
610 | dir++; | |
611 | idx += ENTRIES_PER_PAGEPAGE; | |
612 | if (idx >= limit) | |
613 | goto done1; | |
614 | } | |
615 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
616 | middir = *dir; | |
1ae70006 HD |
617 | if (punch_hole) |
618 | needs_lock = &info->lock; | |
a2646d1e | 619 | if (upper_limit >= stage) { |
1ae70006 HD |
620 | if (needs_lock) { |
621 | spin_lock(needs_lock); | |
622 | *dir = NULL; | |
623 | spin_unlock(needs_lock); | |
624 | needs_lock = NULL; | |
625 | } else | |
626 | *dir = NULL; | |
a2646d1e HD |
627 | nr_pages_to_free++; |
628 | list_add(&middir->lru, &pages_to_free); | |
629 | } | |
1da177e4 LT |
630 | shmem_dir_unmap(dir); |
631 | cond_resched(); | |
632 | dir = shmem_dir_map(middir); | |
633 | diroff = 0; | |
634 | } | |
1ae70006 | 635 | punch_lock = needs_lock; |
1da177e4 | 636 | subdir = dir[diroff]; |
1ae70006 HD |
637 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
638 | if (needs_lock) { | |
639 | spin_lock(needs_lock); | |
640 | dir[diroff] = NULL; | |
641 | spin_unlock(needs_lock); | |
642 | punch_lock = NULL; | |
643 | } else | |
644 | dir[diroff] = NULL; | |
645 | nr_pages_to_free++; | |
646 | list_add(&subdir->lru, &pages_to_free); | |
647 | } | |
648 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
649 | size = limit - idx; |
650 | if (size > ENTRIES_PER_PAGE) | |
651 | size = ENTRIES_PER_PAGE; | |
652 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 653 | offset, size, &dir, punch_lock); |
1da177e4 LT |
654 | if (!dir) |
655 | dir = shmem_dir_map(middir); | |
656 | nr_swaps_freed += freed; | |
1ae70006 | 657 | if (offset || punch_lock) { |
1da177e4 | 658 | spin_lock(&info->lock); |
1ae70006 HD |
659 | set_page_private(subdir, |
660 | page_private(subdir) - freed); | |
1da177e4 | 661 | spin_unlock(&info->lock); |
1ae70006 HD |
662 | } else |
663 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 664 | } |
1ae70006 | 665 | offset = 0; |
1da177e4 LT |
666 | } |
667 | done1: | |
668 | shmem_dir_unmap(dir); | |
669 | done2: | |
670 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
671 | /* | |
672 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
673 | * may have swizzled a page in from swap since vmtruncate or | |
674 | * generic_delete_inode did it, before we lowered next_index. | |
675 | * Also, though shmem_getpage checks i_size before adding to | |
676 | * cache, no recheck after: so fix the narrow window there too. | |
16a10019 HD |
677 | * |
678 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
679 | * every time for punch_hole (which never got a chance to clear | |
680 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
681 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 682 | */ |
f6b3ec23 | 683 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
684 | if (punch_hole) |
685 | unmap_mapping_range(inode->i_mapping, start, | |
686 | end - start, 1); | |
1da177e4 LT |
687 | } |
688 | ||
689 | spin_lock(&info->lock); | |
690 | info->flags &= ~SHMEM_TRUNCATE; | |
691 | info->swapped -= nr_swaps_freed; | |
692 | if (nr_pages_to_free) | |
693 | shmem_free_blocks(inode, nr_pages_to_free); | |
694 | shmem_recalc_inode(inode); | |
695 | spin_unlock(&info->lock); | |
696 | ||
697 | /* | |
698 | * Empty swap vector directory pages to be freed? | |
699 | */ | |
700 | if (!list_empty(&pages_to_free)) { | |
701 | pages_to_free.prev->next = NULL; | |
702 | shmem_free_pages(pages_to_free.next); | |
703 | } | |
704 | } | |
705 | ||
f6b3ec23 BP |
706 | static void shmem_truncate(struct inode *inode) |
707 | { | |
708 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
709 | } | |
710 | ||
1da177e4 LT |
711 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
712 | { | |
713 | struct inode *inode = dentry->d_inode; | |
714 | struct page *page = NULL; | |
715 | int error; | |
716 | ||
39f0247d | 717 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
718 | if (attr->ia_size < inode->i_size) { |
719 | /* | |
720 | * If truncating down to a partial page, then | |
721 | * if that page is already allocated, hold it | |
722 | * in memory until the truncation is over, so | |
723 | * truncate_partial_page cannnot miss it were | |
724 | * it assigned to swap. | |
725 | */ | |
726 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
727 | (void) shmem_getpage(inode, | |
728 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
729 | &page, SGP_READ, NULL); | |
730 | } | |
731 | /* | |
732 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
733 | * detect if any pages might have been added to cache | |
734 | * after truncate_inode_pages. But we needn't bother | |
735 | * if it's being fully truncated to zero-length: the | |
736 | * nrpages check is efficient enough in that case. | |
737 | */ | |
738 | if (attr->ia_size) { | |
739 | struct shmem_inode_info *info = SHMEM_I(inode); | |
740 | spin_lock(&info->lock); | |
741 | info->flags &= ~SHMEM_PAGEIN; | |
742 | spin_unlock(&info->lock); | |
743 | } | |
744 | } | |
745 | } | |
746 | ||
747 | error = inode_change_ok(inode, attr); | |
748 | if (!error) | |
749 | error = inode_setattr(inode, attr); | |
39f0247d AG |
750 | #ifdef CONFIG_TMPFS_POSIX_ACL |
751 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
752 | error = generic_acl_chmod(inode, &shmem_acl_ops); | |
753 | #endif | |
1da177e4 LT |
754 | if (page) |
755 | page_cache_release(page); | |
756 | return error; | |
757 | } | |
758 | ||
759 | static void shmem_delete_inode(struct inode *inode) | |
760 | { | |
761 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
762 | struct shmem_inode_info *info = SHMEM_I(inode); | |
763 | ||
764 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 765 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
766 | shmem_unacct_size(info->flags, inode->i_size); |
767 | inode->i_size = 0; | |
768 | shmem_truncate(inode); | |
769 | if (!list_empty(&info->swaplist)) { | |
770 | spin_lock(&shmem_swaplist_lock); | |
771 | list_del_init(&info->swaplist); | |
772 | spin_unlock(&shmem_swaplist_lock); | |
773 | } | |
774 | } | |
0edd73b3 HD |
775 | BUG_ON(inode->i_blocks); |
776 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
777 | spin_lock(&sbinfo->stat_lock); |
778 | sbinfo->free_inodes++; | |
779 | spin_unlock(&sbinfo->stat_lock); | |
780 | } | |
781 | clear_inode(inode); | |
782 | } | |
783 | ||
784 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
785 | { | |
786 | swp_entry_t *ptr; | |
787 | ||
788 | for (ptr = dir; ptr < edir; ptr++) { | |
789 | if (ptr->val == entry.val) | |
790 | return ptr - dir; | |
791 | } | |
792 | return -1; | |
793 | } | |
794 | ||
795 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
796 | { | |
797 | struct inode *inode; | |
798 | unsigned long idx; | |
799 | unsigned long size; | |
800 | unsigned long limit; | |
801 | unsigned long stage; | |
802 | struct page **dir; | |
803 | struct page *subdir; | |
804 | swp_entry_t *ptr; | |
805 | int offset; | |
806 | ||
807 | idx = 0; | |
808 | ptr = info->i_direct; | |
809 | spin_lock(&info->lock); | |
810 | limit = info->next_index; | |
811 | size = limit; | |
812 | if (size > SHMEM_NR_DIRECT) | |
813 | size = SHMEM_NR_DIRECT; | |
814 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
815 | if (offset >= 0) { | |
816 | shmem_swp_balance_unmap(); | |
817 | goto found; | |
818 | } | |
819 | if (!info->i_indirect) | |
820 | goto lost2; | |
821 | ||
822 | dir = shmem_dir_map(info->i_indirect); | |
823 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
824 | ||
825 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
826 | if (unlikely(idx == stage)) { | |
827 | shmem_dir_unmap(dir-1); | |
828 | dir = shmem_dir_map(info->i_indirect) + | |
829 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
830 | while (!*dir) { | |
831 | dir++; | |
832 | idx += ENTRIES_PER_PAGEPAGE; | |
833 | if (idx >= limit) | |
834 | goto lost1; | |
835 | } | |
836 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
837 | subdir = *dir; | |
838 | shmem_dir_unmap(dir); | |
839 | dir = shmem_dir_map(subdir); | |
840 | } | |
841 | subdir = *dir; | |
4c21e2f2 | 842 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
843 | ptr = shmem_swp_map(subdir); |
844 | size = limit - idx; | |
845 | if (size > ENTRIES_PER_PAGE) | |
846 | size = ENTRIES_PER_PAGE; | |
847 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
848 | if (offset >= 0) { | |
849 | shmem_dir_unmap(dir); | |
850 | goto found; | |
851 | } | |
852 | shmem_swp_unmap(ptr); | |
853 | } | |
854 | } | |
855 | lost1: | |
856 | shmem_dir_unmap(dir-1); | |
857 | lost2: | |
858 | spin_unlock(&info->lock); | |
859 | return 0; | |
860 | found: | |
861 | idx += offset; | |
862 | inode = &info->vfs_inode; | |
863 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { | |
864 | info->flags |= SHMEM_PAGEIN; | |
865 | shmem_swp_set(info, ptr + offset, 0); | |
866 | } | |
867 | shmem_swp_unmap(ptr); | |
868 | spin_unlock(&info->lock); | |
869 | /* | |
870 | * Decrement swap count even when the entry is left behind: | |
871 | * try_to_unuse will skip over mms, then reincrement count. | |
872 | */ | |
873 | swap_free(entry); | |
874 | return 1; | |
875 | } | |
876 | ||
877 | /* | |
878 | * shmem_unuse() search for an eventually swapped out shmem page. | |
879 | */ | |
880 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
881 | { | |
882 | struct list_head *p, *next; | |
883 | struct shmem_inode_info *info; | |
884 | int found = 0; | |
885 | ||
886 | spin_lock(&shmem_swaplist_lock); | |
887 | list_for_each_safe(p, next, &shmem_swaplist) { | |
888 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
889 | if (!info->swapped) | |
890 | list_del_init(&info->swaplist); | |
891 | else if (shmem_unuse_inode(info, entry, page)) { | |
892 | /* move head to start search for next from here */ | |
893 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
894 | found = 1; | |
895 | break; | |
896 | } | |
897 | } | |
898 | spin_unlock(&shmem_swaplist_lock); | |
899 | return found; | |
900 | } | |
901 | ||
902 | /* | |
903 | * Move the page from the page cache to the swap cache. | |
904 | */ | |
905 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
906 | { | |
907 | struct shmem_inode_info *info; | |
908 | swp_entry_t *entry, swap; | |
909 | struct address_space *mapping; | |
910 | unsigned long index; | |
911 | struct inode *inode; | |
912 | ||
913 | BUG_ON(!PageLocked(page)); | |
914 | BUG_ON(page_mapped(page)); | |
915 | ||
916 | mapping = page->mapping; | |
917 | index = page->index; | |
918 | inode = mapping->host; | |
919 | info = SHMEM_I(inode); | |
920 | if (info->flags & VM_LOCKED) | |
921 | goto redirty; | |
922 | swap = get_swap_page(); | |
923 | if (!swap.val) | |
924 | goto redirty; | |
925 | ||
926 | spin_lock(&info->lock); | |
927 | shmem_recalc_inode(inode); | |
928 | if (index >= info->next_index) { | |
929 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
930 | goto unlock; | |
931 | } | |
932 | entry = shmem_swp_entry(info, index, NULL); | |
933 | BUG_ON(!entry); | |
934 | BUG_ON(entry->val); | |
935 | ||
936 | if (move_to_swap_cache(page, swap) == 0) { | |
937 | shmem_swp_set(info, entry, swap.val); | |
938 | shmem_swp_unmap(entry); | |
939 | spin_unlock(&info->lock); | |
940 | if (list_empty(&info->swaplist)) { | |
941 | spin_lock(&shmem_swaplist_lock); | |
942 | /* move instead of add in case we're racing */ | |
943 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
944 | spin_unlock(&shmem_swaplist_lock); | |
945 | } | |
946 | unlock_page(page); | |
947 | return 0; | |
948 | } | |
949 | ||
950 | shmem_swp_unmap(entry); | |
951 | unlock: | |
952 | spin_unlock(&info->lock); | |
953 | swap_free(swap); | |
954 | redirty: | |
955 | set_page_dirty(page); | |
994fc28c | 956 | return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */ |
1da177e4 LT |
957 | } |
958 | ||
959 | #ifdef CONFIG_NUMA | |
d15c023b | 960 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
b00dc3ad HD |
961 | { |
962 | char *nodelist = strchr(value, ':'); | |
963 | int err = 1; | |
964 | ||
965 | if (nodelist) { | |
966 | /* NUL-terminate policy string */ | |
967 | *nodelist++ = '\0'; | |
968 | if (nodelist_parse(nodelist, *policy_nodes)) | |
969 | goto out; | |
970 | } | |
971 | if (!strcmp(value, "default")) { | |
972 | *policy = MPOL_DEFAULT; | |
973 | /* Don't allow a nodelist */ | |
974 | if (!nodelist) | |
975 | err = 0; | |
976 | } else if (!strcmp(value, "prefer")) { | |
977 | *policy = MPOL_PREFERRED; | |
978 | /* Insist on a nodelist of one node only */ | |
979 | if (nodelist) { | |
980 | char *rest = nodelist; | |
981 | while (isdigit(*rest)) | |
982 | rest++; | |
983 | if (!*rest) | |
984 | err = 0; | |
985 | } | |
986 | } else if (!strcmp(value, "bind")) { | |
987 | *policy = MPOL_BIND; | |
988 | /* Insist on a nodelist */ | |
989 | if (nodelist) | |
990 | err = 0; | |
991 | } else if (!strcmp(value, "interleave")) { | |
992 | *policy = MPOL_INTERLEAVE; | |
993 | /* Default to nodes online if no nodelist */ | |
994 | if (!nodelist) | |
995 | *policy_nodes = node_online_map; | |
996 | err = 0; | |
997 | } | |
998 | out: | |
999 | /* Restore string for error message */ | |
1000 | if (nodelist) | |
1001 | *--nodelist = ':'; | |
1002 | return err; | |
1003 | } | |
1004 | ||
1da177e4 LT |
1005 | static struct page *shmem_swapin_async(struct shared_policy *p, |
1006 | swp_entry_t entry, unsigned long idx) | |
1007 | { | |
1008 | struct page *page; | |
1009 | struct vm_area_struct pvma; | |
1010 | ||
1011 | /* Create a pseudo vma that just contains the policy */ | |
1012 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
1013 | pvma.vm_end = PAGE_SIZE; | |
1014 | pvma.vm_pgoff = idx; | |
1015 | pvma.vm_policy = mpol_shared_policy_lookup(p, idx); | |
1016 | page = read_swap_cache_async(entry, &pvma, 0); | |
1017 | mpol_free(pvma.vm_policy); | |
1018 | return page; | |
1019 | } | |
1020 | ||
1021 | struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry, | |
1022 | unsigned long idx) | |
1023 | { | |
1024 | struct shared_policy *p = &info->policy; | |
1025 | int i, num; | |
1026 | struct page *page; | |
1027 | unsigned long offset; | |
1028 | ||
1029 | num = valid_swaphandles(entry, &offset); | |
1030 | for (i = 0; i < num; offset++, i++) { | |
1031 | page = shmem_swapin_async(p, | |
1032 | swp_entry(swp_type(entry), offset), idx); | |
1033 | if (!page) | |
1034 | break; | |
1035 | page_cache_release(page); | |
1036 | } | |
1037 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
1038 | return shmem_swapin_async(p, entry, idx); | |
1039 | } | |
1040 | ||
1041 | static struct page * | |
6daa0e28 | 1042 | shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info, |
1da177e4 LT |
1043 | unsigned long idx) |
1044 | { | |
1045 | struct vm_area_struct pvma; | |
1046 | struct page *page; | |
1047 | ||
1048 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
1049 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
1050 | pvma.vm_pgoff = idx; | |
1051 | pvma.vm_end = PAGE_SIZE; | |
1052 | page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0); | |
1053 | mpol_free(pvma.vm_policy); | |
1054 | return page; | |
1055 | } | |
1056 | #else | |
b00dc3ad HD |
1057 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
1058 | { | |
1059 | return 1; | |
1060 | } | |
1061 | ||
1da177e4 LT |
1062 | static inline struct page * |
1063 | shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx) | |
1064 | { | |
1065 | swapin_readahead(entry, 0, NULL); | |
1066 | return read_swap_cache_async(entry, NULL, 0); | |
1067 | } | |
1068 | ||
1069 | static inline struct page * | |
dd0fc66f | 1070 | shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx) |
1da177e4 LT |
1071 | { |
1072 | return alloc_page(gfp | __GFP_ZERO); | |
1073 | } | |
1074 | #endif | |
1075 | ||
1076 | /* | |
1077 | * shmem_getpage - either get the page from swap or allocate a new one | |
1078 | * | |
1079 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1080 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1081 | * entry since a page cannot live in both the swap and page cache | |
1082 | */ | |
1083 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1084 | struct page **pagep, enum sgp_type sgp, int *type) | |
1085 | { | |
1086 | struct address_space *mapping = inode->i_mapping; | |
1087 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1088 | struct shmem_sb_info *sbinfo; | |
1089 | struct page *filepage = *pagep; | |
1090 | struct page *swappage; | |
1091 | swp_entry_t *entry; | |
1092 | swp_entry_t swap; | |
1093 | int error; | |
1094 | ||
1095 | if (idx >= SHMEM_MAX_INDEX) | |
1096 | return -EFBIG; | |
1097 | /* | |
1098 | * Normally, filepage is NULL on entry, and either found | |
1099 | * uptodate immediately, or allocated and zeroed, or read | |
1100 | * in under swappage, which is then assigned to filepage. | |
1101 | * But shmem_prepare_write passes in a locked filepage, | |
1102 | * which may be found not uptodate by other callers too, | |
1103 | * and may need to be copied from the swappage read in. | |
1104 | */ | |
1105 | repeat: | |
1106 | if (!filepage) | |
1107 | filepage = find_lock_page(mapping, idx); | |
1108 | if (filepage && PageUptodate(filepage)) | |
1109 | goto done; | |
1110 | error = 0; | |
1111 | if (sgp == SGP_QUICK) | |
1112 | goto failed; | |
1113 | ||
1114 | spin_lock(&info->lock); | |
1115 | shmem_recalc_inode(inode); | |
1116 | entry = shmem_swp_alloc(info, idx, sgp); | |
1117 | if (IS_ERR(entry)) { | |
1118 | spin_unlock(&info->lock); | |
1119 | error = PTR_ERR(entry); | |
1120 | goto failed; | |
1121 | } | |
1122 | swap = *entry; | |
1123 | ||
1124 | if (swap.val) { | |
1125 | /* Look it up and read it in.. */ | |
1126 | swappage = lookup_swap_cache(swap); | |
1127 | if (!swappage) { | |
1128 | shmem_swp_unmap(entry); | |
1da177e4 LT |
1129 | /* here we actually do the io */ |
1130 | if (type && *type == VM_FAULT_MINOR) { | |
f8891e5e | 1131 | __count_vm_event(PGMAJFAULT); |
1da177e4 LT |
1132 | *type = VM_FAULT_MAJOR; |
1133 | } | |
f8891e5e | 1134 | spin_unlock(&info->lock); |
1da177e4 LT |
1135 | swappage = shmem_swapin(info, swap, idx); |
1136 | if (!swappage) { | |
1137 | spin_lock(&info->lock); | |
1138 | entry = shmem_swp_alloc(info, idx, sgp); | |
1139 | if (IS_ERR(entry)) | |
1140 | error = PTR_ERR(entry); | |
1141 | else { | |
1142 | if (entry->val == swap.val) | |
1143 | error = -ENOMEM; | |
1144 | shmem_swp_unmap(entry); | |
1145 | } | |
1146 | spin_unlock(&info->lock); | |
1147 | if (error) | |
1148 | goto failed; | |
1149 | goto repeat; | |
1150 | } | |
1151 | wait_on_page_locked(swappage); | |
1152 | page_cache_release(swappage); | |
1153 | goto repeat; | |
1154 | } | |
1155 | ||
1156 | /* We have to do this with page locked to prevent races */ | |
1157 | if (TestSetPageLocked(swappage)) { | |
1158 | shmem_swp_unmap(entry); | |
1159 | spin_unlock(&info->lock); | |
1160 | wait_on_page_locked(swappage); | |
1161 | page_cache_release(swappage); | |
1162 | goto repeat; | |
1163 | } | |
1164 | if (PageWriteback(swappage)) { | |
1165 | shmem_swp_unmap(entry); | |
1166 | spin_unlock(&info->lock); | |
1167 | wait_on_page_writeback(swappage); | |
1168 | unlock_page(swappage); | |
1169 | page_cache_release(swappage); | |
1170 | goto repeat; | |
1171 | } | |
1172 | if (!PageUptodate(swappage)) { | |
1173 | shmem_swp_unmap(entry); | |
1174 | spin_unlock(&info->lock); | |
1175 | unlock_page(swappage); | |
1176 | page_cache_release(swappage); | |
1177 | error = -EIO; | |
1178 | goto failed; | |
1179 | } | |
1180 | ||
1181 | if (filepage) { | |
1182 | shmem_swp_set(info, entry, 0); | |
1183 | shmem_swp_unmap(entry); | |
1184 | delete_from_swap_cache(swappage); | |
1185 | spin_unlock(&info->lock); | |
1186 | copy_highpage(filepage, swappage); | |
1187 | unlock_page(swappage); | |
1188 | page_cache_release(swappage); | |
1189 | flush_dcache_page(filepage); | |
1190 | SetPageUptodate(filepage); | |
1191 | set_page_dirty(filepage); | |
1192 | swap_free(swap); | |
1193 | } else if (!(error = move_from_swap_cache( | |
1194 | swappage, idx, mapping))) { | |
1195 | info->flags |= SHMEM_PAGEIN; | |
1196 | shmem_swp_set(info, entry, 0); | |
1197 | shmem_swp_unmap(entry); | |
1198 | spin_unlock(&info->lock); | |
1199 | filepage = swappage; | |
1200 | swap_free(swap); | |
1201 | } else { | |
1202 | shmem_swp_unmap(entry); | |
1203 | spin_unlock(&info->lock); | |
1204 | unlock_page(swappage); | |
1205 | page_cache_release(swappage); | |
1206 | if (error == -ENOMEM) { | |
1207 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
3fcfab16 | 1208 | congestion_wait(WRITE, HZ/50); |
1da177e4 LT |
1209 | } |
1210 | goto repeat; | |
1211 | } | |
1212 | } else if (sgp == SGP_READ && !filepage) { | |
1213 | shmem_swp_unmap(entry); | |
1214 | filepage = find_get_page(mapping, idx); | |
1215 | if (filepage && | |
1216 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1217 | spin_unlock(&info->lock); | |
1218 | wait_on_page_locked(filepage); | |
1219 | page_cache_release(filepage); | |
1220 | filepage = NULL; | |
1221 | goto repeat; | |
1222 | } | |
1223 | spin_unlock(&info->lock); | |
1224 | } else { | |
1225 | shmem_swp_unmap(entry); | |
1226 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1227 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1228 | spin_lock(&sbinfo->stat_lock); |
1229 | if (sbinfo->free_blocks == 0 || | |
1230 | shmem_acct_block(info->flags)) { | |
1231 | spin_unlock(&sbinfo->stat_lock); | |
1232 | spin_unlock(&info->lock); | |
1233 | error = -ENOSPC; | |
1234 | goto failed; | |
1235 | } | |
1236 | sbinfo->free_blocks--; | |
1237 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1238 | spin_unlock(&sbinfo->stat_lock); | |
1239 | } else if (shmem_acct_block(info->flags)) { | |
1240 | spin_unlock(&info->lock); | |
1241 | error = -ENOSPC; | |
1242 | goto failed; | |
1243 | } | |
1244 | ||
1245 | if (!filepage) { | |
1246 | spin_unlock(&info->lock); | |
1247 | filepage = shmem_alloc_page(mapping_gfp_mask(mapping), | |
1248 | info, | |
1249 | idx); | |
1250 | if (!filepage) { | |
1251 | shmem_unacct_blocks(info->flags, 1); | |
1252 | shmem_free_blocks(inode, 1); | |
1253 | error = -ENOMEM; | |
1254 | goto failed; | |
1255 | } | |
1256 | ||
1257 | spin_lock(&info->lock); | |
1258 | entry = shmem_swp_alloc(info, idx, sgp); | |
1259 | if (IS_ERR(entry)) | |
1260 | error = PTR_ERR(entry); | |
1261 | else { | |
1262 | swap = *entry; | |
1263 | shmem_swp_unmap(entry); | |
1264 | } | |
1265 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1266 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1267 | spin_unlock(&info->lock); | |
1268 | page_cache_release(filepage); | |
1269 | shmem_unacct_blocks(info->flags, 1); | |
1270 | shmem_free_blocks(inode, 1); | |
1271 | filepage = NULL; | |
1272 | if (error) | |
1273 | goto failed; | |
1274 | goto repeat; | |
1275 | } | |
1276 | info->flags |= SHMEM_PAGEIN; | |
1277 | } | |
1278 | ||
1279 | info->alloced++; | |
1280 | spin_unlock(&info->lock); | |
1281 | flush_dcache_page(filepage); | |
1282 | SetPageUptodate(filepage); | |
1283 | } | |
1284 | done: | |
1285 | if (*pagep != filepage) { | |
1286 | unlock_page(filepage); | |
1287 | *pagep = filepage; | |
1288 | } | |
1289 | return 0; | |
1290 | ||
1291 | failed: | |
1292 | if (*pagep != filepage) { | |
1293 | unlock_page(filepage); | |
1294 | page_cache_release(filepage); | |
1295 | } | |
1296 | return error; | |
1297 | } | |
1298 | ||
9b83a6a8 AB |
1299 | static struct page *shmem_nopage(struct vm_area_struct *vma, |
1300 | unsigned long address, int *type) | |
1da177e4 | 1301 | { |
d3ac7f89 | 1302 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1303 | struct page *page = NULL; |
1304 | unsigned long idx; | |
1305 | int error; | |
1306 | ||
1307 | idx = (address - vma->vm_start) >> PAGE_SHIFT; | |
1308 | idx += vma->vm_pgoff; | |
1309 | idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT; | |
1310 | if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
1311 | return NOPAGE_SIGBUS; | |
1312 | ||
1313 | error = shmem_getpage(inode, idx, &page, SGP_CACHE, type); | |
1314 | if (error) | |
1315 | return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS; | |
1316 | ||
1317 | mark_page_accessed(page); | |
1318 | return page; | |
1319 | } | |
1320 | ||
1321 | static int shmem_populate(struct vm_area_struct *vma, | |
1322 | unsigned long addr, unsigned long len, | |
1323 | pgprot_t prot, unsigned long pgoff, int nonblock) | |
1324 | { | |
d3ac7f89 | 1325 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1326 | struct mm_struct *mm = vma->vm_mm; |
1327 | enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE; | |
1328 | unsigned long size; | |
1329 | ||
1330 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1331 | if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size) | |
1332 | return -EINVAL; | |
1333 | ||
1334 | while ((long) len > 0) { | |
1335 | struct page *page = NULL; | |
1336 | int err; | |
1337 | /* | |
1338 | * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE | |
1339 | */ | |
1340 | err = shmem_getpage(inode, pgoff, &page, sgp, NULL); | |
1341 | if (err) | |
1342 | return err; | |
d44ed4f8 | 1343 | /* Page may still be null, but only if nonblock was set. */ |
1da177e4 LT |
1344 | if (page) { |
1345 | mark_page_accessed(page); | |
1346 | err = install_page(mm, vma, addr, page, prot); | |
1347 | if (err) { | |
1348 | page_cache_release(page); | |
1349 | return err; | |
1350 | } | |
65500d23 | 1351 | } else if (vma->vm_flags & VM_NONLINEAR) { |
d44ed4f8 PBG |
1352 | /* No page was found just because we can't read it in |
1353 | * now (being here implies nonblock != 0), but the page | |
1354 | * may exist, so set the PTE to fault it in later. */ | |
1da177e4 LT |
1355 | err = install_file_pte(mm, vma, addr, pgoff, prot); |
1356 | if (err) | |
1357 | return err; | |
1358 | } | |
1359 | ||
1360 | len -= PAGE_SIZE; | |
1361 | addr += PAGE_SIZE; | |
1362 | pgoff++; | |
1363 | } | |
1364 | return 0; | |
1365 | } | |
1366 | ||
1367 | #ifdef CONFIG_NUMA | |
1368 | int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) | |
1369 | { | |
d3ac7f89 | 1370 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1371 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1372 | } | |
1373 | ||
1374 | struct mempolicy * | |
1375 | shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) | |
1376 | { | |
d3ac7f89 | 1377 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1378 | unsigned long idx; |
1379 | ||
1380 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1381 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1382 | } | |
1383 | #endif | |
1384 | ||
1385 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1386 | { | |
d3ac7f89 | 1387 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1388 | struct shmem_inode_info *info = SHMEM_I(inode); |
1389 | int retval = -ENOMEM; | |
1390 | ||
1391 | spin_lock(&info->lock); | |
1392 | if (lock && !(info->flags & VM_LOCKED)) { | |
1393 | if (!user_shm_lock(inode->i_size, user)) | |
1394 | goto out_nomem; | |
1395 | info->flags |= VM_LOCKED; | |
1396 | } | |
1397 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1398 | user_shm_unlock(inode->i_size, user); | |
1399 | info->flags &= ~VM_LOCKED; | |
1400 | } | |
1401 | retval = 0; | |
1402 | out_nomem: | |
1403 | spin_unlock(&info->lock); | |
1404 | return retval; | |
1405 | } | |
1406 | ||
9b83a6a8 | 1407 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1408 | { |
1409 | file_accessed(file); | |
1410 | vma->vm_ops = &shmem_vm_ops; | |
1411 | return 0; | |
1412 | } | |
1413 | ||
1414 | static struct inode * | |
1415 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1416 | { | |
1417 | struct inode *inode; | |
1418 | struct shmem_inode_info *info; | |
1419 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1420 | ||
0edd73b3 | 1421 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1422 | spin_lock(&sbinfo->stat_lock); |
1423 | if (!sbinfo->free_inodes) { | |
1424 | spin_unlock(&sbinfo->stat_lock); | |
1425 | return NULL; | |
1426 | } | |
1427 | sbinfo->free_inodes--; | |
1428 | spin_unlock(&sbinfo->stat_lock); | |
1429 | } | |
1430 | ||
1431 | inode = new_inode(sb); | |
1432 | if (inode) { | |
1433 | inode->i_mode = mode; | |
1434 | inode->i_uid = current->fsuid; | |
1435 | inode->i_gid = current->fsgid; | |
1da177e4 LT |
1436 | inode->i_blocks = 0; |
1437 | inode->i_mapping->a_ops = &shmem_aops; | |
1438 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1439 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1440 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1441 | info = SHMEM_I(inode); |
1442 | memset(info, 0, (char *)inode - (char *)info); | |
1443 | spin_lock_init(&info->lock); | |
1444 | INIT_LIST_HEAD(&info->swaplist); | |
1445 | ||
1446 | switch (mode & S_IFMT) { | |
1447 | default: | |
39f0247d | 1448 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1449 | init_special_inode(inode, mode, dev); |
1450 | break; | |
1451 | case S_IFREG: | |
1452 | inode->i_op = &shmem_inode_operations; | |
1453 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1454 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1455 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1456 | break; |
1457 | case S_IFDIR: | |
d8c76e6f | 1458 | inc_nlink(inode); |
1da177e4 LT |
1459 | /* Some things misbehave if size == 0 on a directory */ |
1460 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1461 | inode->i_op = &shmem_dir_inode_operations; | |
1462 | inode->i_fop = &simple_dir_operations; | |
1463 | break; | |
1464 | case S_IFLNK: | |
1465 | /* | |
1466 | * Must not load anything in the rbtree, | |
1467 | * mpol_free_shared_policy will not be called. | |
1468 | */ | |
7339ff83 RH |
1469 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1470 | NULL); | |
1da177e4 LT |
1471 | break; |
1472 | } | |
0edd73b3 | 1473 | } else if (sbinfo->max_inodes) { |
1da177e4 LT |
1474 | spin_lock(&sbinfo->stat_lock); |
1475 | sbinfo->free_inodes++; | |
1476 | spin_unlock(&sbinfo->stat_lock); | |
1477 | } | |
1478 | return inode; | |
1479 | } | |
1480 | ||
1481 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1482 | static const struct inode_operations shmem_symlink_inode_operations; |
1483 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1484 | |
1485 | /* | |
1486 | * Normally tmpfs makes no use of shmem_prepare_write, but it | |
1487 | * lets a tmpfs file be used read-write below the loop driver. | |
1488 | */ | |
1489 | static int | |
1490 | shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) | |
1491 | { | |
1492 | struct inode *inode = page->mapping->host; | |
1493 | return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL); | |
1494 | } | |
1495 | ||
1496 | static ssize_t | |
1497 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
1498 | { | |
d3ac7f89 | 1499 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1500 | loff_t pos; |
1501 | unsigned long written; | |
1502 | ssize_t err; | |
1503 | ||
1504 | if ((ssize_t) count < 0) | |
1505 | return -EINVAL; | |
1506 | ||
1507 | if (!access_ok(VERIFY_READ, buf, count)) | |
1508 | return -EFAULT; | |
1509 | ||
1b1dcc1b | 1510 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1511 | |
1512 | pos = *ppos; | |
1513 | written = 0; | |
1514 | ||
1515 | err = generic_write_checks(file, &pos, &count, 0); | |
1516 | if (err || !count) | |
1517 | goto out; | |
1518 | ||
d3ac7f89 | 1519 | err = remove_suid(file->f_path.dentry); |
1da177e4 LT |
1520 | if (err) |
1521 | goto out; | |
1522 | ||
1523 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
1524 | ||
1525 | do { | |
1526 | struct page *page = NULL; | |
1527 | unsigned long bytes, index, offset; | |
1528 | char *kaddr; | |
1529 | int left; | |
1530 | ||
1531 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ | |
1532 | index = pos >> PAGE_CACHE_SHIFT; | |
1533 | bytes = PAGE_CACHE_SIZE - offset; | |
1534 | if (bytes > count) | |
1535 | bytes = count; | |
1536 | ||
1537 | /* | |
1538 | * We don't hold page lock across copy from user - | |
1539 | * what would it guard against? - so no deadlock here. | |
1540 | * But it still may be a good idea to prefault below. | |
1541 | */ | |
1542 | ||
1543 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); | |
1544 | if (err) | |
1545 | break; | |
1546 | ||
1547 | left = bytes; | |
1548 | if (PageHighMem(page)) { | |
1549 | volatile unsigned char dummy; | |
1550 | __get_user(dummy, buf); | |
1551 | __get_user(dummy, buf + bytes - 1); | |
1552 | ||
1553 | kaddr = kmap_atomic(page, KM_USER0); | |
1554 | left = __copy_from_user_inatomic(kaddr + offset, | |
1555 | buf, bytes); | |
1556 | kunmap_atomic(kaddr, KM_USER0); | |
1557 | } | |
1558 | if (left) { | |
1559 | kaddr = kmap(page); | |
1560 | left = __copy_from_user(kaddr + offset, buf, bytes); | |
1561 | kunmap(page); | |
1562 | } | |
1563 | ||
1564 | written += bytes; | |
1565 | count -= bytes; | |
1566 | pos += bytes; | |
1567 | buf += bytes; | |
1568 | if (pos > inode->i_size) | |
1569 | i_size_write(inode, pos); | |
1570 | ||
1571 | flush_dcache_page(page); | |
1572 | set_page_dirty(page); | |
1573 | mark_page_accessed(page); | |
1574 | page_cache_release(page); | |
1575 | ||
1576 | if (left) { | |
1577 | pos -= left; | |
1578 | written -= left; | |
1579 | err = -EFAULT; | |
1580 | break; | |
1581 | } | |
1582 | ||
1583 | /* | |
1584 | * Our dirty pages are not counted in nr_dirty, | |
1585 | * and we do not attempt to balance dirty pages. | |
1586 | */ | |
1587 | ||
1588 | cond_resched(); | |
1589 | } while (count); | |
1590 | ||
1591 | *ppos = pos; | |
1592 | if (written) | |
1593 | err = written; | |
1594 | out: | |
1b1dcc1b | 1595 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1596 | return err; |
1597 | } | |
1598 | ||
1599 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) | |
1600 | { | |
d3ac7f89 | 1601 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1602 | struct address_space *mapping = inode->i_mapping; |
1603 | unsigned long index, offset; | |
1604 | ||
1605 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1606 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1607 | ||
1608 | for (;;) { | |
1609 | struct page *page = NULL; | |
1610 | unsigned long end_index, nr, ret; | |
1611 | loff_t i_size = i_size_read(inode); | |
1612 | ||
1613 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1614 | if (index > end_index) | |
1615 | break; | |
1616 | if (index == end_index) { | |
1617 | nr = i_size & ~PAGE_CACHE_MASK; | |
1618 | if (nr <= offset) | |
1619 | break; | |
1620 | } | |
1621 | ||
1622 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); | |
1623 | if (desc->error) { | |
1624 | if (desc->error == -EINVAL) | |
1625 | desc->error = 0; | |
1626 | break; | |
1627 | } | |
1628 | ||
1629 | /* | |
1630 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1631 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1632 | */ |
1633 | nr = PAGE_CACHE_SIZE; | |
1634 | i_size = i_size_read(inode); | |
1635 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1636 | if (index == end_index) { | |
1637 | nr = i_size & ~PAGE_CACHE_MASK; | |
1638 | if (nr <= offset) { | |
1639 | if (page) | |
1640 | page_cache_release(page); | |
1641 | break; | |
1642 | } | |
1643 | } | |
1644 | nr -= offset; | |
1645 | ||
1646 | if (page) { | |
1647 | /* | |
1648 | * If users can be writing to this page using arbitrary | |
1649 | * virtual addresses, take care about potential aliasing | |
1650 | * before reading the page on the kernel side. | |
1651 | */ | |
1652 | if (mapping_writably_mapped(mapping)) | |
1653 | flush_dcache_page(page); | |
1654 | /* | |
1655 | * Mark the page accessed if we read the beginning. | |
1656 | */ | |
1657 | if (!offset) | |
1658 | mark_page_accessed(page); | |
b5810039 | 1659 | } else { |
1da177e4 | 1660 | page = ZERO_PAGE(0); |
b5810039 NP |
1661 | page_cache_get(page); |
1662 | } | |
1da177e4 LT |
1663 | |
1664 | /* | |
1665 | * Ok, we have the page, and it's up-to-date, so | |
1666 | * now we can copy it to user space... | |
1667 | * | |
1668 | * The actor routine returns how many bytes were actually used.. | |
1669 | * NOTE! This may not be the same as how much of a user buffer | |
1670 | * we filled up (we may be padding etc), so we can only update | |
1671 | * "pos" here (the actor routine has to update the user buffer | |
1672 | * pointers and the remaining count). | |
1673 | */ | |
1674 | ret = actor(desc, page, offset, nr); | |
1675 | offset += ret; | |
1676 | index += offset >> PAGE_CACHE_SHIFT; | |
1677 | offset &= ~PAGE_CACHE_MASK; | |
1678 | ||
1679 | page_cache_release(page); | |
1680 | if (ret != nr || !desc->count) | |
1681 | break; | |
1682 | ||
1683 | cond_resched(); | |
1684 | } | |
1685 | ||
1686 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1687 | file_accessed(filp); | |
1688 | } | |
1689 | ||
1690 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1691 | { | |
1692 | read_descriptor_t desc; | |
1693 | ||
1694 | if ((ssize_t) count < 0) | |
1695 | return -EINVAL; | |
1696 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1697 | return -EFAULT; | |
1698 | if (!count) | |
1699 | return 0; | |
1700 | ||
1701 | desc.written = 0; | |
1702 | desc.count = count; | |
1703 | desc.arg.buf = buf; | |
1704 | desc.error = 0; | |
1705 | ||
1706 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1707 | if (desc.written) | |
1708 | return desc.written; | |
1709 | return desc.error; | |
1710 | } | |
1711 | ||
1712 | static ssize_t shmem_file_sendfile(struct file *in_file, loff_t *ppos, | |
1713 | size_t count, read_actor_t actor, void *target) | |
1714 | { | |
1715 | read_descriptor_t desc; | |
1716 | ||
1717 | if (!count) | |
1718 | return 0; | |
1719 | ||
1720 | desc.written = 0; | |
1721 | desc.count = count; | |
1722 | desc.arg.data = target; | |
1723 | desc.error = 0; | |
1724 | ||
1725 | do_shmem_file_read(in_file, ppos, &desc, actor); | |
1726 | if (desc.written) | |
1727 | return desc.written; | |
1728 | return desc.error; | |
1729 | } | |
1730 | ||
726c3342 | 1731 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1732 | { |
726c3342 | 1733 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1734 | |
1735 | buf->f_type = TMPFS_MAGIC; | |
1736 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1737 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1738 | spin_lock(&sbinfo->stat_lock); |
1739 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1740 | buf->f_blocks = sbinfo->max_blocks; |
1741 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1742 | } |
1743 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1744 | buf->f_files = sbinfo->max_inodes; |
1745 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1746 | } |
1747 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1748 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1749 | return 0; |
1750 | } | |
1751 | ||
1752 | /* | |
1753 | * File creation. Allocate an inode, and we're done.. | |
1754 | */ | |
1755 | static int | |
1756 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1757 | { | |
1758 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1759 | int error = -ENOSPC; | |
1760 | ||
1761 | if (inode) { | |
570bc1c2 SS |
1762 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1763 | NULL); | |
1764 | if (error) { | |
1765 | if (error != -EOPNOTSUPP) { | |
1766 | iput(inode); | |
1767 | return error; | |
1768 | } | |
39f0247d AG |
1769 | } |
1770 | error = shmem_acl_init(inode, dir); | |
1771 | if (error) { | |
1772 | iput(inode); | |
1773 | return error; | |
570bc1c2 | 1774 | } |
1da177e4 LT |
1775 | if (dir->i_mode & S_ISGID) { |
1776 | inode->i_gid = dir->i_gid; | |
1777 | if (S_ISDIR(mode)) | |
1778 | inode->i_mode |= S_ISGID; | |
1779 | } | |
1780 | dir->i_size += BOGO_DIRENT_SIZE; | |
1781 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1782 | d_instantiate(dentry, inode); | |
1783 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1784 | } |
1785 | return error; | |
1786 | } | |
1787 | ||
1788 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1789 | { | |
1790 | int error; | |
1791 | ||
1792 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1793 | return error; | |
d8c76e6f | 1794 | inc_nlink(dir); |
1da177e4 LT |
1795 | return 0; |
1796 | } | |
1797 | ||
1798 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1799 | struct nameidata *nd) | |
1800 | { | |
1801 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1802 | } | |
1803 | ||
1804 | /* | |
1805 | * Link a file.. | |
1806 | */ | |
1807 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1808 | { | |
1809 | struct inode *inode = old_dentry->d_inode; | |
1810 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
1811 | ||
1812 | /* | |
1813 | * No ordinary (disk based) filesystem counts links as inodes; | |
1814 | * but each new link needs a new dentry, pinning lowmem, and | |
1815 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1816 | */ | |
0edd73b3 | 1817 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1818 | spin_lock(&sbinfo->stat_lock); |
1819 | if (!sbinfo->free_inodes) { | |
1820 | spin_unlock(&sbinfo->stat_lock); | |
1821 | return -ENOSPC; | |
1822 | } | |
1823 | sbinfo->free_inodes--; | |
1824 | spin_unlock(&sbinfo->stat_lock); | |
1825 | } | |
1826 | ||
1827 | dir->i_size += BOGO_DIRENT_SIZE; | |
1828 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1829 | inc_nlink(inode); |
1da177e4 LT |
1830 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1831 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1832 | d_instantiate(dentry, inode); | |
1833 | return 0; | |
1834 | } | |
1835 | ||
1836 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1837 | { | |
1838 | struct inode *inode = dentry->d_inode; | |
1839 | ||
1840 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { | |
1841 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1842 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1843 | spin_lock(&sbinfo->stat_lock); |
1844 | sbinfo->free_inodes++; | |
1845 | spin_unlock(&sbinfo->stat_lock); | |
1846 | } | |
1847 | } | |
1848 | ||
1849 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1850 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1851 | drop_nlink(inode); |
1da177e4 LT |
1852 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1853 | return 0; | |
1854 | } | |
1855 | ||
1856 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1857 | { | |
1858 | if (!simple_empty(dentry)) | |
1859 | return -ENOTEMPTY; | |
1860 | ||
9a53c3a7 DH |
1861 | drop_nlink(dentry->d_inode); |
1862 | drop_nlink(dir); | |
1da177e4 LT |
1863 | return shmem_unlink(dir, dentry); |
1864 | } | |
1865 | ||
1866 | /* | |
1867 | * The VFS layer already does all the dentry stuff for rename, | |
1868 | * we just have to decrement the usage count for the target if | |
1869 | * it exists so that the VFS layer correctly free's it when it | |
1870 | * gets overwritten. | |
1871 | */ | |
1872 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1873 | { | |
1874 | struct inode *inode = old_dentry->d_inode; | |
1875 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1876 | ||
1877 | if (!simple_empty(new_dentry)) | |
1878 | return -ENOTEMPTY; | |
1879 | ||
1880 | if (new_dentry->d_inode) { | |
1881 | (void) shmem_unlink(new_dir, new_dentry); | |
1882 | if (they_are_dirs) | |
9a53c3a7 | 1883 | drop_nlink(old_dir); |
1da177e4 | 1884 | } else if (they_are_dirs) { |
9a53c3a7 | 1885 | drop_nlink(old_dir); |
d8c76e6f | 1886 | inc_nlink(new_dir); |
1da177e4 LT |
1887 | } |
1888 | ||
1889 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1890 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1891 | old_dir->i_ctime = old_dir->i_mtime = | |
1892 | new_dir->i_ctime = new_dir->i_mtime = | |
1893 | inode->i_ctime = CURRENT_TIME; | |
1894 | return 0; | |
1895 | } | |
1896 | ||
1897 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1898 | { | |
1899 | int error; | |
1900 | int len; | |
1901 | struct inode *inode; | |
1902 | struct page *page = NULL; | |
1903 | char *kaddr; | |
1904 | struct shmem_inode_info *info; | |
1905 | ||
1906 | len = strlen(symname) + 1; | |
1907 | if (len > PAGE_CACHE_SIZE) | |
1908 | return -ENAMETOOLONG; | |
1909 | ||
1910 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1911 | if (!inode) | |
1912 | return -ENOSPC; | |
1913 | ||
570bc1c2 SS |
1914 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1915 | NULL); | |
1916 | if (error) { | |
1917 | if (error != -EOPNOTSUPP) { | |
1918 | iput(inode); | |
1919 | return error; | |
1920 | } | |
1921 | error = 0; | |
1922 | } | |
1923 | ||
1da177e4 LT |
1924 | info = SHMEM_I(inode); |
1925 | inode->i_size = len-1; | |
1926 | if (len <= (char *)inode - (char *)info) { | |
1927 | /* do it inline */ | |
1928 | memcpy(info, symname, len); | |
1929 | inode->i_op = &shmem_symlink_inline_operations; | |
1930 | } else { | |
1931 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1932 | if (error) { | |
1933 | iput(inode); | |
1934 | return error; | |
1935 | } | |
1936 | inode->i_op = &shmem_symlink_inode_operations; | |
1937 | kaddr = kmap_atomic(page, KM_USER0); | |
1938 | memcpy(kaddr, symname, len); | |
1939 | kunmap_atomic(kaddr, KM_USER0); | |
1940 | set_page_dirty(page); | |
1941 | page_cache_release(page); | |
1942 | } | |
1943 | if (dir->i_mode & S_ISGID) | |
1944 | inode->i_gid = dir->i_gid; | |
1945 | dir->i_size += BOGO_DIRENT_SIZE; | |
1946 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1947 | d_instantiate(dentry, inode); | |
1948 | dget(dentry); | |
1949 | return 0; | |
1950 | } | |
1951 | ||
cc314eef | 1952 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1953 | { |
1954 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1955 | return NULL; |
1da177e4 LT |
1956 | } |
1957 | ||
cc314eef | 1958 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1959 | { |
1960 | struct page *page = NULL; | |
1961 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1962 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
cc314eef | 1963 | return page; |
1da177e4 LT |
1964 | } |
1965 | ||
cc314eef | 1966 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1967 | { |
1968 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1969 | struct page *page = cookie; |
1da177e4 LT |
1970 | kunmap(page); |
1971 | mark_page_accessed(page); | |
1972 | page_cache_release(page); | |
1da177e4 LT |
1973 | } |
1974 | } | |
1975 | ||
92e1d5be | 1976 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
1977 | .readlink = generic_readlink, |
1978 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1979 | }; |
1980 | ||
92e1d5be | 1981 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
1982 | .truncate = shmem_truncate, |
1983 | .readlink = generic_readlink, | |
1984 | .follow_link = shmem_follow_link, | |
1985 | .put_link = shmem_put_link, | |
1da177e4 LT |
1986 | }; |
1987 | ||
39f0247d AG |
1988 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1989 | /** | |
1990 | * Superblocks without xattr inode operations will get security.* xattr | |
1991 | * support from the VFS "for free". As soon as we have any other xattrs | |
1992 | * like ACLs, we also need to implement the security.* handlers at | |
1993 | * filesystem level, though. | |
1994 | */ | |
1995 | ||
1996 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
1997 | size_t list_len, const char *name, | |
1998 | size_t name_len) | |
1999 | { | |
2000 | return security_inode_listsecurity(inode, list, list_len); | |
2001 | } | |
2002 | ||
2003 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
2004 | void *buffer, size_t size) | |
2005 | { | |
2006 | if (strcmp(name, "") == 0) | |
2007 | return -EINVAL; | |
2008 | return security_inode_getsecurity(inode, name, buffer, size, | |
2009 | -EOPNOTSUPP); | |
2010 | } | |
2011 | ||
2012 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
2013 | const void *value, size_t size, int flags) | |
2014 | { | |
2015 | if (strcmp(name, "") == 0) | |
2016 | return -EINVAL; | |
2017 | return security_inode_setsecurity(inode, name, value, size, flags); | |
2018 | } | |
2019 | ||
1f370a23 | 2020 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
2021 | .prefix = XATTR_SECURITY_PREFIX, |
2022 | .list = shmem_xattr_security_list, | |
2023 | .get = shmem_xattr_security_get, | |
2024 | .set = shmem_xattr_security_set, | |
2025 | }; | |
2026 | ||
2027 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
2028 | &shmem_xattr_acl_access_handler, | |
2029 | &shmem_xattr_acl_default_handler, | |
2030 | &shmem_xattr_security_handler, | |
2031 | NULL | |
2032 | }; | |
2033 | #endif | |
2034 | ||
91828a40 DG |
2035 | static struct dentry *shmem_get_parent(struct dentry *child) |
2036 | { | |
2037 | return ERR_PTR(-ESTALE); | |
2038 | } | |
2039 | ||
2040 | static int shmem_match(struct inode *ino, void *vfh) | |
2041 | { | |
2042 | __u32 *fh = vfh; | |
2043 | __u64 inum = fh[2]; | |
2044 | inum = (inum << 32) | fh[1]; | |
2045 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2046 | } | |
2047 | ||
2048 | static struct dentry *shmem_get_dentry(struct super_block *sb, void *vfh) | |
2049 | { | |
2050 | struct dentry *de = NULL; | |
2051 | struct inode *inode; | |
2052 | __u32 *fh = vfh; | |
2053 | __u64 inum = fh[2]; | |
2054 | inum = (inum << 32) | fh[1]; | |
2055 | ||
2056 | inode = ilookup5(sb, (unsigned long)(inum+fh[0]), shmem_match, vfh); | |
2057 | if (inode) { | |
2058 | de = d_find_alias(inode); | |
2059 | iput(inode); | |
2060 | } | |
2061 | ||
2062 | return de? de: ERR_PTR(-ESTALE); | |
2063 | } | |
2064 | ||
2065 | static struct dentry *shmem_decode_fh(struct super_block *sb, __u32 *fh, | |
2066 | int len, int type, | |
2067 | int (*acceptable)(void *context, struct dentry *de), | |
2068 | void *context) | |
2069 | { | |
2070 | if (len < 3) | |
2071 | return ERR_PTR(-ESTALE); | |
2072 | ||
2073 | return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, | |
2074 | context); | |
2075 | } | |
2076 | ||
2077 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2078 | int connectable) | |
2079 | { | |
2080 | struct inode *inode = dentry->d_inode; | |
2081 | ||
2082 | if (*len < 3) | |
2083 | return 255; | |
2084 | ||
2085 | if (hlist_unhashed(&inode->i_hash)) { | |
2086 | /* Unfortunately insert_inode_hash is not idempotent, | |
2087 | * so as we hash inodes here rather than at creation | |
2088 | * time, we need a lock to ensure we only try | |
2089 | * to do it once | |
2090 | */ | |
2091 | static DEFINE_SPINLOCK(lock); | |
2092 | spin_lock(&lock); | |
2093 | if (hlist_unhashed(&inode->i_hash)) | |
2094 | __insert_inode_hash(inode, | |
2095 | inode->i_ino + inode->i_generation); | |
2096 | spin_unlock(&lock); | |
2097 | } | |
2098 | ||
2099 | fh[0] = inode->i_generation; | |
2100 | fh[1] = inode->i_ino; | |
2101 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2102 | ||
2103 | *len = 3; | |
2104 | return 1; | |
2105 | } | |
2106 | ||
2107 | static struct export_operations shmem_export_ops = { | |
2108 | .get_parent = shmem_get_parent, | |
2109 | .get_dentry = shmem_get_dentry, | |
2110 | .encode_fh = shmem_encode_fh, | |
2111 | .decode_fh = shmem_decode_fh, | |
2112 | }; | |
2113 | ||
7339ff83 RH |
2114 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
2115 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, | |
2116 | int *policy, nodemask_t *policy_nodes) | |
1da177e4 LT |
2117 | { |
2118 | char *this_char, *value, *rest; | |
2119 | ||
b00dc3ad HD |
2120 | while (options != NULL) { |
2121 | this_char = options; | |
2122 | for (;;) { | |
2123 | /* | |
2124 | * NUL-terminate this option: unfortunately, | |
2125 | * mount options form a comma-separated list, | |
2126 | * but mpol's nodelist may also contain commas. | |
2127 | */ | |
2128 | options = strchr(options, ','); | |
2129 | if (options == NULL) | |
2130 | break; | |
2131 | options++; | |
2132 | if (!isdigit(*options)) { | |
2133 | options[-1] = '\0'; | |
2134 | break; | |
2135 | } | |
2136 | } | |
1da177e4 LT |
2137 | if (!*this_char) |
2138 | continue; | |
2139 | if ((value = strchr(this_char,'=')) != NULL) { | |
2140 | *value++ = 0; | |
2141 | } else { | |
2142 | printk(KERN_ERR | |
2143 | "tmpfs: No value for mount option '%s'\n", | |
2144 | this_char); | |
2145 | return 1; | |
2146 | } | |
2147 | ||
2148 | if (!strcmp(this_char,"size")) { | |
2149 | unsigned long long size; | |
2150 | size = memparse(value,&rest); | |
2151 | if (*rest == '%') { | |
2152 | size <<= PAGE_SHIFT; | |
2153 | size *= totalram_pages; | |
2154 | do_div(size, 100); | |
2155 | rest++; | |
2156 | } | |
2157 | if (*rest) | |
2158 | goto bad_val; | |
2159 | *blocks = size >> PAGE_CACHE_SHIFT; | |
2160 | } else if (!strcmp(this_char,"nr_blocks")) { | |
2161 | *blocks = memparse(value,&rest); | |
2162 | if (*rest) | |
2163 | goto bad_val; | |
2164 | } else if (!strcmp(this_char,"nr_inodes")) { | |
2165 | *inodes = memparse(value,&rest); | |
2166 | if (*rest) | |
2167 | goto bad_val; | |
2168 | } else if (!strcmp(this_char,"mode")) { | |
2169 | if (!mode) | |
2170 | continue; | |
2171 | *mode = simple_strtoul(value,&rest,8); | |
2172 | if (*rest) | |
2173 | goto bad_val; | |
2174 | } else if (!strcmp(this_char,"uid")) { | |
2175 | if (!uid) | |
2176 | continue; | |
2177 | *uid = simple_strtoul(value,&rest,0); | |
2178 | if (*rest) | |
2179 | goto bad_val; | |
2180 | } else if (!strcmp(this_char,"gid")) { | |
2181 | if (!gid) | |
2182 | continue; | |
2183 | *gid = simple_strtoul(value,&rest,0); | |
2184 | if (*rest) | |
2185 | goto bad_val; | |
7339ff83 | 2186 | } else if (!strcmp(this_char,"mpol")) { |
b00dc3ad | 2187 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
7339ff83 | 2188 | goto bad_val; |
1da177e4 LT |
2189 | } else { |
2190 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2191 | this_char); | |
2192 | return 1; | |
2193 | } | |
2194 | } | |
2195 | return 0; | |
2196 | ||
2197 | bad_val: | |
2198 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2199 | value, this_char); | |
2200 | return 1; | |
2201 | ||
2202 | } | |
2203 | ||
2204 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2205 | { | |
2206 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
2207 | unsigned long max_blocks = sbinfo->max_blocks; |
2208 | unsigned long max_inodes = sbinfo->max_inodes; | |
7339ff83 RH |
2209 | int policy = sbinfo->policy; |
2210 | nodemask_t policy_nodes = sbinfo->policy_nodes; | |
0edd73b3 HD |
2211 | unsigned long blocks; |
2212 | unsigned long inodes; | |
2213 | int error = -EINVAL; | |
2214 | ||
7339ff83 RH |
2215 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
2216 | &max_inodes, &policy, &policy_nodes)) | |
0edd73b3 | 2217 | return error; |
1da177e4 | 2218 | |
0edd73b3 HD |
2219 | spin_lock(&sbinfo->stat_lock); |
2220 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2221 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
2222 | if (max_blocks < blocks) | |
2223 | goto out; | |
2224 | if (max_inodes < inodes) | |
2225 | goto out; | |
2226 | /* | |
2227 | * Those tests also disallow limited->unlimited while any are in | |
2228 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2229 | * but we must separately disallow unlimited->limited, because | |
2230 | * in that case we have no record of how much is already in use. | |
2231 | */ | |
2232 | if (max_blocks && !sbinfo->max_blocks) | |
2233 | goto out; | |
2234 | if (max_inodes && !sbinfo->max_inodes) | |
2235 | goto out; | |
2236 | ||
2237 | error = 0; | |
2238 | sbinfo->max_blocks = max_blocks; | |
2239 | sbinfo->free_blocks = max_blocks - blocks; | |
2240 | sbinfo->max_inodes = max_inodes; | |
2241 | sbinfo->free_inodes = max_inodes - inodes; | |
7339ff83 RH |
2242 | sbinfo->policy = policy; |
2243 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2244 | out: |
2245 | spin_unlock(&sbinfo->stat_lock); | |
2246 | return error; | |
1da177e4 LT |
2247 | } |
2248 | #endif | |
2249 | ||
2250 | static void shmem_put_super(struct super_block *sb) | |
2251 | { | |
2252 | kfree(sb->s_fs_info); | |
2253 | sb->s_fs_info = NULL; | |
2254 | } | |
2255 | ||
1da177e4 LT |
2256 | static int shmem_fill_super(struct super_block *sb, |
2257 | void *data, int silent) | |
2258 | { | |
2259 | struct inode *inode; | |
2260 | struct dentry *root; | |
2261 | int mode = S_IRWXUGO | S_ISVTX; | |
2262 | uid_t uid = current->fsuid; | |
2263 | gid_t gid = current->fsgid; | |
2264 | int err = -ENOMEM; | |
0edd73b3 | 2265 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
2266 | unsigned long blocks = 0; |
2267 | unsigned long inodes = 0; | |
7339ff83 RH |
2268 | int policy = MPOL_DEFAULT; |
2269 | nodemask_t policy_nodes = node_online_map; | |
1da177e4 | 2270 | |
0edd73b3 | 2271 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2272 | /* |
2273 | * Per default we only allow half of the physical ram per | |
2274 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2275 | * but the internal instance is left unlimited. | |
2276 | */ | |
2277 | if (!(sb->s_flags & MS_NOUSER)) { | |
2278 | blocks = totalram_pages / 2; | |
2279 | inodes = totalram_pages - totalhigh_pages; | |
2280 | if (inodes > blocks) | |
2281 | inodes = blocks; | |
7339ff83 RH |
2282 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
2283 | &inodes, &policy, &policy_nodes)) | |
1da177e4 LT |
2284 | return -EINVAL; |
2285 | } | |
91828a40 | 2286 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2287 | #else |
2288 | sb->s_flags |= MS_NOUSER; | |
2289 | #endif | |
2290 | ||
0edd73b3 HD |
2291 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
2292 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2293 | L1_CACHE_BYTES), GFP_KERNEL); | |
2294 | if (!sbinfo) | |
2295 | return -ENOMEM; | |
2296 | ||
2297 | spin_lock_init(&sbinfo->stat_lock); | |
2298 | sbinfo->max_blocks = blocks; | |
2299 | sbinfo->free_blocks = blocks; | |
2300 | sbinfo->max_inodes = inodes; | |
2301 | sbinfo->free_inodes = inodes; | |
7339ff83 RH |
2302 | sbinfo->policy = policy; |
2303 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2304 | |
2305 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
2306 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2307 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2308 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2309 | sb->s_magic = TMPFS_MAGIC; | |
2310 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2311 | sb->s_time_gran = 1; |
39f0247d AG |
2312 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2313 | sb->s_xattr = shmem_xattr_handlers; | |
2314 | sb->s_flags |= MS_POSIXACL; | |
2315 | #endif | |
0edd73b3 | 2316 | |
1da177e4 LT |
2317 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2318 | if (!inode) | |
2319 | goto failed; | |
2320 | inode->i_uid = uid; | |
2321 | inode->i_gid = gid; | |
2322 | root = d_alloc_root(inode); | |
2323 | if (!root) | |
2324 | goto failed_iput; | |
2325 | sb->s_root = root; | |
2326 | return 0; | |
2327 | ||
2328 | failed_iput: | |
2329 | iput(inode); | |
2330 | failed: | |
2331 | shmem_put_super(sb); | |
2332 | return err; | |
2333 | } | |
2334 | ||
fcc234f8 | 2335 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2336 | |
2337 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2338 | { | |
2339 | struct shmem_inode_info *p; | |
e94b1766 | 2340 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2341 | if (!p) |
2342 | return NULL; | |
2343 | return &p->vfs_inode; | |
2344 | } | |
2345 | ||
2346 | static void shmem_destroy_inode(struct inode *inode) | |
2347 | { | |
2348 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2349 | /* only struct inode is valid if it's an inline symlink */ | |
2350 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2351 | } | |
39f0247d | 2352 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2353 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2354 | } | |
2355 | ||
fcc234f8 PE |
2356 | static void init_once(void *foo, struct kmem_cache *cachep, |
2357 | unsigned long flags) | |
1da177e4 LT |
2358 | { |
2359 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2360 | ||
50953fe9 | 2361 | if (flags & SLAB_CTOR_CONSTRUCTOR) { |
1da177e4 | 2362 | inode_init_once(&p->vfs_inode); |
39f0247d AG |
2363 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2364 | p->i_acl = NULL; | |
2365 | p->i_default_acl = NULL; | |
2366 | #endif | |
1da177e4 LT |
2367 | } |
2368 | } | |
2369 | ||
2370 | static int init_inodecache(void) | |
2371 | { | |
2372 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2373 | sizeof(struct shmem_inode_info), | |
2374 | 0, 0, init_once, NULL); | |
2375 | if (shmem_inode_cachep == NULL) | |
2376 | return -ENOMEM; | |
2377 | return 0; | |
2378 | } | |
2379 | ||
2380 | static void destroy_inodecache(void) | |
2381 | { | |
1a1d92c1 | 2382 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2383 | } |
2384 | ||
f5e54d6e | 2385 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2386 | .writepage = shmem_writepage, |
76719325 | 2387 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 LT |
2388 | #ifdef CONFIG_TMPFS |
2389 | .prepare_write = shmem_prepare_write, | |
2390 | .commit_write = simple_commit_write, | |
2391 | #endif | |
304dbdb7 | 2392 | .migratepage = migrate_page, |
1da177e4 LT |
2393 | }; |
2394 | ||
15ad7cdc | 2395 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2396 | .mmap = shmem_mmap, |
2397 | #ifdef CONFIG_TMPFS | |
2398 | .llseek = generic_file_llseek, | |
2399 | .read = shmem_file_read, | |
2400 | .write = shmem_file_write, | |
2401 | .fsync = simple_sync_file, | |
2402 | .sendfile = shmem_file_sendfile, | |
2403 | #endif | |
2404 | }; | |
2405 | ||
92e1d5be | 2406 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2407 | .truncate = shmem_truncate, |
2408 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2409 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2410 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2411 | .setxattr = generic_setxattr, | |
2412 | .getxattr = generic_getxattr, | |
2413 | .listxattr = generic_listxattr, | |
2414 | .removexattr = generic_removexattr, | |
2415 | .permission = shmem_permission, | |
2416 | #endif | |
2417 | ||
1da177e4 LT |
2418 | }; |
2419 | ||
92e1d5be | 2420 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2421 | #ifdef CONFIG_TMPFS |
2422 | .create = shmem_create, | |
2423 | .lookup = simple_lookup, | |
2424 | .link = shmem_link, | |
2425 | .unlink = shmem_unlink, | |
2426 | .symlink = shmem_symlink, | |
2427 | .mkdir = shmem_mkdir, | |
2428 | .rmdir = shmem_rmdir, | |
2429 | .mknod = shmem_mknod, | |
2430 | .rename = shmem_rename, | |
1da177e4 | 2431 | #endif |
39f0247d AG |
2432 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2433 | .setattr = shmem_notify_change, | |
2434 | .setxattr = generic_setxattr, | |
2435 | .getxattr = generic_getxattr, | |
2436 | .listxattr = generic_listxattr, | |
2437 | .removexattr = generic_removexattr, | |
2438 | .permission = shmem_permission, | |
2439 | #endif | |
2440 | }; | |
2441 | ||
92e1d5be | 2442 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2443 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2444 | .setattr = shmem_notify_change, | |
2445 | .setxattr = generic_setxattr, | |
2446 | .getxattr = generic_getxattr, | |
2447 | .listxattr = generic_listxattr, | |
2448 | .removexattr = generic_removexattr, | |
2449 | .permission = shmem_permission, | |
2450 | #endif | |
1da177e4 LT |
2451 | }; |
2452 | ||
759b9775 | 2453 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2454 | .alloc_inode = shmem_alloc_inode, |
2455 | .destroy_inode = shmem_destroy_inode, | |
2456 | #ifdef CONFIG_TMPFS | |
2457 | .statfs = shmem_statfs, | |
2458 | .remount_fs = shmem_remount_fs, | |
2459 | #endif | |
2460 | .delete_inode = shmem_delete_inode, | |
2461 | .drop_inode = generic_delete_inode, | |
2462 | .put_super = shmem_put_super, | |
2463 | }; | |
2464 | ||
2465 | static struct vm_operations_struct shmem_vm_ops = { | |
2466 | .nopage = shmem_nopage, | |
2467 | .populate = shmem_populate, | |
2468 | #ifdef CONFIG_NUMA | |
2469 | .set_policy = shmem_set_policy, | |
2470 | .get_policy = shmem_get_policy, | |
2471 | #endif | |
2472 | }; | |
2473 | ||
2474 | ||
454e2398 DH |
2475 | static int shmem_get_sb(struct file_system_type *fs_type, |
2476 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2477 | { |
454e2398 | 2478 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2479 | } |
2480 | ||
2481 | static struct file_system_type tmpfs_fs_type = { | |
2482 | .owner = THIS_MODULE, | |
2483 | .name = "tmpfs", | |
2484 | .get_sb = shmem_get_sb, | |
2485 | .kill_sb = kill_litter_super, | |
2486 | }; | |
2487 | static struct vfsmount *shm_mnt; | |
2488 | ||
2489 | static int __init init_tmpfs(void) | |
2490 | { | |
2491 | int error; | |
2492 | ||
2493 | error = init_inodecache(); | |
2494 | if (error) | |
2495 | goto out3; | |
2496 | ||
2497 | error = register_filesystem(&tmpfs_fs_type); | |
2498 | if (error) { | |
2499 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2500 | goto out2; | |
2501 | } | |
95dc112a | 2502 | |
1f5ce9e9 | 2503 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2504 | tmpfs_fs_type.name, NULL); |
2505 | if (IS_ERR(shm_mnt)) { | |
2506 | error = PTR_ERR(shm_mnt); | |
2507 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2508 | goto out1; | |
2509 | } | |
2510 | return 0; | |
2511 | ||
2512 | out1: | |
2513 | unregister_filesystem(&tmpfs_fs_type); | |
2514 | out2: | |
2515 | destroy_inodecache(); | |
2516 | out3: | |
2517 | shm_mnt = ERR_PTR(error); | |
2518 | return error; | |
2519 | } | |
2520 | module_init(init_tmpfs) | |
2521 | ||
2522 | /* | |
2523 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2524 | * | |
2525 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2526 | * @size: size to be set for the file | |
2527 | * | |
2528 | */ | |
2529 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2530 | { | |
2531 | int error; | |
2532 | struct file *file; | |
2533 | struct inode *inode; | |
2534 | struct dentry *dentry, *root; | |
2535 | struct qstr this; | |
2536 | ||
2537 | if (IS_ERR(shm_mnt)) | |
2538 | return (void *)shm_mnt; | |
2539 | ||
2540 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2541 | return ERR_PTR(-EINVAL); | |
2542 | ||
2543 | if (shmem_acct_size(flags, size)) | |
2544 | return ERR_PTR(-ENOMEM); | |
2545 | ||
2546 | error = -ENOMEM; | |
2547 | this.name = name; | |
2548 | this.len = strlen(name); | |
2549 | this.hash = 0; /* will go */ | |
2550 | root = shm_mnt->mnt_root; | |
2551 | dentry = d_alloc(root, &this); | |
2552 | if (!dentry) | |
2553 | goto put_memory; | |
2554 | ||
2555 | error = -ENFILE; | |
2556 | file = get_empty_filp(); | |
2557 | if (!file) | |
2558 | goto put_dentry; | |
2559 | ||
2560 | error = -ENOSPC; | |
2561 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2562 | if (!inode) | |
2563 | goto close_file; | |
2564 | ||
2565 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2566 | d_instantiate(dentry, inode); | |
2567 | inode->i_size = size; | |
2568 | inode->i_nlink = 0; /* It is unlinked */ | |
d3ac7f89 JJS |
2569 | file->f_path.mnt = mntget(shm_mnt); |
2570 | file->f_path.dentry = dentry; | |
1da177e4 LT |
2571 | file->f_mapping = inode->i_mapping; |
2572 | file->f_op = &shmem_file_operations; | |
2573 | file->f_mode = FMODE_WRITE | FMODE_READ; | |
2574 | return file; | |
2575 | ||
2576 | close_file: | |
2577 | put_filp(file); | |
2578 | put_dentry: | |
2579 | dput(dentry); | |
2580 | put_memory: | |
2581 | shmem_unacct_size(flags, size); | |
2582 | return ERR_PTR(error); | |
2583 | } | |
2584 | ||
2585 | /* | |
2586 | * shmem_zero_setup - setup a shared anonymous mapping | |
2587 | * | |
2588 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2589 | */ | |
2590 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2591 | { | |
2592 | struct file *file; | |
2593 | loff_t size = vma->vm_end - vma->vm_start; | |
2594 | ||
2595 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2596 | if (IS_ERR(file)) | |
2597 | return PTR_ERR(file); | |
2598 | ||
2599 | if (vma->vm_file) | |
2600 | fput(vma->vm_file); | |
2601 | vma->vm_file = file; | |
2602 | vma->vm_ops = &shmem_vm_ops; | |
2603 | return 0; | |
2604 | } |