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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 | 29 | #include <linux/xattr.h> |
a5694255 | 30 | #include <linux/exportfs.h> |
39f0247d | 31 | #include <linux/generic_acl.h> |
1da177e4 LT |
32 | #include <linux/mm.h> |
33 | #include <linux/mman.h> | |
34 | #include <linux/file.h> | |
35 | #include <linux/swap.h> | |
36 | #include <linux/pagemap.h> | |
37 | #include <linux/string.h> | |
38 | #include <linux/slab.h> | |
39 | #include <linux/backing-dev.h> | |
40 | #include <linux/shmem_fs.h> | |
41 | #include <linux/mount.h> | |
42 | #include <linux/writeback.h> | |
43 | #include <linux/vfs.h> | |
44 | #include <linux/blkdev.h> | |
45 | #include <linux/security.h> | |
46 | #include <linux/swapops.h> | |
47 | #include <linux/mempolicy.h> | |
48 | #include <linux/namei.h> | |
b00dc3ad | 49 | #include <linux/ctype.h> |
304dbdb7 | 50 | #include <linux/migrate.h> |
c1f60a5a | 51 | #include <linux/highmem.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 { | |
1da177e4 LT |
81 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
82 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
83 | SGP_WRITE, /* may exceed i_size, may allocate page */ | |
84 | }; | |
85 | ||
86 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
87 | struct page **pagep, enum sgp_type sgp, int *type); | |
88 | ||
6daa0e28 | 89 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
90 | { |
91 | /* | |
92 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
93 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
94 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 | 95 | * |
e12ba74d | 96 | * Mobility flags are masked out as swap vectors cannot move |
1da177e4 | 97 | */ |
e12ba74d | 98 | return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO, |
769848c0 | 99 | PAGE_CACHE_SHIFT-PAGE_SHIFT); |
1da177e4 LT |
100 | } |
101 | ||
102 | static inline void shmem_dir_free(struct page *page) | |
103 | { | |
104 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
105 | } | |
106 | ||
107 | static struct page **shmem_dir_map(struct page *page) | |
108 | { | |
109 | return (struct page **)kmap_atomic(page, KM_USER0); | |
110 | } | |
111 | ||
112 | static inline void shmem_dir_unmap(struct page **dir) | |
113 | { | |
114 | kunmap_atomic(dir, KM_USER0); | |
115 | } | |
116 | ||
117 | static swp_entry_t *shmem_swp_map(struct page *page) | |
118 | { | |
119 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
120 | } | |
121 | ||
122 | static inline void shmem_swp_balance_unmap(void) | |
123 | { | |
124 | /* | |
125 | * When passing a pointer to an i_direct entry, to code which | |
126 | * also handles indirect entries and so will shmem_swp_unmap, | |
127 | * we must arrange for the preempt count to remain in balance. | |
128 | * What kmap_atomic of a lowmem page does depends on config | |
129 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
130 | */ | |
131 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
132 | } | |
133 | ||
134 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
135 | { | |
136 | kunmap_atomic(entry, KM_USER1); | |
137 | } | |
138 | ||
139 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
140 | { | |
141 | return sb->s_fs_info; | |
142 | } | |
143 | ||
144 | /* | |
145 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
146 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
147 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
148 | * consistent with the pre-accounting of private mappings ... | |
149 | */ | |
150 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
151 | { | |
152 | return (flags & VM_ACCOUNT)? | |
153 | security_vm_enough_memory(VM_ACCT(size)): 0; | |
154 | } | |
155 | ||
156 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
157 | { | |
158 | if (flags & VM_ACCOUNT) | |
159 | vm_unacct_memory(VM_ACCT(size)); | |
160 | } | |
161 | ||
162 | /* | |
163 | * ... whereas tmpfs objects are accounted incrementally as | |
164 | * pages are allocated, in order to allow huge sparse files. | |
165 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
166 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
167 | */ | |
168 | static inline int shmem_acct_block(unsigned long flags) | |
169 | { | |
170 | return (flags & VM_ACCOUNT)? | |
171 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); | |
172 | } | |
173 | ||
174 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
175 | { | |
176 | if (!(flags & VM_ACCOUNT)) | |
177 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); | |
178 | } | |
179 | ||
759b9775 | 180 | static const struct super_operations shmem_ops; |
f5e54d6e | 181 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 182 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
183 | static const struct inode_operations shmem_inode_operations; |
184 | static const struct inode_operations shmem_dir_inode_operations; | |
185 | static const struct inode_operations shmem_special_inode_operations; | |
1da177e4 LT |
186 | static struct vm_operations_struct shmem_vm_ops; |
187 | ||
6c231b7b | 188 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 LT |
189 | .ra_pages = 0, /* No readahead */ |
190 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
191 | .unplug_io_fn = default_unplug_io_fn, | |
192 | }; | |
193 | ||
194 | static LIST_HEAD(shmem_swaplist); | |
195 | static DEFINE_SPINLOCK(shmem_swaplist_lock); | |
196 | ||
197 | static void shmem_free_blocks(struct inode *inode, long pages) | |
198 | { | |
199 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 200 | if (sbinfo->max_blocks) { |
1da177e4 LT |
201 | spin_lock(&sbinfo->stat_lock); |
202 | sbinfo->free_blocks += pages; | |
203 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
204 | spin_unlock(&sbinfo->stat_lock); | |
205 | } | |
206 | } | |
207 | ||
5b04c689 PE |
208 | static int shmem_reserve_inode(struct super_block *sb) |
209 | { | |
210 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
211 | if (sbinfo->max_inodes) { | |
212 | spin_lock(&sbinfo->stat_lock); | |
213 | if (!sbinfo->free_inodes) { | |
214 | spin_unlock(&sbinfo->stat_lock); | |
215 | return -ENOSPC; | |
216 | } | |
217 | sbinfo->free_inodes--; | |
218 | spin_unlock(&sbinfo->stat_lock); | |
219 | } | |
220 | return 0; | |
221 | } | |
222 | ||
223 | static void shmem_free_inode(struct super_block *sb) | |
224 | { | |
225 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
226 | if (sbinfo->max_inodes) { | |
227 | spin_lock(&sbinfo->stat_lock); | |
228 | sbinfo->free_inodes++; | |
229 | spin_unlock(&sbinfo->stat_lock); | |
230 | } | |
231 | } | |
232 | ||
1da177e4 LT |
233 | /* |
234 | * shmem_recalc_inode - recalculate the size of an inode | |
235 | * | |
236 | * @inode: inode to recalc | |
237 | * | |
238 | * We have to calculate the free blocks since the mm can drop | |
239 | * undirtied hole pages behind our back. | |
240 | * | |
241 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
242 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
243 | * | |
244 | * It has to be called with the spinlock held. | |
245 | */ | |
246 | static void shmem_recalc_inode(struct inode *inode) | |
247 | { | |
248 | struct shmem_inode_info *info = SHMEM_I(inode); | |
249 | long freed; | |
250 | ||
251 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
252 | if (freed > 0) { | |
253 | info->alloced -= freed; | |
254 | shmem_unacct_blocks(info->flags, freed); | |
255 | shmem_free_blocks(inode, freed); | |
256 | } | |
257 | } | |
258 | ||
259 | /* | |
260 | * shmem_swp_entry - find the swap vector position in the info structure | |
261 | * | |
262 | * @info: info structure for the inode | |
263 | * @index: index of the page to find | |
264 | * @page: optional page to add to the structure. Has to be preset to | |
265 | * all zeros | |
266 | * | |
267 | * If there is no space allocated yet it will return NULL when | |
268 | * page is NULL, else it will use the page for the needed block, | |
269 | * setting it to NULL on return to indicate that it has been used. | |
270 | * | |
271 | * The swap vector is organized the following way: | |
272 | * | |
273 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
274 | * shmem_inode_info structure. So small files do not need an addional | |
275 | * allocation. | |
276 | * | |
277 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
278 | * i_indirect which points to a page which holds in the first half | |
279 | * doubly indirect blocks, in the second half triple indirect blocks: | |
280 | * | |
281 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
282 | * following layout (for SHMEM_NR_DIRECT == 16): | |
283 | * | |
284 | * i_indirect -> dir --> 16-19 | |
285 | * | +-> 20-23 | |
286 | * | | |
287 | * +-->dir2 --> 24-27 | |
288 | * | +-> 28-31 | |
289 | * | +-> 32-35 | |
290 | * | +-> 36-39 | |
291 | * | | |
292 | * +-->dir3 --> 40-43 | |
293 | * +-> 44-47 | |
294 | * +-> 48-51 | |
295 | * +-> 52-55 | |
296 | */ | |
297 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
298 | { | |
299 | unsigned long offset; | |
300 | struct page **dir; | |
301 | struct page *subdir; | |
302 | ||
303 | if (index < SHMEM_NR_DIRECT) { | |
304 | shmem_swp_balance_unmap(); | |
305 | return info->i_direct+index; | |
306 | } | |
307 | if (!info->i_indirect) { | |
308 | if (page) { | |
309 | info->i_indirect = *page; | |
310 | *page = NULL; | |
311 | } | |
312 | return NULL; /* need another page */ | |
313 | } | |
314 | ||
315 | index -= SHMEM_NR_DIRECT; | |
316 | offset = index % ENTRIES_PER_PAGE; | |
317 | index /= ENTRIES_PER_PAGE; | |
318 | dir = shmem_dir_map(info->i_indirect); | |
319 | ||
320 | if (index >= ENTRIES_PER_PAGE/2) { | |
321 | index -= ENTRIES_PER_PAGE/2; | |
322 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
323 | index %= ENTRIES_PER_PAGE; | |
324 | subdir = *dir; | |
325 | if (!subdir) { | |
326 | if (page) { | |
327 | *dir = *page; | |
328 | *page = NULL; | |
329 | } | |
330 | shmem_dir_unmap(dir); | |
331 | return NULL; /* need another page */ | |
332 | } | |
333 | shmem_dir_unmap(dir); | |
334 | dir = shmem_dir_map(subdir); | |
335 | } | |
336 | ||
337 | dir += index; | |
338 | subdir = *dir; | |
339 | if (!subdir) { | |
340 | if (!page || !(subdir = *page)) { | |
341 | shmem_dir_unmap(dir); | |
342 | return NULL; /* need a page */ | |
343 | } | |
344 | *dir = subdir; | |
345 | *page = NULL; | |
346 | } | |
347 | shmem_dir_unmap(dir); | |
348 | return shmem_swp_map(subdir) + offset; | |
349 | } | |
350 | ||
351 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
352 | { | |
353 | long incdec = value? 1: -1; | |
354 | ||
355 | entry->val = value; | |
356 | info->swapped += incdec; | |
4c21e2f2 HD |
357 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
358 | struct page *page = kmap_atomic_to_page(entry); | |
359 | set_page_private(page, page_private(page) + incdec); | |
360 | } | |
1da177e4 LT |
361 | } |
362 | ||
363 | /* | |
364 | * shmem_swp_alloc - get the position of the swap entry for the page. | |
365 | * If it does not exist allocate the entry. | |
366 | * | |
367 | * @info: info structure for the inode | |
368 | * @index: index of the page to find | |
369 | * @sgp: check and recheck i_size? skip allocation? | |
370 | */ | |
371 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
372 | { | |
373 | struct inode *inode = &info->vfs_inode; | |
374 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
375 | struct page *page = NULL; | |
376 | swp_entry_t *entry; | |
377 | ||
378 | if (sgp != SGP_WRITE && | |
379 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
380 | return ERR_PTR(-EINVAL); | |
381 | ||
382 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
383 | if (sgp == SGP_READ) | |
384 | return shmem_swp_map(ZERO_PAGE(0)); | |
385 | /* | |
386 | * Test free_blocks against 1 not 0, since we have 1 data | |
387 | * page (and perhaps indirect index pages) yet to allocate: | |
388 | * a waste to allocate index if we cannot allocate data. | |
389 | */ | |
0edd73b3 | 390 | if (sbinfo->max_blocks) { |
1da177e4 LT |
391 | spin_lock(&sbinfo->stat_lock); |
392 | if (sbinfo->free_blocks <= 1) { | |
393 | spin_unlock(&sbinfo->stat_lock); | |
394 | return ERR_PTR(-ENOSPC); | |
395 | } | |
396 | sbinfo->free_blocks--; | |
397 | inode->i_blocks += BLOCKS_PER_PAGE; | |
398 | spin_unlock(&sbinfo->stat_lock); | |
399 | } | |
400 | ||
401 | spin_unlock(&info->lock); | |
769848c0 | 402 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
4c21e2f2 HD |
403 | if (page) |
404 | set_page_private(page, 0); | |
1da177e4 LT |
405 | spin_lock(&info->lock); |
406 | ||
407 | if (!page) { | |
408 | shmem_free_blocks(inode, 1); | |
409 | return ERR_PTR(-ENOMEM); | |
410 | } | |
411 | if (sgp != SGP_WRITE && | |
412 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
413 | entry = ERR_PTR(-EINVAL); | |
414 | break; | |
415 | } | |
416 | if (info->next_index <= index) | |
417 | info->next_index = index + 1; | |
418 | } | |
419 | if (page) { | |
420 | /* another task gave its page, or truncated the file */ | |
421 | shmem_free_blocks(inode, 1); | |
422 | shmem_dir_free(page); | |
423 | } | |
424 | if (info->next_index <= index && !IS_ERR(entry)) | |
425 | info->next_index = index + 1; | |
426 | return entry; | |
427 | } | |
428 | ||
429 | /* | |
430 | * shmem_free_swp - free some swap entries in a directory | |
431 | * | |
1ae70006 HD |
432 | * @dir: pointer to the directory |
433 | * @edir: pointer after last entry of the directory | |
434 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 435 | */ |
1ae70006 HD |
436 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
437 | spinlock_t *punch_lock) | |
1da177e4 | 438 | { |
1ae70006 | 439 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
440 | swp_entry_t *ptr; |
441 | int freed = 0; | |
442 | ||
443 | for (ptr = dir; ptr < edir; ptr++) { | |
444 | if (ptr->val) { | |
1ae70006 HD |
445 | if (unlikely(punch_lock)) { |
446 | punch_unlock = punch_lock; | |
447 | punch_lock = NULL; | |
448 | spin_lock(punch_unlock); | |
449 | if (!ptr->val) | |
450 | continue; | |
451 | } | |
1da177e4 LT |
452 | free_swap_and_cache(*ptr); |
453 | *ptr = (swp_entry_t){0}; | |
454 | freed++; | |
455 | } | |
456 | } | |
1ae70006 HD |
457 | if (punch_unlock) |
458 | spin_unlock(punch_unlock); | |
1da177e4 LT |
459 | return freed; |
460 | } | |
461 | ||
1ae70006 HD |
462 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
463 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
464 | { |
465 | swp_entry_t *ptr; | |
466 | int freed = 0; | |
467 | ||
468 | ptr = shmem_swp_map(subdir); | |
469 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
470 | int size = limit - offset; | |
471 | if (size > LATENCY_LIMIT) | |
472 | size = LATENCY_LIMIT; | |
1ae70006 HD |
473 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
474 | punch_lock); | |
1da177e4 LT |
475 | if (need_resched()) { |
476 | shmem_swp_unmap(ptr); | |
477 | if (*dir) { | |
478 | shmem_dir_unmap(*dir); | |
479 | *dir = NULL; | |
480 | } | |
481 | cond_resched(); | |
482 | ptr = shmem_swp_map(subdir); | |
483 | } | |
484 | } | |
485 | shmem_swp_unmap(ptr); | |
486 | return freed; | |
487 | } | |
488 | ||
489 | static void shmem_free_pages(struct list_head *next) | |
490 | { | |
491 | struct page *page; | |
492 | int freed = 0; | |
493 | ||
494 | do { | |
495 | page = container_of(next, struct page, lru); | |
496 | next = next->next; | |
497 | shmem_dir_free(page); | |
498 | freed++; | |
499 | if (freed >= LATENCY_LIMIT) { | |
500 | cond_resched(); | |
501 | freed = 0; | |
502 | } | |
503 | } while (next); | |
504 | } | |
505 | ||
f6b3ec23 | 506 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
507 | { |
508 | struct shmem_inode_info *info = SHMEM_I(inode); | |
509 | unsigned long idx; | |
510 | unsigned long size; | |
511 | unsigned long limit; | |
512 | unsigned long stage; | |
513 | unsigned long diroff; | |
514 | struct page **dir; | |
515 | struct page *topdir; | |
516 | struct page *middir; | |
517 | struct page *subdir; | |
518 | swp_entry_t *ptr; | |
519 | LIST_HEAD(pages_to_free); | |
520 | long nr_pages_to_free = 0; | |
521 | long nr_swaps_freed = 0; | |
522 | int offset; | |
523 | int freed; | |
a2646d1e | 524 | int punch_hole; |
1ae70006 HD |
525 | spinlock_t *needs_lock; |
526 | spinlock_t *punch_lock; | |
a2646d1e | 527 | unsigned long upper_limit; |
1da177e4 LT |
528 | |
529 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 530 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
531 | if (idx >= info->next_index) |
532 | return; | |
533 | ||
534 | spin_lock(&info->lock); | |
535 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
536 | if (likely(end == (loff_t) -1)) { |
537 | limit = info->next_index; | |
a2646d1e | 538 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 539 | info->next_index = idx; |
1ae70006 | 540 | needs_lock = NULL; |
a2646d1e | 541 | punch_hole = 0; |
f6b3ec23 | 542 | } else { |
a2646d1e HD |
543 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
544 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
545 | PAGE_CACHE_SHIFT; | |
546 | upper_limit = SHMEM_MAX_INDEX; | |
547 | } else { | |
548 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
549 | upper_limit = limit; | |
550 | } | |
1ae70006 | 551 | needs_lock = &info->lock; |
f6b3ec23 BP |
552 | punch_hole = 1; |
553 | } | |
554 | ||
1da177e4 | 555 | topdir = info->i_indirect; |
f6b3ec23 | 556 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
557 | info->i_indirect = NULL; |
558 | nr_pages_to_free++; | |
559 | list_add(&topdir->lru, &pages_to_free); | |
560 | } | |
561 | spin_unlock(&info->lock); | |
562 | ||
563 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
564 | ptr = info->i_direct; | |
565 | size = limit; | |
566 | if (size > SHMEM_NR_DIRECT) | |
567 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 568 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 569 | } |
92a3d03a BP |
570 | |
571 | /* | |
572 | * If there are no indirect blocks or we are punching a hole | |
573 | * below indirect blocks, nothing to be done. | |
574 | */ | |
a2646d1e | 575 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
576 | goto done2; |
577 | ||
1ae70006 HD |
578 | /* |
579 | * The truncation case has already dropped info->lock, and we're safe | |
580 | * because i_size and next_index have already been lowered, preventing | |
581 | * access beyond. But in the punch_hole case, we still need to take | |
582 | * the lock when updating the swap directory, because there might be | |
583 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
584 | * shmem_writepage. However, whenever we find we can remove a whole | |
585 | * directory page (not at the misaligned start or end of the range), | |
586 | * we first NULLify its pointer in the level above, and then have no | |
587 | * need to take the lock when updating its contents: needs_lock and | |
588 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
589 | */ | |
590 | ||
a2646d1e | 591 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
592 | limit -= SHMEM_NR_DIRECT; |
593 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
594 | offset = idx % ENTRIES_PER_PAGE; | |
595 | idx -= offset; | |
596 | ||
597 | dir = shmem_dir_map(topdir); | |
598 | stage = ENTRIES_PER_PAGEPAGE/2; | |
599 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
600 | middir = topdir; | |
601 | diroff = idx/ENTRIES_PER_PAGE; | |
602 | } else { | |
603 | dir += ENTRIES_PER_PAGE/2; | |
604 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
605 | while (stage <= idx) | |
606 | stage += ENTRIES_PER_PAGEPAGE; | |
607 | middir = *dir; | |
608 | if (*dir) { | |
609 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
610 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 611 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
612 | if (needs_lock) { |
613 | spin_lock(needs_lock); | |
614 | *dir = NULL; | |
615 | spin_unlock(needs_lock); | |
616 | needs_lock = NULL; | |
617 | } else | |
618 | *dir = NULL; | |
1da177e4 LT |
619 | nr_pages_to_free++; |
620 | list_add(&middir->lru, &pages_to_free); | |
621 | } | |
622 | shmem_dir_unmap(dir); | |
623 | dir = shmem_dir_map(middir); | |
624 | } else { | |
625 | diroff = 0; | |
626 | offset = 0; | |
627 | idx = stage; | |
628 | } | |
629 | } | |
630 | ||
631 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
632 | if (unlikely(idx == stage)) { | |
633 | shmem_dir_unmap(dir); | |
634 | dir = shmem_dir_map(topdir) + | |
635 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
636 | while (!*dir) { | |
637 | dir++; | |
638 | idx += ENTRIES_PER_PAGEPAGE; | |
639 | if (idx >= limit) | |
640 | goto done1; | |
641 | } | |
642 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
643 | middir = *dir; | |
1ae70006 HD |
644 | if (punch_hole) |
645 | needs_lock = &info->lock; | |
a2646d1e | 646 | if (upper_limit >= stage) { |
1ae70006 HD |
647 | if (needs_lock) { |
648 | spin_lock(needs_lock); | |
649 | *dir = NULL; | |
650 | spin_unlock(needs_lock); | |
651 | needs_lock = NULL; | |
652 | } else | |
653 | *dir = NULL; | |
a2646d1e HD |
654 | nr_pages_to_free++; |
655 | list_add(&middir->lru, &pages_to_free); | |
656 | } | |
1da177e4 LT |
657 | shmem_dir_unmap(dir); |
658 | cond_resched(); | |
659 | dir = shmem_dir_map(middir); | |
660 | diroff = 0; | |
661 | } | |
1ae70006 | 662 | punch_lock = needs_lock; |
1da177e4 | 663 | subdir = dir[diroff]; |
1ae70006 HD |
664 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
665 | if (needs_lock) { | |
666 | spin_lock(needs_lock); | |
667 | dir[diroff] = NULL; | |
668 | spin_unlock(needs_lock); | |
669 | punch_lock = NULL; | |
670 | } else | |
671 | dir[diroff] = NULL; | |
672 | nr_pages_to_free++; | |
673 | list_add(&subdir->lru, &pages_to_free); | |
674 | } | |
675 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
676 | size = limit - idx; |
677 | if (size > ENTRIES_PER_PAGE) | |
678 | size = ENTRIES_PER_PAGE; | |
679 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 680 | offset, size, &dir, punch_lock); |
1da177e4 LT |
681 | if (!dir) |
682 | dir = shmem_dir_map(middir); | |
683 | nr_swaps_freed += freed; | |
1ae70006 | 684 | if (offset || punch_lock) { |
1da177e4 | 685 | spin_lock(&info->lock); |
1ae70006 HD |
686 | set_page_private(subdir, |
687 | page_private(subdir) - freed); | |
1da177e4 | 688 | spin_unlock(&info->lock); |
1ae70006 HD |
689 | } else |
690 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 691 | } |
1ae70006 | 692 | offset = 0; |
1da177e4 LT |
693 | } |
694 | done1: | |
695 | shmem_dir_unmap(dir); | |
696 | done2: | |
697 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
698 | /* | |
699 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
700 | * may have swizzled a page in from swap since vmtruncate or | |
701 | * generic_delete_inode did it, before we lowered next_index. | |
702 | * Also, though shmem_getpage checks i_size before adding to | |
703 | * cache, no recheck after: so fix the narrow window there too. | |
16a10019 HD |
704 | * |
705 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
706 | * every time for punch_hole (which never got a chance to clear | |
707 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
708 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 709 | */ |
f6b3ec23 | 710 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
711 | if (punch_hole) |
712 | unmap_mapping_range(inode->i_mapping, start, | |
713 | end - start, 1); | |
1da177e4 LT |
714 | } |
715 | ||
716 | spin_lock(&info->lock); | |
717 | info->flags &= ~SHMEM_TRUNCATE; | |
718 | info->swapped -= nr_swaps_freed; | |
719 | if (nr_pages_to_free) | |
720 | shmem_free_blocks(inode, nr_pages_to_free); | |
721 | shmem_recalc_inode(inode); | |
722 | spin_unlock(&info->lock); | |
723 | ||
724 | /* | |
725 | * Empty swap vector directory pages to be freed? | |
726 | */ | |
727 | if (!list_empty(&pages_to_free)) { | |
728 | pages_to_free.prev->next = NULL; | |
729 | shmem_free_pages(pages_to_free.next); | |
730 | } | |
731 | } | |
732 | ||
f6b3ec23 BP |
733 | static void shmem_truncate(struct inode *inode) |
734 | { | |
735 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
736 | } | |
737 | ||
1da177e4 LT |
738 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
739 | { | |
740 | struct inode *inode = dentry->d_inode; | |
741 | struct page *page = NULL; | |
742 | int error; | |
743 | ||
39f0247d | 744 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
745 | if (attr->ia_size < inode->i_size) { |
746 | /* | |
747 | * If truncating down to a partial page, then | |
748 | * if that page is already allocated, hold it | |
749 | * in memory until the truncation is over, so | |
750 | * truncate_partial_page cannnot miss it were | |
751 | * it assigned to swap. | |
752 | */ | |
753 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
754 | (void) shmem_getpage(inode, | |
755 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
756 | &page, SGP_READ, NULL); | |
d3602444 HD |
757 | if (page) |
758 | unlock_page(page); | |
1da177e4 LT |
759 | } |
760 | /* | |
761 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
762 | * detect if any pages might have been added to cache | |
763 | * after truncate_inode_pages. But we needn't bother | |
764 | * if it's being fully truncated to zero-length: the | |
765 | * nrpages check is efficient enough in that case. | |
766 | */ | |
767 | if (attr->ia_size) { | |
768 | struct shmem_inode_info *info = SHMEM_I(inode); | |
769 | spin_lock(&info->lock); | |
770 | info->flags &= ~SHMEM_PAGEIN; | |
771 | spin_unlock(&info->lock); | |
772 | } | |
773 | } | |
774 | } | |
775 | ||
776 | error = inode_change_ok(inode, attr); | |
777 | if (!error) | |
778 | error = inode_setattr(inode, attr); | |
39f0247d AG |
779 | #ifdef CONFIG_TMPFS_POSIX_ACL |
780 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
781 | error = generic_acl_chmod(inode, &shmem_acl_ops); | |
782 | #endif | |
1da177e4 LT |
783 | if (page) |
784 | page_cache_release(page); | |
785 | return error; | |
786 | } | |
787 | ||
788 | static void shmem_delete_inode(struct inode *inode) | |
789 | { | |
1da177e4 LT |
790 | struct shmem_inode_info *info = SHMEM_I(inode); |
791 | ||
792 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 793 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
794 | shmem_unacct_size(info->flags, inode->i_size); |
795 | inode->i_size = 0; | |
796 | shmem_truncate(inode); | |
797 | if (!list_empty(&info->swaplist)) { | |
798 | spin_lock(&shmem_swaplist_lock); | |
799 | list_del_init(&info->swaplist); | |
800 | spin_unlock(&shmem_swaplist_lock); | |
801 | } | |
802 | } | |
0edd73b3 | 803 | BUG_ON(inode->i_blocks); |
5b04c689 | 804 | shmem_free_inode(inode->i_sb); |
1da177e4 LT |
805 | clear_inode(inode); |
806 | } | |
807 | ||
808 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
809 | { | |
810 | swp_entry_t *ptr; | |
811 | ||
812 | for (ptr = dir; ptr < edir; ptr++) { | |
813 | if (ptr->val == entry.val) | |
814 | return ptr - dir; | |
815 | } | |
816 | return -1; | |
817 | } | |
818 | ||
819 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
820 | { | |
821 | struct inode *inode; | |
822 | unsigned long idx; | |
823 | unsigned long size; | |
824 | unsigned long limit; | |
825 | unsigned long stage; | |
826 | struct page **dir; | |
827 | struct page *subdir; | |
828 | swp_entry_t *ptr; | |
829 | int offset; | |
d9fe526a | 830 | int error; |
1da177e4 LT |
831 | |
832 | idx = 0; | |
833 | ptr = info->i_direct; | |
834 | spin_lock(&info->lock); | |
835 | limit = info->next_index; | |
836 | size = limit; | |
837 | if (size > SHMEM_NR_DIRECT) | |
838 | size = SHMEM_NR_DIRECT; | |
839 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
840 | if (offset >= 0) { | |
841 | shmem_swp_balance_unmap(); | |
842 | goto found; | |
843 | } | |
844 | if (!info->i_indirect) | |
845 | goto lost2; | |
846 | ||
847 | dir = shmem_dir_map(info->i_indirect); | |
848 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
849 | ||
850 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
851 | if (unlikely(idx == stage)) { | |
852 | shmem_dir_unmap(dir-1); | |
853 | dir = shmem_dir_map(info->i_indirect) + | |
854 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
855 | while (!*dir) { | |
856 | dir++; | |
857 | idx += ENTRIES_PER_PAGEPAGE; | |
858 | if (idx >= limit) | |
859 | goto lost1; | |
860 | } | |
861 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
862 | subdir = *dir; | |
863 | shmem_dir_unmap(dir); | |
864 | dir = shmem_dir_map(subdir); | |
865 | } | |
866 | subdir = *dir; | |
4c21e2f2 | 867 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
868 | ptr = shmem_swp_map(subdir); |
869 | size = limit - idx; | |
870 | if (size > ENTRIES_PER_PAGE) | |
871 | size = ENTRIES_PER_PAGE; | |
872 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
873 | if (offset >= 0) { | |
874 | shmem_dir_unmap(dir); | |
875 | goto found; | |
876 | } | |
877 | shmem_swp_unmap(ptr); | |
878 | } | |
879 | } | |
880 | lost1: | |
881 | shmem_dir_unmap(dir-1); | |
882 | lost2: | |
883 | spin_unlock(&info->lock); | |
884 | return 0; | |
885 | found: | |
886 | idx += offset; | |
887 | inode = &info->vfs_inode; | |
d9fe526a HD |
888 | error = add_to_page_cache(page, inode->i_mapping, idx, GFP_ATOMIC); |
889 | if (error == -EEXIST) { | |
890 | struct page *filepage = find_get_page(inode->i_mapping, idx); | |
891 | if (filepage) { | |
892 | /* | |
893 | * There might be a more uptodate page coming down | |
894 | * from a stacked writepage: forget our swappage if so. | |
895 | */ | |
896 | if (PageUptodate(filepage)) | |
897 | error = 0; | |
898 | page_cache_release(filepage); | |
899 | } | |
900 | } | |
901 | if (!error) { | |
73b1262f HD |
902 | delete_from_swap_cache(page); |
903 | set_page_dirty(page); | |
1da177e4 LT |
904 | info->flags |= SHMEM_PAGEIN; |
905 | shmem_swp_set(info, ptr + offset, 0); | |
906 | } | |
907 | shmem_swp_unmap(ptr); | |
908 | spin_unlock(&info->lock); | |
909 | /* | |
910 | * Decrement swap count even when the entry is left behind: | |
911 | * try_to_unuse will skip over mms, then reincrement count. | |
912 | */ | |
913 | swap_free(entry); | |
914 | return 1; | |
915 | } | |
916 | ||
917 | /* | |
918 | * shmem_unuse() search for an eventually swapped out shmem page. | |
919 | */ | |
920 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
921 | { | |
922 | struct list_head *p, *next; | |
923 | struct shmem_inode_info *info; | |
924 | int found = 0; | |
925 | ||
926 | spin_lock(&shmem_swaplist_lock); | |
927 | list_for_each_safe(p, next, &shmem_swaplist) { | |
928 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
929 | if (!info->swapped) | |
930 | list_del_init(&info->swaplist); | |
931 | else if (shmem_unuse_inode(info, entry, page)) { | |
932 | /* move head to start search for next from here */ | |
933 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
934 | found = 1; | |
935 | break; | |
936 | } | |
937 | } | |
938 | spin_unlock(&shmem_swaplist_lock); | |
939 | return found; | |
940 | } | |
941 | ||
942 | /* | |
943 | * Move the page from the page cache to the swap cache. | |
944 | */ | |
945 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
946 | { | |
947 | struct shmem_inode_info *info; | |
948 | swp_entry_t *entry, swap; | |
949 | struct address_space *mapping; | |
950 | unsigned long index; | |
951 | struct inode *inode; | |
952 | ||
953 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
954 | mapping = page->mapping; |
955 | index = page->index; | |
956 | inode = mapping->host; | |
957 | info = SHMEM_I(inode); | |
958 | if (info->flags & VM_LOCKED) | |
959 | goto redirty; | |
d9fe526a | 960 | if (!total_swap_pages) |
1da177e4 LT |
961 | goto redirty; |
962 | ||
d9fe526a HD |
963 | /* |
964 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
965 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
966 | * may use the ->writepage of its underlying filesystem, in which case | |
967 | * tmpfs should write out to swap only in response to memory pressure, | |
968 | * and not for pdflush or sync. However, in those cases, we do still | |
969 | * want to check if there's a redundant swappage to be discarded. | |
970 | */ | |
971 | if (wbc->for_reclaim) | |
972 | swap = get_swap_page(); | |
973 | else | |
974 | swap.val = 0; | |
975 | ||
1da177e4 | 976 | spin_lock(&info->lock); |
1da177e4 LT |
977 | if (index >= info->next_index) { |
978 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
979 | goto unlock; | |
980 | } | |
981 | entry = shmem_swp_entry(info, index, NULL); | |
d9fe526a HD |
982 | if (entry->val) { |
983 | /* | |
984 | * The more uptodate page coming down from a stacked | |
985 | * writepage should replace our old swappage. | |
986 | */ | |
987 | free_swap_and_cache(*entry); | |
988 | shmem_swp_set(info, entry, 0); | |
989 | } | |
990 | shmem_recalc_inode(inode); | |
1da177e4 | 991 | |
d9fe526a | 992 | if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
73b1262f | 993 | remove_from_page_cache(page); |
1da177e4 LT |
994 | shmem_swp_set(info, entry, swap.val); |
995 | shmem_swp_unmap(entry); | |
996 | spin_unlock(&info->lock); | |
997 | if (list_empty(&info->swaplist)) { | |
998 | spin_lock(&shmem_swaplist_lock); | |
999 | /* move instead of add in case we're racing */ | |
1000 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
1001 | spin_unlock(&shmem_swaplist_lock); | |
1002 | } | |
73b1262f | 1003 | swap_duplicate(swap); |
d9fe526a | 1004 | BUG_ON(page_mapped(page)); |
73b1262f HD |
1005 | page_cache_release(page); /* pagecache ref */ |
1006 | set_page_dirty(page); | |
1da177e4 LT |
1007 | unlock_page(page); |
1008 | return 0; | |
1009 | } | |
1010 | ||
1011 | shmem_swp_unmap(entry); | |
1012 | unlock: | |
1013 | spin_unlock(&info->lock); | |
1014 | swap_free(swap); | |
1015 | redirty: | |
1016 | set_page_dirty(page); | |
d9fe526a HD |
1017 | if (wbc->for_reclaim) |
1018 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1019 | unlock_page(page); | |
1020 | return 0; | |
1da177e4 LT |
1021 | } |
1022 | ||
1023 | #ifdef CONFIG_NUMA | |
d15c023b | 1024 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
b00dc3ad HD |
1025 | { |
1026 | char *nodelist = strchr(value, ':'); | |
1027 | int err = 1; | |
1028 | ||
1029 | if (nodelist) { | |
1030 | /* NUL-terminate policy string */ | |
1031 | *nodelist++ = '\0'; | |
1032 | if (nodelist_parse(nodelist, *policy_nodes)) | |
1033 | goto out; | |
37b07e41 | 1034 | if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY])) |
a210906c | 1035 | goto out; |
b00dc3ad HD |
1036 | } |
1037 | if (!strcmp(value, "default")) { | |
1038 | *policy = MPOL_DEFAULT; | |
1039 | /* Don't allow a nodelist */ | |
1040 | if (!nodelist) | |
1041 | err = 0; | |
1042 | } else if (!strcmp(value, "prefer")) { | |
1043 | *policy = MPOL_PREFERRED; | |
1044 | /* Insist on a nodelist of one node only */ | |
1045 | if (nodelist) { | |
1046 | char *rest = nodelist; | |
1047 | while (isdigit(*rest)) | |
1048 | rest++; | |
1049 | if (!*rest) | |
1050 | err = 0; | |
1051 | } | |
1052 | } else if (!strcmp(value, "bind")) { | |
1053 | *policy = MPOL_BIND; | |
1054 | /* Insist on a nodelist */ | |
1055 | if (nodelist) | |
1056 | err = 0; | |
1057 | } else if (!strcmp(value, "interleave")) { | |
1058 | *policy = MPOL_INTERLEAVE; | |
37b07e41 LS |
1059 | /* |
1060 | * Default to online nodes with memory if no nodelist | |
1061 | */ | |
b00dc3ad | 1062 | if (!nodelist) |
37b07e41 | 1063 | *policy_nodes = node_states[N_HIGH_MEMORY]; |
b00dc3ad HD |
1064 | err = 0; |
1065 | } | |
1066 | out: | |
1067 | /* Restore string for error message */ | |
1068 | if (nodelist) | |
1069 | *--nodelist = ':'; | |
1070 | return err; | |
1071 | } | |
1072 | ||
02098fea HD |
1073 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1074 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1075 | { |
1da177e4 | 1076 | struct vm_area_struct pvma; |
c4cc6d07 | 1077 | struct page *page; |
1da177e4 LT |
1078 | |
1079 | /* Create a pseudo vma that just contains the policy */ | |
c4cc6d07 | 1080 | pvma.vm_start = 0; |
1da177e4 | 1081 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1082 | pvma.vm_ops = NULL; |
1083 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
02098fea | 1084 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1085 | mpol_free(pvma.vm_policy); |
1086 | return page; | |
1087 | } | |
1088 | ||
02098fea HD |
1089 | static struct page *shmem_alloc_page(gfp_t gfp, |
1090 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1091 | { |
1092 | struct vm_area_struct pvma; | |
1093 | struct page *page; | |
1094 | ||
c4cc6d07 HD |
1095 | /* Create a pseudo vma that just contains the policy */ |
1096 | pvma.vm_start = 0; | |
1da177e4 | 1097 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1098 | pvma.vm_ops = NULL; |
1099 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
e84e2e13 | 1100 | page = alloc_page_vma(gfp, &pvma, 0); |
1da177e4 LT |
1101 | mpol_free(pvma.vm_policy); |
1102 | return page; | |
1103 | } | |
1104 | #else | |
37b07e41 LS |
1105 | static inline int shmem_parse_mpol(char *value, int *policy, |
1106 | nodemask_t *policy_nodes) | |
b00dc3ad HD |
1107 | { |
1108 | return 1; | |
1109 | } | |
1110 | ||
02098fea HD |
1111 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1112 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1113 | { |
02098fea | 1114 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1115 | } |
1116 | ||
02098fea HD |
1117 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1118 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1119 | { |
e84e2e13 | 1120 | return alloc_page(gfp); |
1da177e4 LT |
1121 | } |
1122 | #endif | |
1123 | ||
1124 | /* | |
1125 | * shmem_getpage - either get the page from swap or allocate a new one | |
1126 | * | |
1127 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1128 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1129 | * entry since a page cannot live in both the swap and page cache | |
1130 | */ | |
1131 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1132 | struct page **pagep, enum sgp_type sgp, int *type) | |
1133 | { | |
1134 | struct address_space *mapping = inode->i_mapping; | |
1135 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1136 | struct shmem_sb_info *sbinfo; | |
1137 | struct page *filepage = *pagep; | |
1138 | struct page *swappage; | |
1139 | swp_entry_t *entry; | |
1140 | swp_entry_t swap; | |
02098fea | 1141 | gfp_t gfp; |
1da177e4 LT |
1142 | int error; |
1143 | ||
1144 | if (idx >= SHMEM_MAX_INDEX) | |
1145 | return -EFBIG; | |
54cb8821 NP |
1146 | |
1147 | if (type) | |
83c54070 | 1148 | *type = 0; |
54cb8821 | 1149 | |
1da177e4 LT |
1150 | /* |
1151 | * Normally, filepage is NULL on entry, and either found | |
1152 | * uptodate immediately, or allocated and zeroed, or read | |
1153 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1154 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1155 | * filepage, which may be found not uptodate by other callers |
1156 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1157 | */ |
1158 | repeat: | |
1159 | if (!filepage) | |
1160 | filepage = find_lock_page(mapping, idx); | |
1161 | if (filepage && PageUptodate(filepage)) | |
1162 | goto done; | |
1163 | error = 0; | |
02098fea | 1164 | gfp = mapping_gfp_mask(mapping); |
1da177e4 LT |
1165 | |
1166 | spin_lock(&info->lock); | |
1167 | shmem_recalc_inode(inode); | |
1168 | entry = shmem_swp_alloc(info, idx, sgp); | |
1169 | if (IS_ERR(entry)) { | |
1170 | spin_unlock(&info->lock); | |
1171 | error = PTR_ERR(entry); | |
1172 | goto failed; | |
1173 | } | |
1174 | swap = *entry; | |
1175 | ||
1176 | if (swap.val) { | |
1177 | /* Look it up and read it in.. */ | |
1178 | swappage = lookup_swap_cache(swap); | |
1179 | if (!swappage) { | |
1180 | shmem_swp_unmap(entry); | |
1da177e4 | 1181 | /* here we actually do the io */ |
83c54070 | 1182 | if (type && !(*type & VM_FAULT_MAJOR)) { |
f8891e5e | 1183 | __count_vm_event(PGMAJFAULT); |
83c54070 | 1184 | *type |= VM_FAULT_MAJOR; |
1da177e4 | 1185 | } |
f8891e5e | 1186 | spin_unlock(&info->lock); |
02098fea | 1187 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1188 | if (!swappage) { |
1189 | spin_lock(&info->lock); | |
1190 | entry = shmem_swp_alloc(info, idx, sgp); | |
1191 | if (IS_ERR(entry)) | |
1192 | error = PTR_ERR(entry); | |
1193 | else { | |
1194 | if (entry->val == swap.val) | |
1195 | error = -ENOMEM; | |
1196 | shmem_swp_unmap(entry); | |
1197 | } | |
1198 | spin_unlock(&info->lock); | |
1199 | if (error) | |
1200 | goto failed; | |
1201 | goto repeat; | |
1202 | } | |
1203 | wait_on_page_locked(swappage); | |
1204 | page_cache_release(swappage); | |
1205 | goto repeat; | |
1206 | } | |
1207 | ||
1208 | /* We have to do this with page locked to prevent races */ | |
1209 | if (TestSetPageLocked(swappage)) { | |
1210 | shmem_swp_unmap(entry); | |
1211 | spin_unlock(&info->lock); | |
1212 | wait_on_page_locked(swappage); | |
1213 | page_cache_release(swappage); | |
1214 | goto repeat; | |
1215 | } | |
1216 | if (PageWriteback(swappage)) { | |
1217 | shmem_swp_unmap(entry); | |
1218 | spin_unlock(&info->lock); | |
1219 | wait_on_page_writeback(swappage); | |
1220 | unlock_page(swappage); | |
1221 | page_cache_release(swappage); | |
1222 | goto repeat; | |
1223 | } | |
1224 | if (!PageUptodate(swappage)) { | |
1225 | shmem_swp_unmap(entry); | |
1226 | spin_unlock(&info->lock); | |
1227 | unlock_page(swappage); | |
1228 | page_cache_release(swappage); | |
1229 | error = -EIO; | |
1230 | goto failed; | |
1231 | } | |
1232 | ||
1233 | if (filepage) { | |
1234 | shmem_swp_set(info, entry, 0); | |
1235 | shmem_swp_unmap(entry); | |
1236 | delete_from_swap_cache(swappage); | |
1237 | spin_unlock(&info->lock); | |
1238 | copy_highpage(filepage, swappage); | |
1239 | unlock_page(swappage); | |
1240 | page_cache_release(swappage); | |
1241 | flush_dcache_page(filepage); | |
1242 | SetPageUptodate(filepage); | |
1243 | set_page_dirty(filepage); | |
1244 | swap_free(swap); | |
73b1262f HD |
1245 | } else if (!(error = add_to_page_cache( |
1246 | swappage, mapping, idx, GFP_ATOMIC))) { | |
1da177e4 LT |
1247 | info->flags |= SHMEM_PAGEIN; |
1248 | shmem_swp_set(info, entry, 0); | |
1249 | shmem_swp_unmap(entry); | |
73b1262f | 1250 | delete_from_swap_cache(swappage); |
1da177e4 LT |
1251 | spin_unlock(&info->lock); |
1252 | filepage = swappage; | |
73b1262f | 1253 | set_page_dirty(filepage); |
1da177e4 LT |
1254 | swap_free(swap); |
1255 | } else { | |
1256 | shmem_swp_unmap(entry); | |
1257 | spin_unlock(&info->lock); | |
1258 | unlock_page(swappage); | |
1259 | page_cache_release(swappage); | |
1260 | if (error == -ENOMEM) { | |
1261 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
3fcfab16 | 1262 | congestion_wait(WRITE, HZ/50); |
1da177e4 LT |
1263 | } |
1264 | goto repeat; | |
1265 | } | |
1266 | } else if (sgp == SGP_READ && !filepage) { | |
1267 | shmem_swp_unmap(entry); | |
1268 | filepage = find_get_page(mapping, idx); | |
1269 | if (filepage && | |
1270 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1271 | spin_unlock(&info->lock); | |
1272 | wait_on_page_locked(filepage); | |
1273 | page_cache_release(filepage); | |
1274 | filepage = NULL; | |
1275 | goto repeat; | |
1276 | } | |
1277 | spin_unlock(&info->lock); | |
1278 | } else { | |
1279 | shmem_swp_unmap(entry); | |
1280 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1281 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1282 | spin_lock(&sbinfo->stat_lock); |
1283 | if (sbinfo->free_blocks == 0 || | |
1284 | shmem_acct_block(info->flags)) { | |
1285 | spin_unlock(&sbinfo->stat_lock); | |
1286 | spin_unlock(&info->lock); | |
1287 | error = -ENOSPC; | |
1288 | goto failed; | |
1289 | } | |
1290 | sbinfo->free_blocks--; | |
1291 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1292 | spin_unlock(&sbinfo->stat_lock); | |
1293 | } else if (shmem_acct_block(info->flags)) { | |
1294 | spin_unlock(&info->lock); | |
1295 | error = -ENOSPC; | |
1296 | goto failed; | |
1297 | } | |
1298 | ||
1299 | if (!filepage) { | |
1300 | spin_unlock(&info->lock); | |
02098fea | 1301 | filepage = shmem_alloc_page(gfp, info, idx); |
1da177e4 LT |
1302 | if (!filepage) { |
1303 | shmem_unacct_blocks(info->flags, 1); | |
1304 | shmem_free_blocks(inode, 1); | |
1305 | error = -ENOMEM; | |
1306 | goto failed; | |
1307 | } | |
1308 | ||
1309 | spin_lock(&info->lock); | |
1310 | entry = shmem_swp_alloc(info, idx, sgp); | |
1311 | if (IS_ERR(entry)) | |
1312 | error = PTR_ERR(entry); | |
1313 | else { | |
1314 | swap = *entry; | |
1315 | shmem_swp_unmap(entry); | |
1316 | } | |
1317 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1318 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1319 | spin_unlock(&info->lock); | |
1320 | page_cache_release(filepage); | |
1321 | shmem_unacct_blocks(info->flags, 1); | |
1322 | shmem_free_blocks(inode, 1); | |
1323 | filepage = NULL; | |
1324 | if (error) | |
1325 | goto failed; | |
1326 | goto repeat; | |
1327 | } | |
1328 | info->flags |= SHMEM_PAGEIN; | |
1329 | } | |
1330 | ||
1331 | info->alloced++; | |
1332 | spin_unlock(&info->lock); | |
e84e2e13 | 1333 | clear_highpage(filepage); |
1da177e4 LT |
1334 | flush_dcache_page(filepage); |
1335 | SetPageUptodate(filepage); | |
1336 | } | |
1337 | done: | |
d3602444 | 1338 | *pagep = filepage; |
1da177e4 LT |
1339 | return 0; |
1340 | ||
1341 | failed: | |
1342 | if (*pagep != filepage) { | |
1343 | unlock_page(filepage); | |
1344 | page_cache_release(filepage); | |
1345 | } | |
1346 | return error; | |
1347 | } | |
1348 | ||
d0217ac0 | 1349 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1350 | { |
d3ac7f89 | 1351 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1352 | int error; |
d0217ac0 | 1353 | int ret; |
1da177e4 | 1354 | |
d0217ac0 NP |
1355 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1356 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1357 | |
27d54b39 | 1358 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1359 | if (error) |
1360 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1da177e4 | 1361 | |
d0217ac0 | 1362 | mark_page_accessed(vmf->page); |
83c54070 | 1363 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1364 | } |
1365 | ||
1da177e4 | 1366 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1367 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1368 | { |
d3ac7f89 | 1369 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1370 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1371 | } | |
1372 | ||
d8dc74f2 AB |
1373 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1374 | unsigned long addr) | |
1da177e4 | 1375 | { |
d3ac7f89 | 1376 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1377 | unsigned long idx; |
1378 | ||
1379 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1380 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1381 | } | |
1382 | #endif | |
1383 | ||
1384 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1385 | { | |
d3ac7f89 | 1386 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1387 | struct shmem_inode_info *info = SHMEM_I(inode); |
1388 | int retval = -ENOMEM; | |
1389 | ||
1390 | spin_lock(&info->lock); | |
1391 | if (lock && !(info->flags & VM_LOCKED)) { | |
1392 | if (!user_shm_lock(inode->i_size, user)) | |
1393 | goto out_nomem; | |
1394 | info->flags |= VM_LOCKED; | |
1395 | } | |
1396 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1397 | user_shm_unlock(inode->i_size, user); | |
1398 | info->flags &= ~VM_LOCKED; | |
1399 | } | |
1400 | retval = 0; | |
1401 | out_nomem: | |
1402 | spin_unlock(&info->lock); | |
1403 | return retval; | |
1404 | } | |
1405 | ||
9b83a6a8 | 1406 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1407 | { |
1408 | file_accessed(file); | |
1409 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1410 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
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 | ||
5b04c689 PE |
1421 | if (shmem_reserve_inode(sb)) |
1422 | return NULL; | |
1da177e4 LT |
1423 | |
1424 | inode = new_inode(sb); | |
1425 | if (inode) { | |
1426 | inode->i_mode = mode; | |
1427 | inode->i_uid = current->fsuid; | |
1428 | inode->i_gid = current->fsgid; | |
1da177e4 LT |
1429 | inode->i_blocks = 0; |
1430 | inode->i_mapping->a_ops = &shmem_aops; | |
1431 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1432 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1433 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1434 | info = SHMEM_I(inode); |
1435 | memset(info, 0, (char *)inode - (char *)info); | |
1436 | spin_lock_init(&info->lock); | |
1437 | INIT_LIST_HEAD(&info->swaplist); | |
1438 | ||
1439 | switch (mode & S_IFMT) { | |
1440 | default: | |
39f0247d | 1441 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1442 | init_special_inode(inode, mode, dev); |
1443 | break; | |
1444 | case S_IFREG: | |
1445 | inode->i_op = &shmem_inode_operations; | |
1446 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1447 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1448 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1449 | break; |
1450 | case S_IFDIR: | |
d8c76e6f | 1451 | inc_nlink(inode); |
1da177e4 LT |
1452 | /* Some things misbehave if size == 0 on a directory */ |
1453 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1454 | inode->i_op = &shmem_dir_inode_operations; | |
1455 | inode->i_fop = &simple_dir_operations; | |
1456 | break; | |
1457 | case S_IFLNK: | |
1458 | /* | |
1459 | * Must not load anything in the rbtree, | |
1460 | * mpol_free_shared_policy will not be called. | |
1461 | */ | |
7339ff83 RH |
1462 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1463 | NULL); | |
1da177e4 LT |
1464 | break; |
1465 | } | |
5b04c689 PE |
1466 | } else |
1467 | shmem_free_inode(sb); | |
1da177e4 LT |
1468 | return inode; |
1469 | } | |
1470 | ||
1471 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1472 | static const struct inode_operations shmem_symlink_inode_operations; |
1473 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1474 | |
1475 | /* | |
800d15a5 | 1476 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1477 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1478 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1479 | */ |
ae976416 HD |
1480 | static int shmem_readpage(struct file *file, struct page *page) |
1481 | { | |
1482 | struct inode *inode = page->mapping->host; | |
1483 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1484 | unlock_page(page); | |
1485 | return error; | |
1486 | } | |
1487 | ||
1da177e4 | 1488 | static int |
800d15a5 NP |
1489 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1490 | loff_t pos, unsigned len, unsigned flags, | |
1491 | struct page **pagep, void **fsdata) | |
1da177e4 | 1492 | { |
800d15a5 NP |
1493 | struct inode *inode = mapping->host; |
1494 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1495 | *pagep = NULL; | |
1496 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1497 | } | |
1498 | ||
1499 | static int | |
1500 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1501 | loff_t pos, unsigned len, unsigned copied, | |
1502 | struct page *page, void *fsdata) | |
1503 | { | |
1504 | struct inode *inode = mapping->host; | |
1505 | ||
d3602444 HD |
1506 | if (pos + copied > inode->i_size) |
1507 | i_size_write(inode, pos + copied); | |
1508 | ||
1509 | unlock_page(page); | |
800d15a5 NP |
1510 | set_page_dirty(page); |
1511 | page_cache_release(page); | |
1512 | ||
800d15a5 | 1513 | return copied; |
1da177e4 LT |
1514 | } |
1515 | ||
1da177e4 LT |
1516 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1517 | { | |
d3ac7f89 | 1518 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1519 | struct address_space *mapping = inode->i_mapping; |
1520 | unsigned long index, offset; | |
1521 | ||
1522 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1523 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1524 | ||
1525 | for (;;) { | |
1526 | struct page *page = NULL; | |
1527 | unsigned long end_index, nr, ret; | |
1528 | loff_t i_size = i_size_read(inode); | |
1529 | ||
1530 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1531 | if (index > end_index) | |
1532 | break; | |
1533 | if (index == end_index) { | |
1534 | nr = i_size & ~PAGE_CACHE_MASK; | |
1535 | if (nr <= offset) | |
1536 | break; | |
1537 | } | |
1538 | ||
1539 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); | |
1540 | if (desc->error) { | |
1541 | if (desc->error == -EINVAL) | |
1542 | desc->error = 0; | |
1543 | break; | |
1544 | } | |
d3602444 HD |
1545 | if (page) |
1546 | unlock_page(page); | |
1da177e4 LT |
1547 | |
1548 | /* | |
1549 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1550 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1551 | */ |
1552 | nr = PAGE_CACHE_SIZE; | |
1553 | i_size = i_size_read(inode); | |
1554 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1555 | if (index == end_index) { | |
1556 | nr = i_size & ~PAGE_CACHE_MASK; | |
1557 | if (nr <= offset) { | |
1558 | if (page) | |
1559 | page_cache_release(page); | |
1560 | break; | |
1561 | } | |
1562 | } | |
1563 | nr -= offset; | |
1564 | ||
1565 | if (page) { | |
1566 | /* | |
1567 | * If users can be writing to this page using arbitrary | |
1568 | * virtual addresses, take care about potential aliasing | |
1569 | * before reading the page on the kernel side. | |
1570 | */ | |
1571 | if (mapping_writably_mapped(mapping)) | |
1572 | flush_dcache_page(page); | |
1573 | /* | |
1574 | * Mark the page accessed if we read the beginning. | |
1575 | */ | |
1576 | if (!offset) | |
1577 | mark_page_accessed(page); | |
b5810039 | 1578 | } else { |
1da177e4 | 1579 | page = ZERO_PAGE(0); |
b5810039 NP |
1580 | page_cache_get(page); |
1581 | } | |
1da177e4 LT |
1582 | |
1583 | /* | |
1584 | * Ok, we have the page, and it's up-to-date, so | |
1585 | * now we can copy it to user space... | |
1586 | * | |
1587 | * The actor routine returns how many bytes were actually used.. | |
1588 | * NOTE! This may not be the same as how much of a user buffer | |
1589 | * we filled up (we may be padding etc), so we can only update | |
1590 | * "pos" here (the actor routine has to update the user buffer | |
1591 | * pointers and the remaining count). | |
1592 | */ | |
1593 | ret = actor(desc, page, offset, nr); | |
1594 | offset += ret; | |
1595 | index += offset >> PAGE_CACHE_SHIFT; | |
1596 | offset &= ~PAGE_CACHE_MASK; | |
1597 | ||
1598 | page_cache_release(page); | |
1599 | if (ret != nr || !desc->count) | |
1600 | break; | |
1601 | ||
1602 | cond_resched(); | |
1603 | } | |
1604 | ||
1605 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1606 | file_accessed(filp); | |
1607 | } | |
1608 | ||
1609 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1610 | { | |
1611 | read_descriptor_t desc; | |
1612 | ||
1613 | if ((ssize_t) count < 0) | |
1614 | return -EINVAL; | |
1615 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1616 | return -EFAULT; | |
1617 | if (!count) | |
1618 | return 0; | |
1619 | ||
1620 | desc.written = 0; | |
1621 | desc.count = count; | |
1622 | desc.arg.buf = buf; | |
1623 | desc.error = 0; | |
1624 | ||
1625 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1626 | if (desc.written) | |
1627 | return desc.written; | |
1628 | return desc.error; | |
1629 | } | |
1630 | ||
726c3342 | 1631 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1632 | { |
726c3342 | 1633 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1634 | |
1635 | buf->f_type = TMPFS_MAGIC; | |
1636 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1637 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1638 | spin_lock(&sbinfo->stat_lock); |
1639 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1640 | buf->f_blocks = sbinfo->max_blocks; |
1641 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1642 | } |
1643 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1644 | buf->f_files = sbinfo->max_inodes; |
1645 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1646 | } |
1647 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1648 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1649 | return 0; |
1650 | } | |
1651 | ||
1652 | /* | |
1653 | * File creation. Allocate an inode, and we're done.. | |
1654 | */ | |
1655 | static int | |
1656 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1657 | { | |
1658 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1659 | int error = -ENOSPC; | |
1660 | ||
1661 | if (inode) { | |
570bc1c2 SS |
1662 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1663 | NULL); | |
1664 | if (error) { | |
1665 | if (error != -EOPNOTSUPP) { | |
1666 | iput(inode); | |
1667 | return error; | |
1668 | } | |
39f0247d AG |
1669 | } |
1670 | error = shmem_acl_init(inode, dir); | |
1671 | if (error) { | |
1672 | iput(inode); | |
1673 | return error; | |
570bc1c2 | 1674 | } |
1da177e4 LT |
1675 | if (dir->i_mode & S_ISGID) { |
1676 | inode->i_gid = dir->i_gid; | |
1677 | if (S_ISDIR(mode)) | |
1678 | inode->i_mode |= S_ISGID; | |
1679 | } | |
1680 | dir->i_size += BOGO_DIRENT_SIZE; | |
1681 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1682 | d_instantiate(dentry, inode); | |
1683 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1684 | } |
1685 | return error; | |
1686 | } | |
1687 | ||
1688 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1689 | { | |
1690 | int error; | |
1691 | ||
1692 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1693 | return error; | |
d8c76e6f | 1694 | inc_nlink(dir); |
1da177e4 LT |
1695 | return 0; |
1696 | } | |
1697 | ||
1698 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1699 | struct nameidata *nd) | |
1700 | { | |
1701 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1702 | } | |
1703 | ||
1704 | /* | |
1705 | * Link a file.. | |
1706 | */ | |
1707 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1708 | { | |
1709 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1710 | int ret; |
1da177e4 LT |
1711 | |
1712 | /* | |
1713 | * No ordinary (disk based) filesystem counts links as inodes; | |
1714 | * but each new link needs a new dentry, pinning lowmem, and | |
1715 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1716 | */ | |
5b04c689 PE |
1717 | ret = shmem_reserve_inode(inode->i_sb); |
1718 | if (ret) | |
1719 | goto out; | |
1da177e4 LT |
1720 | |
1721 | dir->i_size += BOGO_DIRENT_SIZE; | |
1722 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1723 | inc_nlink(inode); |
1da177e4 LT |
1724 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1725 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1726 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1727 | out: |
1728 | return ret; | |
1da177e4 LT |
1729 | } |
1730 | ||
1731 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1732 | { | |
1733 | struct inode *inode = dentry->d_inode; | |
1734 | ||
5b04c689 PE |
1735 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1736 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1737 | |
1738 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1739 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1740 | drop_nlink(inode); |
1da177e4 LT |
1741 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1742 | return 0; | |
1743 | } | |
1744 | ||
1745 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1746 | { | |
1747 | if (!simple_empty(dentry)) | |
1748 | return -ENOTEMPTY; | |
1749 | ||
9a53c3a7 DH |
1750 | drop_nlink(dentry->d_inode); |
1751 | drop_nlink(dir); | |
1da177e4 LT |
1752 | return shmem_unlink(dir, dentry); |
1753 | } | |
1754 | ||
1755 | /* | |
1756 | * The VFS layer already does all the dentry stuff for rename, | |
1757 | * we just have to decrement the usage count for the target if | |
1758 | * it exists so that the VFS layer correctly free's it when it | |
1759 | * gets overwritten. | |
1760 | */ | |
1761 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1762 | { | |
1763 | struct inode *inode = old_dentry->d_inode; | |
1764 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1765 | ||
1766 | if (!simple_empty(new_dentry)) | |
1767 | return -ENOTEMPTY; | |
1768 | ||
1769 | if (new_dentry->d_inode) { | |
1770 | (void) shmem_unlink(new_dir, new_dentry); | |
1771 | if (they_are_dirs) | |
9a53c3a7 | 1772 | drop_nlink(old_dir); |
1da177e4 | 1773 | } else if (they_are_dirs) { |
9a53c3a7 | 1774 | drop_nlink(old_dir); |
d8c76e6f | 1775 | inc_nlink(new_dir); |
1da177e4 LT |
1776 | } |
1777 | ||
1778 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1779 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1780 | old_dir->i_ctime = old_dir->i_mtime = | |
1781 | new_dir->i_ctime = new_dir->i_mtime = | |
1782 | inode->i_ctime = CURRENT_TIME; | |
1783 | return 0; | |
1784 | } | |
1785 | ||
1786 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1787 | { | |
1788 | int error; | |
1789 | int len; | |
1790 | struct inode *inode; | |
1791 | struct page *page = NULL; | |
1792 | char *kaddr; | |
1793 | struct shmem_inode_info *info; | |
1794 | ||
1795 | len = strlen(symname) + 1; | |
1796 | if (len > PAGE_CACHE_SIZE) | |
1797 | return -ENAMETOOLONG; | |
1798 | ||
1799 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1800 | if (!inode) | |
1801 | return -ENOSPC; | |
1802 | ||
570bc1c2 SS |
1803 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1804 | NULL); | |
1805 | if (error) { | |
1806 | if (error != -EOPNOTSUPP) { | |
1807 | iput(inode); | |
1808 | return error; | |
1809 | } | |
1810 | error = 0; | |
1811 | } | |
1812 | ||
1da177e4 LT |
1813 | info = SHMEM_I(inode); |
1814 | inode->i_size = len-1; | |
1815 | if (len <= (char *)inode - (char *)info) { | |
1816 | /* do it inline */ | |
1817 | memcpy(info, symname, len); | |
1818 | inode->i_op = &shmem_symlink_inline_operations; | |
1819 | } else { | |
1820 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1821 | if (error) { | |
1822 | iput(inode); | |
1823 | return error; | |
1824 | } | |
d3602444 | 1825 | unlock_page(page); |
1da177e4 LT |
1826 | inode->i_op = &shmem_symlink_inode_operations; |
1827 | kaddr = kmap_atomic(page, KM_USER0); | |
1828 | memcpy(kaddr, symname, len); | |
1829 | kunmap_atomic(kaddr, KM_USER0); | |
1830 | set_page_dirty(page); | |
1831 | page_cache_release(page); | |
1832 | } | |
1833 | if (dir->i_mode & S_ISGID) | |
1834 | inode->i_gid = dir->i_gid; | |
1835 | dir->i_size += BOGO_DIRENT_SIZE; | |
1836 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1837 | d_instantiate(dentry, inode); | |
1838 | dget(dentry); | |
1839 | return 0; | |
1840 | } | |
1841 | ||
cc314eef | 1842 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1843 | { |
1844 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1845 | return NULL; |
1da177e4 LT |
1846 | } |
1847 | ||
cc314eef | 1848 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1849 | { |
1850 | struct page *page = NULL; | |
1851 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1852 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
1853 | if (page) |
1854 | unlock_page(page); | |
cc314eef | 1855 | return page; |
1da177e4 LT |
1856 | } |
1857 | ||
cc314eef | 1858 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1859 | { |
1860 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1861 | struct page *page = cookie; |
1da177e4 LT |
1862 | kunmap(page); |
1863 | mark_page_accessed(page); | |
1864 | page_cache_release(page); | |
1da177e4 LT |
1865 | } |
1866 | } | |
1867 | ||
92e1d5be | 1868 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
1869 | .readlink = generic_readlink, |
1870 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1871 | }; |
1872 | ||
92e1d5be | 1873 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
1874 | .truncate = shmem_truncate, |
1875 | .readlink = generic_readlink, | |
1876 | .follow_link = shmem_follow_link, | |
1877 | .put_link = shmem_put_link, | |
1da177e4 LT |
1878 | }; |
1879 | ||
39f0247d AG |
1880 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1881 | /** | |
1882 | * Superblocks without xattr inode operations will get security.* xattr | |
1883 | * support from the VFS "for free". As soon as we have any other xattrs | |
1884 | * like ACLs, we also need to implement the security.* handlers at | |
1885 | * filesystem level, though. | |
1886 | */ | |
1887 | ||
1888 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
1889 | size_t list_len, const char *name, | |
1890 | size_t name_len) | |
1891 | { | |
1892 | return security_inode_listsecurity(inode, list, list_len); | |
1893 | } | |
1894 | ||
1895 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
1896 | void *buffer, size_t size) | |
1897 | { | |
1898 | if (strcmp(name, "") == 0) | |
1899 | return -EINVAL; | |
1900 | return security_inode_getsecurity(inode, name, buffer, size, | |
1901 | -EOPNOTSUPP); | |
1902 | } | |
1903 | ||
1904 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
1905 | const void *value, size_t size, int flags) | |
1906 | { | |
1907 | if (strcmp(name, "") == 0) | |
1908 | return -EINVAL; | |
1909 | return security_inode_setsecurity(inode, name, value, size, flags); | |
1910 | } | |
1911 | ||
1f370a23 | 1912 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
1913 | .prefix = XATTR_SECURITY_PREFIX, |
1914 | .list = shmem_xattr_security_list, | |
1915 | .get = shmem_xattr_security_get, | |
1916 | .set = shmem_xattr_security_set, | |
1917 | }; | |
1918 | ||
1919 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
1920 | &shmem_xattr_acl_access_handler, | |
1921 | &shmem_xattr_acl_default_handler, | |
1922 | &shmem_xattr_security_handler, | |
1923 | NULL | |
1924 | }; | |
1925 | #endif | |
1926 | ||
91828a40 DG |
1927 | static struct dentry *shmem_get_parent(struct dentry *child) |
1928 | { | |
1929 | return ERR_PTR(-ESTALE); | |
1930 | } | |
1931 | ||
1932 | static int shmem_match(struct inode *ino, void *vfh) | |
1933 | { | |
1934 | __u32 *fh = vfh; | |
1935 | __u64 inum = fh[2]; | |
1936 | inum = (inum << 32) | fh[1]; | |
1937 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1938 | } | |
1939 | ||
480b116c CH |
1940 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
1941 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 1942 | { |
91828a40 | 1943 | struct inode *inode; |
480b116c CH |
1944 | struct dentry *dentry = NULL; |
1945 | u64 inum = fid->raw[2]; | |
1946 | inum = (inum << 32) | fid->raw[1]; | |
1947 | ||
1948 | if (fh_len < 3) | |
1949 | return NULL; | |
91828a40 | 1950 | |
480b116c CH |
1951 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
1952 | shmem_match, fid->raw); | |
91828a40 | 1953 | if (inode) { |
480b116c | 1954 | dentry = d_find_alias(inode); |
91828a40 DG |
1955 | iput(inode); |
1956 | } | |
1957 | ||
480b116c | 1958 | return dentry; |
91828a40 DG |
1959 | } |
1960 | ||
1961 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
1962 | int connectable) | |
1963 | { | |
1964 | struct inode *inode = dentry->d_inode; | |
1965 | ||
1966 | if (*len < 3) | |
1967 | return 255; | |
1968 | ||
1969 | if (hlist_unhashed(&inode->i_hash)) { | |
1970 | /* Unfortunately insert_inode_hash is not idempotent, | |
1971 | * so as we hash inodes here rather than at creation | |
1972 | * time, we need a lock to ensure we only try | |
1973 | * to do it once | |
1974 | */ | |
1975 | static DEFINE_SPINLOCK(lock); | |
1976 | spin_lock(&lock); | |
1977 | if (hlist_unhashed(&inode->i_hash)) | |
1978 | __insert_inode_hash(inode, | |
1979 | inode->i_ino + inode->i_generation); | |
1980 | spin_unlock(&lock); | |
1981 | } | |
1982 | ||
1983 | fh[0] = inode->i_generation; | |
1984 | fh[1] = inode->i_ino; | |
1985 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
1986 | ||
1987 | *len = 3; | |
1988 | return 1; | |
1989 | } | |
1990 | ||
39655164 | 1991 | static const struct export_operations shmem_export_ops = { |
91828a40 | 1992 | .get_parent = shmem_get_parent, |
91828a40 | 1993 | .encode_fh = shmem_encode_fh, |
480b116c | 1994 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
1995 | }; |
1996 | ||
7339ff83 RH |
1997 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
1998 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, | |
1999 | int *policy, nodemask_t *policy_nodes) | |
1da177e4 LT |
2000 | { |
2001 | char *this_char, *value, *rest; | |
2002 | ||
b00dc3ad HD |
2003 | while (options != NULL) { |
2004 | this_char = options; | |
2005 | for (;;) { | |
2006 | /* | |
2007 | * NUL-terminate this option: unfortunately, | |
2008 | * mount options form a comma-separated list, | |
2009 | * but mpol's nodelist may also contain commas. | |
2010 | */ | |
2011 | options = strchr(options, ','); | |
2012 | if (options == NULL) | |
2013 | break; | |
2014 | options++; | |
2015 | if (!isdigit(*options)) { | |
2016 | options[-1] = '\0'; | |
2017 | break; | |
2018 | } | |
2019 | } | |
1da177e4 LT |
2020 | if (!*this_char) |
2021 | continue; | |
2022 | if ((value = strchr(this_char,'=')) != NULL) { | |
2023 | *value++ = 0; | |
2024 | } else { | |
2025 | printk(KERN_ERR | |
2026 | "tmpfs: No value for mount option '%s'\n", | |
2027 | this_char); | |
2028 | return 1; | |
2029 | } | |
2030 | ||
2031 | if (!strcmp(this_char,"size")) { | |
2032 | unsigned long long size; | |
2033 | size = memparse(value,&rest); | |
2034 | if (*rest == '%') { | |
2035 | size <<= PAGE_SHIFT; | |
2036 | size *= totalram_pages; | |
2037 | do_div(size, 100); | |
2038 | rest++; | |
2039 | } | |
2040 | if (*rest) | |
2041 | goto bad_val; | |
818db359 | 2042 | *blocks = DIV_ROUND_UP(size, PAGE_CACHE_SIZE); |
1da177e4 LT |
2043 | } else if (!strcmp(this_char,"nr_blocks")) { |
2044 | *blocks = memparse(value,&rest); | |
2045 | if (*rest) | |
2046 | goto bad_val; | |
2047 | } else if (!strcmp(this_char,"nr_inodes")) { | |
2048 | *inodes = memparse(value,&rest); | |
2049 | if (*rest) | |
2050 | goto bad_val; | |
2051 | } else if (!strcmp(this_char,"mode")) { | |
2052 | if (!mode) | |
2053 | continue; | |
2054 | *mode = simple_strtoul(value,&rest,8); | |
2055 | if (*rest) | |
2056 | goto bad_val; | |
2057 | } else if (!strcmp(this_char,"uid")) { | |
2058 | if (!uid) | |
2059 | continue; | |
2060 | *uid = simple_strtoul(value,&rest,0); | |
2061 | if (*rest) | |
2062 | goto bad_val; | |
2063 | } else if (!strcmp(this_char,"gid")) { | |
2064 | if (!gid) | |
2065 | continue; | |
2066 | *gid = simple_strtoul(value,&rest,0); | |
2067 | if (*rest) | |
2068 | goto bad_val; | |
7339ff83 | 2069 | } else if (!strcmp(this_char,"mpol")) { |
b00dc3ad | 2070 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
7339ff83 | 2071 | goto bad_val; |
1da177e4 LT |
2072 | } else { |
2073 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2074 | this_char); | |
2075 | return 1; | |
2076 | } | |
2077 | } | |
2078 | return 0; | |
2079 | ||
2080 | bad_val: | |
2081 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2082 | value, this_char); | |
2083 | return 1; | |
2084 | ||
2085 | } | |
2086 | ||
2087 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2088 | { | |
2089 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
2090 | unsigned long max_blocks = sbinfo->max_blocks; |
2091 | unsigned long max_inodes = sbinfo->max_inodes; | |
7339ff83 RH |
2092 | int policy = sbinfo->policy; |
2093 | nodemask_t policy_nodes = sbinfo->policy_nodes; | |
0edd73b3 HD |
2094 | unsigned long blocks; |
2095 | unsigned long inodes; | |
2096 | int error = -EINVAL; | |
2097 | ||
7339ff83 RH |
2098 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
2099 | &max_inodes, &policy, &policy_nodes)) | |
0edd73b3 | 2100 | return error; |
1da177e4 | 2101 | |
0edd73b3 HD |
2102 | spin_lock(&sbinfo->stat_lock); |
2103 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2104 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
2105 | if (max_blocks < blocks) | |
2106 | goto out; | |
2107 | if (max_inodes < inodes) | |
2108 | goto out; | |
2109 | /* | |
2110 | * Those tests also disallow limited->unlimited while any are in | |
2111 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2112 | * but we must separately disallow unlimited->limited, because | |
2113 | * in that case we have no record of how much is already in use. | |
2114 | */ | |
2115 | if (max_blocks && !sbinfo->max_blocks) | |
2116 | goto out; | |
2117 | if (max_inodes && !sbinfo->max_inodes) | |
2118 | goto out; | |
2119 | ||
2120 | error = 0; | |
2121 | sbinfo->max_blocks = max_blocks; | |
2122 | sbinfo->free_blocks = max_blocks - blocks; | |
2123 | sbinfo->max_inodes = max_inodes; | |
2124 | sbinfo->free_inodes = max_inodes - inodes; | |
7339ff83 RH |
2125 | sbinfo->policy = policy; |
2126 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2127 | out: |
2128 | spin_unlock(&sbinfo->stat_lock); | |
2129 | return error; | |
1da177e4 LT |
2130 | } |
2131 | #endif | |
2132 | ||
2133 | static void shmem_put_super(struct super_block *sb) | |
2134 | { | |
2135 | kfree(sb->s_fs_info); | |
2136 | sb->s_fs_info = NULL; | |
2137 | } | |
2138 | ||
1da177e4 LT |
2139 | static int shmem_fill_super(struct super_block *sb, |
2140 | void *data, int silent) | |
2141 | { | |
2142 | struct inode *inode; | |
2143 | struct dentry *root; | |
2144 | int mode = S_IRWXUGO | S_ISVTX; | |
2145 | uid_t uid = current->fsuid; | |
2146 | gid_t gid = current->fsgid; | |
2147 | int err = -ENOMEM; | |
0edd73b3 | 2148 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
2149 | unsigned long blocks = 0; |
2150 | unsigned long inodes = 0; | |
7339ff83 | 2151 | int policy = MPOL_DEFAULT; |
37b07e41 | 2152 | nodemask_t policy_nodes = node_states[N_HIGH_MEMORY]; |
1da177e4 | 2153 | |
0edd73b3 | 2154 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2155 | /* |
2156 | * Per default we only allow half of the physical ram per | |
2157 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2158 | * but the internal instance is left unlimited. | |
2159 | */ | |
2160 | if (!(sb->s_flags & MS_NOUSER)) { | |
2161 | blocks = totalram_pages / 2; | |
2162 | inodes = totalram_pages - totalhigh_pages; | |
2163 | if (inodes > blocks) | |
2164 | inodes = blocks; | |
7339ff83 RH |
2165 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
2166 | &inodes, &policy, &policy_nodes)) | |
1da177e4 LT |
2167 | return -EINVAL; |
2168 | } | |
91828a40 | 2169 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2170 | #else |
2171 | sb->s_flags |= MS_NOUSER; | |
2172 | #endif | |
2173 | ||
0edd73b3 HD |
2174 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
2175 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2176 | L1_CACHE_BYTES), GFP_KERNEL); | |
2177 | if (!sbinfo) | |
2178 | return -ENOMEM; | |
2179 | ||
2180 | spin_lock_init(&sbinfo->stat_lock); | |
2181 | sbinfo->max_blocks = blocks; | |
2182 | sbinfo->free_blocks = blocks; | |
2183 | sbinfo->max_inodes = inodes; | |
2184 | sbinfo->free_inodes = inodes; | |
7339ff83 RH |
2185 | sbinfo->policy = policy; |
2186 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2187 | |
2188 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
2189 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2190 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2191 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2192 | sb->s_magic = TMPFS_MAGIC; | |
2193 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2194 | sb->s_time_gran = 1; |
39f0247d AG |
2195 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2196 | sb->s_xattr = shmem_xattr_handlers; | |
2197 | sb->s_flags |= MS_POSIXACL; | |
2198 | #endif | |
0edd73b3 | 2199 | |
1da177e4 LT |
2200 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2201 | if (!inode) | |
2202 | goto failed; | |
2203 | inode->i_uid = uid; | |
2204 | inode->i_gid = gid; | |
2205 | root = d_alloc_root(inode); | |
2206 | if (!root) | |
2207 | goto failed_iput; | |
2208 | sb->s_root = root; | |
2209 | return 0; | |
2210 | ||
2211 | failed_iput: | |
2212 | iput(inode); | |
2213 | failed: | |
2214 | shmem_put_super(sb); | |
2215 | return err; | |
2216 | } | |
2217 | ||
fcc234f8 | 2218 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2219 | |
2220 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2221 | { | |
2222 | struct shmem_inode_info *p; | |
e94b1766 | 2223 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2224 | if (!p) |
2225 | return NULL; | |
2226 | return &p->vfs_inode; | |
2227 | } | |
2228 | ||
2229 | static void shmem_destroy_inode(struct inode *inode) | |
2230 | { | |
2231 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2232 | /* only struct inode is valid if it's an inline symlink */ | |
2233 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2234 | } | |
39f0247d | 2235 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2236 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2237 | } | |
2238 | ||
4ba9b9d0 | 2239 | static void init_once(struct kmem_cache *cachep, void *foo) |
1da177e4 LT |
2240 | { |
2241 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2242 | ||
a35afb83 | 2243 | inode_init_once(&p->vfs_inode); |
39f0247d | 2244 | #ifdef CONFIG_TMPFS_POSIX_ACL |
a35afb83 CL |
2245 | p->i_acl = NULL; |
2246 | p->i_default_acl = NULL; | |
39f0247d | 2247 | #endif |
1da177e4 LT |
2248 | } |
2249 | ||
2250 | static int init_inodecache(void) | |
2251 | { | |
2252 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2253 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2254 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2255 | return 0; |
2256 | } | |
2257 | ||
2258 | static void destroy_inodecache(void) | |
2259 | { | |
1a1d92c1 | 2260 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2261 | } |
2262 | ||
f5e54d6e | 2263 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2264 | .writepage = shmem_writepage, |
76719325 | 2265 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2266 | #ifdef CONFIG_TMPFS |
ae976416 | 2267 | .readpage = shmem_readpage, |
800d15a5 NP |
2268 | .write_begin = shmem_write_begin, |
2269 | .write_end = shmem_write_end, | |
1da177e4 | 2270 | #endif |
304dbdb7 | 2271 | .migratepage = migrate_page, |
1da177e4 LT |
2272 | }; |
2273 | ||
15ad7cdc | 2274 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2275 | .mmap = shmem_mmap, |
2276 | #ifdef CONFIG_TMPFS | |
2277 | .llseek = generic_file_llseek, | |
2278 | .read = shmem_file_read, | |
5402b976 HD |
2279 | .write = do_sync_write, |
2280 | .aio_write = generic_file_aio_write, | |
1da177e4 | 2281 | .fsync = simple_sync_file, |
ae976416 HD |
2282 | .splice_read = generic_file_splice_read, |
2283 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2284 | #endif |
2285 | }; | |
2286 | ||
92e1d5be | 2287 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2288 | .truncate = shmem_truncate, |
2289 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2290 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2291 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2292 | .setxattr = generic_setxattr, | |
2293 | .getxattr = generic_getxattr, | |
2294 | .listxattr = generic_listxattr, | |
2295 | .removexattr = generic_removexattr, | |
2296 | .permission = shmem_permission, | |
2297 | #endif | |
2298 | ||
1da177e4 LT |
2299 | }; |
2300 | ||
92e1d5be | 2301 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2302 | #ifdef CONFIG_TMPFS |
2303 | .create = shmem_create, | |
2304 | .lookup = simple_lookup, | |
2305 | .link = shmem_link, | |
2306 | .unlink = shmem_unlink, | |
2307 | .symlink = shmem_symlink, | |
2308 | .mkdir = shmem_mkdir, | |
2309 | .rmdir = shmem_rmdir, | |
2310 | .mknod = shmem_mknod, | |
2311 | .rename = shmem_rename, | |
1da177e4 | 2312 | #endif |
39f0247d AG |
2313 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2314 | .setattr = shmem_notify_change, | |
2315 | .setxattr = generic_setxattr, | |
2316 | .getxattr = generic_getxattr, | |
2317 | .listxattr = generic_listxattr, | |
2318 | .removexattr = generic_removexattr, | |
2319 | .permission = shmem_permission, | |
2320 | #endif | |
2321 | }; | |
2322 | ||
92e1d5be | 2323 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2324 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2325 | .setattr = shmem_notify_change, | |
2326 | .setxattr = generic_setxattr, | |
2327 | .getxattr = generic_getxattr, | |
2328 | .listxattr = generic_listxattr, | |
2329 | .removexattr = generic_removexattr, | |
2330 | .permission = shmem_permission, | |
2331 | #endif | |
1da177e4 LT |
2332 | }; |
2333 | ||
759b9775 | 2334 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2335 | .alloc_inode = shmem_alloc_inode, |
2336 | .destroy_inode = shmem_destroy_inode, | |
2337 | #ifdef CONFIG_TMPFS | |
2338 | .statfs = shmem_statfs, | |
2339 | .remount_fs = shmem_remount_fs, | |
2340 | #endif | |
2341 | .delete_inode = shmem_delete_inode, | |
2342 | .drop_inode = generic_delete_inode, | |
2343 | .put_super = shmem_put_super, | |
2344 | }; | |
2345 | ||
2346 | static struct vm_operations_struct shmem_vm_ops = { | |
54cb8821 | 2347 | .fault = shmem_fault, |
1da177e4 LT |
2348 | #ifdef CONFIG_NUMA |
2349 | .set_policy = shmem_set_policy, | |
2350 | .get_policy = shmem_get_policy, | |
2351 | #endif | |
2352 | }; | |
2353 | ||
2354 | ||
454e2398 DH |
2355 | static int shmem_get_sb(struct file_system_type *fs_type, |
2356 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2357 | { |
454e2398 | 2358 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2359 | } |
2360 | ||
2361 | static struct file_system_type tmpfs_fs_type = { | |
2362 | .owner = THIS_MODULE, | |
2363 | .name = "tmpfs", | |
2364 | .get_sb = shmem_get_sb, | |
2365 | .kill_sb = kill_litter_super, | |
2366 | }; | |
2367 | static struct vfsmount *shm_mnt; | |
2368 | ||
2369 | static int __init init_tmpfs(void) | |
2370 | { | |
2371 | int error; | |
2372 | ||
e0bf68dd PZ |
2373 | error = bdi_init(&shmem_backing_dev_info); |
2374 | if (error) | |
2375 | goto out4; | |
2376 | ||
1da177e4 LT |
2377 | error = init_inodecache(); |
2378 | if (error) | |
2379 | goto out3; | |
2380 | ||
2381 | error = register_filesystem(&tmpfs_fs_type); | |
2382 | if (error) { | |
2383 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2384 | goto out2; | |
2385 | } | |
95dc112a | 2386 | |
1f5ce9e9 | 2387 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2388 | tmpfs_fs_type.name, NULL); |
2389 | if (IS_ERR(shm_mnt)) { | |
2390 | error = PTR_ERR(shm_mnt); | |
2391 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2392 | goto out1; | |
2393 | } | |
2394 | return 0; | |
2395 | ||
2396 | out1: | |
2397 | unregister_filesystem(&tmpfs_fs_type); | |
2398 | out2: | |
2399 | destroy_inodecache(); | |
2400 | out3: | |
e0bf68dd PZ |
2401 | bdi_destroy(&shmem_backing_dev_info); |
2402 | out4: | |
1da177e4 LT |
2403 | shm_mnt = ERR_PTR(error); |
2404 | return error; | |
2405 | } | |
2406 | module_init(init_tmpfs) | |
2407 | ||
2408 | /* | |
2409 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2410 | * | |
2411 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2412 | * @size: size to be set for the file | |
2413 | * | |
2414 | */ | |
2415 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2416 | { | |
2417 | int error; | |
2418 | struct file *file; | |
2419 | struct inode *inode; | |
2420 | struct dentry *dentry, *root; | |
2421 | struct qstr this; | |
2422 | ||
2423 | if (IS_ERR(shm_mnt)) | |
2424 | return (void *)shm_mnt; | |
2425 | ||
2426 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2427 | return ERR_PTR(-EINVAL); | |
2428 | ||
2429 | if (shmem_acct_size(flags, size)) | |
2430 | return ERR_PTR(-ENOMEM); | |
2431 | ||
2432 | error = -ENOMEM; | |
2433 | this.name = name; | |
2434 | this.len = strlen(name); | |
2435 | this.hash = 0; /* will go */ | |
2436 | root = shm_mnt->mnt_root; | |
2437 | dentry = d_alloc(root, &this); | |
2438 | if (!dentry) | |
2439 | goto put_memory; | |
2440 | ||
2441 | error = -ENFILE; | |
2442 | file = get_empty_filp(); | |
2443 | if (!file) | |
2444 | goto put_dentry; | |
2445 | ||
2446 | error = -ENOSPC; | |
2447 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2448 | if (!inode) | |
2449 | goto close_file; | |
2450 | ||
2451 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2452 | d_instantiate(dentry, inode); | |
2453 | inode->i_size = size; | |
2454 | inode->i_nlink = 0; /* It is unlinked */ | |
ce8d2cdf DH |
2455 | init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ, |
2456 | &shmem_file_operations); | |
1da177e4 LT |
2457 | return file; |
2458 | ||
2459 | close_file: | |
2460 | put_filp(file); | |
2461 | put_dentry: | |
2462 | dput(dentry); | |
2463 | put_memory: | |
2464 | shmem_unacct_size(flags, size); | |
2465 | return ERR_PTR(error); | |
2466 | } | |
2467 | ||
2468 | /* | |
2469 | * shmem_zero_setup - setup a shared anonymous mapping | |
2470 | * | |
2471 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2472 | */ | |
2473 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2474 | { | |
2475 | struct file *file; | |
2476 | loff_t size = vma->vm_end - vma->vm_start; | |
2477 | ||
2478 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2479 | if (IS_ERR(file)) | |
2480 | return PTR_ERR(file); | |
2481 | ||
2482 | if (vma->vm_file) | |
2483 | fput(vma->vm_file); | |
2484 | vma->vm_file = file; | |
2485 | vma->vm_ops = &shmem_vm_ops; | |
2486 | return 0; | |
2487 | } |