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; | |
830 | ||
831 | idx = 0; | |
832 | ptr = info->i_direct; | |
833 | spin_lock(&info->lock); | |
834 | limit = info->next_index; | |
835 | size = limit; | |
836 | if (size > SHMEM_NR_DIRECT) | |
837 | size = SHMEM_NR_DIRECT; | |
838 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
839 | if (offset >= 0) { | |
840 | shmem_swp_balance_unmap(); | |
841 | goto found; | |
842 | } | |
843 | if (!info->i_indirect) | |
844 | goto lost2; | |
845 | ||
846 | dir = shmem_dir_map(info->i_indirect); | |
847 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
848 | ||
849 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
850 | if (unlikely(idx == stage)) { | |
851 | shmem_dir_unmap(dir-1); | |
852 | dir = shmem_dir_map(info->i_indirect) + | |
853 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
854 | while (!*dir) { | |
855 | dir++; | |
856 | idx += ENTRIES_PER_PAGEPAGE; | |
857 | if (idx >= limit) | |
858 | goto lost1; | |
859 | } | |
860 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
861 | subdir = *dir; | |
862 | shmem_dir_unmap(dir); | |
863 | dir = shmem_dir_map(subdir); | |
864 | } | |
865 | subdir = *dir; | |
4c21e2f2 | 866 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
867 | ptr = shmem_swp_map(subdir); |
868 | size = limit - idx; | |
869 | if (size > ENTRIES_PER_PAGE) | |
870 | size = ENTRIES_PER_PAGE; | |
871 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
872 | if (offset >= 0) { | |
873 | shmem_dir_unmap(dir); | |
874 | goto found; | |
875 | } | |
876 | shmem_swp_unmap(ptr); | |
877 | } | |
878 | } | |
879 | lost1: | |
880 | shmem_dir_unmap(dir-1); | |
881 | lost2: | |
882 | spin_unlock(&info->lock); | |
883 | return 0; | |
884 | found: | |
885 | idx += offset; | |
886 | inode = &info->vfs_inode; | |
887 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { | |
888 | info->flags |= SHMEM_PAGEIN; | |
889 | shmem_swp_set(info, ptr + offset, 0); | |
890 | } | |
891 | shmem_swp_unmap(ptr); | |
892 | spin_unlock(&info->lock); | |
893 | /* | |
894 | * Decrement swap count even when the entry is left behind: | |
895 | * try_to_unuse will skip over mms, then reincrement count. | |
896 | */ | |
897 | swap_free(entry); | |
898 | return 1; | |
899 | } | |
900 | ||
901 | /* | |
902 | * shmem_unuse() search for an eventually swapped out shmem page. | |
903 | */ | |
904 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
905 | { | |
906 | struct list_head *p, *next; | |
907 | struct shmem_inode_info *info; | |
908 | int found = 0; | |
909 | ||
910 | spin_lock(&shmem_swaplist_lock); | |
911 | list_for_each_safe(p, next, &shmem_swaplist) { | |
912 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
913 | if (!info->swapped) | |
914 | list_del_init(&info->swaplist); | |
915 | else if (shmem_unuse_inode(info, entry, page)) { | |
916 | /* move head to start search for next from here */ | |
917 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
918 | found = 1; | |
919 | break; | |
920 | } | |
921 | } | |
922 | spin_unlock(&shmem_swaplist_lock); | |
923 | return found; | |
924 | } | |
925 | ||
926 | /* | |
927 | * Move the page from the page cache to the swap cache. | |
928 | */ | |
929 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
930 | { | |
931 | struct shmem_inode_info *info; | |
932 | swp_entry_t *entry, swap; | |
933 | struct address_space *mapping; | |
934 | unsigned long index; | |
935 | struct inode *inode; | |
936 | ||
937 | BUG_ON(!PageLocked(page)); | |
487e9bf2 HD |
938 | /* |
939 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
940 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
941 | * may use the ->writepage of its underlying filesystem, in which case | |
942 | * we want to do nothing when that underlying filesystem is tmpfs | |
943 | * (writing out to swap is useful as a response to memory pressure, but | |
944 | * of no use to stabilize the data) - just redirty the page, unlock it | |
945 | * and claim success in this case. AOP_WRITEPAGE_ACTIVATE, and the | |
946 | * page_mapped check below, must be avoided unless we're in reclaim. | |
947 | */ | |
948 | if (!wbc->for_reclaim) { | |
949 | set_page_dirty(page); | |
950 | unlock_page(page); | |
951 | return 0; | |
952 | } | |
1da177e4 LT |
953 | BUG_ON(page_mapped(page)); |
954 | ||
955 | mapping = page->mapping; | |
956 | index = page->index; | |
957 | inode = mapping->host; | |
958 | info = SHMEM_I(inode); | |
959 | if (info->flags & VM_LOCKED) | |
960 | goto redirty; | |
961 | swap = get_swap_page(); | |
962 | if (!swap.val) | |
963 | goto redirty; | |
964 | ||
965 | spin_lock(&info->lock); | |
966 | shmem_recalc_inode(inode); | |
967 | if (index >= info->next_index) { | |
968 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
969 | goto unlock; | |
970 | } | |
971 | entry = shmem_swp_entry(info, index, NULL); | |
972 | BUG_ON(!entry); | |
973 | BUG_ON(entry->val); | |
974 | ||
975 | if (move_to_swap_cache(page, swap) == 0) { | |
976 | shmem_swp_set(info, entry, swap.val); | |
977 | shmem_swp_unmap(entry); | |
978 | spin_unlock(&info->lock); | |
979 | if (list_empty(&info->swaplist)) { | |
980 | spin_lock(&shmem_swaplist_lock); | |
981 | /* move instead of add in case we're racing */ | |
982 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
983 | spin_unlock(&shmem_swaplist_lock); | |
984 | } | |
985 | unlock_page(page); | |
986 | return 0; | |
987 | } | |
988 | ||
989 | shmem_swp_unmap(entry); | |
990 | unlock: | |
991 | spin_unlock(&info->lock); | |
992 | swap_free(swap); | |
993 | redirty: | |
994 | set_page_dirty(page); | |
994fc28c | 995 | return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */ |
1da177e4 LT |
996 | } |
997 | ||
998 | #ifdef CONFIG_NUMA | |
d15c023b | 999 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
b00dc3ad HD |
1000 | { |
1001 | char *nodelist = strchr(value, ':'); | |
1002 | int err = 1; | |
1003 | ||
1004 | if (nodelist) { | |
1005 | /* NUL-terminate policy string */ | |
1006 | *nodelist++ = '\0'; | |
1007 | if (nodelist_parse(nodelist, *policy_nodes)) | |
1008 | goto out; | |
37b07e41 | 1009 | if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY])) |
a210906c | 1010 | goto out; |
b00dc3ad HD |
1011 | } |
1012 | if (!strcmp(value, "default")) { | |
1013 | *policy = MPOL_DEFAULT; | |
1014 | /* Don't allow a nodelist */ | |
1015 | if (!nodelist) | |
1016 | err = 0; | |
1017 | } else if (!strcmp(value, "prefer")) { | |
1018 | *policy = MPOL_PREFERRED; | |
1019 | /* Insist on a nodelist of one node only */ | |
1020 | if (nodelist) { | |
1021 | char *rest = nodelist; | |
1022 | while (isdigit(*rest)) | |
1023 | rest++; | |
1024 | if (!*rest) | |
1025 | err = 0; | |
1026 | } | |
1027 | } else if (!strcmp(value, "bind")) { | |
1028 | *policy = MPOL_BIND; | |
1029 | /* Insist on a nodelist */ | |
1030 | if (nodelist) | |
1031 | err = 0; | |
1032 | } else if (!strcmp(value, "interleave")) { | |
1033 | *policy = MPOL_INTERLEAVE; | |
37b07e41 LS |
1034 | /* |
1035 | * Default to online nodes with memory if no nodelist | |
1036 | */ | |
b00dc3ad | 1037 | if (!nodelist) |
37b07e41 | 1038 | *policy_nodes = node_states[N_HIGH_MEMORY]; |
b00dc3ad HD |
1039 | err = 0; |
1040 | } | |
1041 | out: | |
1042 | /* Restore string for error message */ | |
1043 | if (nodelist) | |
1044 | *--nodelist = ':'; | |
1045 | return err; | |
1046 | } | |
1047 | ||
02098fea HD |
1048 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1049 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1050 | { |
1da177e4 | 1051 | struct vm_area_struct pvma; |
c4cc6d07 | 1052 | struct page *page; |
1da177e4 LT |
1053 | |
1054 | /* Create a pseudo vma that just contains the policy */ | |
c4cc6d07 | 1055 | pvma.vm_start = 0; |
1da177e4 | 1056 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1057 | pvma.vm_ops = NULL; |
1058 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
02098fea | 1059 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1060 | mpol_free(pvma.vm_policy); |
1061 | return page; | |
1062 | } | |
1063 | ||
02098fea HD |
1064 | static struct page *shmem_alloc_page(gfp_t gfp, |
1065 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1066 | { |
1067 | struct vm_area_struct pvma; | |
1068 | struct page *page; | |
1069 | ||
c4cc6d07 HD |
1070 | /* Create a pseudo vma that just contains the policy */ |
1071 | pvma.vm_start = 0; | |
1da177e4 | 1072 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1073 | pvma.vm_ops = NULL; |
1074 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
e84e2e13 | 1075 | page = alloc_page_vma(gfp, &pvma, 0); |
1da177e4 LT |
1076 | mpol_free(pvma.vm_policy); |
1077 | return page; | |
1078 | } | |
1079 | #else | |
37b07e41 LS |
1080 | static inline int shmem_parse_mpol(char *value, int *policy, |
1081 | nodemask_t *policy_nodes) | |
b00dc3ad HD |
1082 | { |
1083 | return 1; | |
1084 | } | |
1085 | ||
02098fea HD |
1086 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1087 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1088 | { |
02098fea | 1089 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1090 | } |
1091 | ||
02098fea HD |
1092 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1093 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1094 | { |
e84e2e13 | 1095 | return alloc_page(gfp); |
1da177e4 LT |
1096 | } |
1097 | #endif | |
1098 | ||
1099 | /* | |
1100 | * shmem_getpage - either get the page from swap or allocate a new one | |
1101 | * | |
1102 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1103 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1104 | * entry since a page cannot live in both the swap and page cache | |
1105 | */ | |
1106 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1107 | struct page **pagep, enum sgp_type sgp, int *type) | |
1108 | { | |
1109 | struct address_space *mapping = inode->i_mapping; | |
1110 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1111 | struct shmem_sb_info *sbinfo; | |
1112 | struct page *filepage = *pagep; | |
1113 | struct page *swappage; | |
1114 | swp_entry_t *entry; | |
1115 | swp_entry_t swap; | |
02098fea | 1116 | gfp_t gfp; |
1da177e4 LT |
1117 | int error; |
1118 | ||
1119 | if (idx >= SHMEM_MAX_INDEX) | |
1120 | return -EFBIG; | |
54cb8821 NP |
1121 | |
1122 | if (type) | |
83c54070 | 1123 | *type = 0; |
54cb8821 | 1124 | |
1da177e4 LT |
1125 | /* |
1126 | * Normally, filepage is NULL on entry, and either found | |
1127 | * uptodate immediately, or allocated and zeroed, or read | |
1128 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1129 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1130 | * filepage, which may be found not uptodate by other callers |
1131 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1132 | */ |
1133 | repeat: | |
1134 | if (!filepage) | |
1135 | filepage = find_lock_page(mapping, idx); | |
1136 | if (filepage && PageUptodate(filepage)) | |
1137 | goto done; | |
1138 | error = 0; | |
02098fea | 1139 | gfp = mapping_gfp_mask(mapping); |
1da177e4 LT |
1140 | |
1141 | spin_lock(&info->lock); | |
1142 | shmem_recalc_inode(inode); | |
1143 | entry = shmem_swp_alloc(info, idx, sgp); | |
1144 | if (IS_ERR(entry)) { | |
1145 | spin_unlock(&info->lock); | |
1146 | error = PTR_ERR(entry); | |
1147 | goto failed; | |
1148 | } | |
1149 | swap = *entry; | |
1150 | ||
1151 | if (swap.val) { | |
1152 | /* Look it up and read it in.. */ | |
1153 | swappage = lookup_swap_cache(swap); | |
1154 | if (!swappage) { | |
1155 | shmem_swp_unmap(entry); | |
1da177e4 | 1156 | /* here we actually do the io */ |
83c54070 | 1157 | if (type && !(*type & VM_FAULT_MAJOR)) { |
f8891e5e | 1158 | __count_vm_event(PGMAJFAULT); |
83c54070 | 1159 | *type |= VM_FAULT_MAJOR; |
1da177e4 | 1160 | } |
f8891e5e | 1161 | spin_unlock(&info->lock); |
02098fea | 1162 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1163 | if (!swappage) { |
1164 | spin_lock(&info->lock); | |
1165 | entry = shmem_swp_alloc(info, idx, sgp); | |
1166 | if (IS_ERR(entry)) | |
1167 | error = PTR_ERR(entry); | |
1168 | else { | |
1169 | if (entry->val == swap.val) | |
1170 | error = -ENOMEM; | |
1171 | shmem_swp_unmap(entry); | |
1172 | } | |
1173 | spin_unlock(&info->lock); | |
1174 | if (error) | |
1175 | goto failed; | |
1176 | goto repeat; | |
1177 | } | |
1178 | wait_on_page_locked(swappage); | |
1179 | page_cache_release(swappage); | |
1180 | goto repeat; | |
1181 | } | |
1182 | ||
1183 | /* We have to do this with page locked to prevent races */ | |
1184 | if (TestSetPageLocked(swappage)) { | |
1185 | shmem_swp_unmap(entry); | |
1186 | spin_unlock(&info->lock); | |
1187 | wait_on_page_locked(swappage); | |
1188 | page_cache_release(swappage); | |
1189 | goto repeat; | |
1190 | } | |
1191 | if (PageWriteback(swappage)) { | |
1192 | shmem_swp_unmap(entry); | |
1193 | spin_unlock(&info->lock); | |
1194 | wait_on_page_writeback(swappage); | |
1195 | unlock_page(swappage); | |
1196 | page_cache_release(swappage); | |
1197 | goto repeat; | |
1198 | } | |
1199 | if (!PageUptodate(swappage)) { | |
1200 | shmem_swp_unmap(entry); | |
1201 | spin_unlock(&info->lock); | |
1202 | unlock_page(swappage); | |
1203 | page_cache_release(swappage); | |
1204 | error = -EIO; | |
1205 | goto failed; | |
1206 | } | |
1207 | ||
1208 | if (filepage) { | |
1209 | shmem_swp_set(info, entry, 0); | |
1210 | shmem_swp_unmap(entry); | |
1211 | delete_from_swap_cache(swappage); | |
1212 | spin_unlock(&info->lock); | |
1213 | copy_highpage(filepage, swappage); | |
1214 | unlock_page(swappage); | |
1215 | page_cache_release(swappage); | |
1216 | flush_dcache_page(filepage); | |
1217 | SetPageUptodate(filepage); | |
1218 | set_page_dirty(filepage); | |
1219 | swap_free(swap); | |
1220 | } else if (!(error = move_from_swap_cache( | |
1221 | swappage, idx, mapping))) { | |
1222 | info->flags |= SHMEM_PAGEIN; | |
1223 | shmem_swp_set(info, entry, 0); | |
1224 | shmem_swp_unmap(entry); | |
1225 | spin_unlock(&info->lock); | |
1226 | filepage = swappage; | |
1227 | swap_free(swap); | |
1228 | } else { | |
1229 | shmem_swp_unmap(entry); | |
1230 | spin_unlock(&info->lock); | |
1231 | unlock_page(swappage); | |
1232 | page_cache_release(swappage); | |
1233 | if (error == -ENOMEM) { | |
1234 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
3fcfab16 | 1235 | congestion_wait(WRITE, HZ/50); |
1da177e4 LT |
1236 | } |
1237 | goto repeat; | |
1238 | } | |
1239 | } else if (sgp == SGP_READ && !filepage) { | |
1240 | shmem_swp_unmap(entry); | |
1241 | filepage = find_get_page(mapping, idx); | |
1242 | if (filepage && | |
1243 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1244 | spin_unlock(&info->lock); | |
1245 | wait_on_page_locked(filepage); | |
1246 | page_cache_release(filepage); | |
1247 | filepage = NULL; | |
1248 | goto repeat; | |
1249 | } | |
1250 | spin_unlock(&info->lock); | |
1251 | } else { | |
1252 | shmem_swp_unmap(entry); | |
1253 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1254 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1255 | spin_lock(&sbinfo->stat_lock); |
1256 | if (sbinfo->free_blocks == 0 || | |
1257 | shmem_acct_block(info->flags)) { | |
1258 | spin_unlock(&sbinfo->stat_lock); | |
1259 | spin_unlock(&info->lock); | |
1260 | error = -ENOSPC; | |
1261 | goto failed; | |
1262 | } | |
1263 | sbinfo->free_blocks--; | |
1264 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1265 | spin_unlock(&sbinfo->stat_lock); | |
1266 | } else if (shmem_acct_block(info->flags)) { | |
1267 | spin_unlock(&info->lock); | |
1268 | error = -ENOSPC; | |
1269 | goto failed; | |
1270 | } | |
1271 | ||
1272 | if (!filepage) { | |
1273 | spin_unlock(&info->lock); | |
02098fea | 1274 | filepage = shmem_alloc_page(gfp, info, idx); |
1da177e4 LT |
1275 | if (!filepage) { |
1276 | shmem_unacct_blocks(info->flags, 1); | |
1277 | shmem_free_blocks(inode, 1); | |
1278 | error = -ENOMEM; | |
1279 | goto failed; | |
1280 | } | |
1281 | ||
1282 | spin_lock(&info->lock); | |
1283 | entry = shmem_swp_alloc(info, idx, sgp); | |
1284 | if (IS_ERR(entry)) | |
1285 | error = PTR_ERR(entry); | |
1286 | else { | |
1287 | swap = *entry; | |
1288 | shmem_swp_unmap(entry); | |
1289 | } | |
1290 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1291 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1292 | spin_unlock(&info->lock); | |
1293 | page_cache_release(filepage); | |
1294 | shmem_unacct_blocks(info->flags, 1); | |
1295 | shmem_free_blocks(inode, 1); | |
1296 | filepage = NULL; | |
1297 | if (error) | |
1298 | goto failed; | |
1299 | goto repeat; | |
1300 | } | |
1301 | info->flags |= SHMEM_PAGEIN; | |
1302 | } | |
1303 | ||
1304 | info->alloced++; | |
1305 | spin_unlock(&info->lock); | |
e84e2e13 | 1306 | clear_highpage(filepage); |
1da177e4 LT |
1307 | flush_dcache_page(filepage); |
1308 | SetPageUptodate(filepage); | |
1309 | } | |
1310 | done: | |
d3602444 | 1311 | *pagep = filepage; |
1da177e4 LT |
1312 | return 0; |
1313 | ||
1314 | failed: | |
1315 | if (*pagep != filepage) { | |
1316 | unlock_page(filepage); | |
1317 | page_cache_release(filepage); | |
1318 | } | |
1319 | return error; | |
1320 | } | |
1321 | ||
d0217ac0 | 1322 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1323 | { |
d3ac7f89 | 1324 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1325 | int error; |
d0217ac0 | 1326 | int ret; |
1da177e4 | 1327 | |
d0217ac0 NP |
1328 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1329 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1330 | |
27d54b39 | 1331 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1332 | if (error) |
1333 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1da177e4 | 1334 | |
d0217ac0 | 1335 | mark_page_accessed(vmf->page); |
83c54070 | 1336 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1337 | } |
1338 | ||
1da177e4 | 1339 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1340 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1341 | { |
d3ac7f89 | 1342 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1343 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1344 | } | |
1345 | ||
d8dc74f2 AB |
1346 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1347 | unsigned long addr) | |
1da177e4 | 1348 | { |
d3ac7f89 | 1349 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1350 | unsigned long idx; |
1351 | ||
1352 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1353 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1354 | } | |
1355 | #endif | |
1356 | ||
1357 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1358 | { | |
d3ac7f89 | 1359 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1360 | struct shmem_inode_info *info = SHMEM_I(inode); |
1361 | int retval = -ENOMEM; | |
1362 | ||
1363 | spin_lock(&info->lock); | |
1364 | if (lock && !(info->flags & VM_LOCKED)) { | |
1365 | if (!user_shm_lock(inode->i_size, user)) | |
1366 | goto out_nomem; | |
1367 | info->flags |= VM_LOCKED; | |
1368 | } | |
1369 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1370 | user_shm_unlock(inode->i_size, user); | |
1371 | info->flags &= ~VM_LOCKED; | |
1372 | } | |
1373 | retval = 0; | |
1374 | out_nomem: | |
1375 | spin_unlock(&info->lock); | |
1376 | return retval; | |
1377 | } | |
1378 | ||
9b83a6a8 | 1379 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1380 | { |
1381 | file_accessed(file); | |
1382 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1383 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1384 | return 0; |
1385 | } | |
1386 | ||
1387 | static struct inode * | |
1388 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1389 | { | |
1390 | struct inode *inode; | |
1391 | struct shmem_inode_info *info; | |
1392 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1393 | ||
5b04c689 PE |
1394 | if (shmem_reserve_inode(sb)) |
1395 | return NULL; | |
1da177e4 LT |
1396 | |
1397 | inode = new_inode(sb); | |
1398 | if (inode) { | |
1399 | inode->i_mode = mode; | |
1400 | inode->i_uid = current->fsuid; | |
1401 | inode->i_gid = current->fsgid; | |
1da177e4 LT |
1402 | inode->i_blocks = 0; |
1403 | inode->i_mapping->a_ops = &shmem_aops; | |
1404 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1405 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1406 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1407 | info = SHMEM_I(inode); |
1408 | memset(info, 0, (char *)inode - (char *)info); | |
1409 | spin_lock_init(&info->lock); | |
1410 | INIT_LIST_HEAD(&info->swaplist); | |
1411 | ||
1412 | switch (mode & S_IFMT) { | |
1413 | default: | |
39f0247d | 1414 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1415 | init_special_inode(inode, mode, dev); |
1416 | break; | |
1417 | case S_IFREG: | |
1418 | inode->i_op = &shmem_inode_operations; | |
1419 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1420 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1421 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1422 | break; |
1423 | case S_IFDIR: | |
d8c76e6f | 1424 | inc_nlink(inode); |
1da177e4 LT |
1425 | /* Some things misbehave if size == 0 on a directory */ |
1426 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1427 | inode->i_op = &shmem_dir_inode_operations; | |
1428 | inode->i_fop = &simple_dir_operations; | |
1429 | break; | |
1430 | case S_IFLNK: | |
1431 | /* | |
1432 | * Must not load anything in the rbtree, | |
1433 | * mpol_free_shared_policy will not be called. | |
1434 | */ | |
7339ff83 RH |
1435 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1436 | NULL); | |
1da177e4 LT |
1437 | break; |
1438 | } | |
5b04c689 PE |
1439 | } else |
1440 | shmem_free_inode(sb); | |
1da177e4 LT |
1441 | return inode; |
1442 | } | |
1443 | ||
1444 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1445 | static const struct inode_operations shmem_symlink_inode_operations; |
1446 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1447 | |
1448 | /* | |
800d15a5 | 1449 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1450 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1451 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1452 | */ |
ae976416 HD |
1453 | static int shmem_readpage(struct file *file, struct page *page) |
1454 | { | |
1455 | struct inode *inode = page->mapping->host; | |
1456 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1457 | unlock_page(page); | |
1458 | return error; | |
1459 | } | |
1460 | ||
1da177e4 | 1461 | static int |
800d15a5 NP |
1462 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1463 | loff_t pos, unsigned len, unsigned flags, | |
1464 | struct page **pagep, void **fsdata) | |
1da177e4 | 1465 | { |
800d15a5 NP |
1466 | struct inode *inode = mapping->host; |
1467 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1468 | *pagep = NULL; | |
1469 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1470 | } | |
1471 | ||
1472 | static int | |
1473 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1474 | loff_t pos, unsigned len, unsigned copied, | |
1475 | struct page *page, void *fsdata) | |
1476 | { | |
1477 | struct inode *inode = mapping->host; | |
1478 | ||
d3602444 HD |
1479 | if (pos + copied > inode->i_size) |
1480 | i_size_write(inode, pos + copied); | |
1481 | ||
1482 | unlock_page(page); | |
800d15a5 NP |
1483 | set_page_dirty(page); |
1484 | page_cache_release(page); | |
1485 | ||
800d15a5 | 1486 | return copied; |
1da177e4 LT |
1487 | } |
1488 | ||
1da177e4 LT |
1489 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1490 | { | |
d3ac7f89 | 1491 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1492 | struct address_space *mapping = inode->i_mapping; |
1493 | unsigned long index, offset; | |
1494 | ||
1495 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1496 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1497 | ||
1498 | for (;;) { | |
1499 | struct page *page = NULL; | |
1500 | unsigned long end_index, nr, ret; | |
1501 | loff_t i_size = i_size_read(inode); | |
1502 | ||
1503 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1504 | if (index > end_index) | |
1505 | break; | |
1506 | if (index == end_index) { | |
1507 | nr = i_size & ~PAGE_CACHE_MASK; | |
1508 | if (nr <= offset) | |
1509 | break; | |
1510 | } | |
1511 | ||
1512 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); | |
1513 | if (desc->error) { | |
1514 | if (desc->error == -EINVAL) | |
1515 | desc->error = 0; | |
1516 | break; | |
1517 | } | |
d3602444 HD |
1518 | if (page) |
1519 | unlock_page(page); | |
1da177e4 LT |
1520 | |
1521 | /* | |
1522 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1523 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1524 | */ |
1525 | nr = PAGE_CACHE_SIZE; | |
1526 | i_size = i_size_read(inode); | |
1527 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1528 | if (index == end_index) { | |
1529 | nr = i_size & ~PAGE_CACHE_MASK; | |
1530 | if (nr <= offset) { | |
1531 | if (page) | |
1532 | page_cache_release(page); | |
1533 | break; | |
1534 | } | |
1535 | } | |
1536 | nr -= offset; | |
1537 | ||
1538 | if (page) { | |
1539 | /* | |
1540 | * If users can be writing to this page using arbitrary | |
1541 | * virtual addresses, take care about potential aliasing | |
1542 | * before reading the page on the kernel side. | |
1543 | */ | |
1544 | if (mapping_writably_mapped(mapping)) | |
1545 | flush_dcache_page(page); | |
1546 | /* | |
1547 | * Mark the page accessed if we read the beginning. | |
1548 | */ | |
1549 | if (!offset) | |
1550 | mark_page_accessed(page); | |
b5810039 | 1551 | } else { |
1da177e4 | 1552 | page = ZERO_PAGE(0); |
b5810039 NP |
1553 | page_cache_get(page); |
1554 | } | |
1da177e4 LT |
1555 | |
1556 | /* | |
1557 | * Ok, we have the page, and it's up-to-date, so | |
1558 | * now we can copy it to user space... | |
1559 | * | |
1560 | * The actor routine returns how many bytes were actually used.. | |
1561 | * NOTE! This may not be the same as how much of a user buffer | |
1562 | * we filled up (we may be padding etc), so we can only update | |
1563 | * "pos" here (the actor routine has to update the user buffer | |
1564 | * pointers and the remaining count). | |
1565 | */ | |
1566 | ret = actor(desc, page, offset, nr); | |
1567 | offset += ret; | |
1568 | index += offset >> PAGE_CACHE_SHIFT; | |
1569 | offset &= ~PAGE_CACHE_MASK; | |
1570 | ||
1571 | page_cache_release(page); | |
1572 | if (ret != nr || !desc->count) | |
1573 | break; | |
1574 | ||
1575 | cond_resched(); | |
1576 | } | |
1577 | ||
1578 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1579 | file_accessed(filp); | |
1580 | } | |
1581 | ||
1582 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1583 | { | |
1584 | read_descriptor_t desc; | |
1585 | ||
1586 | if ((ssize_t) count < 0) | |
1587 | return -EINVAL; | |
1588 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1589 | return -EFAULT; | |
1590 | if (!count) | |
1591 | return 0; | |
1592 | ||
1593 | desc.written = 0; | |
1594 | desc.count = count; | |
1595 | desc.arg.buf = buf; | |
1596 | desc.error = 0; | |
1597 | ||
1598 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1599 | if (desc.written) | |
1600 | return desc.written; | |
1601 | return desc.error; | |
1602 | } | |
1603 | ||
726c3342 | 1604 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1605 | { |
726c3342 | 1606 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1607 | |
1608 | buf->f_type = TMPFS_MAGIC; | |
1609 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1610 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1611 | spin_lock(&sbinfo->stat_lock); |
1612 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1613 | buf->f_blocks = sbinfo->max_blocks; |
1614 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1615 | } |
1616 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1617 | buf->f_files = sbinfo->max_inodes; |
1618 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1619 | } |
1620 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1621 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1622 | return 0; |
1623 | } | |
1624 | ||
1625 | /* | |
1626 | * File creation. Allocate an inode, and we're done.. | |
1627 | */ | |
1628 | static int | |
1629 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1630 | { | |
1631 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1632 | int error = -ENOSPC; | |
1633 | ||
1634 | if (inode) { | |
570bc1c2 SS |
1635 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1636 | NULL); | |
1637 | if (error) { | |
1638 | if (error != -EOPNOTSUPP) { | |
1639 | iput(inode); | |
1640 | return error; | |
1641 | } | |
39f0247d AG |
1642 | } |
1643 | error = shmem_acl_init(inode, dir); | |
1644 | if (error) { | |
1645 | iput(inode); | |
1646 | return error; | |
570bc1c2 | 1647 | } |
1da177e4 LT |
1648 | if (dir->i_mode & S_ISGID) { |
1649 | inode->i_gid = dir->i_gid; | |
1650 | if (S_ISDIR(mode)) | |
1651 | inode->i_mode |= S_ISGID; | |
1652 | } | |
1653 | dir->i_size += BOGO_DIRENT_SIZE; | |
1654 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1655 | d_instantiate(dentry, inode); | |
1656 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1657 | } |
1658 | return error; | |
1659 | } | |
1660 | ||
1661 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1662 | { | |
1663 | int error; | |
1664 | ||
1665 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1666 | return error; | |
d8c76e6f | 1667 | inc_nlink(dir); |
1da177e4 LT |
1668 | return 0; |
1669 | } | |
1670 | ||
1671 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1672 | struct nameidata *nd) | |
1673 | { | |
1674 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1675 | } | |
1676 | ||
1677 | /* | |
1678 | * Link a file.. | |
1679 | */ | |
1680 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1681 | { | |
1682 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1683 | int ret; |
1da177e4 LT |
1684 | |
1685 | /* | |
1686 | * No ordinary (disk based) filesystem counts links as inodes; | |
1687 | * but each new link needs a new dentry, pinning lowmem, and | |
1688 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1689 | */ | |
5b04c689 PE |
1690 | ret = shmem_reserve_inode(inode->i_sb); |
1691 | if (ret) | |
1692 | goto out; | |
1da177e4 LT |
1693 | |
1694 | dir->i_size += BOGO_DIRENT_SIZE; | |
1695 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1696 | inc_nlink(inode); |
1da177e4 LT |
1697 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1698 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1699 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1700 | out: |
1701 | return ret; | |
1da177e4 LT |
1702 | } |
1703 | ||
1704 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1705 | { | |
1706 | struct inode *inode = dentry->d_inode; | |
1707 | ||
5b04c689 PE |
1708 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1709 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1710 | |
1711 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1712 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1713 | drop_nlink(inode); |
1da177e4 LT |
1714 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1715 | return 0; | |
1716 | } | |
1717 | ||
1718 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1719 | { | |
1720 | if (!simple_empty(dentry)) | |
1721 | return -ENOTEMPTY; | |
1722 | ||
9a53c3a7 DH |
1723 | drop_nlink(dentry->d_inode); |
1724 | drop_nlink(dir); | |
1da177e4 LT |
1725 | return shmem_unlink(dir, dentry); |
1726 | } | |
1727 | ||
1728 | /* | |
1729 | * The VFS layer already does all the dentry stuff for rename, | |
1730 | * we just have to decrement the usage count for the target if | |
1731 | * it exists so that the VFS layer correctly free's it when it | |
1732 | * gets overwritten. | |
1733 | */ | |
1734 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1735 | { | |
1736 | struct inode *inode = old_dentry->d_inode; | |
1737 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1738 | ||
1739 | if (!simple_empty(new_dentry)) | |
1740 | return -ENOTEMPTY; | |
1741 | ||
1742 | if (new_dentry->d_inode) { | |
1743 | (void) shmem_unlink(new_dir, new_dentry); | |
1744 | if (they_are_dirs) | |
9a53c3a7 | 1745 | drop_nlink(old_dir); |
1da177e4 | 1746 | } else if (they_are_dirs) { |
9a53c3a7 | 1747 | drop_nlink(old_dir); |
d8c76e6f | 1748 | inc_nlink(new_dir); |
1da177e4 LT |
1749 | } |
1750 | ||
1751 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1752 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1753 | old_dir->i_ctime = old_dir->i_mtime = | |
1754 | new_dir->i_ctime = new_dir->i_mtime = | |
1755 | inode->i_ctime = CURRENT_TIME; | |
1756 | return 0; | |
1757 | } | |
1758 | ||
1759 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1760 | { | |
1761 | int error; | |
1762 | int len; | |
1763 | struct inode *inode; | |
1764 | struct page *page = NULL; | |
1765 | char *kaddr; | |
1766 | struct shmem_inode_info *info; | |
1767 | ||
1768 | len = strlen(symname) + 1; | |
1769 | if (len > PAGE_CACHE_SIZE) | |
1770 | return -ENAMETOOLONG; | |
1771 | ||
1772 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1773 | if (!inode) | |
1774 | return -ENOSPC; | |
1775 | ||
570bc1c2 SS |
1776 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1777 | NULL); | |
1778 | if (error) { | |
1779 | if (error != -EOPNOTSUPP) { | |
1780 | iput(inode); | |
1781 | return error; | |
1782 | } | |
1783 | error = 0; | |
1784 | } | |
1785 | ||
1da177e4 LT |
1786 | info = SHMEM_I(inode); |
1787 | inode->i_size = len-1; | |
1788 | if (len <= (char *)inode - (char *)info) { | |
1789 | /* do it inline */ | |
1790 | memcpy(info, symname, len); | |
1791 | inode->i_op = &shmem_symlink_inline_operations; | |
1792 | } else { | |
1793 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1794 | if (error) { | |
1795 | iput(inode); | |
1796 | return error; | |
1797 | } | |
d3602444 | 1798 | unlock_page(page); |
1da177e4 LT |
1799 | inode->i_op = &shmem_symlink_inode_operations; |
1800 | kaddr = kmap_atomic(page, KM_USER0); | |
1801 | memcpy(kaddr, symname, len); | |
1802 | kunmap_atomic(kaddr, KM_USER0); | |
1803 | set_page_dirty(page); | |
1804 | page_cache_release(page); | |
1805 | } | |
1806 | if (dir->i_mode & S_ISGID) | |
1807 | inode->i_gid = dir->i_gid; | |
1808 | dir->i_size += BOGO_DIRENT_SIZE; | |
1809 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1810 | d_instantiate(dentry, inode); | |
1811 | dget(dentry); | |
1812 | return 0; | |
1813 | } | |
1814 | ||
cc314eef | 1815 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1816 | { |
1817 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1818 | return NULL; |
1da177e4 LT |
1819 | } |
1820 | ||
cc314eef | 1821 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1822 | { |
1823 | struct page *page = NULL; | |
1824 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1825 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
1826 | if (page) |
1827 | unlock_page(page); | |
cc314eef | 1828 | return page; |
1da177e4 LT |
1829 | } |
1830 | ||
cc314eef | 1831 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1832 | { |
1833 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1834 | struct page *page = cookie; |
1da177e4 LT |
1835 | kunmap(page); |
1836 | mark_page_accessed(page); | |
1837 | page_cache_release(page); | |
1da177e4 LT |
1838 | } |
1839 | } | |
1840 | ||
92e1d5be | 1841 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
1842 | .readlink = generic_readlink, |
1843 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1844 | }; |
1845 | ||
92e1d5be | 1846 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
1847 | .truncate = shmem_truncate, |
1848 | .readlink = generic_readlink, | |
1849 | .follow_link = shmem_follow_link, | |
1850 | .put_link = shmem_put_link, | |
1da177e4 LT |
1851 | }; |
1852 | ||
39f0247d AG |
1853 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1854 | /** | |
1855 | * Superblocks without xattr inode operations will get security.* xattr | |
1856 | * support from the VFS "for free". As soon as we have any other xattrs | |
1857 | * like ACLs, we also need to implement the security.* handlers at | |
1858 | * filesystem level, though. | |
1859 | */ | |
1860 | ||
1861 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
1862 | size_t list_len, const char *name, | |
1863 | size_t name_len) | |
1864 | { | |
1865 | return security_inode_listsecurity(inode, list, list_len); | |
1866 | } | |
1867 | ||
1868 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
1869 | void *buffer, size_t size) | |
1870 | { | |
1871 | if (strcmp(name, "") == 0) | |
1872 | return -EINVAL; | |
1873 | return security_inode_getsecurity(inode, name, buffer, size, | |
1874 | -EOPNOTSUPP); | |
1875 | } | |
1876 | ||
1877 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
1878 | const void *value, size_t size, int flags) | |
1879 | { | |
1880 | if (strcmp(name, "") == 0) | |
1881 | return -EINVAL; | |
1882 | return security_inode_setsecurity(inode, name, value, size, flags); | |
1883 | } | |
1884 | ||
1f370a23 | 1885 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
1886 | .prefix = XATTR_SECURITY_PREFIX, |
1887 | .list = shmem_xattr_security_list, | |
1888 | .get = shmem_xattr_security_get, | |
1889 | .set = shmem_xattr_security_set, | |
1890 | }; | |
1891 | ||
1892 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
1893 | &shmem_xattr_acl_access_handler, | |
1894 | &shmem_xattr_acl_default_handler, | |
1895 | &shmem_xattr_security_handler, | |
1896 | NULL | |
1897 | }; | |
1898 | #endif | |
1899 | ||
91828a40 DG |
1900 | static struct dentry *shmem_get_parent(struct dentry *child) |
1901 | { | |
1902 | return ERR_PTR(-ESTALE); | |
1903 | } | |
1904 | ||
1905 | static int shmem_match(struct inode *ino, void *vfh) | |
1906 | { | |
1907 | __u32 *fh = vfh; | |
1908 | __u64 inum = fh[2]; | |
1909 | inum = (inum << 32) | fh[1]; | |
1910 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1911 | } | |
1912 | ||
480b116c CH |
1913 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
1914 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 1915 | { |
91828a40 | 1916 | struct inode *inode; |
480b116c CH |
1917 | struct dentry *dentry = NULL; |
1918 | u64 inum = fid->raw[2]; | |
1919 | inum = (inum << 32) | fid->raw[1]; | |
1920 | ||
1921 | if (fh_len < 3) | |
1922 | return NULL; | |
91828a40 | 1923 | |
480b116c CH |
1924 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
1925 | shmem_match, fid->raw); | |
91828a40 | 1926 | if (inode) { |
480b116c | 1927 | dentry = d_find_alias(inode); |
91828a40 DG |
1928 | iput(inode); |
1929 | } | |
1930 | ||
480b116c | 1931 | return dentry; |
91828a40 DG |
1932 | } |
1933 | ||
1934 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
1935 | int connectable) | |
1936 | { | |
1937 | struct inode *inode = dentry->d_inode; | |
1938 | ||
1939 | if (*len < 3) | |
1940 | return 255; | |
1941 | ||
1942 | if (hlist_unhashed(&inode->i_hash)) { | |
1943 | /* Unfortunately insert_inode_hash is not idempotent, | |
1944 | * so as we hash inodes here rather than at creation | |
1945 | * time, we need a lock to ensure we only try | |
1946 | * to do it once | |
1947 | */ | |
1948 | static DEFINE_SPINLOCK(lock); | |
1949 | spin_lock(&lock); | |
1950 | if (hlist_unhashed(&inode->i_hash)) | |
1951 | __insert_inode_hash(inode, | |
1952 | inode->i_ino + inode->i_generation); | |
1953 | spin_unlock(&lock); | |
1954 | } | |
1955 | ||
1956 | fh[0] = inode->i_generation; | |
1957 | fh[1] = inode->i_ino; | |
1958 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
1959 | ||
1960 | *len = 3; | |
1961 | return 1; | |
1962 | } | |
1963 | ||
39655164 | 1964 | static const struct export_operations shmem_export_ops = { |
91828a40 | 1965 | .get_parent = shmem_get_parent, |
91828a40 | 1966 | .encode_fh = shmem_encode_fh, |
480b116c | 1967 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
1968 | }; |
1969 | ||
7339ff83 RH |
1970 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
1971 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, | |
1972 | int *policy, nodemask_t *policy_nodes) | |
1da177e4 LT |
1973 | { |
1974 | char *this_char, *value, *rest; | |
1975 | ||
b00dc3ad HD |
1976 | while (options != NULL) { |
1977 | this_char = options; | |
1978 | for (;;) { | |
1979 | /* | |
1980 | * NUL-terminate this option: unfortunately, | |
1981 | * mount options form a comma-separated list, | |
1982 | * but mpol's nodelist may also contain commas. | |
1983 | */ | |
1984 | options = strchr(options, ','); | |
1985 | if (options == NULL) | |
1986 | break; | |
1987 | options++; | |
1988 | if (!isdigit(*options)) { | |
1989 | options[-1] = '\0'; | |
1990 | break; | |
1991 | } | |
1992 | } | |
1da177e4 LT |
1993 | if (!*this_char) |
1994 | continue; | |
1995 | if ((value = strchr(this_char,'=')) != NULL) { | |
1996 | *value++ = 0; | |
1997 | } else { | |
1998 | printk(KERN_ERR | |
1999 | "tmpfs: No value for mount option '%s'\n", | |
2000 | this_char); | |
2001 | return 1; | |
2002 | } | |
2003 | ||
2004 | if (!strcmp(this_char,"size")) { | |
2005 | unsigned long long size; | |
2006 | size = memparse(value,&rest); | |
2007 | if (*rest == '%') { | |
2008 | size <<= PAGE_SHIFT; | |
2009 | size *= totalram_pages; | |
2010 | do_div(size, 100); | |
2011 | rest++; | |
2012 | } | |
2013 | if (*rest) | |
2014 | goto bad_val; | |
818db359 | 2015 | *blocks = DIV_ROUND_UP(size, PAGE_CACHE_SIZE); |
1da177e4 LT |
2016 | } else if (!strcmp(this_char,"nr_blocks")) { |
2017 | *blocks = memparse(value,&rest); | |
2018 | if (*rest) | |
2019 | goto bad_val; | |
2020 | } else if (!strcmp(this_char,"nr_inodes")) { | |
2021 | *inodes = memparse(value,&rest); | |
2022 | if (*rest) | |
2023 | goto bad_val; | |
2024 | } else if (!strcmp(this_char,"mode")) { | |
2025 | if (!mode) | |
2026 | continue; | |
2027 | *mode = simple_strtoul(value,&rest,8); | |
2028 | if (*rest) | |
2029 | goto bad_val; | |
2030 | } else if (!strcmp(this_char,"uid")) { | |
2031 | if (!uid) | |
2032 | continue; | |
2033 | *uid = simple_strtoul(value,&rest,0); | |
2034 | if (*rest) | |
2035 | goto bad_val; | |
2036 | } else if (!strcmp(this_char,"gid")) { | |
2037 | if (!gid) | |
2038 | continue; | |
2039 | *gid = simple_strtoul(value,&rest,0); | |
2040 | if (*rest) | |
2041 | goto bad_val; | |
7339ff83 | 2042 | } else if (!strcmp(this_char,"mpol")) { |
b00dc3ad | 2043 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
7339ff83 | 2044 | goto bad_val; |
1da177e4 LT |
2045 | } else { |
2046 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2047 | this_char); | |
2048 | return 1; | |
2049 | } | |
2050 | } | |
2051 | return 0; | |
2052 | ||
2053 | bad_val: | |
2054 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2055 | value, this_char); | |
2056 | return 1; | |
2057 | ||
2058 | } | |
2059 | ||
2060 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2061 | { | |
2062 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
2063 | unsigned long max_blocks = sbinfo->max_blocks; |
2064 | unsigned long max_inodes = sbinfo->max_inodes; | |
7339ff83 RH |
2065 | int policy = sbinfo->policy; |
2066 | nodemask_t policy_nodes = sbinfo->policy_nodes; | |
0edd73b3 HD |
2067 | unsigned long blocks; |
2068 | unsigned long inodes; | |
2069 | int error = -EINVAL; | |
2070 | ||
7339ff83 RH |
2071 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
2072 | &max_inodes, &policy, &policy_nodes)) | |
0edd73b3 | 2073 | return error; |
1da177e4 | 2074 | |
0edd73b3 HD |
2075 | spin_lock(&sbinfo->stat_lock); |
2076 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2077 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
2078 | if (max_blocks < blocks) | |
2079 | goto out; | |
2080 | if (max_inodes < inodes) | |
2081 | goto out; | |
2082 | /* | |
2083 | * Those tests also disallow limited->unlimited while any are in | |
2084 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2085 | * but we must separately disallow unlimited->limited, because | |
2086 | * in that case we have no record of how much is already in use. | |
2087 | */ | |
2088 | if (max_blocks && !sbinfo->max_blocks) | |
2089 | goto out; | |
2090 | if (max_inodes && !sbinfo->max_inodes) | |
2091 | goto out; | |
2092 | ||
2093 | error = 0; | |
2094 | sbinfo->max_blocks = max_blocks; | |
2095 | sbinfo->free_blocks = max_blocks - blocks; | |
2096 | sbinfo->max_inodes = max_inodes; | |
2097 | sbinfo->free_inodes = max_inodes - inodes; | |
7339ff83 RH |
2098 | sbinfo->policy = policy; |
2099 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2100 | out: |
2101 | spin_unlock(&sbinfo->stat_lock); | |
2102 | return error; | |
1da177e4 LT |
2103 | } |
2104 | #endif | |
2105 | ||
2106 | static void shmem_put_super(struct super_block *sb) | |
2107 | { | |
2108 | kfree(sb->s_fs_info); | |
2109 | sb->s_fs_info = NULL; | |
2110 | } | |
2111 | ||
1da177e4 LT |
2112 | static int shmem_fill_super(struct super_block *sb, |
2113 | void *data, int silent) | |
2114 | { | |
2115 | struct inode *inode; | |
2116 | struct dentry *root; | |
2117 | int mode = S_IRWXUGO | S_ISVTX; | |
2118 | uid_t uid = current->fsuid; | |
2119 | gid_t gid = current->fsgid; | |
2120 | int err = -ENOMEM; | |
0edd73b3 | 2121 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
2122 | unsigned long blocks = 0; |
2123 | unsigned long inodes = 0; | |
7339ff83 | 2124 | int policy = MPOL_DEFAULT; |
37b07e41 | 2125 | nodemask_t policy_nodes = node_states[N_HIGH_MEMORY]; |
1da177e4 | 2126 | |
0edd73b3 | 2127 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2128 | /* |
2129 | * Per default we only allow half of the physical ram per | |
2130 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2131 | * but the internal instance is left unlimited. | |
2132 | */ | |
2133 | if (!(sb->s_flags & MS_NOUSER)) { | |
2134 | blocks = totalram_pages / 2; | |
2135 | inodes = totalram_pages - totalhigh_pages; | |
2136 | if (inodes > blocks) | |
2137 | inodes = blocks; | |
7339ff83 RH |
2138 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
2139 | &inodes, &policy, &policy_nodes)) | |
1da177e4 LT |
2140 | return -EINVAL; |
2141 | } | |
91828a40 | 2142 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2143 | #else |
2144 | sb->s_flags |= MS_NOUSER; | |
2145 | #endif | |
2146 | ||
0edd73b3 HD |
2147 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
2148 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2149 | L1_CACHE_BYTES), GFP_KERNEL); | |
2150 | if (!sbinfo) | |
2151 | return -ENOMEM; | |
2152 | ||
2153 | spin_lock_init(&sbinfo->stat_lock); | |
2154 | sbinfo->max_blocks = blocks; | |
2155 | sbinfo->free_blocks = blocks; | |
2156 | sbinfo->max_inodes = inodes; | |
2157 | sbinfo->free_inodes = inodes; | |
7339ff83 RH |
2158 | sbinfo->policy = policy; |
2159 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2160 | |
2161 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
2162 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2163 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2164 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2165 | sb->s_magic = TMPFS_MAGIC; | |
2166 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2167 | sb->s_time_gran = 1; |
39f0247d AG |
2168 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2169 | sb->s_xattr = shmem_xattr_handlers; | |
2170 | sb->s_flags |= MS_POSIXACL; | |
2171 | #endif | |
0edd73b3 | 2172 | |
1da177e4 LT |
2173 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2174 | if (!inode) | |
2175 | goto failed; | |
2176 | inode->i_uid = uid; | |
2177 | inode->i_gid = gid; | |
2178 | root = d_alloc_root(inode); | |
2179 | if (!root) | |
2180 | goto failed_iput; | |
2181 | sb->s_root = root; | |
2182 | return 0; | |
2183 | ||
2184 | failed_iput: | |
2185 | iput(inode); | |
2186 | failed: | |
2187 | shmem_put_super(sb); | |
2188 | return err; | |
2189 | } | |
2190 | ||
fcc234f8 | 2191 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2192 | |
2193 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2194 | { | |
2195 | struct shmem_inode_info *p; | |
e94b1766 | 2196 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2197 | if (!p) |
2198 | return NULL; | |
2199 | return &p->vfs_inode; | |
2200 | } | |
2201 | ||
2202 | static void shmem_destroy_inode(struct inode *inode) | |
2203 | { | |
2204 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2205 | /* only struct inode is valid if it's an inline symlink */ | |
2206 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2207 | } | |
39f0247d | 2208 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2209 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2210 | } | |
2211 | ||
4ba9b9d0 | 2212 | static void init_once(struct kmem_cache *cachep, void *foo) |
1da177e4 LT |
2213 | { |
2214 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2215 | ||
a35afb83 | 2216 | inode_init_once(&p->vfs_inode); |
39f0247d | 2217 | #ifdef CONFIG_TMPFS_POSIX_ACL |
a35afb83 CL |
2218 | p->i_acl = NULL; |
2219 | p->i_default_acl = NULL; | |
39f0247d | 2220 | #endif |
1da177e4 LT |
2221 | } |
2222 | ||
2223 | static int init_inodecache(void) | |
2224 | { | |
2225 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2226 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2227 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2228 | return 0; |
2229 | } | |
2230 | ||
2231 | static void destroy_inodecache(void) | |
2232 | { | |
1a1d92c1 | 2233 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2234 | } |
2235 | ||
f5e54d6e | 2236 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2237 | .writepage = shmem_writepage, |
76719325 | 2238 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2239 | #ifdef CONFIG_TMPFS |
ae976416 | 2240 | .readpage = shmem_readpage, |
800d15a5 NP |
2241 | .write_begin = shmem_write_begin, |
2242 | .write_end = shmem_write_end, | |
1da177e4 | 2243 | #endif |
304dbdb7 | 2244 | .migratepage = migrate_page, |
1da177e4 LT |
2245 | }; |
2246 | ||
15ad7cdc | 2247 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2248 | .mmap = shmem_mmap, |
2249 | #ifdef CONFIG_TMPFS | |
2250 | .llseek = generic_file_llseek, | |
2251 | .read = shmem_file_read, | |
5402b976 HD |
2252 | .write = do_sync_write, |
2253 | .aio_write = generic_file_aio_write, | |
1da177e4 | 2254 | .fsync = simple_sync_file, |
ae976416 HD |
2255 | .splice_read = generic_file_splice_read, |
2256 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2257 | #endif |
2258 | }; | |
2259 | ||
92e1d5be | 2260 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2261 | .truncate = shmem_truncate, |
2262 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2263 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2264 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2265 | .setxattr = generic_setxattr, | |
2266 | .getxattr = generic_getxattr, | |
2267 | .listxattr = generic_listxattr, | |
2268 | .removexattr = generic_removexattr, | |
2269 | .permission = shmem_permission, | |
2270 | #endif | |
2271 | ||
1da177e4 LT |
2272 | }; |
2273 | ||
92e1d5be | 2274 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2275 | #ifdef CONFIG_TMPFS |
2276 | .create = shmem_create, | |
2277 | .lookup = simple_lookup, | |
2278 | .link = shmem_link, | |
2279 | .unlink = shmem_unlink, | |
2280 | .symlink = shmem_symlink, | |
2281 | .mkdir = shmem_mkdir, | |
2282 | .rmdir = shmem_rmdir, | |
2283 | .mknod = shmem_mknod, | |
2284 | .rename = shmem_rename, | |
1da177e4 | 2285 | #endif |
39f0247d AG |
2286 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2287 | .setattr = shmem_notify_change, | |
2288 | .setxattr = generic_setxattr, | |
2289 | .getxattr = generic_getxattr, | |
2290 | .listxattr = generic_listxattr, | |
2291 | .removexattr = generic_removexattr, | |
2292 | .permission = shmem_permission, | |
2293 | #endif | |
2294 | }; | |
2295 | ||
92e1d5be | 2296 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2297 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2298 | .setattr = shmem_notify_change, | |
2299 | .setxattr = generic_setxattr, | |
2300 | .getxattr = generic_getxattr, | |
2301 | .listxattr = generic_listxattr, | |
2302 | .removexattr = generic_removexattr, | |
2303 | .permission = shmem_permission, | |
2304 | #endif | |
1da177e4 LT |
2305 | }; |
2306 | ||
759b9775 | 2307 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2308 | .alloc_inode = shmem_alloc_inode, |
2309 | .destroy_inode = shmem_destroy_inode, | |
2310 | #ifdef CONFIG_TMPFS | |
2311 | .statfs = shmem_statfs, | |
2312 | .remount_fs = shmem_remount_fs, | |
2313 | #endif | |
2314 | .delete_inode = shmem_delete_inode, | |
2315 | .drop_inode = generic_delete_inode, | |
2316 | .put_super = shmem_put_super, | |
2317 | }; | |
2318 | ||
2319 | static struct vm_operations_struct shmem_vm_ops = { | |
54cb8821 | 2320 | .fault = shmem_fault, |
1da177e4 LT |
2321 | #ifdef CONFIG_NUMA |
2322 | .set_policy = shmem_set_policy, | |
2323 | .get_policy = shmem_get_policy, | |
2324 | #endif | |
2325 | }; | |
2326 | ||
2327 | ||
454e2398 DH |
2328 | static int shmem_get_sb(struct file_system_type *fs_type, |
2329 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2330 | { |
454e2398 | 2331 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2332 | } |
2333 | ||
2334 | static struct file_system_type tmpfs_fs_type = { | |
2335 | .owner = THIS_MODULE, | |
2336 | .name = "tmpfs", | |
2337 | .get_sb = shmem_get_sb, | |
2338 | .kill_sb = kill_litter_super, | |
2339 | }; | |
2340 | static struct vfsmount *shm_mnt; | |
2341 | ||
2342 | static int __init init_tmpfs(void) | |
2343 | { | |
2344 | int error; | |
2345 | ||
e0bf68dd PZ |
2346 | error = bdi_init(&shmem_backing_dev_info); |
2347 | if (error) | |
2348 | goto out4; | |
2349 | ||
1da177e4 LT |
2350 | error = init_inodecache(); |
2351 | if (error) | |
2352 | goto out3; | |
2353 | ||
2354 | error = register_filesystem(&tmpfs_fs_type); | |
2355 | if (error) { | |
2356 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2357 | goto out2; | |
2358 | } | |
95dc112a | 2359 | |
1f5ce9e9 | 2360 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2361 | tmpfs_fs_type.name, NULL); |
2362 | if (IS_ERR(shm_mnt)) { | |
2363 | error = PTR_ERR(shm_mnt); | |
2364 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2365 | goto out1; | |
2366 | } | |
2367 | return 0; | |
2368 | ||
2369 | out1: | |
2370 | unregister_filesystem(&tmpfs_fs_type); | |
2371 | out2: | |
2372 | destroy_inodecache(); | |
2373 | out3: | |
e0bf68dd PZ |
2374 | bdi_destroy(&shmem_backing_dev_info); |
2375 | out4: | |
1da177e4 LT |
2376 | shm_mnt = ERR_PTR(error); |
2377 | return error; | |
2378 | } | |
2379 | module_init(init_tmpfs) | |
2380 | ||
2381 | /* | |
2382 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2383 | * | |
2384 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2385 | * @size: size to be set for the file | |
2386 | * | |
2387 | */ | |
2388 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2389 | { | |
2390 | int error; | |
2391 | struct file *file; | |
2392 | struct inode *inode; | |
2393 | struct dentry *dentry, *root; | |
2394 | struct qstr this; | |
2395 | ||
2396 | if (IS_ERR(shm_mnt)) | |
2397 | return (void *)shm_mnt; | |
2398 | ||
2399 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2400 | return ERR_PTR(-EINVAL); | |
2401 | ||
2402 | if (shmem_acct_size(flags, size)) | |
2403 | return ERR_PTR(-ENOMEM); | |
2404 | ||
2405 | error = -ENOMEM; | |
2406 | this.name = name; | |
2407 | this.len = strlen(name); | |
2408 | this.hash = 0; /* will go */ | |
2409 | root = shm_mnt->mnt_root; | |
2410 | dentry = d_alloc(root, &this); | |
2411 | if (!dentry) | |
2412 | goto put_memory; | |
2413 | ||
2414 | error = -ENFILE; | |
2415 | file = get_empty_filp(); | |
2416 | if (!file) | |
2417 | goto put_dentry; | |
2418 | ||
2419 | error = -ENOSPC; | |
2420 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2421 | if (!inode) | |
2422 | goto close_file; | |
2423 | ||
2424 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2425 | d_instantiate(dentry, inode); | |
2426 | inode->i_size = size; | |
2427 | inode->i_nlink = 0; /* It is unlinked */ | |
ce8d2cdf DH |
2428 | init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ, |
2429 | &shmem_file_operations); | |
1da177e4 LT |
2430 | return file; |
2431 | ||
2432 | close_file: | |
2433 | put_filp(file); | |
2434 | put_dentry: | |
2435 | dput(dentry); | |
2436 | put_memory: | |
2437 | shmem_unacct_size(flags, size); | |
2438 | return ERR_PTR(error); | |
2439 | } | |
2440 | ||
2441 | /* | |
2442 | * shmem_zero_setup - setup a shared anonymous mapping | |
2443 | * | |
2444 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2445 | */ | |
2446 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2447 | { | |
2448 | struct file *file; | |
2449 | loff_t size = vma->vm_end - vma->vm_start; | |
2450 | ||
2451 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2452 | if (IS_ERR(file)) | |
2453 | return PTR_ERR(file); | |
2454 | ||
2455 | if (vma->vm_file) | |
2456 | fput(vma->vm_file); | |
2457 | vma->vm_file = file; | |
2458 | vma->vm_ops = &shmem_vm_ops; | |
2459 | return 0; | |
2460 | } |