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 */ | |
a0ee5ec5 | 83 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
84 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
85 | }; | |
86 | ||
87 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
88 | struct page **pagep, enum sgp_type sgp, int *type); | |
89 | ||
6daa0e28 | 90 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
91 | { |
92 | /* | |
93 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
94 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
95 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 | 96 | * |
e12ba74d | 97 | * Mobility flags are masked out as swap vectors cannot move |
1da177e4 | 98 | */ |
e12ba74d | 99 | return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO, |
769848c0 | 100 | PAGE_CACHE_SHIFT-PAGE_SHIFT); |
1da177e4 LT |
101 | } |
102 | ||
103 | static inline void shmem_dir_free(struct page *page) | |
104 | { | |
105 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
106 | } | |
107 | ||
108 | static struct page **shmem_dir_map(struct page *page) | |
109 | { | |
110 | return (struct page **)kmap_atomic(page, KM_USER0); | |
111 | } | |
112 | ||
113 | static inline void shmem_dir_unmap(struct page **dir) | |
114 | { | |
115 | kunmap_atomic(dir, KM_USER0); | |
116 | } | |
117 | ||
118 | static swp_entry_t *shmem_swp_map(struct page *page) | |
119 | { | |
120 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
121 | } | |
122 | ||
123 | static inline void shmem_swp_balance_unmap(void) | |
124 | { | |
125 | /* | |
126 | * When passing a pointer to an i_direct entry, to code which | |
127 | * also handles indirect entries and so will shmem_swp_unmap, | |
128 | * we must arrange for the preempt count to remain in balance. | |
129 | * What kmap_atomic of a lowmem page does depends on config | |
130 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
131 | */ | |
132 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
133 | } | |
134 | ||
135 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
136 | { | |
137 | kunmap_atomic(entry, KM_USER1); | |
138 | } | |
139 | ||
140 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
141 | { | |
142 | return sb->s_fs_info; | |
143 | } | |
144 | ||
145 | /* | |
146 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
147 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
148 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
149 | * consistent with the pre-accounting of private mappings ... | |
150 | */ | |
151 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
152 | { | |
153 | return (flags & VM_ACCOUNT)? | |
154 | security_vm_enough_memory(VM_ACCT(size)): 0; | |
155 | } | |
156 | ||
157 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
158 | { | |
159 | if (flags & VM_ACCOUNT) | |
160 | vm_unacct_memory(VM_ACCT(size)); | |
161 | } | |
162 | ||
163 | /* | |
164 | * ... whereas tmpfs objects are accounted incrementally as | |
165 | * pages are allocated, in order to allow huge sparse files. | |
166 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
167 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
168 | */ | |
169 | static inline int shmem_acct_block(unsigned long flags) | |
170 | { | |
171 | return (flags & VM_ACCOUNT)? | |
172 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); | |
173 | } | |
174 | ||
175 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
176 | { | |
177 | if (!(flags & VM_ACCOUNT)) | |
178 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); | |
179 | } | |
180 | ||
759b9775 | 181 | static const struct super_operations shmem_ops; |
f5e54d6e | 182 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 183 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
184 | static const struct inode_operations shmem_inode_operations; |
185 | static const struct inode_operations shmem_dir_inode_operations; | |
186 | static const struct inode_operations shmem_special_inode_operations; | |
1da177e4 LT |
187 | static struct vm_operations_struct shmem_vm_ops; |
188 | ||
6c231b7b | 189 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 LT |
190 | .ra_pages = 0, /* No readahead */ |
191 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
192 | .unplug_io_fn = default_unplug_io_fn, | |
193 | }; | |
194 | ||
195 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 196 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 LT |
197 | |
198 | static void shmem_free_blocks(struct inode *inode, long pages) | |
199 | { | |
200 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 201 | if (sbinfo->max_blocks) { |
1da177e4 LT |
202 | spin_lock(&sbinfo->stat_lock); |
203 | sbinfo->free_blocks += pages; | |
204 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
205 | spin_unlock(&sbinfo->stat_lock); | |
206 | } | |
207 | } | |
208 | ||
5b04c689 PE |
209 | static int shmem_reserve_inode(struct super_block *sb) |
210 | { | |
211 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
212 | if (sbinfo->max_inodes) { | |
213 | spin_lock(&sbinfo->stat_lock); | |
214 | if (!sbinfo->free_inodes) { | |
215 | spin_unlock(&sbinfo->stat_lock); | |
216 | return -ENOSPC; | |
217 | } | |
218 | sbinfo->free_inodes--; | |
219 | spin_unlock(&sbinfo->stat_lock); | |
220 | } | |
221 | return 0; | |
222 | } | |
223 | ||
224 | static void shmem_free_inode(struct super_block *sb) | |
225 | { | |
226 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
227 | if (sbinfo->max_inodes) { | |
228 | spin_lock(&sbinfo->stat_lock); | |
229 | sbinfo->free_inodes++; | |
230 | spin_unlock(&sbinfo->stat_lock); | |
231 | } | |
232 | } | |
233 | ||
1da177e4 LT |
234 | /* |
235 | * shmem_recalc_inode - recalculate the size of an inode | |
236 | * | |
237 | * @inode: inode to recalc | |
238 | * | |
239 | * We have to calculate the free blocks since the mm can drop | |
240 | * undirtied hole pages behind our back. | |
241 | * | |
242 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
243 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
244 | * | |
245 | * It has to be called with the spinlock held. | |
246 | */ | |
247 | static void shmem_recalc_inode(struct inode *inode) | |
248 | { | |
249 | struct shmem_inode_info *info = SHMEM_I(inode); | |
250 | long freed; | |
251 | ||
252 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
253 | if (freed > 0) { | |
254 | info->alloced -= freed; | |
255 | shmem_unacct_blocks(info->flags, freed); | |
256 | shmem_free_blocks(inode, freed); | |
257 | } | |
258 | } | |
259 | ||
260 | /* | |
261 | * shmem_swp_entry - find the swap vector position in the info structure | |
262 | * | |
263 | * @info: info structure for the inode | |
264 | * @index: index of the page to find | |
265 | * @page: optional page to add to the structure. Has to be preset to | |
266 | * all zeros | |
267 | * | |
268 | * If there is no space allocated yet it will return NULL when | |
269 | * page is NULL, else it will use the page for the needed block, | |
270 | * setting it to NULL on return to indicate that it has been used. | |
271 | * | |
272 | * The swap vector is organized the following way: | |
273 | * | |
274 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
275 | * shmem_inode_info structure. So small files do not need an addional | |
276 | * allocation. | |
277 | * | |
278 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
279 | * i_indirect which points to a page which holds in the first half | |
280 | * doubly indirect blocks, in the second half triple indirect blocks: | |
281 | * | |
282 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
283 | * following layout (for SHMEM_NR_DIRECT == 16): | |
284 | * | |
285 | * i_indirect -> dir --> 16-19 | |
286 | * | +-> 20-23 | |
287 | * | | |
288 | * +-->dir2 --> 24-27 | |
289 | * | +-> 28-31 | |
290 | * | +-> 32-35 | |
291 | * | +-> 36-39 | |
292 | * | | |
293 | * +-->dir3 --> 40-43 | |
294 | * +-> 44-47 | |
295 | * +-> 48-51 | |
296 | * +-> 52-55 | |
297 | */ | |
298 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
299 | { | |
300 | unsigned long offset; | |
301 | struct page **dir; | |
302 | struct page *subdir; | |
303 | ||
304 | if (index < SHMEM_NR_DIRECT) { | |
305 | shmem_swp_balance_unmap(); | |
306 | return info->i_direct+index; | |
307 | } | |
308 | if (!info->i_indirect) { | |
309 | if (page) { | |
310 | info->i_indirect = *page; | |
311 | *page = NULL; | |
312 | } | |
313 | return NULL; /* need another page */ | |
314 | } | |
315 | ||
316 | index -= SHMEM_NR_DIRECT; | |
317 | offset = index % ENTRIES_PER_PAGE; | |
318 | index /= ENTRIES_PER_PAGE; | |
319 | dir = shmem_dir_map(info->i_indirect); | |
320 | ||
321 | if (index >= ENTRIES_PER_PAGE/2) { | |
322 | index -= ENTRIES_PER_PAGE/2; | |
323 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
324 | index %= ENTRIES_PER_PAGE; | |
325 | subdir = *dir; | |
326 | if (!subdir) { | |
327 | if (page) { | |
328 | *dir = *page; | |
329 | *page = NULL; | |
330 | } | |
331 | shmem_dir_unmap(dir); | |
332 | return NULL; /* need another page */ | |
333 | } | |
334 | shmem_dir_unmap(dir); | |
335 | dir = shmem_dir_map(subdir); | |
336 | } | |
337 | ||
338 | dir += index; | |
339 | subdir = *dir; | |
340 | if (!subdir) { | |
341 | if (!page || !(subdir = *page)) { | |
342 | shmem_dir_unmap(dir); | |
343 | return NULL; /* need a page */ | |
344 | } | |
345 | *dir = subdir; | |
346 | *page = NULL; | |
347 | } | |
348 | shmem_dir_unmap(dir); | |
349 | return shmem_swp_map(subdir) + offset; | |
350 | } | |
351 | ||
352 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
353 | { | |
354 | long incdec = value? 1: -1; | |
355 | ||
356 | entry->val = value; | |
357 | info->swapped += incdec; | |
4c21e2f2 HD |
358 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
359 | struct page *page = kmap_atomic_to_page(entry); | |
360 | set_page_private(page, page_private(page) + incdec); | |
361 | } | |
1da177e4 LT |
362 | } |
363 | ||
364 | /* | |
365 | * shmem_swp_alloc - get the position of the swap entry for the page. | |
366 | * If it does not exist allocate the entry. | |
367 | * | |
368 | * @info: info structure for the inode | |
369 | * @index: index of the page to find | |
370 | * @sgp: check and recheck i_size? skip allocation? | |
371 | */ | |
372 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
373 | { | |
374 | struct inode *inode = &info->vfs_inode; | |
375 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
376 | struct page *page = NULL; | |
377 | swp_entry_t *entry; | |
378 | ||
379 | if (sgp != SGP_WRITE && | |
380 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
381 | return ERR_PTR(-EINVAL); | |
382 | ||
383 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
384 | if (sgp == SGP_READ) | |
385 | return shmem_swp_map(ZERO_PAGE(0)); | |
386 | /* | |
387 | * Test free_blocks against 1 not 0, since we have 1 data | |
388 | * page (and perhaps indirect index pages) yet to allocate: | |
389 | * a waste to allocate index if we cannot allocate data. | |
390 | */ | |
0edd73b3 | 391 | if (sbinfo->max_blocks) { |
1da177e4 LT |
392 | spin_lock(&sbinfo->stat_lock); |
393 | if (sbinfo->free_blocks <= 1) { | |
394 | spin_unlock(&sbinfo->stat_lock); | |
395 | return ERR_PTR(-ENOSPC); | |
396 | } | |
397 | sbinfo->free_blocks--; | |
398 | inode->i_blocks += BLOCKS_PER_PAGE; | |
399 | spin_unlock(&sbinfo->stat_lock); | |
400 | } | |
401 | ||
402 | spin_unlock(&info->lock); | |
769848c0 | 403 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
4c21e2f2 HD |
404 | if (page) |
405 | set_page_private(page, 0); | |
1da177e4 LT |
406 | spin_lock(&info->lock); |
407 | ||
408 | if (!page) { | |
409 | shmem_free_blocks(inode, 1); | |
410 | return ERR_PTR(-ENOMEM); | |
411 | } | |
412 | if (sgp != SGP_WRITE && | |
413 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
414 | entry = ERR_PTR(-EINVAL); | |
415 | break; | |
416 | } | |
417 | if (info->next_index <= index) | |
418 | info->next_index = index + 1; | |
419 | } | |
420 | if (page) { | |
421 | /* another task gave its page, or truncated the file */ | |
422 | shmem_free_blocks(inode, 1); | |
423 | shmem_dir_free(page); | |
424 | } | |
425 | if (info->next_index <= index && !IS_ERR(entry)) | |
426 | info->next_index = index + 1; | |
427 | return entry; | |
428 | } | |
429 | ||
430 | /* | |
431 | * shmem_free_swp - free some swap entries in a directory | |
432 | * | |
1ae70006 HD |
433 | * @dir: pointer to the directory |
434 | * @edir: pointer after last entry of the directory | |
435 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 436 | */ |
1ae70006 HD |
437 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
438 | spinlock_t *punch_lock) | |
1da177e4 | 439 | { |
1ae70006 | 440 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
441 | swp_entry_t *ptr; |
442 | int freed = 0; | |
443 | ||
444 | for (ptr = dir; ptr < edir; ptr++) { | |
445 | if (ptr->val) { | |
1ae70006 HD |
446 | if (unlikely(punch_lock)) { |
447 | punch_unlock = punch_lock; | |
448 | punch_lock = NULL; | |
449 | spin_lock(punch_unlock); | |
450 | if (!ptr->val) | |
451 | continue; | |
452 | } | |
1da177e4 LT |
453 | free_swap_and_cache(*ptr); |
454 | *ptr = (swp_entry_t){0}; | |
455 | freed++; | |
456 | } | |
457 | } | |
1ae70006 HD |
458 | if (punch_unlock) |
459 | spin_unlock(punch_unlock); | |
1da177e4 LT |
460 | return freed; |
461 | } | |
462 | ||
1ae70006 HD |
463 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
464 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
465 | { |
466 | swp_entry_t *ptr; | |
467 | int freed = 0; | |
468 | ||
469 | ptr = shmem_swp_map(subdir); | |
470 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
471 | int size = limit - offset; | |
472 | if (size > LATENCY_LIMIT) | |
473 | size = LATENCY_LIMIT; | |
1ae70006 HD |
474 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
475 | punch_lock); | |
1da177e4 LT |
476 | if (need_resched()) { |
477 | shmem_swp_unmap(ptr); | |
478 | if (*dir) { | |
479 | shmem_dir_unmap(*dir); | |
480 | *dir = NULL; | |
481 | } | |
482 | cond_resched(); | |
483 | ptr = shmem_swp_map(subdir); | |
484 | } | |
485 | } | |
486 | shmem_swp_unmap(ptr); | |
487 | return freed; | |
488 | } | |
489 | ||
490 | static void shmem_free_pages(struct list_head *next) | |
491 | { | |
492 | struct page *page; | |
493 | int freed = 0; | |
494 | ||
495 | do { | |
496 | page = container_of(next, struct page, lru); | |
497 | next = next->next; | |
498 | shmem_dir_free(page); | |
499 | freed++; | |
500 | if (freed >= LATENCY_LIMIT) { | |
501 | cond_resched(); | |
502 | freed = 0; | |
503 | } | |
504 | } while (next); | |
505 | } | |
506 | ||
f6b3ec23 | 507 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
508 | { |
509 | struct shmem_inode_info *info = SHMEM_I(inode); | |
510 | unsigned long idx; | |
511 | unsigned long size; | |
512 | unsigned long limit; | |
513 | unsigned long stage; | |
514 | unsigned long diroff; | |
515 | struct page **dir; | |
516 | struct page *topdir; | |
517 | struct page *middir; | |
518 | struct page *subdir; | |
519 | swp_entry_t *ptr; | |
520 | LIST_HEAD(pages_to_free); | |
521 | long nr_pages_to_free = 0; | |
522 | long nr_swaps_freed = 0; | |
523 | int offset; | |
524 | int freed; | |
a2646d1e | 525 | int punch_hole; |
1ae70006 HD |
526 | spinlock_t *needs_lock; |
527 | spinlock_t *punch_lock; | |
a2646d1e | 528 | unsigned long upper_limit; |
1da177e4 LT |
529 | |
530 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 531 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
532 | if (idx >= info->next_index) |
533 | return; | |
534 | ||
535 | spin_lock(&info->lock); | |
536 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
537 | if (likely(end == (loff_t) -1)) { |
538 | limit = info->next_index; | |
a2646d1e | 539 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 540 | info->next_index = idx; |
1ae70006 | 541 | needs_lock = NULL; |
a2646d1e | 542 | punch_hole = 0; |
f6b3ec23 | 543 | } else { |
a2646d1e HD |
544 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
545 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
546 | PAGE_CACHE_SHIFT; | |
547 | upper_limit = SHMEM_MAX_INDEX; | |
548 | } else { | |
549 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
550 | upper_limit = limit; | |
551 | } | |
1ae70006 | 552 | needs_lock = &info->lock; |
f6b3ec23 BP |
553 | punch_hole = 1; |
554 | } | |
555 | ||
1da177e4 | 556 | topdir = info->i_indirect; |
f6b3ec23 | 557 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
558 | info->i_indirect = NULL; |
559 | nr_pages_to_free++; | |
560 | list_add(&topdir->lru, &pages_to_free); | |
561 | } | |
562 | spin_unlock(&info->lock); | |
563 | ||
564 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
565 | ptr = info->i_direct; | |
566 | size = limit; | |
567 | if (size > SHMEM_NR_DIRECT) | |
568 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 569 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 570 | } |
92a3d03a BP |
571 | |
572 | /* | |
573 | * If there are no indirect blocks or we are punching a hole | |
574 | * below indirect blocks, nothing to be done. | |
575 | */ | |
a2646d1e | 576 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
577 | goto done2; |
578 | ||
1ae70006 HD |
579 | /* |
580 | * The truncation case has already dropped info->lock, and we're safe | |
581 | * because i_size and next_index have already been lowered, preventing | |
582 | * access beyond. But in the punch_hole case, we still need to take | |
583 | * the lock when updating the swap directory, because there might be | |
584 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
585 | * shmem_writepage. However, whenever we find we can remove a whole | |
586 | * directory page (not at the misaligned start or end of the range), | |
587 | * we first NULLify its pointer in the level above, and then have no | |
588 | * need to take the lock when updating its contents: needs_lock and | |
589 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
590 | */ | |
591 | ||
a2646d1e | 592 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
593 | limit -= SHMEM_NR_DIRECT; |
594 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
595 | offset = idx % ENTRIES_PER_PAGE; | |
596 | idx -= offset; | |
597 | ||
598 | dir = shmem_dir_map(topdir); | |
599 | stage = ENTRIES_PER_PAGEPAGE/2; | |
600 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
601 | middir = topdir; | |
602 | diroff = idx/ENTRIES_PER_PAGE; | |
603 | } else { | |
604 | dir += ENTRIES_PER_PAGE/2; | |
605 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
606 | while (stage <= idx) | |
607 | stage += ENTRIES_PER_PAGEPAGE; | |
608 | middir = *dir; | |
609 | if (*dir) { | |
610 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
611 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 612 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
613 | if (needs_lock) { |
614 | spin_lock(needs_lock); | |
615 | *dir = NULL; | |
616 | spin_unlock(needs_lock); | |
617 | needs_lock = NULL; | |
618 | } else | |
619 | *dir = NULL; | |
1da177e4 LT |
620 | nr_pages_to_free++; |
621 | list_add(&middir->lru, &pages_to_free); | |
622 | } | |
623 | shmem_dir_unmap(dir); | |
624 | dir = shmem_dir_map(middir); | |
625 | } else { | |
626 | diroff = 0; | |
627 | offset = 0; | |
628 | idx = stage; | |
629 | } | |
630 | } | |
631 | ||
632 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
633 | if (unlikely(idx == stage)) { | |
634 | shmem_dir_unmap(dir); | |
635 | dir = shmem_dir_map(topdir) + | |
636 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
637 | while (!*dir) { | |
638 | dir++; | |
639 | idx += ENTRIES_PER_PAGEPAGE; | |
640 | if (idx >= limit) | |
641 | goto done1; | |
642 | } | |
643 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
644 | middir = *dir; | |
1ae70006 HD |
645 | if (punch_hole) |
646 | needs_lock = &info->lock; | |
a2646d1e | 647 | if (upper_limit >= stage) { |
1ae70006 HD |
648 | if (needs_lock) { |
649 | spin_lock(needs_lock); | |
650 | *dir = NULL; | |
651 | spin_unlock(needs_lock); | |
652 | needs_lock = NULL; | |
653 | } else | |
654 | *dir = NULL; | |
a2646d1e HD |
655 | nr_pages_to_free++; |
656 | list_add(&middir->lru, &pages_to_free); | |
657 | } | |
1da177e4 LT |
658 | shmem_dir_unmap(dir); |
659 | cond_resched(); | |
660 | dir = shmem_dir_map(middir); | |
661 | diroff = 0; | |
662 | } | |
1ae70006 | 663 | punch_lock = needs_lock; |
1da177e4 | 664 | subdir = dir[diroff]; |
1ae70006 HD |
665 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
666 | if (needs_lock) { | |
667 | spin_lock(needs_lock); | |
668 | dir[diroff] = NULL; | |
669 | spin_unlock(needs_lock); | |
670 | punch_lock = NULL; | |
671 | } else | |
672 | dir[diroff] = NULL; | |
673 | nr_pages_to_free++; | |
674 | list_add(&subdir->lru, &pages_to_free); | |
675 | } | |
676 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
677 | size = limit - idx; |
678 | if (size > ENTRIES_PER_PAGE) | |
679 | size = ENTRIES_PER_PAGE; | |
680 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 681 | offset, size, &dir, punch_lock); |
1da177e4 LT |
682 | if (!dir) |
683 | dir = shmem_dir_map(middir); | |
684 | nr_swaps_freed += freed; | |
1ae70006 | 685 | if (offset || punch_lock) { |
1da177e4 | 686 | spin_lock(&info->lock); |
1ae70006 HD |
687 | set_page_private(subdir, |
688 | page_private(subdir) - freed); | |
1da177e4 | 689 | spin_unlock(&info->lock); |
1ae70006 HD |
690 | } else |
691 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 692 | } |
1ae70006 | 693 | offset = 0; |
1da177e4 LT |
694 | } |
695 | done1: | |
696 | shmem_dir_unmap(dir); | |
697 | done2: | |
698 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
699 | /* | |
700 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
701 | * may have swizzled a page in from swap since vmtruncate or | |
702 | * generic_delete_inode did it, before we lowered next_index. | |
703 | * Also, though shmem_getpage checks i_size before adding to | |
704 | * cache, no recheck after: so fix the narrow window there too. | |
16a10019 HD |
705 | * |
706 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
707 | * every time for punch_hole (which never got a chance to clear | |
708 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
709 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 710 | */ |
f6b3ec23 | 711 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
712 | if (punch_hole) |
713 | unmap_mapping_range(inode->i_mapping, start, | |
714 | end - start, 1); | |
1da177e4 LT |
715 | } |
716 | ||
717 | spin_lock(&info->lock); | |
718 | info->flags &= ~SHMEM_TRUNCATE; | |
719 | info->swapped -= nr_swaps_freed; | |
720 | if (nr_pages_to_free) | |
721 | shmem_free_blocks(inode, nr_pages_to_free); | |
722 | shmem_recalc_inode(inode); | |
723 | spin_unlock(&info->lock); | |
724 | ||
725 | /* | |
726 | * Empty swap vector directory pages to be freed? | |
727 | */ | |
728 | if (!list_empty(&pages_to_free)) { | |
729 | pages_to_free.prev->next = NULL; | |
730 | shmem_free_pages(pages_to_free.next); | |
731 | } | |
732 | } | |
733 | ||
f6b3ec23 BP |
734 | static void shmem_truncate(struct inode *inode) |
735 | { | |
736 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
737 | } | |
738 | ||
1da177e4 LT |
739 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
740 | { | |
741 | struct inode *inode = dentry->d_inode; | |
742 | struct page *page = NULL; | |
743 | int error; | |
744 | ||
39f0247d | 745 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
746 | if (attr->ia_size < inode->i_size) { |
747 | /* | |
748 | * If truncating down to a partial page, then | |
749 | * if that page is already allocated, hold it | |
750 | * in memory until the truncation is over, so | |
751 | * truncate_partial_page cannnot miss it were | |
752 | * it assigned to swap. | |
753 | */ | |
754 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
755 | (void) shmem_getpage(inode, | |
756 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
757 | &page, SGP_READ, NULL); | |
d3602444 HD |
758 | if (page) |
759 | unlock_page(page); | |
1da177e4 LT |
760 | } |
761 | /* | |
762 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
763 | * detect if any pages might have been added to cache | |
764 | * after truncate_inode_pages. But we needn't bother | |
765 | * if it's being fully truncated to zero-length: the | |
766 | * nrpages check is efficient enough in that case. | |
767 | */ | |
768 | if (attr->ia_size) { | |
769 | struct shmem_inode_info *info = SHMEM_I(inode); | |
770 | spin_lock(&info->lock); | |
771 | info->flags &= ~SHMEM_PAGEIN; | |
772 | spin_unlock(&info->lock); | |
773 | } | |
774 | } | |
775 | } | |
776 | ||
777 | error = inode_change_ok(inode, attr); | |
778 | if (!error) | |
779 | error = inode_setattr(inode, attr); | |
39f0247d AG |
780 | #ifdef CONFIG_TMPFS_POSIX_ACL |
781 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
782 | error = generic_acl_chmod(inode, &shmem_acl_ops); | |
783 | #endif | |
1da177e4 LT |
784 | if (page) |
785 | page_cache_release(page); | |
786 | return error; | |
787 | } | |
788 | ||
789 | static void shmem_delete_inode(struct inode *inode) | |
790 | { | |
1da177e4 LT |
791 | struct shmem_inode_info *info = SHMEM_I(inode); |
792 | ||
793 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 794 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
795 | shmem_unacct_size(info->flags, inode->i_size); |
796 | inode->i_size = 0; | |
797 | shmem_truncate(inode); | |
798 | if (!list_empty(&info->swaplist)) { | |
cb5f7b9a | 799 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 800 | list_del_init(&info->swaplist); |
cb5f7b9a | 801 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
802 | } |
803 | } | |
0edd73b3 | 804 | BUG_ON(inode->i_blocks); |
5b04c689 | 805 | shmem_free_inode(inode->i_sb); |
1da177e4 LT |
806 | clear_inode(inode); |
807 | } | |
808 | ||
809 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
810 | { | |
811 | swp_entry_t *ptr; | |
812 | ||
813 | for (ptr = dir; ptr < edir; ptr++) { | |
814 | if (ptr->val == entry.val) | |
815 | return ptr - dir; | |
816 | } | |
817 | return -1; | |
818 | } | |
819 | ||
820 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
821 | { | |
822 | struct inode *inode; | |
823 | unsigned long idx; | |
824 | unsigned long size; | |
825 | unsigned long limit; | |
826 | unsigned long stage; | |
827 | struct page **dir; | |
828 | struct page *subdir; | |
829 | swp_entry_t *ptr; | |
830 | int offset; | |
d9fe526a | 831 | int error; |
1da177e4 LT |
832 | |
833 | idx = 0; | |
834 | ptr = info->i_direct; | |
835 | spin_lock(&info->lock); | |
836 | limit = info->next_index; | |
837 | size = limit; | |
838 | if (size > SHMEM_NR_DIRECT) | |
839 | size = SHMEM_NR_DIRECT; | |
840 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 841 | if (offset >= 0) |
1da177e4 | 842 | goto found; |
1da177e4 LT |
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); | |
cb5f7b9a HD |
852 | if (cond_resched_lock(&info->lock)) { |
853 | /* check it has not been truncated */ | |
854 | if (limit > info->next_index) { | |
855 | limit = info->next_index; | |
856 | if (idx >= limit) | |
857 | goto lost2; | |
858 | } | |
859 | } | |
1da177e4 LT |
860 | dir = shmem_dir_map(info->i_indirect) + |
861 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
862 | while (!*dir) { | |
863 | dir++; | |
864 | idx += ENTRIES_PER_PAGEPAGE; | |
865 | if (idx >= limit) | |
866 | goto lost1; | |
867 | } | |
868 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
869 | subdir = *dir; | |
870 | shmem_dir_unmap(dir); | |
871 | dir = shmem_dir_map(subdir); | |
872 | } | |
873 | subdir = *dir; | |
4c21e2f2 | 874 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
875 | ptr = shmem_swp_map(subdir); |
876 | size = limit - idx; | |
877 | if (size > ENTRIES_PER_PAGE) | |
878 | size = ENTRIES_PER_PAGE; | |
879 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 880 | shmem_swp_unmap(ptr); |
1da177e4 LT |
881 | if (offset >= 0) { |
882 | shmem_dir_unmap(dir); | |
883 | goto found; | |
884 | } | |
1da177e4 LT |
885 | } |
886 | } | |
887 | lost1: | |
888 | shmem_dir_unmap(dir-1); | |
889 | lost2: | |
890 | spin_unlock(&info->lock); | |
891 | return 0; | |
892 | found: | |
893 | idx += offset; | |
2e0e26c7 HD |
894 | inode = igrab(&info->vfs_inode); |
895 | spin_unlock(&info->lock); | |
896 | ||
897 | /* move head to start search for next from here */ | |
898 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
899 | mutex_unlock(&shmem_swaplist_mutex); | |
900 | ||
901 | error = 1; | |
902 | if (!inode) | |
903 | goto out; | |
904 | ||
905 | spin_lock(&info->lock); | |
906 | ptr = shmem_swp_entry(info, idx, NULL); | |
907 | if (ptr && ptr->val == entry.val) | |
908 | error = add_to_page_cache(page, inode->i_mapping, | |
909 | idx, GFP_ATOMIC); | |
d9fe526a HD |
910 | if (error == -EEXIST) { |
911 | struct page *filepage = find_get_page(inode->i_mapping, idx); | |
2e0e26c7 | 912 | error = 1; |
d9fe526a HD |
913 | if (filepage) { |
914 | /* | |
915 | * There might be a more uptodate page coming down | |
916 | * from a stacked writepage: forget our swappage if so. | |
917 | */ | |
918 | if (PageUptodate(filepage)) | |
919 | error = 0; | |
920 | page_cache_release(filepage); | |
921 | } | |
922 | } | |
923 | if (!error) { | |
73b1262f HD |
924 | delete_from_swap_cache(page); |
925 | set_page_dirty(page); | |
1da177e4 | 926 | info->flags |= SHMEM_PAGEIN; |
2e0e26c7 HD |
927 | shmem_swp_set(info, ptr, 0); |
928 | swap_free(entry); | |
929 | error = 1; /* not an error, but entry was found */ | |
1da177e4 | 930 | } |
2e0e26c7 HD |
931 | if (ptr) |
932 | shmem_swp_unmap(ptr); | |
1da177e4 | 933 | spin_unlock(&info->lock); |
2e0e26c7 HD |
934 | out: |
935 | unlock_page(page); | |
936 | page_cache_release(page); | |
937 | iput(inode); /* allows for NULL */ | |
938 | return error; | |
1da177e4 LT |
939 | } |
940 | ||
941 | /* | |
942 | * shmem_unuse() search for an eventually swapped out shmem page. | |
943 | */ | |
944 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
945 | { | |
946 | struct list_head *p, *next; | |
947 | struct shmem_inode_info *info; | |
948 | int found = 0; | |
949 | ||
cb5f7b9a | 950 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 LT |
951 | list_for_each_safe(p, next, &shmem_swaplist) { |
952 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
2e0e26c7 HD |
953 | if (info->swapped) |
954 | found = shmem_unuse_inode(info, entry, page); | |
955 | else | |
1da177e4 | 956 | list_del_init(&info->swaplist); |
cb5f7b9a | 957 | cond_resched(); |
2e0e26c7 HD |
958 | if (found) |
959 | goto out; | |
1da177e4 | 960 | } |
cb5f7b9a | 961 | mutex_unlock(&shmem_swaplist_mutex); |
2e0e26c7 | 962 | out: return found; /* 0 or 1 or -ENOMEM */ |
1da177e4 LT |
963 | } |
964 | ||
965 | /* | |
966 | * Move the page from the page cache to the swap cache. | |
967 | */ | |
968 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
969 | { | |
970 | struct shmem_inode_info *info; | |
971 | swp_entry_t *entry, swap; | |
972 | struct address_space *mapping; | |
973 | unsigned long index; | |
974 | struct inode *inode; | |
975 | ||
976 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
977 | mapping = page->mapping; |
978 | index = page->index; | |
979 | inode = mapping->host; | |
980 | info = SHMEM_I(inode); | |
981 | if (info->flags & VM_LOCKED) | |
982 | goto redirty; | |
d9fe526a | 983 | if (!total_swap_pages) |
1da177e4 LT |
984 | goto redirty; |
985 | ||
d9fe526a HD |
986 | /* |
987 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
988 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
989 | * may use the ->writepage of its underlying filesystem, in which case | |
990 | * tmpfs should write out to swap only in response to memory pressure, | |
991 | * and not for pdflush or sync. However, in those cases, we do still | |
992 | * want to check if there's a redundant swappage to be discarded. | |
993 | */ | |
994 | if (wbc->for_reclaim) | |
995 | swap = get_swap_page(); | |
996 | else | |
997 | swap.val = 0; | |
998 | ||
1da177e4 | 999 | spin_lock(&info->lock); |
1da177e4 LT |
1000 | if (index >= info->next_index) { |
1001 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
1002 | goto unlock; | |
1003 | } | |
1004 | entry = shmem_swp_entry(info, index, NULL); | |
d9fe526a HD |
1005 | if (entry->val) { |
1006 | /* | |
1007 | * The more uptodate page coming down from a stacked | |
1008 | * writepage should replace our old swappage. | |
1009 | */ | |
1010 | free_swap_and_cache(*entry); | |
1011 | shmem_swp_set(info, entry, 0); | |
1012 | } | |
1013 | shmem_recalc_inode(inode); | |
1da177e4 | 1014 | |
d9fe526a | 1015 | if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
73b1262f | 1016 | remove_from_page_cache(page); |
1da177e4 LT |
1017 | shmem_swp_set(info, entry, swap.val); |
1018 | shmem_swp_unmap(entry); | |
1019 | spin_unlock(&info->lock); | |
1020 | if (list_empty(&info->swaplist)) { | |
cb5f7b9a | 1021 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 LT |
1022 | /* move instead of add in case we're racing */ |
1023 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
cb5f7b9a | 1024 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 | 1025 | } |
73b1262f | 1026 | swap_duplicate(swap); |
d9fe526a | 1027 | BUG_ON(page_mapped(page)); |
73b1262f HD |
1028 | page_cache_release(page); /* pagecache ref */ |
1029 | set_page_dirty(page); | |
1da177e4 LT |
1030 | unlock_page(page); |
1031 | return 0; | |
1032 | } | |
1033 | ||
1034 | shmem_swp_unmap(entry); | |
1035 | unlock: | |
1036 | spin_unlock(&info->lock); | |
1037 | swap_free(swap); | |
1038 | redirty: | |
1039 | set_page_dirty(page); | |
d9fe526a HD |
1040 | if (wbc->for_reclaim) |
1041 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1042 | unlock_page(page); | |
1043 | return 0; | |
1da177e4 LT |
1044 | } |
1045 | ||
1046 | #ifdef CONFIG_NUMA | |
d15c023b | 1047 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
b00dc3ad HD |
1048 | { |
1049 | char *nodelist = strchr(value, ':'); | |
1050 | int err = 1; | |
1051 | ||
1052 | if (nodelist) { | |
1053 | /* NUL-terminate policy string */ | |
1054 | *nodelist++ = '\0'; | |
1055 | if (nodelist_parse(nodelist, *policy_nodes)) | |
1056 | goto out; | |
37b07e41 | 1057 | if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY])) |
a210906c | 1058 | goto out; |
b00dc3ad HD |
1059 | } |
1060 | if (!strcmp(value, "default")) { | |
1061 | *policy = MPOL_DEFAULT; | |
1062 | /* Don't allow a nodelist */ | |
1063 | if (!nodelist) | |
1064 | err = 0; | |
1065 | } else if (!strcmp(value, "prefer")) { | |
1066 | *policy = MPOL_PREFERRED; | |
1067 | /* Insist on a nodelist of one node only */ | |
1068 | if (nodelist) { | |
1069 | char *rest = nodelist; | |
1070 | while (isdigit(*rest)) | |
1071 | rest++; | |
1072 | if (!*rest) | |
1073 | err = 0; | |
1074 | } | |
1075 | } else if (!strcmp(value, "bind")) { | |
1076 | *policy = MPOL_BIND; | |
1077 | /* Insist on a nodelist */ | |
1078 | if (nodelist) | |
1079 | err = 0; | |
1080 | } else if (!strcmp(value, "interleave")) { | |
1081 | *policy = MPOL_INTERLEAVE; | |
37b07e41 LS |
1082 | /* |
1083 | * Default to online nodes with memory if no nodelist | |
1084 | */ | |
b00dc3ad | 1085 | if (!nodelist) |
37b07e41 | 1086 | *policy_nodes = node_states[N_HIGH_MEMORY]; |
b00dc3ad HD |
1087 | err = 0; |
1088 | } | |
1089 | out: | |
1090 | /* Restore string for error message */ | |
1091 | if (nodelist) | |
1092 | *--nodelist = ':'; | |
1093 | return err; | |
1094 | } | |
1095 | ||
02098fea HD |
1096 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1097 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1098 | { |
1da177e4 | 1099 | struct vm_area_struct pvma; |
c4cc6d07 | 1100 | struct page *page; |
1da177e4 LT |
1101 | |
1102 | /* Create a pseudo vma that just contains the policy */ | |
c4cc6d07 | 1103 | pvma.vm_start = 0; |
1da177e4 | 1104 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1105 | pvma.vm_ops = NULL; |
1106 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
02098fea | 1107 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1108 | mpol_free(pvma.vm_policy); |
1109 | return page; | |
1110 | } | |
1111 | ||
02098fea HD |
1112 | static struct page *shmem_alloc_page(gfp_t gfp, |
1113 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1114 | { |
1115 | struct vm_area_struct pvma; | |
1116 | struct page *page; | |
1117 | ||
c4cc6d07 HD |
1118 | /* Create a pseudo vma that just contains the policy */ |
1119 | pvma.vm_start = 0; | |
1da177e4 | 1120 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1121 | pvma.vm_ops = NULL; |
1122 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
e84e2e13 | 1123 | page = alloc_page_vma(gfp, &pvma, 0); |
1da177e4 LT |
1124 | mpol_free(pvma.vm_policy); |
1125 | return page; | |
1126 | } | |
1127 | #else | |
37b07e41 LS |
1128 | static inline int shmem_parse_mpol(char *value, int *policy, |
1129 | nodemask_t *policy_nodes) | |
b00dc3ad HD |
1130 | { |
1131 | return 1; | |
1132 | } | |
1133 | ||
02098fea HD |
1134 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1135 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1136 | { |
02098fea | 1137 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1138 | } |
1139 | ||
02098fea HD |
1140 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1141 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1142 | { |
e84e2e13 | 1143 | return alloc_page(gfp); |
1da177e4 LT |
1144 | } |
1145 | #endif | |
1146 | ||
1147 | /* | |
1148 | * shmem_getpage - either get the page from swap or allocate a new one | |
1149 | * | |
1150 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1151 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1152 | * entry since a page cannot live in both the swap and page cache | |
1153 | */ | |
1154 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1155 | struct page **pagep, enum sgp_type sgp, int *type) | |
1156 | { | |
1157 | struct address_space *mapping = inode->i_mapping; | |
1158 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1159 | struct shmem_sb_info *sbinfo; | |
1160 | struct page *filepage = *pagep; | |
1161 | struct page *swappage; | |
1162 | swp_entry_t *entry; | |
1163 | swp_entry_t swap; | |
02098fea | 1164 | gfp_t gfp; |
1da177e4 LT |
1165 | int error; |
1166 | ||
1167 | if (idx >= SHMEM_MAX_INDEX) | |
1168 | return -EFBIG; | |
54cb8821 NP |
1169 | |
1170 | if (type) | |
83c54070 | 1171 | *type = 0; |
54cb8821 | 1172 | |
1da177e4 LT |
1173 | /* |
1174 | * Normally, filepage is NULL on entry, and either found | |
1175 | * uptodate immediately, or allocated and zeroed, or read | |
1176 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1177 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1178 | * filepage, which may be found not uptodate by other callers |
1179 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1180 | */ |
1181 | repeat: | |
1182 | if (!filepage) | |
1183 | filepage = find_lock_page(mapping, idx); | |
1184 | if (filepage && PageUptodate(filepage)) | |
1185 | goto done; | |
1186 | error = 0; | |
02098fea | 1187 | gfp = mapping_gfp_mask(mapping); |
1da177e4 LT |
1188 | |
1189 | spin_lock(&info->lock); | |
1190 | shmem_recalc_inode(inode); | |
1191 | entry = shmem_swp_alloc(info, idx, sgp); | |
1192 | if (IS_ERR(entry)) { | |
1193 | spin_unlock(&info->lock); | |
1194 | error = PTR_ERR(entry); | |
1195 | goto failed; | |
1196 | } | |
1197 | swap = *entry; | |
1198 | ||
1199 | if (swap.val) { | |
1200 | /* Look it up and read it in.. */ | |
1201 | swappage = lookup_swap_cache(swap); | |
1202 | if (!swappage) { | |
1203 | shmem_swp_unmap(entry); | |
1da177e4 | 1204 | /* here we actually do the io */ |
83c54070 | 1205 | if (type && !(*type & VM_FAULT_MAJOR)) { |
f8891e5e | 1206 | __count_vm_event(PGMAJFAULT); |
83c54070 | 1207 | *type |= VM_FAULT_MAJOR; |
1da177e4 | 1208 | } |
f8891e5e | 1209 | spin_unlock(&info->lock); |
02098fea | 1210 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1211 | if (!swappage) { |
1212 | spin_lock(&info->lock); | |
1213 | entry = shmem_swp_alloc(info, idx, sgp); | |
1214 | if (IS_ERR(entry)) | |
1215 | error = PTR_ERR(entry); | |
1216 | else { | |
1217 | if (entry->val == swap.val) | |
1218 | error = -ENOMEM; | |
1219 | shmem_swp_unmap(entry); | |
1220 | } | |
1221 | spin_unlock(&info->lock); | |
1222 | if (error) | |
1223 | goto failed; | |
1224 | goto repeat; | |
1225 | } | |
1226 | wait_on_page_locked(swappage); | |
1227 | page_cache_release(swappage); | |
1228 | goto repeat; | |
1229 | } | |
1230 | ||
1231 | /* We have to do this with page locked to prevent races */ | |
1232 | if (TestSetPageLocked(swappage)) { | |
1233 | shmem_swp_unmap(entry); | |
1234 | spin_unlock(&info->lock); | |
1235 | wait_on_page_locked(swappage); | |
1236 | page_cache_release(swappage); | |
1237 | goto repeat; | |
1238 | } | |
1239 | if (PageWriteback(swappage)) { | |
1240 | shmem_swp_unmap(entry); | |
1241 | spin_unlock(&info->lock); | |
1242 | wait_on_page_writeback(swappage); | |
1243 | unlock_page(swappage); | |
1244 | page_cache_release(swappage); | |
1245 | goto repeat; | |
1246 | } | |
1247 | if (!PageUptodate(swappage)) { | |
1248 | shmem_swp_unmap(entry); | |
1249 | spin_unlock(&info->lock); | |
1250 | unlock_page(swappage); | |
1251 | page_cache_release(swappage); | |
1252 | error = -EIO; | |
1253 | goto failed; | |
1254 | } | |
1255 | ||
1256 | if (filepage) { | |
1257 | shmem_swp_set(info, entry, 0); | |
1258 | shmem_swp_unmap(entry); | |
1259 | delete_from_swap_cache(swappage); | |
1260 | spin_unlock(&info->lock); | |
1261 | copy_highpage(filepage, swappage); | |
1262 | unlock_page(swappage); | |
1263 | page_cache_release(swappage); | |
1264 | flush_dcache_page(filepage); | |
1265 | SetPageUptodate(filepage); | |
1266 | set_page_dirty(filepage); | |
1267 | swap_free(swap); | |
73b1262f HD |
1268 | } else if (!(error = add_to_page_cache( |
1269 | swappage, mapping, idx, GFP_ATOMIC))) { | |
1da177e4 LT |
1270 | info->flags |= SHMEM_PAGEIN; |
1271 | shmem_swp_set(info, entry, 0); | |
1272 | shmem_swp_unmap(entry); | |
73b1262f | 1273 | delete_from_swap_cache(swappage); |
1da177e4 LT |
1274 | spin_unlock(&info->lock); |
1275 | filepage = swappage; | |
73b1262f | 1276 | set_page_dirty(filepage); |
1da177e4 LT |
1277 | swap_free(swap); |
1278 | } else { | |
1279 | shmem_swp_unmap(entry); | |
1280 | spin_unlock(&info->lock); | |
1281 | unlock_page(swappage); | |
1282 | page_cache_release(swappage); | |
1283 | if (error == -ENOMEM) { | |
1284 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
3fcfab16 | 1285 | congestion_wait(WRITE, HZ/50); |
1da177e4 LT |
1286 | } |
1287 | goto repeat; | |
1288 | } | |
1289 | } else if (sgp == SGP_READ && !filepage) { | |
1290 | shmem_swp_unmap(entry); | |
1291 | filepage = find_get_page(mapping, idx); | |
1292 | if (filepage && | |
1293 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1294 | spin_unlock(&info->lock); | |
1295 | wait_on_page_locked(filepage); | |
1296 | page_cache_release(filepage); | |
1297 | filepage = NULL; | |
1298 | goto repeat; | |
1299 | } | |
1300 | spin_unlock(&info->lock); | |
1301 | } else { | |
1302 | shmem_swp_unmap(entry); | |
1303 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1304 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1305 | spin_lock(&sbinfo->stat_lock); |
1306 | if (sbinfo->free_blocks == 0 || | |
1307 | shmem_acct_block(info->flags)) { | |
1308 | spin_unlock(&sbinfo->stat_lock); | |
1309 | spin_unlock(&info->lock); | |
1310 | error = -ENOSPC; | |
1311 | goto failed; | |
1312 | } | |
1313 | sbinfo->free_blocks--; | |
1314 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1315 | spin_unlock(&sbinfo->stat_lock); | |
1316 | } else if (shmem_acct_block(info->flags)) { | |
1317 | spin_unlock(&info->lock); | |
1318 | error = -ENOSPC; | |
1319 | goto failed; | |
1320 | } | |
1321 | ||
1322 | if (!filepage) { | |
1323 | spin_unlock(&info->lock); | |
02098fea | 1324 | filepage = shmem_alloc_page(gfp, info, idx); |
1da177e4 LT |
1325 | if (!filepage) { |
1326 | shmem_unacct_blocks(info->flags, 1); | |
1327 | shmem_free_blocks(inode, 1); | |
1328 | error = -ENOMEM; | |
1329 | goto failed; | |
1330 | } | |
1331 | ||
1332 | spin_lock(&info->lock); | |
1333 | entry = shmem_swp_alloc(info, idx, sgp); | |
1334 | if (IS_ERR(entry)) | |
1335 | error = PTR_ERR(entry); | |
1336 | else { | |
1337 | swap = *entry; | |
1338 | shmem_swp_unmap(entry); | |
1339 | } | |
1340 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1341 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1342 | spin_unlock(&info->lock); | |
1343 | page_cache_release(filepage); | |
1344 | shmem_unacct_blocks(info->flags, 1); | |
1345 | shmem_free_blocks(inode, 1); | |
1346 | filepage = NULL; | |
1347 | if (error) | |
1348 | goto failed; | |
1349 | goto repeat; | |
1350 | } | |
1351 | info->flags |= SHMEM_PAGEIN; | |
1352 | } | |
1353 | ||
1354 | info->alloced++; | |
1355 | spin_unlock(&info->lock); | |
e84e2e13 | 1356 | clear_highpage(filepage); |
1da177e4 LT |
1357 | flush_dcache_page(filepage); |
1358 | SetPageUptodate(filepage); | |
a0ee5ec5 HD |
1359 | if (sgp == SGP_DIRTY) |
1360 | set_page_dirty(filepage); | |
1da177e4 LT |
1361 | } |
1362 | done: | |
d3602444 | 1363 | *pagep = filepage; |
1da177e4 LT |
1364 | return 0; |
1365 | ||
1366 | failed: | |
1367 | if (*pagep != filepage) { | |
1368 | unlock_page(filepage); | |
1369 | page_cache_release(filepage); | |
1370 | } | |
1371 | return error; | |
1372 | } | |
1373 | ||
d0217ac0 | 1374 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1375 | { |
d3ac7f89 | 1376 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1377 | int error; |
d0217ac0 | 1378 | int ret; |
1da177e4 | 1379 | |
d0217ac0 NP |
1380 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1381 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1382 | |
27d54b39 | 1383 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1384 | if (error) |
1385 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1da177e4 | 1386 | |
d0217ac0 | 1387 | mark_page_accessed(vmf->page); |
83c54070 | 1388 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1389 | } |
1390 | ||
1da177e4 | 1391 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1392 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1393 | { |
d3ac7f89 | 1394 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1395 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1396 | } | |
1397 | ||
d8dc74f2 AB |
1398 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1399 | unsigned long addr) | |
1da177e4 | 1400 | { |
d3ac7f89 | 1401 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1402 | unsigned long idx; |
1403 | ||
1404 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1405 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1406 | } | |
1407 | #endif | |
1408 | ||
1409 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1410 | { | |
d3ac7f89 | 1411 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1412 | struct shmem_inode_info *info = SHMEM_I(inode); |
1413 | int retval = -ENOMEM; | |
1414 | ||
1415 | spin_lock(&info->lock); | |
1416 | if (lock && !(info->flags & VM_LOCKED)) { | |
1417 | if (!user_shm_lock(inode->i_size, user)) | |
1418 | goto out_nomem; | |
1419 | info->flags |= VM_LOCKED; | |
1420 | } | |
1421 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1422 | user_shm_unlock(inode->i_size, user); | |
1423 | info->flags &= ~VM_LOCKED; | |
1424 | } | |
1425 | retval = 0; | |
1426 | out_nomem: | |
1427 | spin_unlock(&info->lock); | |
1428 | return retval; | |
1429 | } | |
1430 | ||
9b83a6a8 | 1431 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1432 | { |
1433 | file_accessed(file); | |
1434 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1435 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1436 | return 0; |
1437 | } | |
1438 | ||
1439 | static struct inode * | |
1440 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1441 | { | |
1442 | struct inode *inode; | |
1443 | struct shmem_inode_info *info; | |
1444 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1445 | ||
5b04c689 PE |
1446 | if (shmem_reserve_inode(sb)) |
1447 | return NULL; | |
1da177e4 LT |
1448 | |
1449 | inode = new_inode(sb); | |
1450 | if (inode) { | |
1451 | inode->i_mode = mode; | |
1452 | inode->i_uid = current->fsuid; | |
1453 | inode->i_gid = current->fsgid; | |
1da177e4 LT |
1454 | inode->i_blocks = 0; |
1455 | inode->i_mapping->a_ops = &shmem_aops; | |
1456 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1457 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1458 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1459 | info = SHMEM_I(inode); |
1460 | memset(info, 0, (char *)inode - (char *)info); | |
1461 | spin_lock_init(&info->lock); | |
1462 | INIT_LIST_HEAD(&info->swaplist); | |
1463 | ||
1464 | switch (mode & S_IFMT) { | |
1465 | default: | |
39f0247d | 1466 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1467 | init_special_inode(inode, mode, dev); |
1468 | break; | |
1469 | case S_IFREG: | |
1470 | inode->i_op = &shmem_inode_operations; | |
1471 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1472 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1473 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1474 | break; |
1475 | case S_IFDIR: | |
d8c76e6f | 1476 | inc_nlink(inode); |
1da177e4 LT |
1477 | /* Some things misbehave if size == 0 on a directory */ |
1478 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1479 | inode->i_op = &shmem_dir_inode_operations; | |
1480 | inode->i_fop = &simple_dir_operations; | |
1481 | break; | |
1482 | case S_IFLNK: | |
1483 | /* | |
1484 | * Must not load anything in the rbtree, | |
1485 | * mpol_free_shared_policy will not be called. | |
1486 | */ | |
7339ff83 RH |
1487 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1488 | NULL); | |
1da177e4 LT |
1489 | break; |
1490 | } | |
5b04c689 PE |
1491 | } else |
1492 | shmem_free_inode(sb); | |
1da177e4 LT |
1493 | return inode; |
1494 | } | |
1495 | ||
1496 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1497 | static const struct inode_operations shmem_symlink_inode_operations; |
1498 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1499 | |
1500 | /* | |
800d15a5 | 1501 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1502 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1503 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1504 | */ |
ae976416 HD |
1505 | static int shmem_readpage(struct file *file, struct page *page) |
1506 | { | |
1507 | struct inode *inode = page->mapping->host; | |
1508 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1509 | unlock_page(page); | |
1510 | return error; | |
1511 | } | |
1512 | ||
1da177e4 | 1513 | static int |
800d15a5 NP |
1514 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1515 | loff_t pos, unsigned len, unsigned flags, | |
1516 | struct page **pagep, void **fsdata) | |
1da177e4 | 1517 | { |
800d15a5 NP |
1518 | struct inode *inode = mapping->host; |
1519 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1520 | *pagep = NULL; | |
1521 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1522 | } | |
1523 | ||
1524 | static int | |
1525 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1526 | loff_t pos, unsigned len, unsigned copied, | |
1527 | struct page *page, void *fsdata) | |
1528 | { | |
1529 | struct inode *inode = mapping->host; | |
1530 | ||
d3602444 HD |
1531 | if (pos + copied > inode->i_size) |
1532 | i_size_write(inode, pos + copied); | |
1533 | ||
1534 | unlock_page(page); | |
800d15a5 NP |
1535 | set_page_dirty(page); |
1536 | page_cache_release(page); | |
1537 | ||
800d15a5 | 1538 | return copied; |
1da177e4 LT |
1539 | } |
1540 | ||
1da177e4 LT |
1541 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1542 | { | |
d3ac7f89 | 1543 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1544 | struct address_space *mapping = inode->i_mapping; |
1545 | unsigned long index, offset; | |
a0ee5ec5 HD |
1546 | enum sgp_type sgp = SGP_READ; |
1547 | ||
1548 | /* | |
1549 | * Might this read be for a stacking filesystem? Then when reading | |
1550 | * holes of a sparse file, we actually need to allocate those pages, | |
1551 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1552 | */ | |
1553 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1554 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1555 | |
1556 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1557 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1558 | ||
1559 | for (;;) { | |
1560 | struct page *page = NULL; | |
1561 | unsigned long end_index, nr, ret; | |
1562 | loff_t i_size = i_size_read(inode); | |
1563 | ||
1564 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1565 | if (index > end_index) | |
1566 | break; | |
1567 | if (index == end_index) { | |
1568 | nr = i_size & ~PAGE_CACHE_MASK; | |
1569 | if (nr <= offset) | |
1570 | break; | |
1571 | } | |
1572 | ||
a0ee5ec5 | 1573 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1574 | if (desc->error) { |
1575 | if (desc->error == -EINVAL) | |
1576 | desc->error = 0; | |
1577 | break; | |
1578 | } | |
d3602444 HD |
1579 | if (page) |
1580 | unlock_page(page); | |
1da177e4 LT |
1581 | |
1582 | /* | |
1583 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1584 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1585 | */ |
1586 | nr = PAGE_CACHE_SIZE; | |
1587 | i_size = i_size_read(inode); | |
1588 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1589 | if (index == end_index) { | |
1590 | nr = i_size & ~PAGE_CACHE_MASK; | |
1591 | if (nr <= offset) { | |
1592 | if (page) | |
1593 | page_cache_release(page); | |
1594 | break; | |
1595 | } | |
1596 | } | |
1597 | nr -= offset; | |
1598 | ||
1599 | if (page) { | |
1600 | /* | |
1601 | * If users can be writing to this page using arbitrary | |
1602 | * virtual addresses, take care about potential aliasing | |
1603 | * before reading the page on the kernel side. | |
1604 | */ | |
1605 | if (mapping_writably_mapped(mapping)) | |
1606 | flush_dcache_page(page); | |
1607 | /* | |
1608 | * Mark the page accessed if we read the beginning. | |
1609 | */ | |
1610 | if (!offset) | |
1611 | mark_page_accessed(page); | |
b5810039 | 1612 | } else { |
1da177e4 | 1613 | page = ZERO_PAGE(0); |
b5810039 NP |
1614 | page_cache_get(page); |
1615 | } | |
1da177e4 LT |
1616 | |
1617 | /* | |
1618 | * Ok, we have the page, and it's up-to-date, so | |
1619 | * now we can copy it to user space... | |
1620 | * | |
1621 | * The actor routine returns how many bytes were actually used.. | |
1622 | * NOTE! This may not be the same as how much of a user buffer | |
1623 | * we filled up (we may be padding etc), so we can only update | |
1624 | * "pos" here (the actor routine has to update the user buffer | |
1625 | * pointers and the remaining count). | |
1626 | */ | |
1627 | ret = actor(desc, page, offset, nr); | |
1628 | offset += ret; | |
1629 | index += offset >> PAGE_CACHE_SHIFT; | |
1630 | offset &= ~PAGE_CACHE_MASK; | |
1631 | ||
1632 | page_cache_release(page); | |
1633 | if (ret != nr || !desc->count) | |
1634 | break; | |
1635 | ||
1636 | cond_resched(); | |
1637 | } | |
1638 | ||
1639 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1640 | file_accessed(filp); | |
1641 | } | |
1642 | ||
1643 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1644 | { | |
1645 | read_descriptor_t desc; | |
1646 | ||
1647 | if ((ssize_t) count < 0) | |
1648 | return -EINVAL; | |
1649 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1650 | return -EFAULT; | |
1651 | if (!count) | |
1652 | return 0; | |
1653 | ||
1654 | desc.written = 0; | |
1655 | desc.count = count; | |
1656 | desc.arg.buf = buf; | |
1657 | desc.error = 0; | |
1658 | ||
1659 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1660 | if (desc.written) | |
1661 | return desc.written; | |
1662 | return desc.error; | |
1663 | } | |
1664 | ||
726c3342 | 1665 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1666 | { |
726c3342 | 1667 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1668 | |
1669 | buf->f_type = TMPFS_MAGIC; | |
1670 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1671 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1672 | spin_lock(&sbinfo->stat_lock); |
1673 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1674 | buf->f_blocks = sbinfo->max_blocks; |
1675 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1676 | } |
1677 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1678 | buf->f_files = sbinfo->max_inodes; |
1679 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1680 | } |
1681 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1682 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1683 | return 0; |
1684 | } | |
1685 | ||
1686 | /* | |
1687 | * File creation. Allocate an inode, and we're done.. | |
1688 | */ | |
1689 | static int | |
1690 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1691 | { | |
1692 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1693 | int error = -ENOSPC; | |
1694 | ||
1695 | if (inode) { | |
570bc1c2 SS |
1696 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1697 | NULL); | |
1698 | if (error) { | |
1699 | if (error != -EOPNOTSUPP) { | |
1700 | iput(inode); | |
1701 | return error; | |
1702 | } | |
39f0247d AG |
1703 | } |
1704 | error = shmem_acl_init(inode, dir); | |
1705 | if (error) { | |
1706 | iput(inode); | |
1707 | return error; | |
570bc1c2 | 1708 | } |
1da177e4 LT |
1709 | if (dir->i_mode & S_ISGID) { |
1710 | inode->i_gid = dir->i_gid; | |
1711 | if (S_ISDIR(mode)) | |
1712 | inode->i_mode |= S_ISGID; | |
1713 | } | |
1714 | dir->i_size += BOGO_DIRENT_SIZE; | |
1715 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1716 | d_instantiate(dentry, inode); | |
1717 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1718 | } |
1719 | return error; | |
1720 | } | |
1721 | ||
1722 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1723 | { | |
1724 | int error; | |
1725 | ||
1726 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1727 | return error; | |
d8c76e6f | 1728 | inc_nlink(dir); |
1da177e4 LT |
1729 | return 0; |
1730 | } | |
1731 | ||
1732 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1733 | struct nameidata *nd) | |
1734 | { | |
1735 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1736 | } | |
1737 | ||
1738 | /* | |
1739 | * Link a file.. | |
1740 | */ | |
1741 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1742 | { | |
1743 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1744 | int ret; |
1da177e4 LT |
1745 | |
1746 | /* | |
1747 | * No ordinary (disk based) filesystem counts links as inodes; | |
1748 | * but each new link needs a new dentry, pinning lowmem, and | |
1749 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1750 | */ | |
5b04c689 PE |
1751 | ret = shmem_reserve_inode(inode->i_sb); |
1752 | if (ret) | |
1753 | goto out; | |
1da177e4 LT |
1754 | |
1755 | dir->i_size += BOGO_DIRENT_SIZE; | |
1756 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1757 | inc_nlink(inode); |
1da177e4 LT |
1758 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1759 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1760 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1761 | out: |
1762 | return ret; | |
1da177e4 LT |
1763 | } |
1764 | ||
1765 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1766 | { | |
1767 | struct inode *inode = dentry->d_inode; | |
1768 | ||
5b04c689 PE |
1769 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1770 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1771 | |
1772 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1773 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1774 | drop_nlink(inode); |
1da177e4 LT |
1775 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1776 | return 0; | |
1777 | } | |
1778 | ||
1779 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1780 | { | |
1781 | if (!simple_empty(dentry)) | |
1782 | return -ENOTEMPTY; | |
1783 | ||
9a53c3a7 DH |
1784 | drop_nlink(dentry->d_inode); |
1785 | drop_nlink(dir); | |
1da177e4 LT |
1786 | return shmem_unlink(dir, dentry); |
1787 | } | |
1788 | ||
1789 | /* | |
1790 | * The VFS layer already does all the dentry stuff for rename, | |
1791 | * we just have to decrement the usage count for the target if | |
1792 | * it exists so that the VFS layer correctly free's it when it | |
1793 | * gets overwritten. | |
1794 | */ | |
1795 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1796 | { | |
1797 | struct inode *inode = old_dentry->d_inode; | |
1798 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1799 | ||
1800 | if (!simple_empty(new_dentry)) | |
1801 | return -ENOTEMPTY; | |
1802 | ||
1803 | if (new_dentry->d_inode) { | |
1804 | (void) shmem_unlink(new_dir, new_dentry); | |
1805 | if (they_are_dirs) | |
9a53c3a7 | 1806 | drop_nlink(old_dir); |
1da177e4 | 1807 | } else if (they_are_dirs) { |
9a53c3a7 | 1808 | drop_nlink(old_dir); |
d8c76e6f | 1809 | inc_nlink(new_dir); |
1da177e4 LT |
1810 | } |
1811 | ||
1812 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1813 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1814 | old_dir->i_ctime = old_dir->i_mtime = | |
1815 | new_dir->i_ctime = new_dir->i_mtime = | |
1816 | inode->i_ctime = CURRENT_TIME; | |
1817 | return 0; | |
1818 | } | |
1819 | ||
1820 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1821 | { | |
1822 | int error; | |
1823 | int len; | |
1824 | struct inode *inode; | |
1825 | struct page *page = NULL; | |
1826 | char *kaddr; | |
1827 | struct shmem_inode_info *info; | |
1828 | ||
1829 | len = strlen(symname) + 1; | |
1830 | if (len > PAGE_CACHE_SIZE) | |
1831 | return -ENAMETOOLONG; | |
1832 | ||
1833 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1834 | if (!inode) | |
1835 | return -ENOSPC; | |
1836 | ||
570bc1c2 SS |
1837 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1838 | NULL); | |
1839 | if (error) { | |
1840 | if (error != -EOPNOTSUPP) { | |
1841 | iput(inode); | |
1842 | return error; | |
1843 | } | |
1844 | error = 0; | |
1845 | } | |
1846 | ||
1da177e4 LT |
1847 | info = SHMEM_I(inode); |
1848 | inode->i_size = len-1; | |
1849 | if (len <= (char *)inode - (char *)info) { | |
1850 | /* do it inline */ | |
1851 | memcpy(info, symname, len); | |
1852 | inode->i_op = &shmem_symlink_inline_operations; | |
1853 | } else { | |
1854 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1855 | if (error) { | |
1856 | iput(inode); | |
1857 | return error; | |
1858 | } | |
d3602444 | 1859 | unlock_page(page); |
1da177e4 LT |
1860 | inode->i_op = &shmem_symlink_inode_operations; |
1861 | kaddr = kmap_atomic(page, KM_USER0); | |
1862 | memcpy(kaddr, symname, len); | |
1863 | kunmap_atomic(kaddr, KM_USER0); | |
1864 | set_page_dirty(page); | |
1865 | page_cache_release(page); | |
1866 | } | |
1867 | if (dir->i_mode & S_ISGID) | |
1868 | inode->i_gid = dir->i_gid; | |
1869 | dir->i_size += BOGO_DIRENT_SIZE; | |
1870 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1871 | d_instantiate(dentry, inode); | |
1872 | dget(dentry); | |
1873 | return 0; | |
1874 | } | |
1875 | ||
cc314eef | 1876 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1877 | { |
1878 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1879 | return NULL; |
1da177e4 LT |
1880 | } |
1881 | ||
cc314eef | 1882 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1883 | { |
1884 | struct page *page = NULL; | |
1885 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1886 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
1887 | if (page) |
1888 | unlock_page(page); | |
cc314eef | 1889 | return page; |
1da177e4 LT |
1890 | } |
1891 | ||
cc314eef | 1892 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1893 | { |
1894 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1895 | struct page *page = cookie; |
1da177e4 LT |
1896 | kunmap(page); |
1897 | mark_page_accessed(page); | |
1898 | page_cache_release(page); | |
1da177e4 LT |
1899 | } |
1900 | } | |
1901 | ||
92e1d5be | 1902 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
1903 | .readlink = generic_readlink, |
1904 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1905 | }; |
1906 | ||
92e1d5be | 1907 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
1908 | .truncate = shmem_truncate, |
1909 | .readlink = generic_readlink, | |
1910 | .follow_link = shmem_follow_link, | |
1911 | .put_link = shmem_put_link, | |
1da177e4 LT |
1912 | }; |
1913 | ||
39f0247d AG |
1914 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1915 | /** | |
1916 | * Superblocks without xattr inode operations will get security.* xattr | |
1917 | * support from the VFS "for free". As soon as we have any other xattrs | |
1918 | * like ACLs, we also need to implement the security.* handlers at | |
1919 | * filesystem level, though. | |
1920 | */ | |
1921 | ||
1922 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
1923 | size_t list_len, const char *name, | |
1924 | size_t name_len) | |
1925 | { | |
1926 | return security_inode_listsecurity(inode, list, list_len); | |
1927 | } | |
1928 | ||
1929 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
1930 | void *buffer, size_t size) | |
1931 | { | |
1932 | if (strcmp(name, "") == 0) | |
1933 | return -EINVAL; | |
1934 | return security_inode_getsecurity(inode, name, buffer, size, | |
1935 | -EOPNOTSUPP); | |
1936 | } | |
1937 | ||
1938 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
1939 | const void *value, size_t size, int flags) | |
1940 | { | |
1941 | if (strcmp(name, "") == 0) | |
1942 | return -EINVAL; | |
1943 | return security_inode_setsecurity(inode, name, value, size, flags); | |
1944 | } | |
1945 | ||
1f370a23 | 1946 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
1947 | .prefix = XATTR_SECURITY_PREFIX, |
1948 | .list = shmem_xattr_security_list, | |
1949 | .get = shmem_xattr_security_get, | |
1950 | .set = shmem_xattr_security_set, | |
1951 | }; | |
1952 | ||
1953 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
1954 | &shmem_xattr_acl_access_handler, | |
1955 | &shmem_xattr_acl_default_handler, | |
1956 | &shmem_xattr_security_handler, | |
1957 | NULL | |
1958 | }; | |
1959 | #endif | |
1960 | ||
91828a40 DG |
1961 | static struct dentry *shmem_get_parent(struct dentry *child) |
1962 | { | |
1963 | return ERR_PTR(-ESTALE); | |
1964 | } | |
1965 | ||
1966 | static int shmem_match(struct inode *ino, void *vfh) | |
1967 | { | |
1968 | __u32 *fh = vfh; | |
1969 | __u64 inum = fh[2]; | |
1970 | inum = (inum << 32) | fh[1]; | |
1971 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1972 | } | |
1973 | ||
480b116c CH |
1974 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
1975 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 1976 | { |
91828a40 | 1977 | struct inode *inode; |
480b116c CH |
1978 | struct dentry *dentry = NULL; |
1979 | u64 inum = fid->raw[2]; | |
1980 | inum = (inum << 32) | fid->raw[1]; | |
1981 | ||
1982 | if (fh_len < 3) | |
1983 | return NULL; | |
91828a40 | 1984 | |
480b116c CH |
1985 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
1986 | shmem_match, fid->raw); | |
91828a40 | 1987 | if (inode) { |
480b116c | 1988 | dentry = d_find_alias(inode); |
91828a40 DG |
1989 | iput(inode); |
1990 | } | |
1991 | ||
480b116c | 1992 | return dentry; |
91828a40 DG |
1993 | } |
1994 | ||
1995 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
1996 | int connectable) | |
1997 | { | |
1998 | struct inode *inode = dentry->d_inode; | |
1999 | ||
2000 | if (*len < 3) | |
2001 | return 255; | |
2002 | ||
2003 | if (hlist_unhashed(&inode->i_hash)) { | |
2004 | /* Unfortunately insert_inode_hash is not idempotent, | |
2005 | * so as we hash inodes here rather than at creation | |
2006 | * time, we need a lock to ensure we only try | |
2007 | * to do it once | |
2008 | */ | |
2009 | static DEFINE_SPINLOCK(lock); | |
2010 | spin_lock(&lock); | |
2011 | if (hlist_unhashed(&inode->i_hash)) | |
2012 | __insert_inode_hash(inode, | |
2013 | inode->i_ino + inode->i_generation); | |
2014 | spin_unlock(&lock); | |
2015 | } | |
2016 | ||
2017 | fh[0] = inode->i_generation; | |
2018 | fh[1] = inode->i_ino; | |
2019 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2020 | ||
2021 | *len = 3; | |
2022 | return 1; | |
2023 | } | |
2024 | ||
39655164 | 2025 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2026 | .get_parent = shmem_get_parent, |
91828a40 | 2027 | .encode_fh = shmem_encode_fh, |
480b116c | 2028 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2029 | }; |
2030 | ||
7339ff83 RH |
2031 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
2032 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, | |
2033 | int *policy, nodemask_t *policy_nodes) | |
1da177e4 LT |
2034 | { |
2035 | char *this_char, *value, *rest; | |
2036 | ||
b00dc3ad HD |
2037 | while (options != NULL) { |
2038 | this_char = options; | |
2039 | for (;;) { | |
2040 | /* | |
2041 | * NUL-terminate this option: unfortunately, | |
2042 | * mount options form a comma-separated list, | |
2043 | * but mpol's nodelist may also contain commas. | |
2044 | */ | |
2045 | options = strchr(options, ','); | |
2046 | if (options == NULL) | |
2047 | break; | |
2048 | options++; | |
2049 | if (!isdigit(*options)) { | |
2050 | options[-1] = '\0'; | |
2051 | break; | |
2052 | } | |
2053 | } | |
1da177e4 LT |
2054 | if (!*this_char) |
2055 | continue; | |
2056 | if ((value = strchr(this_char,'=')) != NULL) { | |
2057 | *value++ = 0; | |
2058 | } else { | |
2059 | printk(KERN_ERR | |
2060 | "tmpfs: No value for mount option '%s'\n", | |
2061 | this_char); | |
2062 | return 1; | |
2063 | } | |
2064 | ||
2065 | if (!strcmp(this_char,"size")) { | |
2066 | unsigned long long size; | |
2067 | size = memparse(value,&rest); | |
2068 | if (*rest == '%') { | |
2069 | size <<= PAGE_SHIFT; | |
2070 | size *= totalram_pages; | |
2071 | do_div(size, 100); | |
2072 | rest++; | |
2073 | } | |
2074 | if (*rest) | |
2075 | goto bad_val; | |
818db359 | 2076 | *blocks = DIV_ROUND_UP(size, PAGE_CACHE_SIZE); |
1da177e4 LT |
2077 | } else if (!strcmp(this_char,"nr_blocks")) { |
2078 | *blocks = memparse(value,&rest); | |
2079 | if (*rest) | |
2080 | goto bad_val; | |
2081 | } else if (!strcmp(this_char,"nr_inodes")) { | |
2082 | *inodes = memparse(value,&rest); | |
2083 | if (*rest) | |
2084 | goto bad_val; | |
2085 | } else if (!strcmp(this_char,"mode")) { | |
2086 | if (!mode) | |
2087 | continue; | |
2088 | *mode = simple_strtoul(value,&rest,8); | |
2089 | if (*rest) | |
2090 | goto bad_val; | |
2091 | } else if (!strcmp(this_char,"uid")) { | |
2092 | if (!uid) | |
2093 | continue; | |
2094 | *uid = simple_strtoul(value,&rest,0); | |
2095 | if (*rest) | |
2096 | goto bad_val; | |
2097 | } else if (!strcmp(this_char,"gid")) { | |
2098 | if (!gid) | |
2099 | continue; | |
2100 | *gid = simple_strtoul(value,&rest,0); | |
2101 | if (*rest) | |
2102 | goto bad_val; | |
7339ff83 | 2103 | } else if (!strcmp(this_char,"mpol")) { |
b00dc3ad | 2104 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
7339ff83 | 2105 | goto bad_val; |
1da177e4 LT |
2106 | } else { |
2107 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2108 | this_char); | |
2109 | return 1; | |
2110 | } | |
2111 | } | |
2112 | return 0; | |
2113 | ||
2114 | bad_val: | |
2115 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2116 | value, this_char); | |
2117 | return 1; | |
2118 | ||
2119 | } | |
2120 | ||
2121 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2122 | { | |
2123 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
2124 | unsigned long max_blocks = sbinfo->max_blocks; |
2125 | unsigned long max_inodes = sbinfo->max_inodes; | |
7339ff83 RH |
2126 | int policy = sbinfo->policy; |
2127 | nodemask_t policy_nodes = sbinfo->policy_nodes; | |
0edd73b3 HD |
2128 | unsigned long blocks; |
2129 | unsigned long inodes; | |
2130 | int error = -EINVAL; | |
2131 | ||
7339ff83 RH |
2132 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
2133 | &max_inodes, &policy, &policy_nodes)) | |
0edd73b3 | 2134 | return error; |
1da177e4 | 2135 | |
0edd73b3 HD |
2136 | spin_lock(&sbinfo->stat_lock); |
2137 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2138 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
2139 | if (max_blocks < blocks) | |
2140 | goto out; | |
2141 | if (max_inodes < inodes) | |
2142 | goto out; | |
2143 | /* | |
2144 | * Those tests also disallow limited->unlimited while any are in | |
2145 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2146 | * but we must separately disallow unlimited->limited, because | |
2147 | * in that case we have no record of how much is already in use. | |
2148 | */ | |
2149 | if (max_blocks && !sbinfo->max_blocks) | |
2150 | goto out; | |
2151 | if (max_inodes && !sbinfo->max_inodes) | |
2152 | goto out; | |
2153 | ||
2154 | error = 0; | |
2155 | sbinfo->max_blocks = max_blocks; | |
2156 | sbinfo->free_blocks = max_blocks - blocks; | |
2157 | sbinfo->max_inodes = max_inodes; | |
2158 | sbinfo->free_inodes = max_inodes - inodes; | |
7339ff83 RH |
2159 | sbinfo->policy = policy; |
2160 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2161 | out: |
2162 | spin_unlock(&sbinfo->stat_lock); | |
2163 | return error; | |
1da177e4 LT |
2164 | } |
2165 | #endif | |
2166 | ||
2167 | static void shmem_put_super(struct super_block *sb) | |
2168 | { | |
2169 | kfree(sb->s_fs_info); | |
2170 | sb->s_fs_info = NULL; | |
2171 | } | |
2172 | ||
1da177e4 LT |
2173 | static int shmem_fill_super(struct super_block *sb, |
2174 | void *data, int silent) | |
2175 | { | |
2176 | struct inode *inode; | |
2177 | struct dentry *root; | |
2178 | int mode = S_IRWXUGO | S_ISVTX; | |
2179 | uid_t uid = current->fsuid; | |
2180 | gid_t gid = current->fsgid; | |
2181 | int err = -ENOMEM; | |
0edd73b3 | 2182 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
2183 | unsigned long blocks = 0; |
2184 | unsigned long inodes = 0; | |
7339ff83 | 2185 | int policy = MPOL_DEFAULT; |
37b07e41 | 2186 | nodemask_t policy_nodes = node_states[N_HIGH_MEMORY]; |
1da177e4 | 2187 | |
0edd73b3 | 2188 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2189 | /* |
2190 | * Per default we only allow half of the physical ram per | |
2191 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2192 | * but the internal instance is left unlimited. | |
2193 | */ | |
2194 | if (!(sb->s_flags & MS_NOUSER)) { | |
2195 | blocks = totalram_pages / 2; | |
2196 | inodes = totalram_pages - totalhigh_pages; | |
2197 | if (inodes > blocks) | |
2198 | inodes = blocks; | |
7339ff83 RH |
2199 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
2200 | &inodes, &policy, &policy_nodes)) | |
1da177e4 LT |
2201 | return -EINVAL; |
2202 | } | |
91828a40 | 2203 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2204 | #else |
2205 | sb->s_flags |= MS_NOUSER; | |
2206 | #endif | |
2207 | ||
0edd73b3 HD |
2208 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
2209 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2210 | L1_CACHE_BYTES), GFP_KERNEL); | |
2211 | if (!sbinfo) | |
2212 | return -ENOMEM; | |
2213 | ||
2214 | spin_lock_init(&sbinfo->stat_lock); | |
2215 | sbinfo->max_blocks = blocks; | |
2216 | sbinfo->free_blocks = blocks; | |
2217 | sbinfo->max_inodes = inodes; | |
2218 | sbinfo->free_inodes = inodes; | |
7339ff83 RH |
2219 | sbinfo->policy = policy; |
2220 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2221 | |
2222 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
2223 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2224 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2225 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2226 | sb->s_magic = TMPFS_MAGIC; | |
2227 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2228 | sb->s_time_gran = 1; |
39f0247d AG |
2229 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2230 | sb->s_xattr = shmem_xattr_handlers; | |
2231 | sb->s_flags |= MS_POSIXACL; | |
2232 | #endif | |
0edd73b3 | 2233 | |
1da177e4 LT |
2234 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2235 | if (!inode) | |
2236 | goto failed; | |
2237 | inode->i_uid = uid; | |
2238 | inode->i_gid = gid; | |
2239 | root = d_alloc_root(inode); | |
2240 | if (!root) | |
2241 | goto failed_iput; | |
2242 | sb->s_root = root; | |
2243 | return 0; | |
2244 | ||
2245 | failed_iput: | |
2246 | iput(inode); | |
2247 | failed: | |
2248 | shmem_put_super(sb); | |
2249 | return err; | |
2250 | } | |
2251 | ||
fcc234f8 | 2252 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2253 | |
2254 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2255 | { | |
2256 | struct shmem_inode_info *p; | |
e94b1766 | 2257 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2258 | if (!p) |
2259 | return NULL; | |
2260 | return &p->vfs_inode; | |
2261 | } | |
2262 | ||
2263 | static void shmem_destroy_inode(struct inode *inode) | |
2264 | { | |
2265 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2266 | /* only struct inode is valid if it's an inline symlink */ | |
2267 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2268 | } | |
39f0247d | 2269 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2270 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2271 | } | |
2272 | ||
4ba9b9d0 | 2273 | static void init_once(struct kmem_cache *cachep, void *foo) |
1da177e4 LT |
2274 | { |
2275 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2276 | ||
a35afb83 | 2277 | inode_init_once(&p->vfs_inode); |
39f0247d | 2278 | #ifdef CONFIG_TMPFS_POSIX_ACL |
a35afb83 CL |
2279 | p->i_acl = NULL; |
2280 | p->i_default_acl = NULL; | |
39f0247d | 2281 | #endif |
1da177e4 LT |
2282 | } |
2283 | ||
2284 | static int init_inodecache(void) | |
2285 | { | |
2286 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2287 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2288 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2289 | return 0; |
2290 | } | |
2291 | ||
2292 | static void destroy_inodecache(void) | |
2293 | { | |
1a1d92c1 | 2294 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2295 | } |
2296 | ||
f5e54d6e | 2297 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2298 | .writepage = shmem_writepage, |
76719325 | 2299 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2300 | #ifdef CONFIG_TMPFS |
ae976416 | 2301 | .readpage = shmem_readpage, |
800d15a5 NP |
2302 | .write_begin = shmem_write_begin, |
2303 | .write_end = shmem_write_end, | |
1da177e4 | 2304 | #endif |
304dbdb7 | 2305 | .migratepage = migrate_page, |
1da177e4 LT |
2306 | }; |
2307 | ||
15ad7cdc | 2308 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2309 | .mmap = shmem_mmap, |
2310 | #ifdef CONFIG_TMPFS | |
2311 | .llseek = generic_file_llseek, | |
2312 | .read = shmem_file_read, | |
5402b976 HD |
2313 | .write = do_sync_write, |
2314 | .aio_write = generic_file_aio_write, | |
1da177e4 | 2315 | .fsync = simple_sync_file, |
ae976416 HD |
2316 | .splice_read = generic_file_splice_read, |
2317 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2318 | #endif |
2319 | }; | |
2320 | ||
92e1d5be | 2321 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2322 | .truncate = shmem_truncate, |
2323 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2324 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2325 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2326 | .setxattr = generic_setxattr, | |
2327 | .getxattr = generic_getxattr, | |
2328 | .listxattr = generic_listxattr, | |
2329 | .removexattr = generic_removexattr, | |
2330 | .permission = shmem_permission, | |
2331 | #endif | |
2332 | ||
1da177e4 LT |
2333 | }; |
2334 | ||
92e1d5be | 2335 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2336 | #ifdef CONFIG_TMPFS |
2337 | .create = shmem_create, | |
2338 | .lookup = simple_lookup, | |
2339 | .link = shmem_link, | |
2340 | .unlink = shmem_unlink, | |
2341 | .symlink = shmem_symlink, | |
2342 | .mkdir = shmem_mkdir, | |
2343 | .rmdir = shmem_rmdir, | |
2344 | .mknod = shmem_mknod, | |
2345 | .rename = shmem_rename, | |
1da177e4 | 2346 | #endif |
39f0247d AG |
2347 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2348 | .setattr = shmem_notify_change, | |
2349 | .setxattr = generic_setxattr, | |
2350 | .getxattr = generic_getxattr, | |
2351 | .listxattr = generic_listxattr, | |
2352 | .removexattr = generic_removexattr, | |
2353 | .permission = shmem_permission, | |
2354 | #endif | |
2355 | }; | |
2356 | ||
92e1d5be | 2357 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2358 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2359 | .setattr = shmem_notify_change, | |
2360 | .setxattr = generic_setxattr, | |
2361 | .getxattr = generic_getxattr, | |
2362 | .listxattr = generic_listxattr, | |
2363 | .removexattr = generic_removexattr, | |
2364 | .permission = shmem_permission, | |
2365 | #endif | |
1da177e4 LT |
2366 | }; |
2367 | ||
759b9775 | 2368 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2369 | .alloc_inode = shmem_alloc_inode, |
2370 | .destroy_inode = shmem_destroy_inode, | |
2371 | #ifdef CONFIG_TMPFS | |
2372 | .statfs = shmem_statfs, | |
2373 | .remount_fs = shmem_remount_fs, | |
2374 | #endif | |
2375 | .delete_inode = shmem_delete_inode, | |
2376 | .drop_inode = generic_delete_inode, | |
2377 | .put_super = shmem_put_super, | |
2378 | }; | |
2379 | ||
2380 | static struct vm_operations_struct shmem_vm_ops = { | |
54cb8821 | 2381 | .fault = shmem_fault, |
1da177e4 LT |
2382 | #ifdef CONFIG_NUMA |
2383 | .set_policy = shmem_set_policy, | |
2384 | .get_policy = shmem_get_policy, | |
2385 | #endif | |
2386 | }; | |
2387 | ||
2388 | ||
454e2398 DH |
2389 | static int shmem_get_sb(struct file_system_type *fs_type, |
2390 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2391 | { |
454e2398 | 2392 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2393 | } |
2394 | ||
2395 | static struct file_system_type tmpfs_fs_type = { | |
2396 | .owner = THIS_MODULE, | |
2397 | .name = "tmpfs", | |
2398 | .get_sb = shmem_get_sb, | |
2399 | .kill_sb = kill_litter_super, | |
2400 | }; | |
2401 | static struct vfsmount *shm_mnt; | |
2402 | ||
2403 | static int __init init_tmpfs(void) | |
2404 | { | |
2405 | int error; | |
2406 | ||
e0bf68dd PZ |
2407 | error = bdi_init(&shmem_backing_dev_info); |
2408 | if (error) | |
2409 | goto out4; | |
2410 | ||
1da177e4 LT |
2411 | error = init_inodecache(); |
2412 | if (error) | |
2413 | goto out3; | |
2414 | ||
2415 | error = register_filesystem(&tmpfs_fs_type); | |
2416 | if (error) { | |
2417 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2418 | goto out2; | |
2419 | } | |
95dc112a | 2420 | |
1f5ce9e9 | 2421 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2422 | tmpfs_fs_type.name, NULL); |
2423 | if (IS_ERR(shm_mnt)) { | |
2424 | error = PTR_ERR(shm_mnt); | |
2425 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2426 | goto out1; | |
2427 | } | |
2428 | return 0; | |
2429 | ||
2430 | out1: | |
2431 | unregister_filesystem(&tmpfs_fs_type); | |
2432 | out2: | |
2433 | destroy_inodecache(); | |
2434 | out3: | |
e0bf68dd PZ |
2435 | bdi_destroy(&shmem_backing_dev_info); |
2436 | out4: | |
1da177e4 LT |
2437 | shm_mnt = ERR_PTR(error); |
2438 | return error; | |
2439 | } | |
2440 | module_init(init_tmpfs) | |
2441 | ||
2442 | /* | |
2443 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2444 | * | |
2445 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2446 | * @size: size to be set for the file | |
2447 | * | |
2448 | */ | |
2449 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2450 | { | |
2451 | int error; | |
2452 | struct file *file; | |
2453 | struct inode *inode; | |
2454 | struct dentry *dentry, *root; | |
2455 | struct qstr this; | |
2456 | ||
2457 | if (IS_ERR(shm_mnt)) | |
2458 | return (void *)shm_mnt; | |
2459 | ||
2460 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2461 | return ERR_PTR(-EINVAL); | |
2462 | ||
2463 | if (shmem_acct_size(flags, size)) | |
2464 | return ERR_PTR(-ENOMEM); | |
2465 | ||
2466 | error = -ENOMEM; | |
2467 | this.name = name; | |
2468 | this.len = strlen(name); | |
2469 | this.hash = 0; /* will go */ | |
2470 | root = shm_mnt->mnt_root; | |
2471 | dentry = d_alloc(root, &this); | |
2472 | if (!dentry) | |
2473 | goto put_memory; | |
2474 | ||
2475 | error = -ENFILE; | |
2476 | file = get_empty_filp(); | |
2477 | if (!file) | |
2478 | goto put_dentry; | |
2479 | ||
2480 | error = -ENOSPC; | |
2481 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2482 | if (!inode) | |
2483 | goto close_file; | |
2484 | ||
2485 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2486 | d_instantiate(dentry, inode); | |
2487 | inode->i_size = size; | |
2488 | inode->i_nlink = 0; /* It is unlinked */ | |
ce8d2cdf DH |
2489 | init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ, |
2490 | &shmem_file_operations); | |
1da177e4 LT |
2491 | return file; |
2492 | ||
2493 | close_file: | |
2494 | put_filp(file); | |
2495 | put_dentry: | |
2496 | dput(dentry); | |
2497 | put_memory: | |
2498 | shmem_unacct_size(flags, size); | |
2499 | return ERR_PTR(error); | |
2500 | } | |
2501 | ||
2502 | /* | |
2503 | * shmem_zero_setup - setup a shared anonymous mapping | |
2504 | * | |
2505 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2506 | */ | |
2507 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2508 | { | |
2509 | struct file *file; | |
2510 | loff_t size = vma->vm_end - vma->vm_start; | |
2511 | ||
2512 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2513 | if (IS_ERR(file)) | |
2514 | return PTR_ERR(file); | |
2515 | ||
2516 | if (vma->vm_file) | |
2517 | fput(vma->vm_file); | |
2518 | vma->vm_file = file; | |
2519 | vma->vm_ops = &shmem_vm_ops; | |
2520 | return 0; | |
2521 | } |