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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
0edd73b3 HD |
9 | * Copyright (C) 2002-2005 Hugh Dickins. |
10 | * Copyright (C) 2002-2005 VERITAS Software Corporation. | |
1da177e4 LT |
11 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
12 | * | |
13 | * Extended attribute support for tmpfs: | |
14 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
15 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
16 | * | |
17 | * This file is released under the GPL. | |
18 | */ | |
19 | ||
20 | /* | |
21 | * This virtual memory filesystem is heavily based on the ramfs. It | |
22 | * extends ramfs by the ability to use swap and honor resource limits | |
23 | * which makes it a completely usable filesystem. | |
24 | */ | |
25 | ||
1da177e4 LT |
26 | #include <linux/module.h> |
27 | #include <linux/init.h> | |
1da177e4 | 28 | #include <linux/fs.h> |
39f0247d AG |
29 | #include <linux/xattr.h> |
30 | #include <linux/generic_acl.h> | |
1da177e4 LT |
31 | #include <linux/mm.h> |
32 | #include <linux/mman.h> | |
33 | #include <linux/file.h> | |
34 | #include <linux/swap.h> | |
35 | #include <linux/pagemap.h> | |
36 | #include <linux/string.h> | |
37 | #include <linux/slab.h> | |
38 | #include <linux/backing-dev.h> | |
39 | #include <linux/shmem_fs.h> | |
40 | #include <linux/mount.h> | |
41 | #include <linux/writeback.h> | |
42 | #include <linux/vfs.h> | |
43 | #include <linux/blkdev.h> | |
44 | #include <linux/security.h> | |
45 | #include <linux/swapops.h> | |
46 | #include <linux/mempolicy.h> | |
47 | #include <linux/namei.h> | |
b00dc3ad | 48 | #include <linux/ctype.h> |
304dbdb7 | 49 | #include <linux/migrate.h> |
c1f60a5a | 50 | #include <linux/highmem.h> |
3fcfab16 | 51 | #include <linux/backing-dev.h> |
304dbdb7 | 52 | |
1da177e4 LT |
53 | #include <asm/uaccess.h> |
54 | #include <asm/div64.h> | |
55 | #include <asm/pgtable.h> | |
56 | ||
57 | /* This magic number is used in glibc for posix shared memory */ | |
58 | #define TMPFS_MAGIC 0x01021994 | |
59 | ||
60 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) | |
61 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) | |
62 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
63 | ||
64 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) | |
65 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) | |
66 | ||
67 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) | |
68 | ||
69 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
70 | #define SHMEM_PAGEIN VM_READ | |
71 | #define SHMEM_TRUNCATE VM_WRITE | |
72 | ||
73 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
74 | #define LATENCY_LIMIT 64 | |
75 | ||
76 | /* Pretend that each entry is of this size in directory's i_size */ | |
77 | #define BOGO_DIRENT_SIZE 20 | |
78 | ||
1da177e4 LT |
79 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
80 | enum sgp_type { | |
81 | SGP_QUICK, /* don't try more than file page cache lookup */ | |
82 | SGP_READ, /* don't exceed i_size, don't allocate page */ | |
83 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
84 | SGP_WRITE, /* may exceed i_size, may allocate page */ | |
85 | }; | |
86 | ||
87 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
88 | struct page **pagep, enum sgp_type sgp, int *type); | |
89 | ||
6daa0e28 | 90 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
91 | { |
92 | /* | |
93 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
94 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
95 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 MG |
96 | * |
97 | * __GFP_MOVABLE is masked out as swap vectors cannot move | |
1da177e4 | 98 | */ |
769848c0 MG |
99 | return alloc_pages((gfp_mask & ~__GFP_MOVABLE) | __GFP_ZERO, |
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); | |
196 | static DEFINE_SPINLOCK(shmem_swaplist_lock); | |
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 | ||
209 | /* | |
210 | * shmem_recalc_inode - recalculate the size of an inode | |
211 | * | |
212 | * @inode: inode to recalc | |
213 | * | |
214 | * We have to calculate the free blocks since the mm can drop | |
215 | * undirtied hole pages behind our back. | |
216 | * | |
217 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
218 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
219 | * | |
220 | * It has to be called with the spinlock held. | |
221 | */ | |
222 | static void shmem_recalc_inode(struct inode *inode) | |
223 | { | |
224 | struct shmem_inode_info *info = SHMEM_I(inode); | |
225 | long freed; | |
226 | ||
227 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
228 | if (freed > 0) { | |
229 | info->alloced -= freed; | |
230 | shmem_unacct_blocks(info->flags, freed); | |
231 | shmem_free_blocks(inode, freed); | |
232 | } | |
233 | } | |
234 | ||
235 | /* | |
236 | * shmem_swp_entry - find the swap vector position in the info structure | |
237 | * | |
238 | * @info: info structure for the inode | |
239 | * @index: index of the page to find | |
240 | * @page: optional page to add to the structure. Has to be preset to | |
241 | * all zeros | |
242 | * | |
243 | * If there is no space allocated yet it will return NULL when | |
244 | * page is NULL, else it will use the page for the needed block, | |
245 | * setting it to NULL on return to indicate that it has been used. | |
246 | * | |
247 | * The swap vector is organized the following way: | |
248 | * | |
249 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
250 | * shmem_inode_info structure. So small files do not need an addional | |
251 | * allocation. | |
252 | * | |
253 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
254 | * i_indirect which points to a page which holds in the first half | |
255 | * doubly indirect blocks, in the second half triple indirect blocks: | |
256 | * | |
257 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
258 | * following layout (for SHMEM_NR_DIRECT == 16): | |
259 | * | |
260 | * i_indirect -> dir --> 16-19 | |
261 | * | +-> 20-23 | |
262 | * | | |
263 | * +-->dir2 --> 24-27 | |
264 | * | +-> 28-31 | |
265 | * | +-> 32-35 | |
266 | * | +-> 36-39 | |
267 | * | | |
268 | * +-->dir3 --> 40-43 | |
269 | * +-> 44-47 | |
270 | * +-> 48-51 | |
271 | * +-> 52-55 | |
272 | */ | |
273 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
274 | { | |
275 | unsigned long offset; | |
276 | struct page **dir; | |
277 | struct page *subdir; | |
278 | ||
279 | if (index < SHMEM_NR_DIRECT) { | |
280 | shmem_swp_balance_unmap(); | |
281 | return info->i_direct+index; | |
282 | } | |
283 | if (!info->i_indirect) { | |
284 | if (page) { | |
285 | info->i_indirect = *page; | |
286 | *page = NULL; | |
287 | } | |
288 | return NULL; /* need another page */ | |
289 | } | |
290 | ||
291 | index -= SHMEM_NR_DIRECT; | |
292 | offset = index % ENTRIES_PER_PAGE; | |
293 | index /= ENTRIES_PER_PAGE; | |
294 | dir = shmem_dir_map(info->i_indirect); | |
295 | ||
296 | if (index >= ENTRIES_PER_PAGE/2) { | |
297 | index -= ENTRIES_PER_PAGE/2; | |
298 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
299 | index %= ENTRIES_PER_PAGE; | |
300 | subdir = *dir; | |
301 | if (!subdir) { | |
302 | if (page) { | |
303 | *dir = *page; | |
304 | *page = NULL; | |
305 | } | |
306 | shmem_dir_unmap(dir); | |
307 | return NULL; /* need another page */ | |
308 | } | |
309 | shmem_dir_unmap(dir); | |
310 | dir = shmem_dir_map(subdir); | |
311 | } | |
312 | ||
313 | dir += index; | |
314 | subdir = *dir; | |
315 | if (!subdir) { | |
316 | if (!page || !(subdir = *page)) { | |
317 | shmem_dir_unmap(dir); | |
318 | return NULL; /* need a page */ | |
319 | } | |
320 | *dir = subdir; | |
321 | *page = NULL; | |
322 | } | |
323 | shmem_dir_unmap(dir); | |
324 | return shmem_swp_map(subdir) + offset; | |
325 | } | |
326 | ||
327 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
328 | { | |
329 | long incdec = value? 1: -1; | |
330 | ||
331 | entry->val = value; | |
332 | info->swapped += incdec; | |
4c21e2f2 HD |
333 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
334 | struct page *page = kmap_atomic_to_page(entry); | |
335 | set_page_private(page, page_private(page) + incdec); | |
336 | } | |
1da177e4 LT |
337 | } |
338 | ||
339 | /* | |
340 | * shmem_swp_alloc - get the position of the swap entry for the page. | |
341 | * If it does not exist allocate the entry. | |
342 | * | |
343 | * @info: info structure for the inode | |
344 | * @index: index of the page to find | |
345 | * @sgp: check and recheck i_size? skip allocation? | |
346 | */ | |
347 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
348 | { | |
349 | struct inode *inode = &info->vfs_inode; | |
350 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
351 | struct page *page = NULL; | |
352 | swp_entry_t *entry; | |
353 | ||
354 | if (sgp != SGP_WRITE && | |
355 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
356 | return ERR_PTR(-EINVAL); | |
357 | ||
358 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
359 | if (sgp == SGP_READ) | |
360 | return shmem_swp_map(ZERO_PAGE(0)); | |
361 | /* | |
362 | * Test free_blocks against 1 not 0, since we have 1 data | |
363 | * page (and perhaps indirect index pages) yet to allocate: | |
364 | * a waste to allocate index if we cannot allocate data. | |
365 | */ | |
0edd73b3 | 366 | if (sbinfo->max_blocks) { |
1da177e4 LT |
367 | spin_lock(&sbinfo->stat_lock); |
368 | if (sbinfo->free_blocks <= 1) { | |
369 | spin_unlock(&sbinfo->stat_lock); | |
370 | return ERR_PTR(-ENOSPC); | |
371 | } | |
372 | sbinfo->free_blocks--; | |
373 | inode->i_blocks += BLOCKS_PER_PAGE; | |
374 | spin_unlock(&sbinfo->stat_lock); | |
375 | } | |
376 | ||
377 | spin_unlock(&info->lock); | |
769848c0 | 378 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
4c21e2f2 HD |
379 | if (page) |
380 | set_page_private(page, 0); | |
1da177e4 LT |
381 | spin_lock(&info->lock); |
382 | ||
383 | if (!page) { | |
384 | shmem_free_blocks(inode, 1); | |
385 | return ERR_PTR(-ENOMEM); | |
386 | } | |
387 | if (sgp != SGP_WRITE && | |
388 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
389 | entry = ERR_PTR(-EINVAL); | |
390 | break; | |
391 | } | |
392 | if (info->next_index <= index) | |
393 | info->next_index = index + 1; | |
394 | } | |
395 | if (page) { | |
396 | /* another task gave its page, or truncated the file */ | |
397 | shmem_free_blocks(inode, 1); | |
398 | shmem_dir_free(page); | |
399 | } | |
400 | if (info->next_index <= index && !IS_ERR(entry)) | |
401 | info->next_index = index + 1; | |
402 | return entry; | |
403 | } | |
404 | ||
405 | /* | |
406 | * shmem_free_swp - free some swap entries in a directory | |
407 | * | |
1ae70006 HD |
408 | * @dir: pointer to the directory |
409 | * @edir: pointer after last entry of the directory | |
410 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 411 | */ |
1ae70006 HD |
412 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
413 | spinlock_t *punch_lock) | |
1da177e4 | 414 | { |
1ae70006 | 415 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
416 | swp_entry_t *ptr; |
417 | int freed = 0; | |
418 | ||
419 | for (ptr = dir; ptr < edir; ptr++) { | |
420 | if (ptr->val) { | |
1ae70006 HD |
421 | if (unlikely(punch_lock)) { |
422 | punch_unlock = punch_lock; | |
423 | punch_lock = NULL; | |
424 | spin_lock(punch_unlock); | |
425 | if (!ptr->val) | |
426 | continue; | |
427 | } | |
1da177e4 LT |
428 | free_swap_and_cache(*ptr); |
429 | *ptr = (swp_entry_t){0}; | |
430 | freed++; | |
431 | } | |
432 | } | |
1ae70006 HD |
433 | if (punch_unlock) |
434 | spin_unlock(punch_unlock); | |
1da177e4 LT |
435 | return freed; |
436 | } | |
437 | ||
1ae70006 HD |
438 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
439 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
440 | { |
441 | swp_entry_t *ptr; | |
442 | int freed = 0; | |
443 | ||
444 | ptr = shmem_swp_map(subdir); | |
445 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
446 | int size = limit - offset; | |
447 | if (size > LATENCY_LIMIT) | |
448 | size = LATENCY_LIMIT; | |
1ae70006 HD |
449 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
450 | punch_lock); | |
1da177e4 LT |
451 | if (need_resched()) { |
452 | shmem_swp_unmap(ptr); | |
453 | if (*dir) { | |
454 | shmem_dir_unmap(*dir); | |
455 | *dir = NULL; | |
456 | } | |
457 | cond_resched(); | |
458 | ptr = shmem_swp_map(subdir); | |
459 | } | |
460 | } | |
461 | shmem_swp_unmap(ptr); | |
462 | return freed; | |
463 | } | |
464 | ||
465 | static void shmem_free_pages(struct list_head *next) | |
466 | { | |
467 | struct page *page; | |
468 | int freed = 0; | |
469 | ||
470 | do { | |
471 | page = container_of(next, struct page, lru); | |
472 | next = next->next; | |
473 | shmem_dir_free(page); | |
474 | freed++; | |
475 | if (freed >= LATENCY_LIMIT) { | |
476 | cond_resched(); | |
477 | freed = 0; | |
478 | } | |
479 | } while (next); | |
480 | } | |
481 | ||
f6b3ec23 | 482 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
483 | { |
484 | struct shmem_inode_info *info = SHMEM_I(inode); | |
485 | unsigned long idx; | |
486 | unsigned long size; | |
487 | unsigned long limit; | |
488 | unsigned long stage; | |
489 | unsigned long diroff; | |
490 | struct page **dir; | |
491 | struct page *topdir; | |
492 | struct page *middir; | |
493 | struct page *subdir; | |
494 | swp_entry_t *ptr; | |
495 | LIST_HEAD(pages_to_free); | |
496 | long nr_pages_to_free = 0; | |
497 | long nr_swaps_freed = 0; | |
498 | int offset; | |
499 | int freed; | |
a2646d1e | 500 | int punch_hole; |
1ae70006 HD |
501 | spinlock_t *needs_lock; |
502 | spinlock_t *punch_lock; | |
a2646d1e | 503 | unsigned long upper_limit; |
1da177e4 LT |
504 | |
505 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 506 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
507 | if (idx >= info->next_index) |
508 | return; | |
509 | ||
510 | spin_lock(&info->lock); | |
511 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
512 | if (likely(end == (loff_t) -1)) { |
513 | limit = info->next_index; | |
a2646d1e | 514 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 515 | info->next_index = idx; |
1ae70006 | 516 | needs_lock = NULL; |
a2646d1e | 517 | punch_hole = 0; |
f6b3ec23 | 518 | } else { |
a2646d1e HD |
519 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
520 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
521 | PAGE_CACHE_SHIFT; | |
522 | upper_limit = SHMEM_MAX_INDEX; | |
523 | } else { | |
524 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
525 | upper_limit = limit; | |
526 | } | |
1ae70006 | 527 | needs_lock = &info->lock; |
f6b3ec23 BP |
528 | punch_hole = 1; |
529 | } | |
530 | ||
1da177e4 | 531 | topdir = info->i_indirect; |
f6b3ec23 | 532 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
533 | info->i_indirect = NULL; |
534 | nr_pages_to_free++; | |
535 | list_add(&topdir->lru, &pages_to_free); | |
536 | } | |
537 | spin_unlock(&info->lock); | |
538 | ||
539 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
540 | ptr = info->i_direct; | |
541 | size = limit; | |
542 | if (size > SHMEM_NR_DIRECT) | |
543 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 544 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 545 | } |
92a3d03a BP |
546 | |
547 | /* | |
548 | * If there are no indirect blocks or we are punching a hole | |
549 | * below indirect blocks, nothing to be done. | |
550 | */ | |
a2646d1e | 551 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
552 | goto done2; |
553 | ||
1ae70006 HD |
554 | /* |
555 | * The truncation case has already dropped info->lock, and we're safe | |
556 | * because i_size and next_index have already been lowered, preventing | |
557 | * access beyond. But in the punch_hole case, we still need to take | |
558 | * the lock when updating the swap directory, because there might be | |
559 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
560 | * shmem_writepage. However, whenever we find we can remove a whole | |
561 | * directory page (not at the misaligned start or end of the range), | |
562 | * we first NULLify its pointer in the level above, and then have no | |
563 | * need to take the lock when updating its contents: needs_lock and | |
564 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
565 | */ | |
566 | ||
a2646d1e | 567 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
568 | limit -= SHMEM_NR_DIRECT; |
569 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
570 | offset = idx % ENTRIES_PER_PAGE; | |
571 | idx -= offset; | |
572 | ||
573 | dir = shmem_dir_map(topdir); | |
574 | stage = ENTRIES_PER_PAGEPAGE/2; | |
575 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
576 | middir = topdir; | |
577 | diroff = idx/ENTRIES_PER_PAGE; | |
578 | } else { | |
579 | dir += ENTRIES_PER_PAGE/2; | |
580 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
581 | while (stage <= idx) | |
582 | stage += ENTRIES_PER_PAGEPAGE; | |
583 | middir = *dir; | |
584 | if (*dir) { | |
585 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
586 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 587 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
588 | if (needs_lock) { |
589 | spin_lock(needs_lock); | |
590 | *dir = NULL; | |
591 | spin_unlock(needs_lock); | |
592 | needs_lock = NULL; | |
593 | } else | |
594 | *dir = NULL; | |
1da177e4 LT |
595 | nr_pages_to_free++; |
596 | list_add(&middir->lru, &pages_to_free); | |
597 | } | |
598 | shmem_dir_unmap(dir); | |
599 | dir = shmem_dir_map(middir); | |
600 | } else { | |
601 | diroff = 0; | |
602 | offset = 0; | |
603 | idx = stage; | |
604 | } | |
605 | } | |
606 | ||
607 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
608 | if (unlikely(idx == stage)) { | |
609 | shmem_dir_unmap(dir); | |
610 | dir = shmem_dir_map(topdir) + | |
611 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
612 | while (!*dir) { | |
613 | dir++; | |
614 | idx += ENTRIES_PER_PAGEPAGE; | |
615 | if (idx >= limit) | |
616 | goto done1; | |
617 | } | |
618 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
619 | middir = *dir; | |
1ae70006 HD |
620 | if (punch_hole) |
621 | needs_lock = &info->lock; | |
a2646d1e | 622 | if (upper_limit >= stage) { |
1ae70006 HD |
623 | if (needs_lock) { |
624 | spin_lock(needs_lock); | |
625 | *dir = NULL; | |
626 | spin_unlock(needs_lock); | |
627 | needs_lock = NULL; | |
628 | } else | |
629 | *dir = NULL; | |
a2646d1e HD |
630 | nr_pages_to_free++; |
631 | list_add(&middir->lru, &pages_to_free); | |
632 | } | |
1da177e4 LT |
633 | shmem_dir_unmap(dir); |
634 | cond_resched(); | |
635 | dir = shmem_dir_map(middir); | |
636 | diroff = 0; | |
637 | } | |
1ae70006 | 638 | punch_lock = needs_lock; |
1da177e4 | 639 | subdir = dir[diroff]; |
1ae70006 HD |
640 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
641 | if (needs_lock) { | |
642 | spin_lock(needs_lock); | |
643 | dir[diroff] = NULL; | |
644 | spin_unlock(needs_lock); | |
645 | punch_lock = NULL; | |
646 | } else | |
647 | dir[diroff] = NULL; | |
648 | nr_pages_to_free++; | |
649 | list_add(&subdir->lru, &pages_to_free); | |
650 | } | |
651 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
652 | size = limit - idx; |
653 | if (size > ENTRIES_PER_PAGE) | |
654 | size = ENTRIES_PER_PAGE; | |
655 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 656 | offset, size, &dir, punch_lock); |
1da177e4 LT |
657 | if (!dir) |
658 | dir = shmem_dir_map(middir); | |
659 | nr_swaps_freed += freed; | |
1ae70006 | 660 | if (offset || punch_lock) { |
1da177e4 | 661 | spin_lock(&info->lock); |
1ae70006 HD |
662 | set_page_private(subdir, |
663 | page_private(subdir) - freed); | |
1da177e4 | 664 | spin_unlock(&info->lock); |
1ae70006 HD |
665 | } else |
666 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 667 | } |
1ae70006 | 668 | offset = 0; |
1da177e4 LT |
669 | } |
670 | done1: | |
671 | shmem_dir_unmap(dir); | |
672 | done2: | |
673 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
674 | /* | |
675 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
676 | * may have swizzled a page in from swap since vmtruncate or | |
677 | * generic_delete_inode did it, before we lowered next_index. | |
678 | * Also, though shmem_getpage checks i_size before adding to | |
679 | * cache, no recheck after: so fix the narrow window there too. | |
16a10019 HD |
680 | * |
681 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
682 | * every time for punch_hole (which never got a chance to clear | |
683 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
684 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 685 | */ |
f6b3ec23 | 686 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
687 | if (punch_hole) |
688 | unmap_mapping_range(inode->i_mapping, start, | |
689 | end - start, 1); | |
1da177e4 LT |
690 | } |
691 | ||
692 | spin_lock(&info->lock); | |
693 | info->flags &= ~SHMEM_TRUNCATE; | |
694 | info->swapped -= nr_swaps_freed; | |
695 | if (nr_pages_to_free) | |
696 | shmem_free_blocks(inode, nr_pages_to_free); | |
697 | shmem_recalc_inode(inode); | |
698 | spin_unlock(&info->lock); | |
699 | ||
700 | /* | |
701 | * Empty swap vector directory pages to be freed? | |
702 | */ | |
703 | if (!list_empty(&pages_to_free)) { | |
704 | pages_to_free.prev->next = NULL; | |
705 | shmem_free_pages(pages_to_free.next); | |
706 | } | |
707 | } | |
708 | ||
f6b3ec23 BP |
709 | static void shmem_truncate(struct inode *inode) |
710 | { | |
711 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
712 | } | |
713 | ||
1da177e4 LT |
714 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
715 | { | |
716 | struct inode *inode = dentry->d_inode; | |
717 | struct page *page = NULL; | |
718 | int error; | |
719 | ||
39f0247d | 720 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
721 | if (attr->ia_size < inode->i_size) { |
722 | /* | |
723 | * If truncating down to a partial page, then | |
724 | * if that page is already allocated, hold it | |
725 | * in memory until the truncation is over, so | |
726 | * truncate_partial_page cannnot miss it were | |
727 | * it assigned to swap. | |
728 | */ | |
729 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
730 | (void) shmem_getpage(inode, | |
731 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
732 | &page, SGP_READ, NULL); | |
733 | } | |
734 | /* | |
735 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
736 | * detect if any pages might have been added to cache | |
737 | * after truncate_inode_pages. But we needn't bother | |
738 | * if it's being fully truncated to zero-length: the | |
739 | * nrpages check is efficient enough in that case. | |
740 | */ | |
741 | if (attr->ia_size) { | |
742 | struct shmem_inode_info *info = SHMEM_I(inode); | |
743 | spin_lock(&info->lock); | |
744 | info->flags &= ~SHMEM_PAGEIN; | |
745 | spin_unlock(&info->lock); | |
746 | } | |
747 | } | |
748 | } | |
749 | ||
750 | error = inode_change_ok(inode, attr); | |
751 | if (!error) | |
752 | error = inode_setattr(inode, attr); | |
39f0247d AG |
753 | #ifdef CONFIG_TMPFS_POSIX_ACL |
754 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
755 | error = generic_acl_chmod(inode, &shmem_acl_ops); | |
756 | #endif | |
1da177e4 LT |
757 | if (page) |
758 | page_cache_release(page); | |
759 | return error; | |
760 | } | |
761 | ||
762 | static void shmem_delete_inode(struct inode *inode) | |
763 | { | |
764 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
765 | struct shmem_inode_info *info = SHMEM_I(inode); | |
766 | ||
767 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 768 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
769 | shmem_unacct_size(info->flags, inode->i_size); |
770 | inode->i_size = 0; | |
771 | shmem_truncate(inode); | |
772 | if (!list_empty(&info->swaplist)) { | |
773 | spin_lock(&shmem_swaplist_lock); | |
774 | list_del_init(&info->swaplist); | |
775 | spin_unlock(&shmem_swaplist_lock); | |
776 | } | |
777 | } | |
0edd73b3 HD |
778 | BUG_ON(inode->i_blocks); |
779 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
780 | spin_lock(&sbinfo->stat_lock); |
781 | sbinfo->free_inodes++; | |
782 | spin_unlock(&sbinfo->stat_lock); | |
783 | } | |
784 | clear_inode(inode); | |
785 | } | |
786 | ||
787 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
788 | { | |
789 | swp_entry_t *ptr; | |
790 | ||
791 | for (ptr = dir; ptr < edir; ptr++) { | |
792 | if (ptr->val == entry.val) | |
793 | return ptr - dir; | |
794 | } | |
795 | return -1; | |
796 | } | |
797 | ||
798 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
799 | { | |
800 | struct inode *inode; | |
801 | unsigned long idx; | |
802 | unsigned long size; | |
803 | unsigned long limit; | |
804 | unsigned long stage; | |
805 | struct page **dir; | |
806 | struct page *subdir; | |
807 | swp_entry_t *ptr; | |
808 | int offset; | |
809 | ||
810 | idx = 0; | |
811 | ptr = info->i_direct; | |
812 | spin_lock(&info->lock); | |
813 | limit = info->next_index; | |
814 | size = limit; | |
815 | if (size > SHMEM_NR_DIRECT) | |
816 | size = SHMEM_NR_DIRECT; | |
817 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
818 | if (offset >= 0) { | |
819 | shmem_swp_balance_unmap(); | |
820 | goto found; | |
821 | } | |
822 | if (!info->i_indirect) | |
823 | goto lost2; | |
824 | ||
825 | dir = shmem_dir_map(info->i_indirect); | |
826 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
827 | ||
828 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
829 | if (unlikely(idx == stage)) { | |
830 | shmem_dir_unmap(dir-1); | |
831 | dir = shmem_dir_map(info->i_indirect) + | |
832 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
833 | while (!*dir) { | |
834 | dir++; | |
835 | idx += ENTRIES_PER_PAGEPAGE; | |
836 | if (idx >= limit) | |
837 | goto lost1; | |
838 | } | |
839 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
840 | subdir = *dir; | |
841 | shmem_dir_unmap(dir); | |
842 | dir = shmem_dir_map(subdir); | |
843 | } | |
844 | subdir = *dir; | |
4c21e2f2 | 845 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
846 | ptr = shmem_swp_map(subdir); |
847 | size = limit - idx; | |
848 | if (size > ENTRIES_PER_PAGE) | |
849 | size = ENTRIES_PER_PAGE; | |
850 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
851 | if (offset >= 0) { | |
852 | shmem_dir_unmap(dir); | |
853 | goto found; | |
854 | } | |
855 | shmem_swp_unmap(ptr); | |
856 | } | |
857 | } | |
858 | lost1: | |
859 | shmem_dir_unmap(dir-1); | |
860 | lost2: | |
861 | spin_unlock(&info->lock); | |
862 | return 0; | |
863 | found: | |
864 | idx += offset; | |
865 | inode = &info->vfs_inode; | |
866 | if (move_from_swap_cache(page, idx, inode->i_mapping) == 0) { | |
867 | info->flags |= SHMEM_PAGEIN; | |
868 | shmem_swp_set(info, ptr + offset, 0); | |
869 | } | |
870 | shmem_swp_unmap(ptr); | |
871 | spin_unlock(&info->lock); | |
872 | /* | |
873 | * Decrement swap count even when the entry is left behind: | |
874 | * try_to_unuse will skip over mms, then reincrement count. | |
875 | */ | |
876 | swap_free(entry); | |
877 | return 1; | |
878 | } | |
879 | ||
880 | /* | |
881 | * shmem_unuse() search for an eventually swapped out shmem page. | |
882 | */ | |
883 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
884 | { | |
885 | struct list_head *p, *next; | |
886 | struct shmem_inode_info *info; | |
887 | int found = 0; | |
888 | ||
889 | spin_lock(&shmem_swaplist_lock); | |
890 | list_for_each_safe(p, next, &shmem_swaplist) { | |
891 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
892 | if (!info->swapped) | |
893 | list_del_init(&info->swaplist); | |
894 | else if (shmem_unuse_inode(info, entry, page)) { | |
895 | /* move head to start search for next from here */ | |
896 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
897 | found = 1; | |
898 | break; | |
899 | } | |
900 | } | |
901 | spin_unlock(&shmem_swaplist_lock); | |
902 | return found; | |
903 | } | |
904 | ||
905 | /* | |
906 | * Move the page from the page cache to the swap cache. | |
907 | */ | |
908 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
909 | { | |
910 | struct shmem_inode_info *info; | |
911 | swp_entry_t *entry, swap; | |
912 | struct address_space *mapping; | |
913 | unsigned long index; | |
914 | struct inode *inode; | |
915 | ||
916 | BUG_ON(!PageLocked(page)); | |
917 | BUG_ON(page_mapped(page)); | |
918 | ||
919 | mapping = page->mapping; | |
920 | index = page->index; | |
921 | inode = mapping->host; | |
922 | info = SHMEM_I(inode); | |
923 | if (info->flags & VM_LOCKED) | |
924 | goto redirty; | |
925 | swap = get_swap_page(); | |
926 | if (!swap.val) | |
927 | goto redirty; | |
928 | ||
929 | spin_lock(&info->lock); | |
930 | shmem_recalc_inode(inode); | |
931 | if (index >= info->next_index) { | |
932 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
933 | goto unlock; | |
934 | } | |
935 | entry = shmem_swp_entry(info, index, NULL); | |
936 | BUG_ON(!entry); | |
937 | BUG_ON(entry->val); | |
938 | ||
939 | if (move_to_swap_cache(page, swap) == 0) { | |
940 | shmem_swp_set(info, entry, swap.val); | |
941 | shmem_swp_unmap(entry); | |
942 | spin_unlock(&info->lock); | |
943 | if (list_empty(&info->swaplist)) { | |
944 | spin_lock(&shmem_swaplist_lock); | |
945 | /* move instead of add in case we're racing */ | |
946 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
947 | spin_unlock(&shmem_swaplist_lock); | |
948 | } | |
949 | unlock_page(page); | |
950 | return 0; | |
951 | } | |
952 | ||
953 | shmem_swp_unmap(entry); | |
954 | unlock: | |
955 | spin_unlock(&info->lock); | |
956 | swap_free(swap); | |
957 | redirty: | |
958 | set_page_dirty(page); | |
994fc28c | 959 | return AOP_WRITEPAGE_ACTIVATE; /* Return with the page locked */ |
1da177e4 LT |
960 | } |
961 | ||
962 | #ifdef CONFIG_NUMA | |
d15c023b | 963 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
b00dc3ad HD |
964 | { |
965 | char *nodelist = strchr(value, ':'); | |
966 | int err = 1; | |
967 | ||
968 | if (nodelist) { | |
969 | /* NUL-terminate policy string */ | |
970 | *nodelist++ = '\0'; | |
971 | if (nodelist_parse(nodelist, *policy_nodes)) | |
972 | goto out; | |
a210906c HD |
973 | if (!nodes_subset(*policy_nodes, node_online_map)) |
974 | goto out; | |
b00dc3ad HD |
975 | } |
976 | if (!strcmp(value, "default")) { | |
977 | *policy = MPOL_DEFAULT; | |
978 | /* Don't allow a nodelist */ | |
979 | if (!nodelist) | |
980 | err = 0; | |
981 | } else if (!strcmp(value, "prefer")) { | |
982 | *policy = MPOL_PREFERRED; | |
983 | /* Insist on a nodelist of one node only */ | |
984 | if (nodelist) { | |
985 | char *rest = nodelist; | |
986 | while (isdigit(*rest)) | |
987 | rest++; | |
988 | if (!*rest) | |
989 | err = 0; | |
990 | } | |
991 | } else if (!strcmp(value, "bind")) { | |
992 | *policy = MPOL_BIND; | |
993 | /* Insist on a nodelist */ | |
994 | if (nodelist) | |
995 | err = 0; | |
996 | } else if (!strcmp(value, "interleave")) { | |
997 | *policy = MPOL_INTERLEAVE; | |
998 | /* Default to nodes online if no nodelist */ | |
999 | if (!nodelist) | |
1000 | *policy_nodes = node_online_map; | |
1001 | err = 0; | |
1002 | } | |
1003 | out: | |
1004 | /* Restore string for error message */ | |
1005 | if (nodelist) | |
1006 | *--nodelist = ':'; | |
1007 | return err; | |
1008 | } | |
1009 | ||
1da177e4 LT |
1010 | static struct page *shmem_swapin_async(struct shared_policy *p, |
1011 | swp_entry_t entry, unsigned long idx) | |
1012 | { | |
1013 | struct page *page; | |
1014 | struct vm_area_struct pvma; | |
1015 | ||
1016 | /* Create a pseudo vma that just contains the policy */ | |
1017 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
1018 | pvma.vm_end = PAGE_SIZE; | |
1019 | pvma.vm_pgoff = idx; | |
1020 | pvma.vm_policy = mpol_shared_policy_lookup(p, idx); | |
1021 | page = read_swap_cache_async(entry, &pvma, 0); | |
1022 | mpol_free(pvma.vm_policy); | |
1023 | return page; | |
1024 | } | |
1025 | ||
1026 | struct page *shmem_swapin(struct shmem_inode_info *info, swp_entry_t entry, | |
1027 | unsigned long idx) | |
1028 | { | |
1029 | struct shared_policy *p = &info->policy; | |
1030 | int i, num; | |
1031 | struct page *page; | |
1032 | unsigned long offset; | |
1033 | ||
1034 | num = valid_swaphandles(entry, &offset); | |
1035 | for (i = 0; i < num; offset++, i++) { | |
1036 | page = shmem_swapin_async(p, | |
1037 | swp_entry(swp_type(entry), offset), idx); | |
1038 | if (!page) | |
1039 | break; | |
1040 | page_cache_release(page); | |
1041 | } | |
1042 | lru_add_drain(); /* Push any new pages onto the LRU now */ | |
1043 | return shmem_swapin_async(p, entry, idx); | |
1044 | } | |
1045 | ||
1046 | static struct page * | |
6daa0e28 | 1047 | shmem_alloc_page(gfp_t gfp, struct shmem_inode_info *info, |
1da177e4 LT |
1048 | unsigned long idx) |
1049 | { | |
1050 | struct vm_area_struct pvma; | |
1051 | struct page *page; | |
1052 | ||
1053 | memset(&pvma, 0, sizeof(struct vm_area_struct)); | |
1054 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
1055 | pvma.vm_pgoff = idx; | |
1056 | pvma.vm_end = PAGE_SIZE; | |
1057 | page = alloc_page_vma(gfp | __GFP_ZERO, &pvma, 0); | |
1058 | mpol_free(pvma.vm_policy); | |
1059 | return page; | |
1060 | } | |
1061 | #else | |
b00dc3ad HD |
1062 | static inline int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) |
1063 | { | |
1064 | return 1; | |
1065 | } | |
1066 | ||
1da177e4 LT |
1067 | static inline struct page * |
1068 | shmem_swapin(struct shmem_inode_info *info,swp_entry_t entry,unsigned long idx) | |
1069 | { | |
1070 | swapin_readahead(entry, 0, NULL); | |
1071 | return read_swap_cache_async(entry, NULL, 0); | |
1072 | } | |
1073 | ||
1074 | static inline struct page * | |
dd0fc66f | 1075 | shmem_alloc_page(gfp_t gfp,struct shmem_inode_info *info, unsigned long idx) |
1da177e4 LT |
1076 | { |
1077 | return alloc_page(gfp | __GFP_ZERO); | |
1078 | } | |
1079 | #endif | |
1080 | ||
1081 | /* | |
1082 | * shmem_getpage - either get the page from swap or allocate a new one | |
1083 | * | |
1084 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1085 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1086 | * entry since a page cannot live in both the swap and page cache | |
1087 | */ | |
1088 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1089 | struct page **pagep, enum sgp_type sgp, int *type) | |
1090 | { | |
1091 | struct address_space *mapping = inode->i_mapping; | |
1092 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1093 | struct shmem_sb_info *sbinfo; | |
1094 | struct page *filepage = *pagep; | |
1095 | struct page *swappage; | |
1096 | swp_entry_t *entry; | |
1097 | swp_entry_t swap; | |
1098 | int error; | |
1099 | ||
1100 | if (idx >= SHMEM_MAX_INDEX) | |
1101 | return -EFBIG; | |
1102 | /* | |
1103 | * Normally, filepage is NULL on entry, and either found | |
1104 | * uptodate immediately, or allocated and zeroed, or read | |
1105 | * in under swappage, which is then assigned to filepage. | |
ae976416 HD |
1106 | * But shmem_readpage and shmem_prepare_write pass in a locked |
1107 | * filepage, which may be found not uptodate by other callers | |
1108 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1109 | */ |
1110 | repeat: | |
1111 | if (!filepage) | |
1112 | filepage = find_lock_page(mapping, idx); | |
1113 | if (filepage && PageUptodate(filepage)) | |
1114 | goto done; | |
1115 | error = 0; | |
1116 | if (sgp == SGP_QUICK) | |
1117 | goto failed; | |
1118 | ||
1119 | spin_lock(&info->lock); | |
1120 | shmem_recalc_inode(inode); | |
1121 | entry = shmem_swp_alloc(info, idx, sgp); | |
1122 | if (IS_ERR(entry)) { | |
1123 | spin_unlock(&info->lock); | |
1124 | error = PTR_ERR(entry); | |
1125 | goto failed; | |
1126 | } | |
1127 | swap = *entry; | |
1128 | ||
1129 | if (swap.val) { | |
1130 | /* Look it up and read it in.. */ | |
1131 | swappage = lookup_swap_cache(swap); | |
1132 | if (!swappage) { | |
1133 | shmem_swp_unmap(entry); | |
1da177e4 LT |
1134 | /* here we actually do the io */ |
1135 | if (type && *type == VM_FAULT_MINOR) { | |
f8891e5e | 1136 | __count_vm_event(PGMAJFAULT); |
1da177e4 LT |
1137 | *type = VM_FAULT_MAJOR; |
1138 | } | |
f8891e5e | 1139 | spin_unlock(&info->lock); |
1da177e4 LT |
1140 | swappage = shmem_swapin(info, swap, idx); |
1141 | if (!swappage) { | |
1142 | spin_lock(&info->lock); | |
1143 | entry = shmem_swp_alloc(info, idx, sgp); | |
1144 | if (IS_ERR(entry)) | |
1145 | error = PTR_ERR(entry); | |
1146 | else { | |
1147 | if (entry->val == swap.val) | |
1148 | error = -ENOMEM; | |
1149 | shmem_swp_unmap(entry); | |
1150 | } | |
1151 | spin_unlock(&info->lock); | |
1152 | if (error) | |
1153 | goto failed; | |
1154 | goto repeat; | |
1155 | } | |
1156 | wait_on_page_locked(swappage); | |
1157 | page_cache_release(swappage); | |
1158 | goto repeat; | |
1159 | } | |
1160 | ||
1161 | /* We have to do this with page locked to prevent races */ | |
1162 | if (TestSetPageLocked(swappage)) { | |
1163 | shmem_swp_unmap(entry); | |
1164 | spin_unlock(&info->lock); | |
1165 | wait_on_page_locked(swappage); | |
1166 | page_cache_release(swappage); | |
1167 | goto repeat; | |
1168 | } | |
1169 | if (PageWriteback(swappage)) { | |
1170 | shmem_swp_unmap(entry); | |
1171 | spin_unlock(&info->lock); | |
1172 | wait_on_page_writeback(swappage); | |
1173 | unlock_page(swappage); | |
1174 | page_cache_release(swappage); | |
1175 | goto repeat; | |
1176 | } | |
1177 | if (!PageUptodate(swappage)) { | |
1178 | shmem_swp_unmap(entry); | |
1179 | spin_unlock(&info->lock); | |
1180 | unlock_page(swappage); | |
1181 | page_cache_release(swappage); | |
1182 | error = -EIO; | |
1183 | goto failed; | |
1184 | } | |
1185 | ||
1186 | if (filepage) { | |
1187 | shmem_swp_set(info, entry, 0); | |
1188 | shmem_swp_unmap(entry); | |
1189 | delete_from_swap_cache(swappage); | |
1190 | spin_unlock(&info->lock); | |
1191 | copy_highpage(filepage, swappage); | |
1192 | unlock_page(swappage); | |
1193 | page_cache_release(swappage); | |
1194 | flush_dcache_page(filepage); | |
1195 | SetPageUptodate(filepage); | |
1196 | set_page_dirty(filepage); | |
1197 | swap_free(swap); | |
1198 | } else if (!(error = move_from_swap_cache( | |
1199 | swappage, idx, mapping))) { | |
1200 | info->flags |= SHMEM_PAGEIN; | |
1201 | shmem_swp_set(info, entry, 0); | |
1202 | shmem_swp_unmap(entry); | |
1203 | spin_unlock(&info->lock); | |
1204 | filepage = swappage; | |
1205 | swap_free(swap); | |
1206 | } else { | |
1207 | shmem_swp_unmap(entry); | |
1208 | spin_unlock(&info->lock); | |
1209 | unlock_page(swappage); | |
1210 | page_cache_release(swappage); | |
1211 | if (error == -ENOMEM) { | |
1212 | /* let kswapd refresh zone for GFP_ATOMICs */ | |
3fcfab16 | 1213 | congestion_wait(WRITE, HZ/50); |
1da177e4 LT |
1214 | } |
1215 | goto repeat; | |
1216 | } | |
1217 | } else if (sgp == SGP_READ && !filepage) { | |
1218 | shmem_swp_unmap(entry); | |
1219 | filepage = find_get_page(mapping, idx); | |
1220 | if (filepage && | |
1221 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1222 | spin_unlock(&info->lock); | |
1223 | wait_on_page_locked(filepage); | |
1224 | page_cache_release(filepage); | |
1225 | filepage = NULL; | |
1226 | goto repeat; | |
1227 | } | |
1228 | spin_unlock(&info->lock); | |
1229 | } else { | |
1230 | shmem_swp_unmap(entry); | |
1231 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1232 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1233 | spin_lock(&sbinfo->stat_lock); |
1234 | if (sbinfo->free_blocks == 0 || | |
1235 | shmem_acct_block(info->flags)) { | |
1236 | spin_unlock(&sbinfo->stat_lock); | |
1237 | spin_unlock(&info->lock); | |
1238 | error = -ENOSPC; | |
1239 | goto failed; | |
1240 | } | |
1241 | sbinfo->free_blocks--; | |
1242 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1243 | spin_unlock(&sbinfo->stat_lock); | |
1244 | } else if (shmem_acct_block(info->flags)) { | |
1245 | spin_unlock(&info->lock); | |
1246 | error = -ENOSPC; | |
1247 | goto failed; | |
1248 | } | |
1249 | ||
1250 | if (!filepage) { | |
1251 | spin_unlock(&info->lock); | |
1252 | filepage = shmem_alloc_page(mapping_gfp_mask(mapping), | |
1253 | info, | |
1254 | idx); | |
1255 | if (!filepage) { | |
1256 | shmem_unacct_blocks(info->flags, 1); | |
1257 | shmem_free_blocks(inode, 1); | |
1258 | error = -ENOMEM; | |
1259 | goto failed; | |
1260 | } | |
1261 | ||
1262 | spin_lock(&info->lock); | |
1263 | entry = shmem_swp_alloc(info, idx, sgp); | |
1264 | if (IS_ERR(entry)) | |
1265 | error = PTR_ERR(entry); | |
1266 | else { | |
1267 | swap = *entry; | |
1268 | shmem_swp_unmap(entry); | |
1269 | } | |
1270 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
1271 | filepage, mapping, idx, GFP_ATOMIC)) { | |
1272 | spin_unlock(&info->lock); | |
1273 | page_cache_release(filepage); | |
1274 | shmem_unacct_blocks(info->flags, 1); | |
1275 | shmem_free_blocks(inode, 1); | |
1276 | filepage = NULL; | |
1277 | if (error) | |
1278 | goto failed; | |
1279 | goto repeat; | |
1280 | } | |
1281 | info->flags |= SHMEM_PAGEIN; | |
1282 | } | |
1283 | ||
1284 | info->alloced++; | |
1285 | spin_unlock(&info->lock); | |
1286 | flush_dcache_page(filepage); | |
1287 | SetPageUptodate(filepage); | |
1288 | } | |
1289 | done: | |
1290 | if (*pagep != filepage) { | |
1291 | unlock_page(filepage); | |
1292 | *pagep = filepage; | |
1293 | } | |
1294 | return 0; | |
1295 | ||
1296 | failed: | |
1297 | if (*pagep != filepage) { | |
1298 | unlock_page(filepage); | |
1299 | page_cache_release(filepage); | |
1300 | } | |
1301 | return error; | |
1302 | } | |
1303 | ||
9b83a6a8 AB |
1304 | static struct page *shmem_nopage(struct vm_area_struct *vma, |
1305 | unsigned long address, int *type) | |
1da177e4 | 1306 | { |
d3ac7f89 | 1307 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1308 | struct page *page = NULL; |
1309 | unsigned long idx; | |
1310 | int error; | |
1311 | ||
1312 | idx = (address - vma->vm_start) >> PAGE_SHIFT; | |
1313 | idx += vma->vm_pgoff; | |
1314 | idx >>= PAGE_CACHE_SHIFT - PAGE_SHIFT; | |
1315 | if (((loff_t) idx << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
1316 | return NOPAGE_SIGBUS; | |
1317 | ||
1318 | error = shmem_getpage(inode, idx, &page, SGP_CACHE, type); | |
1319 | if (error) | |
1320 | return (error == -ENOMEM)? NOPAGE_OOM: NOPAGE_SIGBUS; | |
1321 | ||
1322 | mark_page_accessed(page); | |
1323 | return page; | |
1324 | } | |
1325 | ||
1326 | static int shmem_populate(struct vm_area_struct *vma, | |
1327 | unsigned long addr, unsigned long len, | |
1328 | pgprot_t prot, unsigned long pgoff, int nonblock) | |
1329 | { | |
d3ac7f89 | 1330 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1331 | struct mm_struct *mm = vma->vm_mm; |
1332 | enum sgp_type sgp = nonblock? SGP_QUICK: SGP_CACHE; | |
1333 | unsigned long size; | |
1334 | ||
1335 | size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1336 | if (pgoff >= size || pgoff + (len >> PAGE_SHIFT) > size) | |
1337 | return -EINVAL; | |
1338 | ||
1339 | while ((long) len > 0) { | |
1340 | struct page *page = NULL; | |
1341 | int err; | |
1342 | /* | |
1343 | * Will need changing if PAGE_CACHE_SIZE != PAGE_SIZE | |
1344 | */ | |
1345 | err = shmem_getpage(inode, pgoff, &page, sgp, NULL); | |
1346 | if (err) | |
1347 | return err; | |
d44ed4f8 | 1348 | /* Page may still be null, but only if nonblock was set. */ |
1da177e4 LT |
1349 | if (page) { |
1350 | mark_page_accessed(page); | |
1351 | err = install_page(mm, vma, addr, page, prot); | |
1352 | if (err) { | |
1353 | page_cache_release(page); | |
1354 | return err; | |
1355 | } | |
65500d23 | 1356 | } else if (vma->vm_flags & VM_NONLINEAR) { |
d44ed4f8 PBG |
1357 | /* No page was found just because we can't read it in |
1358 | * now (being here implies nonblock != 0), but the page | |
1359 | * may exist, so set the PTE to fault it in later. */ | |
1da177e4 LT |
1360 | err = install_file_pte(mm, vma, addr, pgoff, prot); |
1361 | if (err) | |
1362 | return err; | |
1363 | } | |
1364 | ||
1365 | len -= PAGE_SIZE; | |
1366 | addr += PAGE_SIZE; | |
1367 | pgoff++; | |
1368 | } | |
1369 | return 0; | |
1370 | } | |
1371 | ||
1372 | #ifdef CONFIG_NUMA | |
1373 | int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) | |
1374 | { | |
d3ac7f89 | 1375 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1376 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1377 | } | |
1378 | ||
1379 | struct mempolicy * | |
1380 | shmem_get_policy(struct vm_area_struct *vma, unsigned long addr) | |
1381 | { | |
d3ac7f89 | 1382 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1383 | unsigned long idx; |
1384 | ||
1385 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1386 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1387 | } | |
1388 | #endif | |
1389 | ||
1390 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1391 | { | |
d3ac7f89 | 1392 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1393 | struct shmem_inode_info *info = SHMEM_I(inode); |
1394 | int retval = -ENOMEM; | |
1395 | ||
1396 | spin_lock(&info->lock); | |
1397 | if (lock && !(info->flags & VM_LOCKED)) { | |
1398 | if (!user_shm_lock(inode->i_size, user)) | |
1399 | goto out_nomem; | |
1400 | info->flags |= VM_LOCKED; | |
1401 | } | |
1402 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1403 | user_shm_unlock(inode->i_size, user); | |
1404 | info->flags &= ~VM_LOCKED; | |
1405 | } | |
1406 | retval = 0; | |
1407 | out_nomem: | |
1408 | spin_unlock(&info->lock); | |
1409 | return retval; | |
1410 | } | |
1411 | ||
9b83a6a8 | 1412 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1413 | { |
1414 | file_accessed(file); | |
1415 | vma->vm_ops = &shmem_vm_ops; | |
1416 | return 0; | |
1417 | } | |
1418 | ||
1419 | static struct inode * | |
1420 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1421 | { | |
1422 | struct inode *inode; | |
1423 | struct shmem_inode_info *info; | |
1424 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1425 | ||
0edd73b3 | 1426 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1427 | spin_lock(&sbinfo->stat_lock); |
1428 | if (!sbinfo->free_inodes) { | |
1429 | spin_unlock(&sbinfo->stat_lock); | |
1430 | return NULL; | |
1431 | } | |
1432 | sbinfo->free_inodes--; | |
1433 | spin_unlock(&sbinfo->stat_lock); | |
1434 | } | |
1435 | ||
1436 | inode = new_inode(sb); | |
1437 | if (inode) { | |
1438 | inode->i_mode = mode; | |
1439 | inode->i_uid = current->fsuid; | |
1440 | inode->i_gid = current->fsgid; | |
1da177e4 LT |
1441 | inode->i_blocks = 0; |
1442 | inode->i_mapping->a_ops = &shmem_aops; | |
1443 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1444 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1445 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1446 | info = SHMEM_I(inode); |
1447 | memset(info, 0, (char *)inode - (char *)info); | |
1448 | spin_lock_init(&info->lock); | |
1449 | INIT_LIST_HEAD(&info->swaplist); | |
1450 | ||
1451 | switch (mode & S_IFMT) { | |
1452 | default: | |
39f0247d | 1453 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1454 | init_special_inode(inode, mode, dev); |
1455 | break; | |
1456 | case S_IFREG: | |
1457 | inode->i_op = &shmem_inode_operations; | |
1458 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1459 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1460 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1461 | break; |
1462 | case S_IFDIR: | |
d8c76e6f | 1463 | inc_nlink(inode); |
1da177e4 LT |
1464 | /* Some things misbehave if size == 0 on a directory */ |
1465 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1466 | inode->i_op = &shmem_dir_inode_operations; | |
1467 | inode->i_fop = &simple_dir_operations; | |
1468 | break; | |
1469 | case S_IFLNK: | |
1470 | /* | |
1471 | * Must not load anything in the rbtree, | |
1472 | * mpol_free_shared_policy will not be called. | |
1473 | */ | |
7339ff83 RH |
1474 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1475 | NULL); | |
1da177e4 LT |
1476 | break; |
1477 | } | |
0edd73b3 | 1478 | } else if (sbinfo->max_inodes) { |
1da177e4 LT |
1479 | spin_lock(&sbinfo->stat_lock); |
1480 | sbinfo->free_inodes++; | |
1481 | spin_unlock(&sbinfo->stat_lock); | |
1482 | } | |
1483 | return inode; | |
1484 | } | |
1485 | ||
1486 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1487 | static const struct inode_operations shmem_symlink_inode_operations; |
1488 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1489 | |
1490 | /* | |
ae976416 HD |
1491 | * Normally tmpfs avoids the use of shmem_readpage and shmem_prepare_write; |
1492 | * but providing them allows a tmpfs file to be used for splice, sendfile, and | |
1493 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1494 | */ |
ae976416 HD |
1495 | static int shmem_readpage(struct file *file, struct page *page) |
1496 | { | |
1497 | struct inode *inode = page->mapping->host; | |
1498 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1499 | unlock_page(page); | |
1500 | return error; | |
1501 | } | |
1502 | ||
1da177e4 LT |
1503 | static int |
1504 | shmem_prepare_write(struct file *file, struct page *page, unsigned offset, unsigned to) | |
1505 | { | |
1506 | struct inode *inode = page->mapping->host; | |
1507 | return shmem_getpage(inode, page->index, &page, SGP_WRITE, NULL); | |
1508 | } | |
1509 | ||
1510 | static ssize_t | |
1511 | shmem_file_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) | |
1512 | { | |
d3ac7f89 | 1513 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1514 | loff_t pos; |
1515 | unsigned long written; | |
1516 | ssize_t err; | |
1517 | ||
1518 | if ((ssize_t) count < 0) | |
1519 | return -EINVAL; | |
1520 | ||
1521 | if (!access_ok(VERIFY_READ, buf, count)) | |
1522 | return -EFAULT; | |
1523 | ||
1b1dcc1b | 1524 | mutex_lock(&inode->i_mutex); |
1da177e4 LT |
1525 | |
1526 | pos = *ppos; | |
1527 | written = 0; | |
1528 | ||
1529 | err = generic_write_checks(file, &pos, &count, 0); | |
1530 | if (err || !count) | |
1531 | goto out; | |
1532 | ||
d3ac7f89 | 1533 | err = remove_suid(file->f_path.dentry); |
1da177e4 LT |
1534 | if (err) |
1535 | goto out; | |
1536 | ||
1537 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
1538 | ||
1539 | do { | |
1540 | struct page *page = NULL; | |
1541 | unsigned long bytes, index, offset; | |
1542 | char *kaddr; | |
1543 | int left; | |
1544 | ||
1545 | offset = (pos & (PAGE_CACHE_SIZE -1)); /* Within page */ | |
1546 | index = pos >> PAGE_CACHE_SHIFT; | |
1547 | bytes = PAGE_CACHE_SIZE - offset; | |
1548 | if (bytes > count) | |
1549 | bytes = count; | |
1550 | ||
1551 | /* | |
1552 | * We don't hold page lock across copy from user - | |
1553 | * what would it guard against? - so no deadlock here. | |
1554 | * But it still may be a good idea to prefault below. | |
1555 | */ | |
1556 | ||
1557 | err = shmem_getpage(inode, index, &page, SGP_WRITE, NULL); | |
1558 | if (err) | |
1559 | break; | |
1560 | ||
1561 | left = bytes; | |
1562 | if (PageHighMem(page)) { | |
1563 | volatile unsigned char dummy; | |
1564 | __get_user(dummy, buf); | |
1565 | __get_user(dummy, buf + bytes - 1); | |
1566 | ||
1567 | kaddr = kmap_atomic(page, KM_USER0); | |
1568 | left = __copy_from_user_inatomic(kaddr + offset, | |
1569 | buf, bytes); | |
1570 | kunmap_atomic(kaddr, KM_USER0); | |
1571 | } | |
1572 | if (left) { | |
1573 | kaddr = kmap(page); | |
1574 | left = __copy_from_user(kaddr + offset, buf, bytes); | |
1575 | kunmap(page); | |
1576 | } | |
1577 | ||
1578 | written += bytes; | |
1579 | count -= bytes; | |
1580 | pos += bytes; | |
1581 | buf += bytes; | |
1582 | if (pos > inode->i_size) | |
1583 | i_size_write(inode, pos); | |
1584 | ||
1585 | flush_dcache_page(page); | |
1586 | set_page_dirty(page); | |
1587 | mark_page_accessed(page); | |
1588 | page_cache_release(page); | |
1589 | ||
1590 | if (left) { | |
1591 | pos -= left; | |
1592 | written -= left; | |
1593 | err = -EFAULT; | |
1594 | break; | |
1595 | } | |
1596 | ||
1597 | /* | |
1598 | * Our dirty pages are not counted in nr_dirty, | |
1599 | * and we do not attempt to balance dirty pages. | |
1600 | */ | |
1601 | ||
1602 | cond_resched(); | |
1603 | } while (count); | |
1604 | ||
1605 | *ppos = pos; | |
1606 | if (written) | |
1607 | err = written; | |
1608 | out: | |
1b1dcc1b | 1609 | mutex_unlock(&inode->i_mutex); |
1da177e4 LT |
1610 | return err; |
1611 | } | |
1612 | ||
1613 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) | |
1614 | { | |
d3ac7f89 | 1615 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1616 | struct address_space *mapping = inode->i_mapping; |
1617 | unsigned long index, offset; | |
1618 | ||
1619 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1620 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1621 | ||
1622 | for (;;) { | |
1623 | struct page *page = NULL; | |
1624 | unsigned long end_index, nr, ret; | |
1625 | loff_t i_size = i_size_read(inode); | |
1626 | ||
1627 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1628 | if (index > end_index) | |
1629 | break; | |
1630 | if (index == end_index) { | |
1631 | nr = i_size & ~PAGE_CACHE_MASK; | |
1632 | if (nr <= offset) | |
1633 | break; | |
1634 | } | |
1635 | ||
1636 | desc->error = shmem_getpage(inode, index, &page, SGP_READ, NULL); | |
1637 | if (desc->error) { | |
1638 | if (desc->error == -EINVAL) | |
1639 | desc->error = 0; | |
1640 | break; | |
1641 | } | |
1642 | ||
1643 | /* | |
1644 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1645 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1646 | */ |
1647 | nr = PAGE_CACHE_SIZE; | |
1648 | i_size = i_size_read(inode); | |
1649 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1650 | if (index == end_index) { | |
1651 | nr = i_size & ~PAGE_CACHE_MASK; | |
1652 | if (nr <= offset) { | |
1653 | if (page) | |
1654 | page_cache_release(page); | |
1655 | break; | |
1656 | } | |
1657 | } | |
1658 | nr -= offset; | |
1659 | ||
1660 | if (page) { | |
1661 | /* | |
1662 | * If users can be writing to this page using arbitrary | |
1663 | * virtual addresses, take care about potential aliasing | |
1664 | * before reading the page on the kernel side. | |
1665 | */ | |
1666 | if (mapping_writably_mapped(mapping)) | |
1667 | flush_dcache_page(page); | |
1668 | /* | |
1669 | * Mark the page accessed if we read the beginning. | |
1670 | */ | |
1671 | if (!offset) | |
1672 | mark_page_accessed(page); | |
b5810039 | 1673 | } else { |
1da177e4 | 1674 | page = ZERO_PAGE(0); |
b5810039 NP |
1675 | page_cache_get(page); |
1676 | } | |
1da177e4 LT |
1677 | |
1678 | /* | |
1679 | * Ok, we have the page, and it's up-to-date, so | |
1680 | * now we can copy it to user space... | |
1681 | * | |
1682 | * The actor routine returns how many bytes were actually used.. | |
1683 | * NOTE! This may not be the same as how much of a user buffer | |
1684 | * we filled up (we may be padding etc), so we can only update | |
1685 | * "pos" here (the actor routine has to update the user buffer | |
1686 | * pointers and the remaining count). | |
1687 | */ | |
1688 | ret = actor(desc, page, offset, nr); | |
1689 | offset += ret; | |
1690 | index += offset >> PAGE_CACHE_SHIFT; | |
1691 | offset &= ~PAGE_CACHE_MASK; | |
1692 | ||
1693 | page_cache_release(page); | |
1694 | if (ret != nr || !desc->count) | |
1695 | break; | |
1696 | ||
1697 | cond_resched(); | |
1698 | } | |
1699 | ||
1700 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1701 | file_accessed(filp); | |
1702 | } | |
1703 | ||
1704 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1705 | { | |
1706 | read_descriptor_t desc; | |
1707 | ||
1708 | if ((ssize_t) count < 0) | |
1709 | return -EINVAL; | |
1710 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1711 | return -EFAULT; | |
1712 | if (!count) | |
1713 | return 0; | |
1714 | ||
1715 | desc.written = 0; | |
1716 | desc.count = count; | |
1717 | desc.arg.buf = buf; | |
1718 | desc.error = 0; | |
1719 | ||
1720 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1721 | if (desc.written) | |
1722 | return desc.written; | |
1723 | return desc.error; | |
1724 | } | |
1725 | ||
726c3342 | 1726 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1727 | { |
726c3342 | 1728 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1729 | |
1730 | buf->f_type = TMPFS_MAGIC; | |
1731 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1732 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1733 | spin_lock(&sbinfo->stat_lock); |
1734 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1735 | buf->f_blocks = sbinfo->max_blocks; |
1736 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1737 | } |
1738 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1739 | buf->f_files = sbinfo->max_inodes; |
1740 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1741 | } |
1742 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1743 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1744 | return 0; |
1745 | } | |
1746 | ||
1747 | /* | |
1748 | * File creation. Allocate an inode, and we're done.. | |
1749 | */ | |
1750 | static int | |
1751 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1752 | { | |
1753 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1754 | int error = -ENOSPC; | |
1755 | ||
1756 | if (inode) { | |
570bc1c2 SS |
1757 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1758 | NULL); | |
1759 | if (error) { | |
1760 | if (error != -EOPNOTSUPP) { | |
1761 | iput(inode); | |
1762 | return error; | |
1763 | } | |
39f0247d AG |
1764 | } |
1765 | error = shmem_acl_init(inode, dir); | |
1766 | if (error) { | |
1767 | iput(inode); | |
1768 | return error; | |
570bc1c2 | 1769 | } |
1da177e4 LT |
1770 | if (dir->i_mode & S_ISGID) { |
1771 | inode->i_gid = dir->i_gid; | |
1772 | if (S_ISDIR(mode)) | |
1773 | inode->i_mode |= S_ISGID; | |
1774 | } | |
1775 | dir->i_size += BOGO_DIRENT_SIZE; | |
1776 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1777 | d_instantiate(dentry, inode); | |
1778 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1779 | } |
1780 | return error; | |
1781 | } | |
1782 | ||
1783 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1784 | { | |
1785 | int error; | |
1786 | ||
1787 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1788 | return error; | |
d8c76e6f | 1789 | inc_nlink(dir); |
1da177e4 LT |
1790 | return 0; |
1791 | } | |
1792 | ||
1793 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1794 | struct nameidata *nd) | |
1795 | { | |
1796 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1797 | } | |
1798 | ||
1799 | /* | |
1800 | * Link a file.. | |
1801 | */ | |
1802 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1803 | { | |
1804 | struct inode *inode = old_dentry->d_inode; | |
1805 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
1806 | ||
1807 | /* | |
1808 | * No ordinary (disk based) filesystem counts links as inodes; | |
1809 | * but each new link needs a new dentry, pinning lowmem, and | |
1810 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1811 | */ | |
0edd73b3 | 1812 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1813 | spin_lock(&sbinfo->stat_lock); |
1814 | if (!sbinfo->free_inodes) { | |
1815 | spin_unlock(&sbinfo->stat_lock); | |
1816 | return -ENOSPC; | |
1817 | } | |
1818 | sbinfo->free_inodes--; | |
1819 | spin_unlock(&sbinfo->stat_lock); | |
1820 | } | |
1821 | ||
1822 | dir->i_size += BOGO_DIRENT_SIZE; | |
1823 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1824 | inc_nlink(inode); |
1da177e4 LT |
1825 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1826 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1827 | d_instantiate(dentry, inode); | |
1828 | return 0; | |
1829 | } | |
1830 | ||
1831 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1832 | { | |
1833 | struct inode *inode = dentry->d_inode; | |
1834 | ||
1835 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) { | |
1836 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1837 | if (sbinfo->max_inodes) { |
1da177e4 LT |
1838 | spin_lock(&sbinfo->stat_lock); |
1839 | sbinfo->free_inodes++; | |
1840 | spin_unlock(&sbinfo->stat_lock); | |
1841 | } | |
1842 | } | |
1843 | ||
1844 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1845 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1846 | drop_nlink(inode); |
1da177e4 LT |
1847 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1848 | return 0; | |
1849 | } | |
1850 | ||
1851 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1852 | { | |
1853 | if (!simple_empty(dentry)) | |
1854 | return -ENOTEMPTY; | |
1855 | ||
9a53c3a7 DH |
1856 | drop_nlink(dentry->d_inode); |
1857 | drop_nlink(dir); | |
1da177e4 LT |
1858 | return shmem_unlink(dir, dentry); |
1859 | } | |
1860 | ||
1861 | /* | |
1862 | * The VFS layer already does all the dentry stuff for rename, | |
1863 | * we just have to decrement the usage count for the target if | |
1864 | * it exists so that the VFS layer correctly free's it when it | |
1865 | * gets overwritten. | |
1866 | */ | |
1867 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1868 | { | |
1869 | struct inode *inode = old_dentry->d_inode; | |
1870 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1871 | ||
1872 | if (!simple_empty(new_dentry)) | |
1873 | return -ENOTEMPTY; | |
1874 | ||
1875 | if (new_dentry->d_inode) { | |
1876 | (void) shmem_unlink(new_dir, new_dentry); | |
1877 | if (they_are_dirs) | |
9a53c3a7 | 1878 | drop_nlink(old_dir); |
1da177e4 | 1879 | } else if (they_are_dirs) { |
9a53c3a7 | 1880 | drop_nlink(old_dir); |
d8c76e6f | 1881 | inc_nlink(new_dir); |
1da177e4 LT |
1882 | } |
1883 | ||
1884 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1885 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1886 | old_dir->i_ctime = old_dir->i_mtime = | |
1887 | new_dir->i_ctime = new_dir->i_mtime = | |
1888 | inode->i_ctime = CURRENT_TIME; | |
1889 | return 0; | |
1890 | } | |
1891 | ||
1892 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1893 | { | |
1894 | int error; | |
1895 | int len; | |
1896 | struct inode *inode; | |
1897 | struct page *page = NULL; | |
1898 | char *kaddr; | |
1899 | struct shmem_inode_info *info; | |
1900 | ||
1901 | len = strlen(symname) + 1; | |
1902 | if (len > PAGE_CACHE_SIZE) | |
1903 | return -ENAMETOOLONG; | |
1904 | ||
1905 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1906 | if (!inode) | |
1907 | return -ENOSPC; | |
1908 | ||
570bc1c2 SS |
1909 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1910 | NULL); | |
1911 | if (error) { | |
1912 | if (error != -EOPNOTSUPP) { | |
1913 | iput(inode); | |
1914 | return error; | |
1915 | } | |
1916 | error = 0; | |
1917 | } | |
1918 | ||
1da177e4 LT |
1919 | info = SHMEM_I(inode); |
1920 | inode->i_size = len-1; | |
1921 | if (len <= (char *)inode - (char *)info) { | |
1922 | /* do it inline */ | |
1923 | memcpy(info, symname, len); | |
1924 | inode->i_op = &shmem_symlink_inline_operations; | |
1925 | } else { | |
1926 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1927 | if (error) { | |
1928 | iput(inode); | |
1929 | return error; | |
1930 | } | |
1931 | inode->i_op = &shmem_symlink_inode_operations; | |
1932 | kaddr = kmap_atomic(page, KM_USER0); | |
1933 | memcpy(kaddr, symname, len); | |
1934 | kunmap_atomic(kaddr, KM_USER0); | |
1935 | set_page_dirty(page); | |
1936 | page_cache_release(page); | |
1937 | } | |
1938 | if (dir->i_mode & S_ISGID) | |
1939 | inode->i_gid = dir->i_gid; | |
1940 | dir->i_size += BOGO_DIRENT_SIZE; | |
1941 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1942 | d_instantiate(dentry, inode); | |
1943 | dget(dentry); | |
1944 | return 0; | |
1945 | } | |
1946 | ||
cc314eef | 1947 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1948 | { |
1949 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1950 | return NULL; |
1da177e4 LT |
1951 | } |
1952 | ||
cc314eef | 1953 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1954 | { |
1955 | struct page *page = NULL; | |
1956 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1957 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
cc314eef | 1958 | return page; |
1da177e4 LT |
1959 | } |
1960 | ||
cc314eef | 1961 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1962 | { |
1963 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1964 | struct page *page = cookie; |
1da177e4 LT |
1965 | kunmap(page); |
1966 | mark_page_accessed(page); | |
1967 | page_cache_release(page); | |
1da177e4 LT |
1968 | } |
1969 | } | |
1970 | ||
92e1d5be | 1971 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
1972 | .readlink = generic_readlink, |
1973 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1974 | }; |
1975 | ||
92e1d5be | 1976 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
1977 | .truncate = shmem_truncate, |
1978 | .readlink = generic_readlink, | |
1979 | .follow_link = shmem_follow_link, | |
1980 | .put_link = shmem_put_link, | |
1da177e4 LT |
1981 | }; |
1982 | ||
39f0247d AG |
1983 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1984 | /** | |
1985 | * Superblocks without xattr inode operations will get security.* xattr | |
1986 | * support from the VFS "for free". As soon as we have any other xattrs | |
1987 | * like ACLs, we also need to implement the security.* handlers at | |
1988 | * filesystem level, though. | |
1989 | */ | |
1990 | ||
1991 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
1992 | size_t list_len, const char *name, | |
1993 | size_t name_len) | |
1994 | { | |
1995 | return security_inode_listsecurity(inode, list, list_len); | |
1996 | } | |
1997 | ||
1998 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
1999 | void *buffer, size_t size) | |
2000 | { | |
2001 | if (strcmp(name, "") == 0) | |
2002 | return -EINVAL; | |
2003 | return security_inode_getsecurity(inode, name, buffer, size, | |
2004 | -EOPNOTSUPP); | |
2005 | } | |
2006 | ||
2007 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
2008 | const void *value, size_t size, int flags) | |
2009 | { | |
2010 | if (strcmp(name, "") == 0) | |
2011 | return -EINVAL; | |
2012 | return security_inode_setsecurity(inode, name, value, size, flags); | |
2013 | } | |
2014 | ||
1f370a23 | 2015 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
2016 | .prefix = XATTR_SECURITY_PREFIX, |
2017 | .list = shmem_xattr_security_list, | |
2018 | .get = shmem_xattr_security_get, | |
2019 | .set = shmem_xattr_security_set, | |
2020 | }; | |
2021 | ||
2022 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
2023 | &shmem_xattr_acl_access_handler, | |
2024 | &shmem_xattr_acl_default_handler, | |
2025 | &shmem_xattr_security_handler, | |
2026 | NULL | |
2027 | }; | |
2028 | #endif | |
2029 | ||
91828a40 DG |
2030 | static struct dentry *shmem_get_parent(struct dentry *child) |
2031 | { | |
2032 | return ERR_PTR(-ESTALE); | |
2033 | } | |
2034 | ||
2035 | static int shmem_match(struct inode *ino, void *vfh) | |
2036 | { | |
2037 | __u32 *fh = vfh; | |
2038 | __u64 inum = fh[2]; | |
2039 | inum = (inum << 32) | fh[1]; | |
2040 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2041 | } | |
2042 | ||
2043 | static struct dentry *shmem_get_dentry(struct super_block *sb, void *vfh) | |
2044 | { | |
2045 | struct dentry *de = NULL; | |
2046 | struct inode *inode; | |
2047 | __u32 *fh = vfh; | |
2048 | __u64 inum = fh[2]; | |
2049 | inum = (inum << 32) | fh[1]; | |
2050 | ||
2051 | inode = ilookup5(sb, (unsigned long)(inum+fh[0]), shmem_match, vfh); | |
2052 | if (inode) { | |
2053 | de = d_find_alias(inode); | |
2054 | iput(inode); | |
2055 | } | |
2056 | ||
2057 | return de? de: ERR_PTR(-ESTALE); | |
2058 | } | |
2059 | ||
2060 | static struct dentry *shmem_decode_fh(struct super_block *sb, __u32 *fh, | |
2061 | int len, int type, | |
2062 | int (*acceptable)(void *context, struct dentry *de), | |
2063 | void *context) | |
2064 | { | |
2065 | if (len < 3) | |
2066 | return ERR_PTR(-ESTALE); | |
2067 | ||
2068 | return sb->s_export_op->find_exported_dentry(sb, fh, NULL, acceptable, | |
2069 | context); | |
2070 | } | |
2071 | ||
2072 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2073 | int connectable) | |
2074 | { | |
2075 | struct inode *inode = dentry->d_inode; | |
2076 | ||
2077 | if (*len < 3) | |
2078 | return 255; | |
2079 | ||
2080 | if (hlist_unhashed(&inode->i_hash)) { | |
2081 | /* Unfortunately insert_inode_hash is not idempotent, | |
2082 | * so as we hash inodes here rather than at creation | |
2083 | * time, we need a lock to ensure we only try | |
2084 | * to do it once | |
2085 | */ | |
2086 | static DEFINE_SPINLOCK(lock); | |
2087 | spin_lock(&lock); | |
2088 | if (hlist_unhashed(&inode->i_hash)) | |
2089 | __insert_inode_hash(inode, | |
2090 | inode->i_ino + inode->i_generation); | |
2091 | spin_unlock(&lock); | |
2092 | } | |
2093 | ||
2094 | fh[0] = inode->i_generation; | |
2095 | fh[1] = inode->i_ino; | |
2096 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2097 | ||
2098 | *len = 3; | |
2099 | return 1; | |
2100 | } | |
2101 | ||
2102 | static struct export_operations shmem_export_ops = { | |
2103 | .get_parent = shmem_get_parent, | |
2104 | .get_dentry = shmem_get_dentry, | |
2105 | .encode_fh = shmem_encode_fh, | |
2106 | .decode_fh = shmem_decode_fh, | |
2107 | }; | |
2108 | ||
7339ff83 RH |
2109 | static int shmem_parse_options(char *options, int *mode, uid_t *uid, |
2110 | gid_t *gid, unsigned long *blocks, unsigned long *inodes, | |
2111 | int *policy, nodemask_t *policy_nodes) | |
1da177e4 LT |
2112 | { |
2113 | char *this_char, *value, *rest; | |
2114 | ||
b00dc3ad HD |
2115 | while (options != NULL) { |
2116 | this_char = options; | |
2117 | for (;;) { | |
2118 | /* | |
2119 | * NUL-terminate this option: unfortunately, | |
2120 | * mount options form a comma-separated list, | |
2121 | * but mpol's nodelist may also contain commas. | |
2122 | */ | |
2123 | options = strchr(options, ','); | |
2124 | if (options == NULL) | |
2125 | break; | |
2126 | options++; | |
2127 | if (!isdigit(*options)) { | |
2128 | options[-1] = '\0'; | |
2129 | break; | |
2130 | } | |
2131 | } | |
1da177e4 LT |
2132 | if (!*this_char) |
2133 | continue; | |
2134 | if ((value = strchr(this_char,'=')) != NULL) { | |
2135 | *value++ = 0; | |
2136 | } else { | |
2137 | printk(KERN_ERR | |
2138 | "tmpfs: No value for mount option '%s'\n", | |
2139 | this_char); | |
2140 | return 1; | |
2141 | } | |
2142 | ||
2143 | if (!strcmp(this_char,"size")) { | |
2144 | unsigned long long size; | |
2145 | size = memparse(value,&rest); | |
2146 | if (*rest == '%') { | |
2147 | size <<= PAGE_SHIFT; | |
2148 | size *= totalram_pages; | |
2149 | do_div(size, 100); | |
2150 | rest++; | |
2151 | } | |
2152 | if (*rest) | |
2153 | goto bad_val; | |
2154 | *blocks = size >> PAGE_CACHE_SHIFT; | |
2155 | } else if (!strcmp(this_char,"nr_blocks")) { | |
2156 | *blocks = memparse(value,&rest); | |
2157 | if (*rest) | |
2158 | goto bad_val; | |
2159 | } else if (!strcmp(this_char,"nr_inodes")) { | |
2160 | *inodes = memparse(value,&rest); | |
2161 | if (*rest) | |
2162 | goto bad_val; | |
2163 | } else if (!strcmp(this_char,"mode")) { | |
2164 | if (!mode) | |
2165 | continue; | |
2166 | *mode = simple_strtoul(value,&rest,8); | |
2167 | if (*rest) | |
2168 | goto bad_val; | |
2169 | } else if (!strcmp(this_char,"uid")) { | |
2170 | if (!uid) | |
2171 | continue; | |
2172 | *uid = simple_strtoul(value,&rest,0); | |
2173 | if (*rest) | |
2174 | goto bad_val; | |
2175 | } else if (!strcmp(this_char,"gid")) { | |
2176 | if (!gid) | |
2177 | continue; | |
2178 | *gid = simple_strtoul(value,&rest,0); | |
2179 | if (*rest) | |
2180 | goto bad_val; | |
7339ff83 | 2181 | } else if (!strcmp(this_char,"mpol")) { |
b00dc3ad | 2182 | if (shmem_parse_mpol(value,policy,policy_nodes)) |
7339ff83 | 2183 | goto bad_val; |
1da177e4 LT |
2184 | } else { |
2185 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2186 | this_char); | |
2187 | return 1; | |
2188 | } | |
2189 | } | |
2190 | return 0; | |
2191 | ||
2192 | bad_val: | |
2193 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2194 | value, this_char); | |
2195 | return 1; | |
2196 | ||
2197 | } | |
2198 | ||
2199 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2200 | { | |
2201 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
0edd73b3 HD |
2202 | unsigned long max_blocks = sbinfo->max_blocks; |
2203 | unsigned long max_inodes = sbinfo->max_inodes; | |
7339ff83 RH |
2204 | int policy = sbinfo->policy; |
2205 | nodemask_t policy_nodes = sbinfo->policy_nodes; | |
0edd73b3 HD |
2206 | unsigned long blocks; |
2207 | unsigned long inodes; | |
2208 | int error = -EINVAL; | |
2209 | ||
7339ff83 RH |
2210 | if (shmem_parse_options(data, NULL, NULL, NULL, &max_blocks, |
2211 | &max_inodes, &policy, &policy_nodes)) | |
0edd73b3 | 2212 | return error; |
1da177e4 | 2213 | |
0edd73b3 HD |
2214 | spin_lock(&sbinfo->stat_lock); |
2215 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2216 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
2217 | if (max_blocks < blocks) | |
2218 | goto out; | |
2219 | if (max_inodes < inodes) | |
2220 | goto out; | |
2221 | /* | |
2222 | * Those tests also disallow limited->unlimited while any are in | |
2223 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2224 | * but we must separately disallow unlimited->limited, because | |
2225 | * in that case we have no record of how much is already in use. | |
2226 | */ | |
2227 | if (max_blocks && !sbinfo->max_blocks) | |
2228 | goto out; | |
2229 | if (max_inodes && !sbinfo->max_inodes) | |
2230 | goto out; | |
2231 | ||
2232 | error = 0; | |
2233 | sbinfo->max_blocks = max_blocks; | |
2234 | sbinfo->free_blocks = max_blocks - blocks; | |
2235 | sbinfo->max_inodes = max_inodes; | |
2236 | sbinfo->free_inodes = max_inodes - inodes; | |
7339ff83 RH |
2237 | sbinfo->policy = policy; |
2238 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2239 | out: |
2240 | spin_unlock(&sbinfo->stat_lock); | |
2241 | return error; | |
1da177e4 LT |
2242 | } |
2243 | #endif | |
2244 | ||
2245 | static void shmem_put_super(struct super_block *sb) | |
2246 | { | |
2247 | kfree(sb->s_fs_info); | |
2248 | sb->s_fs_info = NULL; | |
2249 | } | |
2250 | ||
1da177e4 LT |
2251 | static int shmem_fill_super(struct super_block *sb, |
2252 | void *data, int silent) | |
2253 | { | |
2254 | struct inode *inode; | |
2255 | struct dentry *root; | |
2256 | int mode = S_IRWXUGO | S_ISVTX; | |
2257 | uid_t uid = current->fsuid; | |
2258 | gid_t gid = current->fsgid; | |
2259 | int err = -ENOMEM; | |
0edd73b3 | 2260 | struct shmem_sb_info *sbinfo; |
1da177e4 LT |
2261 | unsigned long blocks = 0; |
2262 | unsigned long inodes = 0; | |
7339ff83 RH |
2263 | int policy = MPOL_DEFAULT; |
2264 | nodemask_t policy_nodes = node_online_map; | |
1da177e4 | 2265 | |
0edd73b3 | 2266 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2267 | /* |
2268 | * Per default we only allow half of the physical ram per | |
2269 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2270 | * but the internal instance is left unlimited. | |
2271 | */ | |
2272 | if (!(sb->s_flags & MS_NOUSER)) { | |
2273 | blocks = totalram_pages / 2; | |
2274 | inodes = totalram_pages - totalhigh_pages; | |
2275 | if (inodes > blocks) | |
2276 | inodes = blocks; | |
7339ff83 RH |
2277 | if (shmem_parse_options(data, &mode, &uid, &gid, &blocks, |
2278 | &inodes, &policy, &policy_nodes)) | |
1da177e4 LT |
2279 | return -EINVAL; |
2280 | } | |
91828a40 | 2281 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2282 | #else |
2283 | sb->s_flags |= MS_NOUSER; | |
2284 | #endif | |
2285 | ||
0edd73b3 HD |
2286 | /* Round up to L1_CACHE_BYTES to resist false sharing */ |
2287 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2288 | L1_CACHE_BYTES), GFP_KERNEL); | |
2289 | if (!sbinfo) | |
2290 | return -ENOMEM; | |
2291 | ||
2292 | spin_lock_init(&sbinfo->stat_lock); | |
2293 | sbinfo->max_blocks = blocks; | |
2294 | sbinfo->free_blocks = blocks; | |
2295 | sbinfo->max_inodes = inodes; | |
2296 | sbinfo->free_inodes = inodes; | |
7339ff83 RH |
2297 | sbinfo->policy = policy; |
2298 | sbinfo->policy_nodes = policy_nodes; | |
0edd73b3 HD |
2299 | |
2300 | sb->s_fs_info = sbinfo; | |
1da177e4 LT |
2301 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2302 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2303 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2304 | sb->s_magic = TMPFS_MAGIC; | |
2305 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2306 | sb->s_time_gran = 1; |
39f0247d AG |
2307 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2308 | sb->s_xattr = shmem_xattr_handlers; | |
2309 | sb->s_flags |= MS_POSIXACL; | |
2310 | #endif | |
0edd73b3 | 2311 | |
1da177e4 LT |
2312 | inode = shmem_get_inode(sb, S_IFDIR | mode, 0); |
2313 | if (!inode) | |
2314 | goto failed; | |
2315 | inode->i_uid = uid; | |
2316 | inode->i_gid = gid; | |
2317 | root = d_alloc_root(inode); | |
2318 | if (!root) | |
2319 | goto failed_iput; | |
2320 | sb->s_root = root; | |
2321 | return 0; | |
2322 | ||
2323 | failed_iput: | |
2324 | iput(inode); | |
2325 | failed: | |
2326 | shmem_put_super(sb); | |
2327 | return err; | |
2328 | } | |
2329 | ||
fcc234f8 | 2330 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2331 | |
2332 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2333 | { | |
2334 | struct shmem_inode_info *p; | |
e94b1766 | 2335 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2336 | if (!p) |
2337 | return NULL; | |
2338 | return &p->vfs_inode; | |
2339 | } | |
2340 | ||
2341 | static void shmem_destroy_inode(struct inode *inode) | |
2342 | { | |
2343 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2344 | /* only struct inode is valid if it's an inline symlink */ | |
2345 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2346 | } | |
39f0247d | 2347 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2348 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2349 | } | |
2350 | ||
fcc234f8 PE |
2351 | static void init_once(void *foo, struct kmem_cache *cachep, |
2352 | unsigned long flags) | |
1da177e4 LT |
2353 | { |
2354 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2355 | ||
a35afb83 | 2356 | inode_init_once(&p->vfs_inode); |
39f0247d | 2357 | #ifdef CONFIG_TMPFS_POSIX_ACL |
a35afb83 CL |
2358 | p->i_acl = NULL; |
2359 | p->i_default_acl = NULL; | |
39f0247d | 2360 | #endif |
1da177e4 LT |
2361 | } |
2362 | ||
2363 | static int init_inodecache(void) | |
2364 | { | |
2365 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2366 | sizeof(struct shmem_inode_info), | |
2367 | 0, 0, init_once, NULL); | |
2368 | if (shmem_inode_cachep == NULL) | |
2369 | return -ENOMEM; | |
2370 | return 0; | |
2371 | } | |
2372 | ||
2373 | static void destroy_inodecache(void) | |
2374 | { | |
1a1d92c1 | 2375 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2376 | } |
2377 | ||
f5e54d6e | 2378 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2379 | .writepage = shmem_writepage, |
76719325 | 2380 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2381 | #ifdef CONFIG_TMPFS |
ae976416 | 2382 | .readpage = shmem_readpage, |
1da177e4 LT |
2383 | .prepare_write = shmem_prepare_write, |
2384 | .commit_write = simple_commit_write, | |
2385 | #endif | |
304dbdb7 | 2386 | .migratepage = migrate_page, |
1da177e4 LT |
2387 | }; |
2388 | ||
15ad7cdc | 2389 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2390 | .mmap = shmem_mmap, |
2391 | #ifdef CONFIG_TMPFS | |
2392 | .llseek = generic_file_llseek, | |
2393 | .read = shmem_file_read, | |
2394 | .write = shmem_file_write, | |
2395 | .fsync = simple_sync_file, | |
ae976416 HD |
2396 | .splice_read = generic_file_splice_read, |
2397 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2398 | #endif |
2399 | }; | |
2400 | ||
92e1d5be | 2401 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2402 | .truncate = shmem_truncate, |
2403 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2404 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2405 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2406 | .setxattr = generic_setxattr, | |
2407 | .getxattr = generic_getxattr, | |
2408 | .listxattr = generic_listxattr, | |
2409 | .removexattr = generic_removexattr, | |
2410 | .permission = shmem_permission, | |
2411 | #endif | |
2412 | ||
1da177e4 LT |
2413 | }; |
2414 | ||
92e1d5be | 2415 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2416 | #ifdef CONFIG_TMPFS |
2417 | .create = shmem_create, | |
2418 | .lookup = simple_lookup, | |
2419 | .link = shmem_link, | |
2420 | .unlink = shmem_unlink, | |
2421 | .symlink = shmem_symlink, | |
2422 | .mkdir = shmem_mkdir, | |
2423 | .rmdir = shmem_rmdir, | |
2424 | .mknod = shmem_mknod, | |
2425 | .rename = shmem_rename, | |
1da177e4 | 2426 | #endif |
39f0247d AG |
2427 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2428 | .setattr = shmem_notify_change, | |
2429 | .setxattr = generic_setxattr, | |
2430 | .getxattr = generic_getxattr, | |
2431 | .listxattr = generic_listxattr, | |
2432 | .removexattr = generic_removexattr, | |
2433 | .permission = shmem_permission, | |
2434 | #endif | |
2435 | }; | |
2436 | ||
92e1d5be | 2437 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2438 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2439 | .setattr = shmem_notify_change, | |
2440 | .setxattr = generic_setxattr, | |
2441 | .getxattr = generic_getxattr, | |
2442 | .listxattr = generic_listxattr, | |
2443 | .removexattr = generic_removexattr, | |
2444 | .permission = shmem_permission, | |
2445 | #endif | |
1da177e4 LT |
2446 | }; |
2447 | ||
759b9775 | 2448 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2449 | .alloc_inode = shmem_alloc_inode, |
2450 | .destroy_inode = shmem_destroy_inode, | |
2451 | #ifdef CONFIG_TMPFS | |
2452 | .statfs = shmem_statfs, | |
2453 | .remount_fs = shmem_remount_fs, | |
2454 | #endif | |
2455 | .delete_inode = shmem_delete_inode, | |
2456 | .drop_inode = generic_delete_inode, | |
2457 | .put_super = shmem_put_super, | |
2458 | }; | |
2459 | ||
2460 | static struct vm_operations_struct shmem_vm_ops = { | |
2461 | .nopage = shmem_nopage, | |
2462 | .populate = shmem_populate, | |
2463 | #ifdef CONFIG_NUMA | |
2464 | .set_policy = shmem_set_policy, | |
2465 | .get_policy = shmem_get_policy, | |
2466 | #endif | |
2467 | }; | |
2468 | ||
2469 | ||
454e2398 DH |
2470 | static int shmem_get_sb(struct file_system_type *fs_type, |
2471 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2472 | { |
454e2398 | 2473 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2474 | } |
2475 | ||
2476 | static struct file_system_type tmpfs_fs_type = { | |
2477 | .owner = THIS_MODULE, | |
2478 | .name = "tmpfs", | |
2479 | .get_sb = shmem_get_sb, | |
2480 | .kill_sb = kill_litter_super, | |
2481 | }; | |
2482 | static struct vfsmount *shm_mnt; | |
2483 | ||
2484 | static int __init init_tmpfs(void) | |
2485 | { | |
2486 | int error; | |
2487 | ||
2488 | error = init_inodecache(); | |
2489 | if (error) | |
2490 | goto out3; | |
2491 | ||
2492 | error = register_filesystem(&tmpfs_fs_type); | |
2493 | if (error) { | |
2494 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2495 | goto out2; | |
2496 | } | |
95dc112a | 2497 | |
1f5ce9e9 | 2498 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2499 | tmpfs_fs_type.name, NULL); |
2500 | if (IS_ERR(shm_mnt)) { | |
2501 | error = PTR_ERR(shm_mnt); | |
2502 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2503 | goto out1; | |
2504 | } | |
2505 | return 0; | |
2506 | ||
2507 | out1: | |
2508 | unregister_filesystem(&tmpfs_fs_type); | |
2509 | out2: | |
2510 | destroy_inodecache(); | |
2511 | out3: | |
2512 | shm_mnt = ERR_PTR(error); | |
2513 | return error; | |
2514 | } | |
2515 | module_init(init_tmpfs) | |
2516 | ||
2517 | /* | |
2518 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2519 | * | |
2520 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2521 | * @size: size to be set for the file | |
2522 | * | |
2523 | */ | |
2524 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2525 | { | |
2526 | int error; | |
2527 | struct file *file; | |
2528 | struct inode *inode; | |
2529 | struct dentry *dentry, *root; | |
2530 | struct qstr this; | |
2531 | ||
2532 | if (IS_ERR(shm_mnt)) | |
2533 | return (void *)shm_mnt; | |
2534 | ||
2535 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2536 | return ERR_PTR(-EINVAL); | |
2537 | ||
2538 | if (shmem_acct_size(flags, size)) | |
2539 | return ERR_PTR(-ENOMEM); | |
2540 | ||
2541 | error = -ENOMEM; | |
2542 | this.name = name; | |
2543 | this.len = strlen(name); | |
2544 | this.hash = 0; /* will go */ | |
2545 | root = shm_mnt->mnt_root; | |
2546 | dentry = d_alloc(root, &this); | |
2547 | if (!dentry) | |
2548 | goto put_memory; | |
2549 | ||
2550 | error = -ENFILE; | |
2551 | file = get_empty_filp(); | |
2552 | if (!file) | |
2553 | goto put_dentry; | |
2554 | ||
2555 | error = -ENOSPC; | |
2556 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2557 | if (!inode) | |
2558 | goto close_file; | |
2559 | ||
2560 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2561 | d_instantiate(dentry, inode); | |
2562 | inode->i_size = size; | |
2563 | inode->i_nlink = 0; /* It is unlinked */ | |
d3ac7f89 JJS |
2564 | file->f_path.mnt = mntget(shm_mnt); |
2565 | file->f_path.dentry = dentry; | |
1da177e4 LT |
2566 | file->f_mapping = inode->i_mapping; |
2567 | file->f_op = &shmem_file_operations; | |
2568 | file->f_mode = FMODE_WRITE | FMODE_READ; | |
2569 | return file; | |
2570 | ||
2571 | close_file: | |
2572 | put_filp(file); | |
2573 | put_dentry: | |
2574 | dput(dentry); | |
2575 | put_memory: | |
2576 | shmem_unacct_size(flags, size); | |
2577 | return ERR_PTR(error); | |
2578 | } | |
2579 | ||
2580 | /* | |
2581 | * shmem_zero_setup - setup a shared anonymous mapping | |
2582 | * | |
2583 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2584 | */ | |
2585 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2586 | { | |
2587 | struct file *file; | |
2588 | loff_t size = vma->vm_end - vma->vm_start; | |
2589 | ||
2590 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2591 | if (IS_ERR(file)) | |
2592 | return PTR_ERR(file); | |
2593 | ||
2594 | if (vma->vm_file) | |
2595 | fput(vma->vm_file); | |
2596 | vma->vm_file = file; | |
2597 | vma->vm_ops = &shmem_vm_ops; | |
2598 | return 0; | |
2599 | } |