Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
0edd73b3 HD |
9 | * Copyright (C) 2002-2005 Hugh Dickins. |
10 | * Copyright (C) 2002-2005 VERITAS Software Corporation. | |
1da177e4 LT |
11 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
12 | * | |
13 | * Extended attribute support for tmpfs: | |
14 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
15 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
16 | * | |
17 | * This file is released under the GPL. | |
18 | */ | |
19 | ||
20 | /* | |
21 | * This virtual memory filesystem is heavily based on the ramfs. It | |
22 | * extends ramfs by the ability to use swap and honor resource limits | |
23 | * which makes it a completely usable filesystem. | |
24 | */ | |
25 | ||
1da177e4 LT |
26 | #include <linux/module.h> |
27 | #include <linux/init.h> | |
1da177e4 | 28 | #include <linux/fs.h> |
39f0247d | 29 | #include <linux/xattr.h> |
a5694255 | 30 | #include <linux/exportfs.h> |
39f0247d | 31 | #include <linux/generic_acl.h> |
1da177e4 LT |
32 | #include <linux/mm.h> |
33 | #include <linux/mman.h> | |
34 | #include <linux/file.h> | |
35 | #include <linux/swap.h> | |
36 | #include <linux/pagemap.h> | |
37 | #include <linux/string.h> | |
38 | #include <linux/slab.h> | |
39 | #include <linux/backing-dev.h> | |
40 | #include <linux/shmem_fs.h> | |
41 | #include <linux/mount.h> | |
42 | #include <linux/writeback.h> | |
43 | #include <linux/vfs.h> | |
44 | #include <linux/blkdev.h> | |
45 | #include <linux/security.h> | |
46 | #include <linux/swapops.h> | |
47 | #include <linux/mempolicy.h> | |
48 | #include <linux/namei.h> | |
b00dc3ad | 49 | #include <linux/ctype.h> |
304dbdb7 | 50 | #include <linux/migrate.h> |
c1f60a5a | 51 | #include <linux/highmem.h> |
680d794b | 52 | #include <linux/seq_file.h> |
304dbdb7 | 53 | |
1da177e4 LT |
54 | #include <asm/uaccess.h> |
55 | #include <asm/div64.h> | |
56 | #include <asm/pgtable.h> | |
57 | ||
58 | /* This magic number is used in glibc for posix shared memory */ | |
59 | #define TMPFS_MAGIC 0x01021994 | |
60 | ||
61 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) | |
62 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) | |
63 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
64 | ||
65 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) | |
66 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) | |
67 | ||
68 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) | |
69 | ||
70 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
71 | #define SHMEM_PAGEIN VM_READ | |
72 | #define SHMEM_TRUNCATE VM_WRITE | |
73 | ||
74 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
75 | #define LATENCY_LIMIT 64 | |
76 | ||
77 | /* Pretend that each entry is of this size in directory's i_size */ | |
78 | #define BOGO_DIRENT_SIZE 20 | |
79 | ||
1da177e4 LT |
80 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
81 | enum sgp_type { | |
1da177e4 LT |
82 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
83 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 84 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
85 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
86 | }; | |
87 | ||
b76db735 | 88 | #ifdef CONFIG_TMPFS |
680d794b | 89 | static unsigned long shmem_default_max_blocks(void) |
90 | { | |
91 | return totalram_pages / 2; | |
92 | } | |
93 | ||
94 | static unsigned long shmem_default_max_inodes(void) | |
95 | { | |
96 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
97 | } | |
b76db735 | 98 | #endif |
680d794b | 99 | |
1da177e4 LT |
100 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
101 | struct page **pagep, enum sgp_type sgp, int *type); | |
102 | ||
6daa0e28 | 103 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
104 | { |
105 | /* | |
106 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
107 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
108 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 | 109 | * |
e12ba74d | 110 | * Mobility flags are masked out as swap vectors cannot move |
1da177e4 | 111 | */ |
e12ba74d | 112 | return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO, |
769848c0 | 113 | PAGE_CACHE_SHIFT-PAGE_SHIFT); |
1da177e4 LT |
114 | } |
115 | ||
116 | static inline void shmem_dir_free(struct page *page) | |
117 | { | |
118 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
119 | } | |
120 | ||
121 | static struct page **shmem_dir_map(struct page *page) | |
122 | { | |
123 | return (struct page **)kmap_atomic(page, KM_USER0); | |
124 | } | |
125 | ||
126 | static inline void shmem_dir_unmap(struct page **dir) | |
127 | { | |
128 | kunmap_atomic(dir, KM_USER0); | |
129 | } | |
130 | ||
131 | static swp_entry_t *shmem_swp_map(struct page *page) | |
132 | { | |
133 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
134 | } | |
135 | ||
136 | static inline void shmem_swp_balance_unmap(void) | |
137 | { | |
138 | /* | |
139 | * When passing a pointer to an i_direct entry, to code which | |
140 | * also handles indirect entries and so will shmem_swp_unmap, | |
141 | * we must arrange for the preempt count to remain in balance. | |
142 | * What kmap_atomic of a lowmem page does depends on config | |
143 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
144 | */ | |
145 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
146 | } | |
147 | ||
148 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
149 | { | |
150 | kunmap_atomic(entry, KM_USER1); | |
151 | } | |
152 | ||
153 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
154 | { | |
155 | return sb->s_fs_info; | |
156 | } | |
157 | ||
158 | /* | |
159 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
160 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
161 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
162 | * consistent with the pre-accounting of private mappings ... | |
163 | */ | |
164 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
165 | { | |
166 | return (flags & VM_ACCOUNT)? | |
167 | security_vm_enough_memory(VM_ACCT(size)): 0; | |
168 | } | |
169 | ||
170 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
171 | { | |
172 | if (flags & VM_ACCOUNT) | |
173 | vm_unacct_memory(VM_ACCT(size)); | |
174 | } | |
175 | ||
176 | /* | |
177 | * ... whereas tmpfs objects are accounted incrementally as | |
178 | * pages are allocated, in order to allow huge sparse files. | |
179 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
180 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
181 | */ | |
182 | static inline int shmem_acct_block(unsigned long flags) | |
183 | { | |
184 | return (flags & VM_ACCOUNT)? | |
185 | 0: security_vm_enough_memory(VM_ACCT(PAGE_CACHE_SIZE)); | |
186 | } | |
187 | ||
188 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
189 | { | |
190 | if (!(flags & VM_ACCOUNT)) | |
191 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); | |
192 | } | |
193 | ||
759b9775 | 194 | static const struct super_operations shmem_ops; |
f5e54d6e | 195 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 196 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
197 | static const struct inode_operations shmem_inode_operations; |
198 | static const struct inode_operations shmem_dir_inode_operations; | |
199 | static const struct inode_operations shmem_special_inode_operations; | |
1da177e4 LT |
200 | static struct vm_operations_struct shmem_vm_ops; |
201 | ||
6c231b7b | 202 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 LT |
203 | .ra_pages = 0, /* No readahead */ |
204 | .capabilities = BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_WRITEBACK, | |
205 | .unplug_io_fn = default_unplug_io_fn, | |
206 | }; | |
207 | ||
208 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 209 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 LT |
210 | |
211 | static void shmem_free_blocks(struct inode *inode, long pages) | |
212 | { | |
213 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 214 | if (sbinfo->max_blocks) { |
1da177e4 LT |
215 | spin_lock(&sbinfo->stat_lock); |
216 | sbinfo->free_blocks += pages; | |
217 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
218 | spin_unlock(&sbinfo->stat_lock); | |
219 | } | |
220 | } | |
221 | ||
5b04c689 PE |
222 | static int shmem_reserve_inode(struct super_block *sb) |
223 | { | |
224 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
225 | if (sbinfo->max_inodes) { | |
226 | spin_lock(&sbinfo->stat_lock); | |
227 | if (!sbinfo->free_inodes) { | |
228 | spin_unlock(&sbinfo->stat_lock); | |
229 | return -ENOSPC; | |
230 | } | |
231 | sbinfo->free_inodes--; | |
232 | spin_unlock(&sbinfo->stat_lock); | |
233 | } | |
234 | return 0; | |
235 | } | |
236 | ||
237 | static void shmem_free_inode(struct super_block *sb) | |
238 | { | |
239 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
240 | if (sbinfo->max_inodes) { | |
241 | spin_lock(&sbinfo->stat_lock); | |
242 | sbinfo->free_inodes++; | |
243 | spin_unlock(&sbinfo->stat_lock); | |
244 | } | |
245 | } | |
246 | ||
1da177e4 LT |
247 | /* |
248 | * shmem_recalc_inode - recalculate the size of an inode | |
249 | * | |
250 | * @inode: inode to recalc | |
251 | * | |
252 | * We have to calculate the free blocks since the mm can drop | |
253 | * undirtied hole pages behind our back. | |
254 | * | |
255 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
256 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
257 | * | |
258 | * It has to be called with the spinlock held. | |
259 | */ | |
260 | static void shmem_recalc_inode(struct inode *inode) | |
261 | { | |
262 | struct shmem_inode_info *info = SHMEM_I(inode); | |
263 | long freed; | |
264 | ||
265 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
266 | if (freed > 0) { | |
267 | info->alloced -= freed; | |
268 | shmem_unacct_blocks(info->flags, freed); | |
269 | shmem_free_blocks(inode, freed); | |
270 | } | |
271 | } | |
272 | ||
273 | /* | |
274 | * shmem_swp_entry - find the swap vector position in the info structure | |
275 | * | |
276 | * @info: info structure for the inode | |
277 | * @index: index of the page to find | |
278 | * @page: optional page to add to the structure. Has to be preset to | |
279 | * all zeros | |
280 | * | |
281 | * If there is no space allocated yet it will return NULL when | |
282 | * page is NULL, else it will use the page for the needed block, | |
283 | * setting it to NULL on return to indicate that it has been used. | |
284 | * | |
285 | * The swap vector is organized the following way: | |
286 | * | |
287 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
288 | * shmem_inode_info structure. So small files do not need an addional | |
289 | * allocation. | |
290 | * | |
291 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
292 | * i_indirect which points to a page which holds in the first half | |
293 | * doubly indirect blocks, in the second half triple indirect blocks: | |
294 | * | |
295 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
296 | * following layout (for SHMEM_NR_DIRECT == 16): | |
297 | * | |
298 | * i_indirect -> dir --> 16-19 | |
299 | * | +-> 20-23 | |
300 | * | | |
301 | * +-->dir2 --> 24-27 | |
302 | * | +-> 28-31 | |
303 | * | +-> 32-35 | |
304 | * | +-> 36-39 | |
305 | * | | |
306 | * +-->dir3 --> 40-43 | |
307 | * +-> 44-47 | |
308 | * +-> 48-51 | |
309 | * +-> 52-55 | |
310 | */ | |
311 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
312 | { | |
313 | unsigned long offset; | |
314 | struct page **dir; | |
315 | struct page *subdir; | |
316 | ||
317 | if (index < SHMEM_NR_DIRECT) { | |
318 | shmem_swp_balance_unmap(); | |
319 | return info->i_direct+index; | |
320 | } | |
321 | if (!info->i_indirect) { | |
322 | if (page) { | |
323 | info->i_indirect = *page; | |
324 | *page = NULL; | |
325 | } | |
326 | return NULL; /* need another page */ | |
327 | } | |
328 | ||
329 | index -= SHMEM_NR_DIRECT; | |
330 | offset = index % ENTRIES_PER_PAGE; | |
331 | index /= ENTRIES_PER_PAGE; | |
332 | dir = shmem_dir_map(info->i_indirect); | |
333 | ||
334 | if (index >= ENTRIES_PER_PAGE/2) { | |
335 | index -= ENTRIES_PER_PAGE/2; | |
336 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
337 | index %= ENTRIES_PER_PAGE; | |
338 | subdir = *dir; | |
339 | if (!subdir) { | |
340 | if (page) { | |
341 | *dir = *page; | |
342 | *page = NULL; | |
343 | } | |
344 | shmem_dir_unmap(dir); | |
345 | return NULL; /* need another page */ | |
346 | } | |
347 | shmem_dir_unmap(dir); | |
348 | dir = shmem_dir_map(subdir); | |
349 | } | |
350 | ||
351 | dir += index; | |
352 | subdir = *dir; | |
353 | if (!subdir) { | |
354 | if (!page || !(subdir = *page)) { | |
355 | shmem_dir_unmap(dir); | |
356 | return NULL; /* need a page */ | |
357 | } | |
358 | *dir = subdir; | |
359 | *page = NULL; | |
360 | } | |
361 | shmem_dir_unmap(dir); | |
362 | return shmem_swp_map(subdir) + offset; | |
363 | } | |
364 | ||
365 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
366 | { | |
367 | long incdec = value? 1: -1; | |
368 | ||
369 | entry->val = value; | |
370 | info->swapped += incdec; | |
4c21e2f2 HD |
371 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
372 | struct page *page = kmap_atomic_to_page(entry); | |
373 | set_page_private(page, page_private(page) + incdec); | |
374 | } | |
1da177e4 LT |
375 | } |
376 | ||
377 | /* | |
378 | * shmem_swp_alloc - get the position of the swap entry for the page. | |
379 | * If it does not exist allocate the entry. | |
380 | * | |
381 | * @info: info structure for the inode | |
382 | * @index: index of the page to find | |
383 | * @sgp: check and recheck i_size? skip allocation? | |
384 | */ | |
385 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
386 | { | |
387 | struct inode *inode = &info->vfs_inode; | |
388 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
389 | struct page *page = NULL; | |
390 | swp_entry_t *entry; | |
391 | ||
392 | if (sgp != SGP_WRITE && | |
393 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
394 | return ERR_PTR(-EINVAL); | |
395 | ||
396 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
397 | if (sgp == SGP_READ) | |
398 | return shmem_swp_map(ZERO_PAGE(0)); | |
399 | /* | |
400 | * Test free_blocks against 1 not 0, since we have 1 data | |
401 | * page (and perhaps indirect index pages) yet to allocate: | |
402 | * a waste to allocate index if we cannot allocate data. | |
403 | */ | |
0edd73b3 | 404 | if (sbinfo->max_blocks) { |
1da177e4 LT |
405 | spin_lock(&sbinfo->stat_lock); |
406 | if (sbinfo->free_blocks <= 1) { | |
407 | spin_unlock(&sbinfo->stat_lock); | |
408 | return ERR_PTR(-ENOSPC); | |
409 | } | |
410 | sbinfo->free_blocks--; | |
411 | inode->i_blocks += BLOCKS_PER_PAGE; | |
412 | spin_unlock(&sbinfo->stat_lock); | |
413 | } | |
414 | ||
415 | spin_unlock(&info->lock); | |
769848c0 | 416 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
4c21e2f2 HD |
417 | if (page) |
418 | set_page_private(page, 0); | |
1da177e4 LT |
419 | spin_lock(&info->lock); |
420 | ||
421 | if (!page) { | |
422 | shmem_free_blocks(inode, 1); | |
423 | return ERR_PTR(-ENOMEM); | |
424 | } | |
425 | if (sgp != SGP_WRITE && | |
426 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
427 | entry = ERR_PTR(-EINVAL); | |
428 | break; | |
429 | } | |
430 | if (info->next_index <= index) | |
431 | info->next_index = index + 1; | |
432 | } | |
433 | if (page) { | |
434 | /* another task gave its page, or truncated the file */ | |
435 | shmem_free_blocks(inode, 1); | |
436 | shmem_dir_free(page); | |
437 | } | |
438 | if (info->next_index <= index && !IS_ERR(entry)) | |
439 | info->next_index = index + 1; | |
440 | return entry; | |
441 | } | |
442 | ||
443 | /* | |
444 | * shmem_free_swp - free some swap entries in a directory | |
445 | * | |
1ae70006 HD |
446 | * @dir: pointer to the directory |
447 | * @edir: pointer after last entry of the directory | |
448 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 449 | */ |
1ae70006 HD |
450 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
451 | spinlock_t *punch_lock) | |
1da177e4 | 452 | { |
1ae70006 | 453 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
454 | swp_entry_t *ptr; |
455 | int freed = 0; | |
456 | ||
457 | for (ptr = dir; ptr < edir; ptr++) { | |
458 | if (ptr->val) { | |
1ae70006 HD |
459 | if (unlikely(punch_lock)) { |
460 | punch_unlock = punch_lock; | |
461 | punch_lock = NULL; | |
462 | spin_lock(punch_unlock); | |
463 | if (!ptr->val) | |
464 | continue; | |
465 | } | |
1da177e4 LT |
466 | free_swap_and_cache(*ptr); |
467 | *ptr = (swp_entry_t){0}; | |
468 | freed++; | |
469 | } | |
470 | } | |
1ae70006 HD |
471 | if (punch_unlock) |
472 | spin_unlock(punch_unlock); | |
1da177e4 LT |
473 | return freed; |
474 | } | |
475 | ||
1ae70006 HD |
476 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
477 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
478 | { |
479 | swp_entry_t *ptr; | |
480 | int freed = 0; | |
481 | ||
482 | ptr = shmem_swp_map(subdir); | |
483 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
484 | int size = limit - offset; | |
485 | if (size > LATENCY_LIMIT) | |
486 | size = LATENCY_LIMIT; | |
1ae70006 HD |
487 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
488 | punch_lock); | |
1da177e4 LT |
489 | if (need_resched()) { |
490 | shmem_swp_unmap(ptr); | |
491 | if (*dir) { | |
492 | shmem_dir_unmap(*dir); | |
493 | *dir = NULL; | |
494 | } | |
495 | cond_resched(); | |
496 | ptr = shmem_swp_map(subdir); | |
497 | } | |
498 | } | |
499 | shmem_swp_unmap(ptr); | |
500 | return freed; | |
501 | } | |
502 | ||
503 | static void shmem_free_pages(struct list_head *next) | |
504 | { | |
505 | struct page *page; | |
506 | int freed = 0; | |
507 | ||
508 | do { | |
509 | page = container_of(next, struct page, lru); | |
510 | next = next->next; | |
511 | shmem_dir_free(page); | |
512 | freed++; | |
513 | if (freed >= LATENCY_LIMIT) { | |
514 | cond_resched(); | |
515 | freed = 0; | |
516 | } | |
517 | } while (next); | |
518 | } | |
519 | ||
f6b3ec23 | 520 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
521 | { |
522 | struct shmem_inode_info *info = SHMEM_I(inode); | |
523 | unsigned long idx; | |
524 | unsigned long size; | |
525 | unsigned long limit; | |
526 | unsigned long stage; | |
527 | unsigned long diroff; | |
528 | struct page **dir; | |
529 | struct page *topdir; | |
530 | struct page *middir; | |
531 | struct page *subdir; | |
532 | swp_entry_t *ptr; | |
533 | LIST_HEAD(pages_to_free); | |
534 | long nr_pages_to_free = 0; | |
535 | long nr_swaps_freed = 0; | |
536 | int offset; | |
537 | int freed; | |
a2646d1e | 538 | int punch_hole; |
1ae70006 HD |
539 | spinlock_t *needs_lock; |
540 | spinlock_t *punch_lock; | |
a2646d1e | 541 | unsigned long upper_limit; |
1da177e4 LT |
542 | |
543 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 544 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
545 | if (idx >= info->next_index) |
546 | return; | |
547 | ||
548 | spin_lock(&info->lock); | |
549 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
550 | if (likely(end == (loff_t) -1)) { |
551 | limit = info->next_index; | |
a2646d1e | 552 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 553 | info->next_index = idx; |
1ae70006 | 554 | needs_lock = NULL; |
a2646d1e | 555 | punch_hole = 0; |
f6b3ec23 | 556 | } else { |
a2646d1e HD |
557 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
558 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
559 | PAGE_CACHE_SHIFT; | |
560 | upper_limit = SHMEM_MAX_INDEX; | |
561 | } else { | |
562 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
563 | upper_limit = limit; | |
564 | } | |
1ae70006 | 565 | needs_lock = &info->lock; |
f6b3ec23 BP |
566 | punch_hole = 1; |
567 | } | |
568 | ||
1da177e4 | 569 | topdir = info->i_indirect; |
f6b3ec23 | 570 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
571 | info->i_indirect = NULL; |
572 | nr_pages_to_free++; | |
573 | list_add(&topdir->lru, &pages_to_free); | |
574 | } | |
575 | spin_unlock(&info->lock); | |
576 | ||
577 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
578 | ptr = info->i_direct; | |
579 | size = limit; | |
580 | if (size > SHMEM_NR_DIRECT) | |
581 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 582 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 583 | } |
92a3d03a BP |
584 | |
585 | /* | |
586 | * If there are no indirect blocks or we are punching a hole | |
587 | * below indirect blocks, nothing to be done. | |
588 | */ | |
a2646d1e | 589 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
590 | goto done2; |
591 | ||
1ae70006 HD |
592 | /* |
593 | * The truncation case has already dropped info->lock, and we're safe | |
594 | * because i_size and next_index have already been lowered, preventing | |
595 | * access beyond. But in the punch_hole case, we still need to take | |
596 | * the lock when updating the swap directory, because there might be | |
597 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
598 | * shmem_writepage. However, whenever we find we can remove a whole | |
599 | * directory page (not at the misaligned start or end of the range), | |
600 | * we first NULLify its pointer in the level above, and then have no | |
601 | * need to take the lock when updating its contents: needs_lock and | |
602 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
603 | */ | |
604 | ||
a2646d1e | 605 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
606 | limit -= SHMEM_NR_DIRECT; |
607 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
608 | offset = idx % ENTRIES_PER_PAGE; | |
609 | idx -= offset; | |
610 | ||
611 | dir = shmem_dir_map(topdir); | |
612 | stage = ENTRIES_PER_PAGEPAGE/2; | |
613 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
614 | middir = topdir; | |
615 | diroff = idx/ENTRIES_PER_PAGE; | |
616 | } else { | |
617 | dir += ENTRIES_PER_PAGE/2; | |
618 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
619 | while (stage <= idx) | |
620 | stage += ENTRIES_PER_PAGEPAGE; | |
621 | middir = *dir; | |
622 | if (*dir) { | |
623 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
624 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 625 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
626 | if (needs_lock) { |
627 | spin_lock(needs_lock); | |
628 | *dir = NULL; | |
629 | spin_unlock(needs_lock); | |
630 | needs_lock = NULL; | |
631 | } else | |
632 | *dir = NULL; | |
1da177e4 LT |
633 | nr_pages_to_free++; |
634 | list_add(&middir->lru, &pages_to_free); | |
635 | } | |
636 | shmem_dir_unmap(dir); | |
637 | dir = shmem_dir_map(middir); | |
638 | } else { | |
639 | diroff = 0; | |
640 | offset = 0; | |
641 | idx = stage; | |
642 | } | |
643 | } | |
644 | ||
645 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
646 | if (unlikely(idx == stage)) { | |
647 | shmem_dir_unmap(dir); | |
648 | dir = shmem_dir_map(topdir) + | |
649 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
650 | while (!*dir) { | |
651 | dir++; | |
652 | idx += ENTRIES_PER_PAGEPAGE; | |
653 | if (idx >= limit) | |
654 | goto done1; | |
655 | } | |
656 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
657 | middir = *dir; | |
1ae70006 HD |
658 | if (punch_hole) |
659 | needs_lock = &info->lock; | |
a2646d1e | 660 | if (upper_limit >= stage) { |
1ae70006 HD |
661 | if (needs_lock) { |
662 | spin_lock(needs_lock); | |
663 | *dir = NULL; | |
664 | spin_unlock(needs_lock); | |
665 | needs_lock = NULL; | |
666 | } else | |
667 | *dir = NULL; | |
a2646d1e HD |
668 | nr_pages_to_free++; |
669 | list_add(&middir->lru, &pages_to_free); | |
670 | } | |
1da177e4 LT |
671 | shmem_dir_unmap(dir); |
672 | cond_resched(); | |
673 | dir = shmem_dir_map(middir); | |
674 | diroff = 0; | |
675 | } | |
1ae70006 | 676 | punch_lock = needs_lock; |
1da177e4 | 677 | subdir = dir[diroff]; |
1ae70006 HD |
678 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
679 | if (needs_lock) { | |
680 | spin_lock(needs_lock); | |
681 | dir[diroff] = NULL; | |
682 | spin_unlock(needs_lock); | |
683 | punch_lock = NULL; | |
684 | } else | |
685 | dir[diroff] = NULL; | |
686 | nr_pages_to_free++; | |
687 | list_add(&subdir->lru, &pages_to_free); | |
688 | } | |
689 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
690 | size = limit - idx; |
691 | if (size > ENTRIES_PER_PAGE) | |
692 | size = ENTRIES_PER_PAGE; | |
693 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 694 | offset, size, &dir, punch_lock); |
1da177e4 LT |
695 | if (!dir) |
696 | dir = shmem_dir_map(middir); | |
697 | nr_swaps_freed += freed; | |
1ae70006 | 698 | if (offset || punch_lock) { |
1da177e4 | 699 | spin_lock(&info->lock); |
1ae70006 HD |
700 | set_page_private(subdir, |
701 | page_private(subdir) - freed); | |
1da177e4 | 702 | spin_unlock(&info->lock); |
1ae70006 HD |
703 | } else |
704 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 705 | } |
1ae70006 | 706 | offset = 0; |
1da177e4 LT |
707 | } |
708 | done1: | |
709 | shmem_dir_unmap(dir); | |
710 | done2: | |
711 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
712 | /* | |
713 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
714 | * may have swizzled a page in from swap since vmtruncate or | |
715 | * generic_delete_inode did it, before we lowered next_index. | |
716 | * Also, though shmem_getpage checks i_size before adding to | |
717 | * cache, no recheck after: so fix the narrow window there too. | |
16a10019 HD |
718 | * |
719 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
720 | * every time for punch_hole (which never got a chance to clear | |
721 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
722 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 723 | */ |
f6b3ec23 | 724 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
725 | if (punch_hole) |
726 | unmap_mapping_range(inode->i_mapping, start, | |
727 | end - start, 1); | |
1da177e4 LT |
728 | } |
729 | ||
730 | spin_lock(&info->lock); | |
731 | info->flags &= ~SHMEM_TRUNCATE; | |
732 | info->swapped -= nr_swaps_freed; | |
733 | if (nr_pages_to_free) | |
734 | shmem_free_blocks(inode, nr_pages_to_free); | |
735 | shmem_recalc_inode(inode); | |
736 | spin_unlock(&info->lock); | |
737 | ||
738 | /* | |
739 | * Empty swap vector directory pages to be freed? | |
740 | */ | |
741 | if (!list_empty(&pages_to_free)) { | |
742 | pages_to_free.prev->next = NULL; | |
743 | shmem_free_pages(pages_to_free.next); | |
744 | } | |
745 | } | |
746 | ||
f6b3ec23 BP |
747 | static void shmem_truncate(struct inode *inode) |
748 | { | |
749 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
750 | } | |
751 | ||
1da177e4 LT |
752 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
753 | { | |
754 | struct inode *inode = dentry->d_inode; | |
755 | struct page *page = NULL; | |
756 | int error; | |
757 | ||
39f0247d | 758 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
759 | if (attr->ia_size < inode->i_size) { |
760 | /* | |
761 | * If truncating down to a partial page, then | |
762 | * if that page is already allocated, hold it | |
763 | * in memory until the truncation is over, so | |
764 | * truncate_partial_page cannnot miss it were | |
765 | * it assigned to swap. | |
766 | */ | |
767 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
768 | (void) shmem_getpage(inode, | |
769 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
770 | &page, SGP_READ, NULL); | |
d3602444 HD |
771 | if (page) |
772 | unlock_page(page); | |
1da177e4 LT |
773 | } |
774 | /* | |
775 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
776 | * detect if any pages might have been added to cache | |
777 | * after truncate_inode_pages. But we needn't bother | |
778 | * if it's being fully truncated to zero-length: the | |
779 | * nrpages check is efficient enough in that case. | |
780 | */ | |
781 | if (attr->ia_size) { | |
782 | struct shmem_inode_info *info = SHMEM_I(inode); | |
783 | spin_lock(&info->lock); | |
784 | info->flags &= ~SHMEM_PAGEIN; | |
785 | spin_unlock(&info->lock); | |
786 | } | |
787 | } | |
788 | } | |
789 | ||
790 | error = inode_change_ok(inode, attr); | |
791 | if (!error) | |
792 | error = inode_setattr(inode, attr); | |
39f0247d AG |
793 | #ifdef CONFIG_TMPFS_POSIX_ACL |
794 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
795 | error = generic_acl_chmod(inode, &shmem_acl_ops); | |
796 | #endif | |
1da177e4 LT |
797 | if (page) |
798 | page_cache_release(page); | |
799 | return error; | |
800 | } | |
801 | ||
802 | static void shmem_delete_inode(struct inode *inode) | |
803 | { | |
1da177e4 LT |
804 | struct shmem_inode_info *info = SHMEM_I(inode); |
805 | ||
806 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 807 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
808 | shmem_unacct_size(info->flags, inode->i_size); |
809 | inode->i_size = 0; | |
810 | shmem_truncate(inode); | |
811 | if (!list_empty(&info->swaplist)) { | |
cb5f7b9a | 812 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 813 | list_del_init(&info->swaplist); |
cb5f7b9a | 814 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
815 | } |
816 | } | |
0edd73b3 | 817 | BUG_ON(inode->i_blocks); |
5b04c689 | 818 | shmem_free_inode(inode->i_sb); |
1da177e4 LT |
819 | clear_inode(inode); |
820 | } | |
821 | ||
822 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
823 | { | |
824 | swp_entry_t *ptr; | |
825 | ||
826 | for (ptr = dir; ptr < edir; ptr++) { | |
827 | if (ptr->val == entry.val) | |
828 | return ptr - dir; | |
829 | } | |
830 | return -1; | |
831 | } | |
832 | ||
833 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
834 | { | |
835 | struct inode *inode; | |
836 | unsigned long idx; | |
837 | unsigned long size; | |
838 | unsigned long limit; | |
839 | unsigned long stage; | |
840 | struct page **dir; | |
841 | struct page *subdir; | |
842 | swp_entry_t *ptr; | |
843 | int offset; | |
d9fe526a | 844 | int error; |
1da177e4 LT |
845 | |
846 | idx = 0; | |
847 | ptr = info->i_direct; | |
848 | spin_lock(&info->lock); | |
1b1b32f2 HD |
849 | if (!info->swapped) { |
850 | list_del_init(&info->swaplist); | |
851 | goto lost2; | |
852 | } | |
1da177e4 LT |
853 | limit = info->next_index; |
854 | size = limit; | |
855 | if (size > SHMEM_NR_DIRECT) | |
856 | size = SHMEM_NR_DIRECT; | |
857 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 858 | if (offset >= 0) |
1da177e4 | 859 | goto found; |
1da177e4 LT |
860 | if (!info->i_indirect) |
861 | goto lost2; | |
862 | ||
863 | dir = shmem_dir_map(info->i_indirect); | |
864 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
865 | ||
866 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
867 | if (unlikely(idx == stage)) { | |
868 | shmem_dir_unmap(dir-1); | |
cb5f7b9a HD |
869 | if (cond_resched_lock(&info->lock)) { |
870 | /* check it has not been truncated */ | |
871 | if (limit > info->next_index) { | |
872 | limit = info->next_index; | |
873 | if (idx >= limit) | |
874 | goto lost2; | |
875 | } | |
876 | } | |
1da177e4 LT |
877 | dir = shmem_dir_map(info->i_indirect) + |
878 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
879 | while (!*dir) { | |
880 | dir++; | |
881 | idx += ENTRIES_PER_PAGEPAGE; | |
882 | if (idx >= limit) | |
883 | goto lost1; | |
884 | } | |
885 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
886 | subdir = *dir; | |
887 | shmem_dir_unmap(dir); | |
888 | dir = shmem_dir_map(subdir); | |
889 | } | |
890 | subdir = *dir; | |
4c21e2f2 | 891 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
892 | ptr = shmem_swp_map(subdir); |
893 | size = limit - idx; | |
894 | if (size > ENTRIES_PER_PAGE) | |
895 | size = ENTRIES_PER_PAGE; | |
896 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 897 | shmem_swp_unmap(ptr); |
1da177e4 LT |
898 | if (offset >= 0) { |
899 | shmem_dir_unmap(dir); | |
900 | goto found; | |
901 | } | |
1da177e4 LT |
902 | } |
903 | } | |
904 | lost1: | |
905 | shmem_dir_unmap(dir-1); | |
906 | lost2: | |
907 | spin_unlock(&info->lock); | |
908 | return 0; | |
909 | found: | |
910 | idx += offset; | |
2e0e26c7 HD |
911 | inode = igrab(&info->vfs_inode); |
912 | spin_unlock(&info->lock); | |
913 | ||
1b1b32f2 HD |
914 | /* |
915 | * Move _head_ to start search for next from here. | |
916 | * But be careful: shmem_delete_inode checks list_empty without taking | |
917 | * mutex, and there's an instant in list_move_tail when info->swaplist | |
918 | * would appear empty, if it were the only one on shmem_swaplist. We | |
919 | * could avoid doing it if inode NULL; or use this minor optimization. | |
920 | */ | |
921 | if (shmem_swaplist.next != &info->swaplist) | |
922 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 HD |
923 | mutex_unlock(&shmem_swaplist_mutex); |
924 | ||
925 | error = 1; | |
926 | if (!inode) | |
927 | goto out; | |
82369553 HD |
928 | /* Precharge page while we can wait, compensate afterwards */ |
929 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
b409f9fc HD |
930 | if (error) |
931 | goto out; | |
82369553 HD |
932 | error = radix_tree_preload(GFP_KERNEL); |
933 | if (error) | |
934 | goto uncharge; | |
b409f9fc | 935 | error = 1; |
2e0e26c7 HD |
936 | |
937 | spin_lock(&info->lock); | |
938 | ptr = shmem_swp_entry(info, idx, NULL); | |
939 | if (ptr && ptr->val == entry.val) | |
940 | error = add_to_page_cache(page, inode->i_mapping, | |
b409f9fc | 941 | idx, GFP_NOWAIT); |
d9fe526a HD |
942 | if (error == -EEXIST) { |
943 | struct page *filepage = find_get_page(inode->i_mapping, idx); | |
2e0e26c7 | 944 | error = 1; |
d9fe526a HD |
945 | if (filepage) { |
946 | /* | |
947 | * There might be a more uptodate page coming down | |
948 | * from a stacked writepage: forget our swappage if so. | |
949 | */ | |
950 | if (PageUptodate(filepage)) | |
951 | error = 0; | |
952 | page_cache_release(filepage); | |
953 | } | |
954 | } | |
955 | if (!error) { | |
73b1262f HD |
956 | delete_from_swap_cache(page); |
957 | set_page_dirty(page); | |
1da177e4 | 958 | info->flags |= SHMEM_PAGEIN; |
2e0e26c7 HD |
959 | shmem_swp_set(info, ptr, 0); |
960 | swap_free(entry); | |
961 | error = 1; /* not an error, but entry was found */ | |
1da177e4 | 962 | } |
2e0e26c7 HD |
963 | if (ptr) |
964 | shmem_swp_unmap(ptr); | |
1da177e4 | 965 | spin_unlock(&info->lock); |
b409f9fc | 966 | radix_tree_preload_end(); |
82369553 HD |
967 | uncharge: |
968 | mem_cgroup_uncharge_page(page); | |
2e0e26c7 HD |
969 | out: |
970 | unlock_page(page); | |
971 | page_cache_release(page); | |
972 | iput(inode); /* allows for NULL */ | |
973 | return error; | |
1da177e4 LT |
974 | } |
975 | ||
976 | /* | |
977 | * shmem_unuse() search for an eventually swapped out shmem page. | |
978 | */ | |
979 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
980 | { | |
981 | struct list_head *p, *next; | |
982 | struct shmem_inode_info *info; | |
983 | int found = 0; | |
984 | ||
cb5f7b9a | 985 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 LT |
986 | list_for_each_safe(p, next, &shmem_swaplist) { |
987 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
1b1b32f2 | 988 | found = shmem_unuse_inode(info, entry, page); |
cb5f7b9a | 989 | cond_resched(); |
2e0e26c7 HD |
990 | if (found) |
991 | goto out; | |
1da177e4 | 992 | } |
cb5f7b9a | 993 | mutex_unlock(&shmem_swaplist_mutex); |
2e0e26c7 | 994 | out: return found; /* 0 or 1 or -ENOMEM */ |
1da177e4 LT |
995 | } |
996 | ||
997 | /* | |
998 | * Move the page from the page cache to the swap cache. | |
999 | */ | |
1000 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
1001 | { | |
1002 | struct shmem_inode_info *info; | |
1003 | swp_entry_t *entry, swap; | |
1004 | struct address_space *mapping; | |
1005 | unsigned long index; | |
1006 | struct inode *inode; | |
1007 | ||
1008 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
1009 | mapping = page->mapping; |
1010 | index = page->index; | |
1011 | inode = mapping->host; | |
1012 | info = SHMEM_I(inode); | |
1013 | if (info->flags & VM_LOCKED) | |
1014 | goto redirty; | |
d9fe526a | 1015 | if (!total_swap_pages) |
1da177e4 LT |
1016 | goto redirty; |
1017 | ||
d9fe526a HD |
1018 | /* |
1019 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
1020 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
1021 | * may use the ->writepage of its underlying filesystem, in which case | |
1022 | * tmpfs should write out to swap only in response to memory pressure, | |
1023 | * and not for pdflush or sync. However, in those cases, we do still | |
1024 | * want to check if there's a redundant swappage to be discarded. | |
1025 | */ | |
1026 | if (wbc->for_reclaim) | |
1027 | swap = get_swap_page(); | |
1028 | else | |
1029 | swap.val = 0; | |
1030 | ||
1da177e4 | 1031 | spin_lock(&info->lock); |
1da177e4 LT |
1032 | if (index >= info->next_index) { |
1033 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
1034 | goto unlock; | |
1035 | } | |
1036 | entry = shmem_swp_entry(info, index, NULL); | |
d9fe526a HD |
1037 | if (entry->val) { |
1038 | /* | |
1039 | * The more uptodate page coming down from a stacked | |
1040 | * writepage should replace our old swappage. | |
1041 | */ | |
1042 | free_swap_and_cache(*entry); | |
1043 | shmem_swp_set(info, entry, 0); | |
1044 | } | |
1045 | shmem_recalc_inode(inode); | |
1da177e4 | 1046 | |
d9fe526a | 1047 | if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
73b1262f | 1048 | remove_from_page_cache(page); |
1da177e4 LT |
1049 | shmem_swp_set(info, entry, swap.val); |
1050 | shmem_swp_unmap(entry); | |
1b1b32f2 HD |
1051 | if (list_empty(&info->swaplist)) |
1052 | inode = igrab(inode); | |
1053 | else | |
1054 | inode = NULL; | |
1da177e4 | 1055 | spin_unlock(&info->lock); |
73b1262f | 1056 | swap_duplicate(swap); |
d9fe526a | 1057 | BUG_ON(page_mapped(page)); |
73b1262f HD |
1058 | page_cache_release(page); /* pagecache ref */ |
1059 | set_page_dirty(page); | |
1da177e4 | 1060 | unlock_page(page); |
1b1b32f2 HD |
1061 | if (inode) { |
1062 | mutex_lock(&shmem_swaplist_mutex); | |
1063 | /* move instead of add in case we're racing */ | |
1064 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
1065 | mutex_unlock(&shmem_swaplist_mutex); | |
1066 | iput(inode); | |
1067 | } | |
1da177e4 LT |
1068 | return 0; |
1069 | } | |
1070 | ||
1071 | shmem_swp_unmap(entry); | |
1072 | unlock: | |
1073 | spin_unlock(&info->lock); | |
1074 | swap_free(swap); | |
1075 | redirty: | |
1076 | set_page_dirty(page); | |
d9fe526a HD |
1077 | if (wbc->for_reclaim) |
1078 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1079 | unlock_page(page); | |
1080 | return 0; | |
1da177e4 LT |
1081 | } |
1082 | ||
1083 | #ifdef CONFIG_NUMA | |
680d794b | 1084 | #ifdef CONFIG_TMPFS |
1085 | static int shmem_parse_mpol(char *value, int *policy, nodemask_t *policy_nodes) | |
b00dc3ad HD |
1086 | { |
1087 | char *nodelist = strchr(value, ':'); | |
1088 | int err = 1; | |
1089 | ||
1090 | if (nodelist) { | |
1091 | /* NUL-terminate policy string */ | |
1092 | *nodelist++ = '\0'; | |
1093 | if (nodelist_parse(nodelist, *policy_nodes)) | |
1094 | goto out; | |
37b07e41 | 1095 | if (!nodes_subset(*policy_nodes, node_states[N_HIGH_MEMORY])) |
a210906c | 1096 | goto out; |
b00dc3ad HD |
1097 | } |
1098 | if (!strcmp(value, "default")) { | |
1099 | *policy = MPOL_DEFAULT; | |
1100 | /* Don't allow a nodelist */ | |
1101 | if (!nodelist) | |
1102 | err = 0; | |
1103 | } else if (!strcmp(value, "prefer")) { | |
1104 | *policy = MPOL_PREFERRED; | |
1105 | /* Insist on a nodelist of one node only */ | |
1106 | if (nodelist) { | |
1107 | char *rest = nodelist; | |
1108 | while (isdigit(*rest)) | |
1109 | rest++; | |
1110 | if (!*rest) | |
1111 | err = 0; | |
1112 | } | |
1113 | } else if (!strcmp(value, "bind")) { | |
1114 | *policy = MPOL_BIND; | |
1115 | /* Insist on a nodelist */ | |
1116 | if (nodelist) | |
1117 | err = 0; | |
1118 | } else if (!strcmp(value, "interleave")) { | |
1119 | *policy = MPOL_INTERLEAVE; | |
37b07e41 LS |
1120 | /* |
1121 | * Default to online nodes with memory if no nodelist | |
1122 | */ | |
b00dc3ad | 1123 | if (!nodelist) |
37b07e41 | 1124 | *policy_nodes = node_states[N_HIGH_MEMORY]; |
b00dc3ad HD |
1125 | err = 0; |
1126 | } | |
1127 | out: | |
1128 | /* Restore string for error message */ | |
1129 | if (nodelist) | |
1130 | *--nodelist = ':'; | |
1131 | return err; | |
1132 | } | |
1133 | ||
680d794b | 1134 | static void shmem_show_mpol(struct seq_file *seq, int policy, |
1135 | const nodemask_t policy_nodes) | |
1136 | { | |
1137 | char *policy_string; | |
1138 | ||
1139 | switch (policy) { | |
1140 | case MPOL_PREFERRED: | |
1141 | policy_string = "prefer"; | |
1142 | break; | |
1143 | case MPOL_BIND: | |
1144 | policy_string = "bind"; | |
1145 | break; | |
1146 | case MPOL_INTERLEAVE: | |
1147 | policy_string = "interleave"; | |
1148 | break; | |
1149 | default: | |
1150 | /* MPOL_DEFAULT */ | |
1151 | return; | |
1152 | } | |
1153 | ||
1154 | seq_printf(seq, ",mpol=%s", policy_string); | |
1155 | ||
1156 | if (policy != MPOL_INTERLEAVE || | |
1157 | !nodes_equal(policy_nodes, node_states[N_HIGH_MEMORY])) { | |
1158 | char buffer[64]; | |
1159 | int len; | |
1160 | ||
1161 | len = nodelist_scnprintf(buffer, sizeof(buffer), policy_nodes); | |
1162 | if (len < sizeof(buffer)) | |
1163 | seq_printf(seq, ":%s", buffer); | |
1164 | else | |
1165 | seq_printf(seq, ":?"); | |
1166 | } | |
1167 | } | |
1168 | #endif /* CONFIG_TMPFS */ | |
1169 | ||
02098fea HD |
1170 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1171 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1172 | { |
1da177e4 | 1173 | struct vm_area_struct pvma; |
c4cc6d07 | 1174 | struct page *page; |
1da177e4 LT |
1175 | |
1176 | /* Create a pseudo vma that just contains the policy */ | |
c4cc6d07 | 1177 | pvma.vm_start = 0; |
1da177e4 | 1178 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1179 | pvma.vm_ops = NULL; |
1180 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
02098fea | 1181 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1182 | mpol_free(pvma.vm_policy); |
1183 | return page; | |
1184 | } | |
1185 | ||
02098fea HD |
1186 | static struct page *shmem_alloc_page(gfp_t gfp, |
1187 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1188 | { |
1189 | struct vm_area_struct pvma; | |
1190 | struct page *page; | |
1191 | ||
c4cc6d07 HD |
1192 | /* Create a pseudo vma that just contains the policy */ |
1193 | pvma.vm_start = 0; | |
1da177e4 | 1194 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1195 | pvma.vm_ops = NULL; |
1196 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
e84e2e13 | 1197 | page = alloc_page_vma(gfp, &pvma, 0); |
1da177e4 LT |
1198 | mpol_free(pvma.vm_policy); |
1199 | return page; | |
1200 | } | |
680d794b | 1201 | #else /* !CONFIG_NUMA */ |
1202 | #ifdef CONFIG_TMPFS | |
37b07e41 LS |
1203 | static inline int shmem_parse_mpol(char *value, int *policy, |
1204 | nodemask_t *policy_nodes) | |
b00dc3ad HD |
1205 | { |
1206 | return 1; | |
1207 | } | |
1208 | ||
680d794b | 1209 | static inline void shmem_show_mpol(struct seq_file *seq, int policy, |
1210 | const nodemask_t policy_nodes) | |
1211 | { | |
1212 | } | |
1213 | #endif /* CONFIG_TMPFS */ | |
1214 | ||
02098fea HD |
1215 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1216 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1217 | { |
02098fea | 1218 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1219 | } |
1220 | ||
02098fea HD |
1221 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1222 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1223 | { |
e84e2e13 | 1224 | return alloc_page(gfp); |
1da177e4 | 1225 | } |
680d794b | 1226 | #endif /* CONFIG_NUMA */ |
1da177e4 LT |
1227 | |
1228 | /* | |
1229 | * shmem_getpage - either get the page from swap or allocate a new one | |
1230 | * | |
1231 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1232 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1233 | * entry since a page cannot live in both the swap and page cache | |
1234 | */ | |
1235 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1236 | struct page **pagep, enum sgp_type sgp, int *type) | |
1237 | { | |
1238 | struct address_space *mapping = inode->i_mapping; | |
1239 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1240 | struct shmem_sb_info *sbinfo; | |
1241 | struct page *filepage = *pagep; | |
1242 | struct page *swappage; | |
1243 | swp_entry_t *entry; | |
1244 | swp_entry_t swap; | |
02098fea | 1245 | gfp_t gfp; |
1da177e4 LT |
1246 | int error; |
1247 | ||
1248 | if (idx >= SHMEM_MAX_INDEX) | |
1249 | return -EFBIG; | |
54cb8821 NP |
1250 | |
1251 | if (type) | |
83c54070 | 1252 | *type = 0; |
54cb8821 | 1253 | |
1da177e4 LT |
1254 | /* |
1255 | * Normally, filepage is NULL on entry, and either found | |
1256 | * uptodate immediately, or allocated and zeroed, or read | |
1257 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1258 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1259 | * filepage, which may be found not uptodate by other callers |
1260 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1261 | */ |
1262 | repeat: | |
1263 | if (!filepage) | |
1264 | filepage = find_lock_page(mapping, idx); | |
1265 | if (filepage && PageUptodate(filepage)) | |
1266 | goto done; | |
1267 | error = 0; | |
02098fea | 1268 | gfp = mapping_gfp_mask(mapping); |
b409f9fc HD |
1269 | if (!filepage) { |
1270 | /* | |
1271 | * Try to preload while we can wait, to not make a habit of | |
1272 | * draining atomic reserves; but don't latch on to this cpu. | |
1273 | */ | |
1274 | error = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
1275 | if (error) | |
1276 | goto failed; | |
1277 | radix_tree_preload_end(); | |
1278 | } | |
1da177e4 LT |
1279 | |
1280 | spin_lock(&info->lock); | |
1281 | shmem_recalc_inode(inode); | |
1282 | entry = shmem_swp_alloc(info, idx, sgp); | |
1283 | if (IS_ERR(entry)) { | |
1284 | spin_unlock(&info->lock); | |
1285 | error = PTR_ERR(entry); | |
1286 | goto failed; | |
1287 | } | |
1288 | swap = *entry; | |
1289 | ||
1290 | if (swap.val) { | |
1291 | /* Look it up and read it in.. */ | |
1292 | swappage = lookup_swap_cache(swap); | |
1293 | if (!swappage) { | |
1294 | shmem_swp_unmap(entry); | |
1da177e4 | 1295 | /* here we actually do the io */ |
83c54070 | 1296 | if (type && !(*type & VM_FAULT_MAJOR)) { |
f8891e5e | 1297 | __count_vm_event(PGMAJFAULT); |
83c54070 | 1298 | *type |= VM_FAULT_MAJOR; |
1da177e4 | 1299 | } |
f8891e5e | 1300 | spin_unlock(&info->lock); |
02098fea | 1301 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1302 | if (!swappage) { |
1303 | spin_lock(&info->lock); | |
1304 | entry = shmem_swp_alloc(info, idx, sgp); | |
1305 | if (IS_ERR(entry)) | |
1306 | error = PTR_ERR(entry); | |
1307 | else { | |
1308 | if (entry->val == swap.val) | |
1309 | error = -ENOMEM; | |
1310 | shmem_swp_unmap(entry); | |
1311 | } | |
1312 | spin_unlock(&info->lock); | |
1313 | if (error) | |
1314 | goto failed; | |
1315 | goto repeat; | |
1316 | } | |
1317 | wait_on_page_locked(swappage); | |
1318 | page_cache_release(swappage); | |
1319 | goto repeat; | |
1320 | } | |
1321 | ||
1322 | /* We have to do this with page locked to prevent races */ | |
1323 | if (TestSetPageLocked(swappage)) { | |
1324 | shmem_swp_unmap(entry); | |
1325 | spin_unlock(&info->lock); | |
1326 | wait_on_page_locked(swappage); | |
1327 | page_cache_release(swappage); | |
1328 | goto repeat; | |
1329 | } | |
1330 | if (PageWriteback(swappage)) { | |
1331 | shmem_swp_unmap(entry); | |
1332 | spin_unlock(&info->lock); | |
1333 | wait_on_page_writeback(swappage); | |
1334 | unlock_page(swappage); | |
1335 | page_cache_release(swappage); | |
1336 | goto repeat; | |
1337 | } | |
1338 | if (!PageUptodate(swappage)) { | |
1339 | shmem_swp_unmap(entry); | |
1340 | spin_unlock(&info->lock); | |
1341 | unlock_page(swappage); | |
1342 | page_cache_release(swappage); | |
1343 | error = -EIO; | |
1344 | goto failed; | |
1345 | } | |
1346 | ||
1347 | if (filepage) { | |
1348 | shmem_swp_set(info, entry, 0); | |
1349 | shmem_swp_unmap(entry); | |
1350 | delete_from_swap_cache(swappage); | |
1351 | spin_unlock(&info->lock); | |
1352 | copy_highpage(filepage, swappage); | |
1353 | unlock_page(swappage); | |
1354 | page_cache_release(swappage); | |
1355 | flush_dcache_page(filepage); | |
1356 | SetPageUptodate(filepage); | |
1357 | set_page_dirty(filepage); | |
1358 | swap_free(swap); | |
73b1262f | 1359 | } else if (!(error = add_to_page_cache( |
b409f9fc | 1360 | swappage, mapping, idx, GFP_NOWAIT))) { |
1da177e4 LT |
1361 | info->flags |= SHMEM_PAGEIN; |
1362 | shmem_swp_set(info, entry, 0); | |
1363 | shmem_swp_unmap(entry); | |
73b1262f | 1364 | delete_from_swap_cache(swappage); |
1da177e4 LT |
1365 | spin_unlock(&info->lock); |
1366 | filepage = swappage; | |
73b1262f | 1367 | set_page_dirty(filepage); |
1da177e4 LT |
1368 | swap_free(swap); |
1369 | } else { | |
1370 | shmem_swp_unmap(entry); | |
1371 | spin_unlock(&info->lock); | |
1372 | unlock_page(swappage); | |
1373 | page_cache_release(swappage); | |
82369553 HD |
1374 | if (error == -ENOMEM) { |
1375 | /* allow reclaim from this memory cgroup */ | |
1376 | error = mem_cgroup_cache_charge(NULL, | |
1377 | current->mm, gfp & ~__GFP_HIGHMEM); | |
1378 | if (error) | |
1379 | goto failed; | |
1380 | } | |
1da177e4 LT |
1381 | goto repeat; |
1382 | } | |
1383 | } else if (sgp == SGP_READ && !filepage) { | |
1384 | shmem_swp_unmap(entry); | |
1385 | filepage = find_get_page(mapping, idx); | |
1386 | if (filepage && | |
1387 | (!PageUptodate(filepage) || TestSetPageLocked(filepage))) { | |
1388 | spin_unlock(&info->lock); | |
1389 | wait_on_page_locked(filepage); | |
1390 | page_cache_release(filepage); | |
1391 | filepage = NULL; | |
1392 | goto repeat; | |
1393 | } | |
1394 | spin_unlock(&info->lock); | |
1395 | } else { | |
1396 | shmem_swp_unmap(entry); | |
1397 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1398 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1399 | spin_lock(&sbinfo->stat_lock); |
1400 | if (sbinfo->free_blocks == 0 || | |
1401 | shmem_acct_block(info->flags)) { | |
1402 | spin_unlock(&sbinfo->stat_lock); | |
1403 | spin_unlock(&info->lock); | |
1404 | error = -ENOSPC; | |
1405 | goto failed; | |
1406 | } | |
1407 | sbinfo->free_blocks--; | |
1408 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1409 | spin_unlock(&sbinfo->stat_lock); | |
1410 | } else if (shmem_acct_block(info->flags)) { | |
1411 | spin_unlock(&info->lock); | |
1412 | error = -ENOSPC; | |
1413 | goto failed; | |
1414 | } | |
1415 | ||
1416 | if (!filepage) { | |
1417 | spin_unlock(&info->lock); | |
02098fea | 1418 | filepage = shmem_alloc_page(gfp, info, idx); |
1da177e4 LT |
1419 | if (!filepage) { |
1420 | shmem_unacct_blocks(info->flags, 1); | |
1421 | shmem_free_blocks(inode, 1); | |
1422 | error = -ENOMEM; | |
1423 | goto failed; | |
1424 | } | |
1425 | ||
82369553 HD |
1426 | /* Precharge page while we can wait, compensate after */ |
1427 | error = mem_cgroup_cache_charge(filepage, current->mm, | |
1428 | gfp & ~__GFP_HIGHMEM); | |
1429 | if (error) { | |
1430 | page_cache_release(filepage); | |
1431 | shmem_unacct_blocks(info->flags, 1); | |
1432 | shmem_free_blocks(inode, 1); | |
1433 | filepage = NULL; | |
1434 | goto failed; | |
1435 | } | |
1436 | ||
1da177e4 LT |
1437 | spin_lock(&info->lock); |
1438 | entry = shmem_swp_alloc(info, idx, sgp); | |
1439 | if (IS_ERR(entry)) | |
1440 | error = PTR_ERR(entry); | |
1441 | else { | |
1442 | swap = *entry; | |
1443 | shmem_swp_unmap(entry); | |
1444 | } | |
1445 | if (error || swap.val || 0 != add_to_page_cache_lru( | |
b409f9fc | 1446 | filepage, mapping, idx, GFP_NOWAIT)) { |
1da177e4 | 1447 | spin_unlock(&info->lock); |
82369553 | 1448 | mem_cgroup_uncharge_page(filepage); |
1da177e4 LT |
1449 | page_cache_release(filepage); |
1450 | shmem_unacct_blocks(info->flags, 1); | |
1451 | shmem_free_blocks(inode, 1); | |
1452 | filepage = NULL; | |
1453 | if (error) | |
1454 | goto failed; | |
1455 | goto repeat; | |
1456 | } | |
82369553 | 1457 | mem_cgroup_uncharge_page(filepage); |
1da177e4 LT |
1458 | info->flags |= SHMEM_PAGEIN; |
1459 | } | |
1460 | ||
1461 | info->alloced++; | |
1462 | spin_unlock(&info->lock); | |
e84e2e13 | 1463 | clear_highpage(filepage); |
1da177e4 LT |
1464 | flush_dcache_page(filepage); |
1465 | SetPageUptodate(filepage); | |
a0ee5ec5 HD |
1466 | if (sgp == SGP_DIRTY) |
1467 | set_page_dirty(filepage); | |
1da177e4 LT |
1468 | } |
1469 | done: | |
d3602444 | 1470 | *pagep = filepage; |
1da177e4 LT |
1471 | return 0; |
1472 | ||
1473 | failed: | |
1474 | if (*pagep != filepage) { | |
1475 | unlock_page(filepage); | |
1476 | page_cache_release(filepage); | |
1477 | } | |
1478 | return error; | |
1479 | } | |
1480 | ||
d0217ac0 | 1481 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1482 | { |
d3ac7f89 | 1483 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1484 | int error; |
d0217ac0 | 1485 | int ret; |
1da177e4 | 1486 | |
d0217ac0 NP |
1487 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1488 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1489 | |
27d54b39 | 1490 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1491 | if (error) |
1492 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1da177e4 | 1493 | |
d0217ac0 | 1494 | mark_page_accessed(vmf->page); |
83c54070 | 1495 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1496 | } |
1497 | ||
1da177e4 | 1498 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1499 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1500 | { |
d3ac7f89 | 1501 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1502 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1503 | } | |
1504 | ||
d8dc74f2 AB |
1505 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1506 | unsigned long addr) | |
1da177e4 | 1507 | { |
d3ac7f89 | 1508 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1509 | unsigned long idx; |
1510 | ||
1511 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1512 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1513 | } | |
1514 | #endif | |
1515 | ||
1516 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1517 | { | |
d3ac7f89 | 1518 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1519 | struct shmem_inode_info *info = SHMEM_I(inode); |
1520 | int retval = -ENOMEM; | |
1521 | ||
1522 | spin_lock(&info->lock); | |
1523 | if (lock && !(info->flags & VM_LOCKED)) { | |
1524 | if (!user_shm_lock(inode->i_size, user)) | |
1525 | goto out_nomem; | |
1526 | info->flags |= VM_LOCKED; | |
1527 | } | |
1528 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1529 | user_shm_unlock(inode->i_size, user); | |
1530 | info->flags &= ~VM_LOCKED; | |
1531 | } | |
1532 | retval = 0; | |
1533 | out_nomem: | |
1534 | spin_unlock(&info->lock); | |
1535 | return retval; | |
1536 | } | |
1537 | ||
9b83a6a8 | 1538 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1539 | { |
1540 | file_accessed(file); | |
1541 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1542 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1543 | return 0; |
1544 | } | |
1545 | ||
1546 | static struct inode * | |
1547 | shmem_get_inode(struct super_block *sb, int mode, dev_t dev) | |
1548 | { | |
1549 | struct inode *inode; | |
1550 | struct shmem_inode_info *info; | |
1551 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1552 | ||
5b04c689 PE |
1553 | if (shmem_reserve_inode(sb)) |
1554 | return NULL; | |
1da177e4 LT |
1555 | |
1556 | inode = new_inode(sb); | |
1557 | if (inode) { | |
1558 | inode->i_mode = mode; | |
1559 | inode->i_uid = current->fsuid; | |
1560 | inode->i_gid = current->fsgid; | |
1da177e4 LT |
1561 | inode->i_blocks = 0; |
1562 | inode->i_mapping->a_ops = &shmem_aops; | |
1563 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; | |
1564 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1565 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1566 | info = SHMEM_I(inode); |
1567 | memset(info, 0, (char *)inode - (char *)info); | |
1568 | spin_lock_init(&info->lock); | |
1569 | INIT_LIST_HEAD(&info->swaplist); | |
1570 | ||
1571 | switch (mode & S_IFMT) { | |
1572 | default: | |
39f0247d | 1573 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1574 | init_special_inode(inode, mode, dev); |
1575 | break; | |
1576 | case S_IFREG: | |
1577 | inode->i_op = &shmem_inode_operations; | |
1578 | inode->i_fop = &shmem_file_operations; | |
7339ff83 RH |
1579 | mpol_shared_policy_init(&info->policy, sbinfo->policy, |
1580 | &sbinfo->policy_nodes); | |
1da177e4 LT |
1581 | break; |
1582 | case S_IFDIR: | |
d8c76e6f | 1583 | inc_nlink(inode); |
1da177e4 LT |
1584 | /* Some things misbehave if size == 0 on a directory */ |
1585 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1586 | inode->i_op = &shmem_dir_inode_operations; | |
1587 | inode->i_fop = &simple_dir_operations; | |
1588 | break; | |
1589 | case S_IFLNK: | |
1590 | /* | |
1591 | * Must not load anything in the rbtree, | |
1592 | * mpol_free_shared_policy will not be called. | |
1593 | */ | |
7339ff83 RH |
1594 | mpol_shared_policy_init(&info->policy, MPOL_DEFAULT, |
1595 | NULL); | |
1da177e4 LT |
1596 | break; |
1597 | } | |
5b04c689 PE |
1598 | } else |
1599 | shmem_free_inode(sb); | |
1da177e4 LT |
1600 | return inode; |
1601 | } | |
1602 | ||
1603 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1604 | static const struct inode_operations shmem_symlink_inode_operations; |
1605 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1606 | |
1607 | /* | |
800d15a5 | 1608 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1609 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1610 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1611 | */ |
ae976416 HD |
1612 | static int shmem_readpage(struct file *file, struct page *page) |
1613 | { | |
1614 | struct inode *inode = page->mapping->host; | |
1615 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1616 | unlock_page(page); | |
1617 | return error; | |
1618 | } | |
1619 | ||
1da177e4 | 1620 | static int |
800d15a5 NP |
1621 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1622 | loff_t pos, unsigned len, unsigned flags, | |
1623 | struct page **pagep, void **fsdata) | |
1da177e4 | 1624 | { |
800d15a5 NP |
1625 | struct inode *inode = mapping->host; |
1626 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1627 | *pagep = NULL; | |
1628 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1629 | } | |
1630 | ||
1631 | static int | |
1632 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1633 | loff_t pos, unsigned len, unsigned copied, | |
1634 | struct page *page, void *fsdata) | |
1635 | { | |
1636 | struct inode *inode = mapping->host; | |
1637 | ||
d3602444 HD |
1638 | if (pos + copied > inode->i_size) |
1639 | i_size_write(inode, pos + copied); | |
1640 | ||
1641 | unlock_page(page); | |
800d15a5 NP |
1642 | set_page_dirty(page); |
1643 | page_cache_release(page); | |
1644 | ||
800d15a5 | 1645 | return copied; |
1da177e4 LT |
1646 | } |
1647 | ||
1da177e4 LT |
1648 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1649 | { | |
d3ac7f89 | 1650 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1651 | struct address_space *mapping = inode->i_mapping; |
1652 | unsigned long index, offset; | |
a0ee5ec5 HD |
1653 | enum sgp_type sgp = SGP_READ; |
1654 | ||
1655 | /* | |
1656 | * Might this read be for a stacking filesystem? Then when reading | |
1657 | * holes of a sparse file, we actually need to allocate those pages, | |
1658 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1659 | */ | |
1660 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1661 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1662 | |
1663 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1664 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1665 | ||
1666 | for (;;) { | |
1667 | struct page *page = NULL; | |
1668 | unsigned long end_index, nr, ret; | |
1669 | loff_t i_size = i_size_read(inode); | |
1670 | ||
1671 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1672 | if (index > end_index) | |
1673 | break; | |
1674 | if (index == end_index) { | |
1675 | nr = i_size & ~PAGE_CACHE_MASK; | |
1676 | if (nr <= offset) | |
1677 | break; | |
1678 | } | |
1679 | ||
a0ee5ec5 | 1680 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1681 | if (desc->error) { |
1682 | if (desc->error == -EINVAL) | |
1683 | desc->error = 0; | |
1684 | break; | |
1685 | } | |
d3602444 HD |
1686 | if (page) |
1687 | unlock_page(page); | |
1da177e4 LT |
1688 | |
1689 | /* | |
1690 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1691 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1692 | */ |
1693 | nr = PAGE_CACHE_SIZE; | |
1694 | i_size = i_size_read(inode); | |
1695 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1696 | if (index == end_index) { | |
1697 | nr = i_size & ~PAGE_CACHE_MASK; | |
1698 | if (nr <= offset) { | |
1699 | if (page) | |
1700 | page_cache_release(page); | |
1701 | break; | |
1702 | } | |
1703 | } | |
1704 | nr -= offset; | |
1705 | ||
1706 | if (page) { | |
1707 | /* | |
1708 | * If users can be writing to this page using arbitrary | |
1709 | * virtual addresses, take care about potential aliasing | |
1710 | * before reading the page on the kernel side. | |
1711 | */ | |
1712 | if (mapping_writably_mapped(mapping)) | |
1713 | flush_dcache_page(page); | |
1714 | /* | |
1715 | * Mark the page accessed if we read the beginning. | |
1716 | */ | |
1717 | if (!offset) | |
1718 | mark_page_accessed(page); | |
b5810039 | 1719 | } else { |
1da177e4 | 1720 | page = ZERO_PAGE(0); |
b5810039 NP |
1721 | page_cache_get(page); |
1722 | } | |
1da177e4 LT |
1723 | |
1724 | /* | |
1725 | * Ok, we have the page, and it's up-to-date, so | |
1726 | * now we can copy it to user space... | |
1727 | * | |
1728 | * The actor routine returns how many bytes were actually used.. | |
1729 | * NOTE! This may not be the same as how much of a user buffer | |
1730 | * we filled up (we may be padding etc), so we can only update | |
1731 | * "pos" here (the actor routine has to update the user buffer | |
1732 | * pointers and the remaining count). | |
1733 | */ | |
1734 | ret = actor(desc, page, offset, nr); | |
1735 | offset += ret; | |
1736 | index += offset >> PAGE_CACHE_SHIFT; | |
1737 | offset &= ~PAGE_CACHE_MASK; | |
1738 | ||
1739 | page_cache_release(page); | |
1740 | if (ret != nr || !desc->count) | |
1741 | break; | |
1742 | ||
1743 | cond_resched(); | |
1744 | } | |
1745 | ||
1746 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1747 | file_accessed(filp); | |
1748 | } | |
1749 | ||
1750 | static ssize_t shmem_file_read(struct file *filp, char __user *buf, size_t count, loff_t *ppos) | |
1751 | { | |
1752 | read_descriptor_t desc; | |
1753 | ||
1754 | if ((ssize_t) count < 0) | |
1755 | return -EINVAL; | |
1756 | if (!access_ok(VERIFY_WRITE, buf, count)) | |
1757 | return -EFAULT; | |
1758 | if (!count) | |
1759 | return 0; | |
1760 | ||
1761 | desc.written = 0; | |
1762 | desc.count = count; | |
1763 | desc.arg.buf = buf; | |
1764 | desc.error = 0; | |
1765 | ||
1766 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1767 | if (desc.written) | |
1768 | return desc.written; | |
1769 | return desc.error; | |
1770 | } | |
1771 | ||
726c3342 | 1772 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1773 | { |
726c3342 | 1774 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1775 | |
1776 | buf->f_type = TMPFS_MAGIC; | |
1777 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1778 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1779 | spin_lock(&sbinfo->stat_lock); |
1780 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1781 | buf->f_blocks = sbinfo->max_blocks; |
1782 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1783 | } |
1784 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1785 | buf->f_files = sbinfo->max_inodes; |
1786 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1787 | } |
1788 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1789 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1790 | return 0; |
1791 | } | |
1792 | ||
1793 | /* | |
1794 | * File creation. Allocate an inode, and we're done.. | |
1795 | */ | |
1796 | static int | |
1797 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1798 | { | |
1799 | struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev); | |
1800 | int error = -ENOSPC; | |
1801 | ||
1802 | if (inode) { | |
570bc1c2 SS |
1803 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1804 | NULL); | |
1805 | if (error) { | |
1806 | if (error != -EOPNOTSUPP) { | |
1807 | iput(inode); | |
1808 | return error; | |
1809 | } | |
39f0247d AG |
1810 | } |
1811 | error = shmem_acl_init(inode, dir); | |
1812 | if (error) { | |
1813 | iput(inode); | |
1814 | return error; | |
570bc1c2 | 1815 | } |
1da177e4 LT |
1816 | if (dir->i_mode & S_ISGID) { |
1817 | inode->i_gid = dir->i_gid; | |
1818 | if (S_ISDIR(mode)) | |
1819 | inode->i_mode |= S_ISGID; | |
1820 | } | |
1821 | dir->i_size += BOGO_DIRENT_SIZE; | |
1822 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1823 | d_instantiate(dentry, inode); | |
1824 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1825 | } |
1826 | return error; | |
1827 | } | |
1828 | ||
1829 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1830 | { | |
1831 | int error; | |
1832 | ||
1833 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1834 | return error; | |
d8c76e6f | 1835 | inc_nlink(dir); |
1da177e4 LT |
1836 | return 0; |
1837 | } | |
1838 | ||
1839 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1840 | struct nameidata *nd) | |
1841 | { | |
1842 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1843 | } | |
1844 | ||
1845 | /* | |
1846 | * Link a file.. | |
1847 | */ | |
1848 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1849 | { | |
1850 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1851 | int ret; |
1da177e4 LT |
1852 | |
1853 | /* | |
1854 | * No ordinary (disk based) filesystem counts links as inodes; | |
1855 | * but each new link needs a new dentry, pinning lowmem, and | |
1856 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1857 | */ | |
5b04c689 PE |
1858 | ret = shmem_reserve_inode(inode->i_sb); |
1859 | if (ret) | |
1860 | goto out; | |
1da177e4 LT |
1861 | |
1862 | dir->i_size += BOGO_DIRENT_SIZE; | |
1863 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1864 | inc_nlink(inode); |
1da177e4 LT |
1865 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1866 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1867 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1868 | out: |
1869 | return ret; | |
1da177e4 LT |
1870 | } |
1871 | ||
1872 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1873 | { | |
1874 | struct inode *inode = dentry->d_inode; | |
1875 | ||
5b04c689 PE |
1876 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1877 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1878 | |
1879 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1880 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1881 | drop_nlink(inode); |
1da177e4 LT |
1882 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1883 | return 0; | |
1884 | } | |
1885 | ||
1886 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1887 | { | |
1888 | if (!simple_empty(dentry)) | |
1889 | return -ENOTEMPTY; | |
1890 | ||
9a53c3a7 DH |
1891 | drop_nlink(dentry->d_inode); |
1892 | drop_nlink(dir); | |
1da177e4 LT |
1893 | return shmem_unlink(dir, dentry); |
1894 | } | |
1895 | ||
1896 | /* | |
1897 | * The VFS layer already does all the dentry stuff for rename, | |
1898 | * we just have to decrement the usage count for the target if | |
1899 | * it exists so that the VFS layer correctly free's it when it | |
1900 | * gets overwritten. | |
1901 | */ | |
1902 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1903 | { | |
1904 | struct inode *inode = old_dentry->d_inode; | |
1905 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1906 | ||
1907 | if (!simple_empty(new_dentry)) | |
1908 | return -ENOTEMPTY; | |
1909 | ||
1910 | if (new_dentry->d_inode) { | |
1911 | (void) shmem_unlink(new_dir, new_dentry); | |
1912 | if (they_are_dirs) | |
9a53c3a7 | 1913 | drop_nlink(old_dir); |
1da177e4 | 1914 | } else if (they_are_dirs) { |
9a53c3a7 | 1915 | drop_nlink(old_dir); |
d8c76e6f | 1916 | inc_nlink(new_dir); |
1da177e4 LT |
1917 | } |
1918 | ||
1919 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1920 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1921 | old_dir->i_ctime = old_dir->i_mtime = | |
1922 | new_dir->i_ctime = new_dir->i_mtime = | |
1923 | inode->i_ctime = CURRENT_TIME; | |
1924 | return 0; | |
1925 | } | |
1926 | ||
1927 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1928 | { | |
1929 | int error; | |
1930 | int len; | |
1931 | struct inode *inode; | |
1932 | struct page *page = NULL; | |
1933 | char *kaddr; | |
1934 | struct shmem_inode_info *info; | |
1935 | ||
1936 | len = strlen(symname) + 1; | |
1937 | if (len > PAGE_CACHE_SIZE) | |
1938 | return -ENAMETOOLONG; | |
1939 | ||
1940 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0); | |
1941 | if (!inode) | |
1942 | return -ENOSPC; | |
1943 | ||
570bc1c2 SS |
1944 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1945 | NULL); | |
1946 | if (error) { | |
1947 | if (error != -EOPNOTSUPP) { | |
1948 | iput(inode); | |
1949 | return error; | |
1950 | } | |
1951 | error = 0; | |
1952 | } | |
1953 | ||
1da177e4 LT |
1954 | info = SHMEM_I(inode); |
1955 | inode->i_size = len-1; | |
1956 | if (len <= (char *)inode - (char *)info) { | |
1957 | /* do it inline */ | |
1958 | memcpy(info, symname, len); | |
1959 | inode->i_op = &shmem_symlink_inline_operations; | |
1960 | } else { | |
1961 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1962 | if (error) { | |
1963 | iput(inode); | |
1964 | return error; | |
1965 | } | |
d3602444 | 1966 | unlock_page(page); |
1da177e4 LT |
1967 | inode->i_op = &shmem_symlink_inode_operations; |
1968 | kaddr = kmap_atomic(page, KM_USER0); | |
1969 | memcpy(kaddr, symname, len); | |
1970 | kunmap_atomic(kaddr, KM_USER0); | |
1971 | set_page_dirty(page); | |
1972 | page_cache_release(page); | |
1973 | } | |
1974 | if (dir->i_mode & S_ISGID) | |
1975 | inode->i_gid = dir->i_gid; | |
1976 | dir->i_size += BOGO_DIRENT_SIZE; | |
1977 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1978 | d_instantiate(dentry, inode); | |
1979 | dget(dentry); | |
1980 | return 0; | |
1981 | } | |
1982 | ||
cc314eef | 1983 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1984 | { |
1985 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1986 | return NULL; |
1da177e4 LT |
1987 | } |
1988 | ||
cc314eef | 1989 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1990 | { |
1991 | struct page *page = NULL; | |
1992 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1993 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
1994 | if (page) |
1995 | unlock_page(page); | |
cc314eef | 1996 | return page; |
1da177e4 LT |
1997 | } |
1998 | ||
cc314eef | 1999 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
2000 | { |
2001 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 2002 | struct page *page = cookie; |
1da177e4 LT |
2003 | kunmap(page); |
2004 | mark_page_accessed(page); | |
2005 | page_cache_release(page); | |
1da177e4 LT |
2006 | } |
2007 | } | |
2008 | ||
92e1d5be | 2009 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
2010 | .readlink = generic_readlink, |
2011 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
2012 | }; |
2013 | ||
92e1d5be | 2014 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
2015 | .truncate = shmem_truncate, |
2016 | .readlink = generic_readlink, | |
2017 | .follow_link = shmem_follow_link, | |
2018 | .put_link = shmem_put_link, | |
1da177e4 LT |
2019 | }; |
2020 | ||
39f0247d AG |
2021 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2022 | /** | |
2023 | * Superblocks without xattr inode operations will get security.* xattr | |
2024 | * support from the VFS "for free". As soon as we have any other xattrs | |
2025 | * like ACLs, we also need to implement the security.* handlers at | |
2026 | * filesystem level, though. | |
2027 | */ | |
2028 | ||
2029 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
2030 | size_t list_len, const char *name, | |
2031 | size_t name_len) | |
2032 | { | |
2033 | return security_inode_listsecurity(inode, list, list_len); | |
2034 | } | |
2035 | ||
2036 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
2037 | void *buffer, size_t size) | |
2038 | { | |
2039 | if (strcmp(name, "") == 0) | |
2040 | return -EINVAL; | |
42492594 | 2041 | return xattr_getsecurity(inode, name, buffer, size); |
39f0247d AG |
2042 | } |
2043 | ||
2044 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
2045 | const void *value, size_t size, int flags) | |
2046 | { | |
2047 | if (strcmp(name, "") == 0) | |
2048 | return -EINVAL; | |
2049 | return security_inode_setsecurity(inode, name, value, size, flags); | |
2050 | } | |
2051 | ||
1f370a23 | 2052 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
2053 | .prefix = XATTR_SECURITY_PREFIX, |
2054 | .list = shmem_xattr_security_list, | |
2055 | .get = shmem_xattr_security_get, | |
2056 | .set = shmem_xattr_security_set, | |
2057 | }; | |
2058 | ||
2059 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
2060 | &shmem_xattr_acl_access_handler, | |
2061 | &shmem_xattr_acl_default_handler, | |
2062 | &shmem_xattr_security_handler, | |
2063 | NULL | |
2064 | }; | |
2065 | #endif | |
2066 | ||
91828a40 DG |
2067 | static struct dentry *shmem_get_parent(struct dentry *child) |
2068 | { | |
2069 | return ERR_PTR(-ESTALE); | |
2070 | } | |
2071 | ||
2072 | static int shmem_match(struct inode *ino, void *vfh) | |
2073 | { | |
2074 | __u32 *fh = vfh; | |
2075 | __u64 inum = fh[2]; | |
2076 | inum = (inum << 32) | fh[1]; | |
2077 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2078 | } | |
2079 | ||
480b116c CH |
2080 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2081 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2082 | { |
91828a40 | 2083 | struct inode *inode; |
480b116c CH |
2084 | struct dentry *dentry = NULL; |
2085 | u64 inum = fid->raw[2]; | |
2086 | inum = (inum << 32) | fid->raw[1]; | |
2087 | ||
2088 | if (fh_len < 3) | |
2089 | return NULL; | |
91828a40 | 2090 | |
480b116c CH |
2091 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2092 | shmem_match, fid->raw); | |
91828a40 | 2093 | if (inode) { |
480b116c | 2094 | dentry = d_find_alias(inode); |
91828a40 DG |
2095 | iput(inode); |
2096 | } | |
2097 | ||
480b116c | 2098 | return dentry; |
91828a40 DG |
2099 | } |
2100 | ||
2101 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2102 | int connectable) | |
2103 | { | |
2104 | struct inode *inode = dentry->d_inode; | |
2105 | ||
2106 | if (*len < 3) | |
2107 | return 255; | |
2108 | ||
2109 | if (hlist_unhashed(&inode->i_hash)) { | |
2110 | /* Unfortunately insert_inode_hash is not idempotent, | |
2111 | * so as we hash inodes here rather than at creation | |
2112 | * time, we need a lock to ensure we only try | |
2113 | * to do it once | |
2114 | */ | |
2115 | static DEFINE_SPINLOCK(lock); | |
2116 | spin_lock(&lock); | |
2117 | if (hlist_unhashed(&inode->i_hash)) | |
2118 | __insert_inode_hash(inode, | |
2119 | inode->i_ino + inode->i_generation); | |
2120 | spin_unlock(&lock); | |
2121 | } | |
2122 | ||
2123 | fh[0] = inode->i_generation; | |
2124 | fh[1] = inode->i_ino; | |
2125 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2126 | ||
2127 | *len = 3; | |
2128 | return 1; | |
2129 | } | |
2130 | ||
39655164 | 2131 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2132 | .get_parent = shmem_get_parent, |
91828a40 | 2133 | .encode_fh = shmem_encode_fh, |
480b116c | 2134 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2135 | }; |
2136 | ||
680d794b | 2137 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2138 | bool remount) | |
1da177e4 LT |
2139 | { |
2140 | char *this_char, *value, *rest; | |
2141 | ||
b00dc3ad HD |
2142 | while (options != NULL) { |
2143 | this_char = options; | |
2144 | for (;;) { | |
2145 | /* | |
2146 | * NUL-terminate this option: unfortunately, | |
2147 | * mount options form a comma-separated list, | |
2148 | * but mpol's nodelist may also contain commas. | |
2149 | */ | |
2150 | options = strchr(options, ','); | |
2151 | if (options == NULL) | |
2152 | break; | |
2153 | options++; | |
2154 | if (!isdigit(*options)) { | |
2155 | options[-1] = '\0'; | |
2156 | break; | |
2157 | } | |
2158 | } | |
1da177e4 LT |
2159 | if (!*this_char) |
2160 | continue; | |
2161 | if ((value = strchr(this_char,'=')) != NULL) { | |
2162 | *value++ = 0; | |
2163 | } else { | |
2164 | printk(KERN_ERR | |
2165 | "tmpfs: No value for mount option '%s'\n", | |
2166 | this_char); | |
2167 | return 1; | |
2168 | } | |
2169 | ||
2170 | if (!strcmp(this_char,"size")) { | |
2171 | unsigned long long size; | |
2172 | size = memparse(value,&rest); | |
2173 | if (*rest == '%') { | |
2174 | size <<= PAGE_SHIFT; | |
2175 | size *= totalram_pages; | |
2176 | do_div(size, 100); | |
2177 | rest++; | |
2178 | } | |
2179 | if (*rest) | |
2180 | goto bad_val; | |
680d794b | 2181 | sbinfo->max_blocks = |
2182 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2183 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2184 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2185 | if (*rest) |
2186 | goto bad_val; | |
2187 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2188 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2189 | if (*rest) |
2190 | goto bad_val; | |
2191 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2192 | if (remount) |
1da177e4 | 2193 | continue; |
680d794b | 2194 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2195 | if (*rest) |
2196 | goto bad_val; | |
2197 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2198 | if (remount) |
1da177e4 | 2199 | continue; |
680d794b | 2200 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2201 | if (*rest) |
2202 | goto bad_val; | |
2203 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2204 | if (remount) |
1da177e4 | 2205 | continue; |
680d794b | 2206 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2207 | if (*rest) |
2208 | goto bad_val; | |
7339ff83 | 2209 | } else if (!strcmp(this_char,"mpol")) { |
680d794b | 2210 | if (shmem_parse_mpol(value, &sbinfo->policy, |
2211 | &sbinfo->policy_nodes)) | |
7339ff83 | 2212 | goto bad_val; |
1da177e4 LT |
2213 | } else { |
2214 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2215 | this_char); | |
2216 | return 1; | |
2217 | } | |
2218 | } | |
2219 | return 0; | |
2220 | ||
2221 | bad_val: | |
2222 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2223 | value, this_char); | |
2224 | return 1; | |
2225 | ||
2226 | } | |
2227 | ||
2228 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2229 | { | |
2230 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2231 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2232 | unsigned long blocks; |
2233 | unsigned long inodes; | |
2234 | int error = -EINVAL; | |
2235 | ||
680d794b | 2236 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2237 | return error; |
1da177e4 | 2238 | |
0edd73b3 HD |
2239 | spin_lock(&sbinfo->stat_lock); |
2240 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2241 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
680d794b | 2242 | if (config.max_blocks < blocks) |
0edd73b3 | 2243 | goto out; |
680d794b | 2244 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2245 | goto out; |
2246 | /* | |
2247 | * Those tests also disallow limited->unlimited while any are in | |
2248 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2249 | * but we must separately disallow unlimited->limited, because | |
2250 | * in that case we have no record of how much is already in use. | |
2251 | */ | |
680d794b | 2252 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2253 | goto out; |
680d794b | 2254 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2255 | goto out; |
2256 | ||
2257 | error = 0; | |
680d794b | 2258 | sbinfo->max_blocks = config.max_blocks; |
2259 | sbinfo->free_blocks = config.max_blocks - blocks; | |
2260 | sbinfo->max_inodes = config.max_inodes; | |
2261 | sbinfo->free_inodes = config.max_inodes - inodes; | |
2262 | sbinfo->policy = config.policy; | |
2263 | sbinfo->policy_nodes = config.policy_nodes; | |
0edd73b3 HD |
2264 | out: |
2265 | spin_unlock(&sbinfo->stat_lock); | |
2266 | return error; | |
1da177e4 | 2267 | } |
680d794b | 2268 | |
2269 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
2270 | { | |
2271 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
2272 | ||
2273 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2274 | seq_printf(seq, ",size=%luk", | |
2275 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2276 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2277 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2278 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
2279 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
2280 | if (sbinfo->uid != 0) | |
2281 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2282 | if (sbinfo->gid != 0) | |
2283 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
2284 | shmem_show_mpol(seq, sbinfo->policy, sbinfo->policy_nodes); | |
2285 | return 0; | |
2286 | } | |
2287 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2288 | |
2289 | static void shmem_put_super(struct super_block *sb) | |
2290 | { | |
2291 | kfree(sb->s_fs_info); | |
2292 | sb->s_fs_info = NULL; | |
2293 | } | |
2294 | ||
1da177e4 LT |
2295 | static int shmem_fill_super(struct super_block *sb, |
2296 | void *data, int silent) | |
2297 | { | |
2298 | struct inode *inode; | |
2299 | struct dentry *root; | |
0edd73b3 | 2300 | struct shmem_sb_info *sbinfo; |
680d794b | 2301 | int err = -ENOMEM; |
2302 | ||
2303 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
2304 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2305 | L1_CACHE_BYTES), GFP_KERNEL); | |
2306 | if (!sbinfo) | |
2307 | return -ENOMEM; | |
2308 | ||
2309 | sbinfo->max_blocks = 0; | |
2310 | sbinfo->max_inodes = 0; | |
2311 | sbinfo->mode = S_IRWXUGO | S_ISVTX; | |
2312 | sbinfo->uid = current->fsuid; | |
2313 | sbinfo->gid = current->fsgid; | |
2314 | sbinfo->policy = MPOL_DEFAULT; | |
2315 | sbinfo->policy_nodes = node_states[N_HIGH_MEMORY]; | |
2316 | sb->s_fs_info = sbinfo; | |
1da177e4 | 2317 | |
0edd73b3 | 2318 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2319 | /* |
2320 | * Per default we only allow half of the physical ram per | |
2321 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2322 | * but the internal instance is left unlimited. | |
2323 | */ | |
2324 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b | 2325 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2326 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2327 | if (shmem_parse_options(data, sbinfo, false)) { | |
2328 | err = -EINVAL; | |
2329 | goto failed; | |
2330 | } | |
1da177e4 | 2331 | } |
91828a40 | 2332 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2333 | #else |
2334 | sb->s_flags |= MS_NOUSER; | |
2335 | #endif | |
2336 | ||
0edd73b3 | 2337 | spin_lock_init(&sbinfo->stat_lock); |
680d794b | 2338 | sbinfo->free_blocks = sbinfo->max_blocks; |
2339 | sbinfo->free_inodes = sbinfo->max_inodes; | |
0edd73b3 | 2340 | |
1da177e4 LT |
2341 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2342 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2343 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2344 | sb->s_magic = TMPFS_MAGIC; | |
2345 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2346 | sb->s_time_gran = 1; |
39f0247d AG |
2347 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2348 | sb->s_xattr = shmem_xattr_handlers; | |
2349 | sb->s_flags |= MS_POSIXACL; | |
2350 | #endif | |
0edd73b3 | 2351 | |
680d794b | 2352 | inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0); |
1da177e4 LT |
2353 | if (!inode) |
2354 | goto failed; | |
680d794b | 2355 | inode->i_uid = sbinfo->uid; |
2356 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2357 | root = d_alloc_root(inode); |
2358 | if (!root) | |
2359 | goto failed_iput; | |
2360 | sb->s_root = root; | |
2361 | return 0; | |
2362 | ||
2363 | failed_iput: | |
2364 | iput(inode); | |
2365 | failed: | |
2366 | shmem_put_super(sb); | |
2367 | return err; | |
2368 | } | |
2369 | ||
fcc234f8 | 2370 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2371 | |
2372 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2373 | { | |
2374 | struct shmem_inode_info *p; | |
e94b1766 | 2375 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2376 | if (!p) |
2377 | return NULL; | |
2378 | return &p->vfs_inode; | |
2379 | } | |
2380 | ||
2381 | static void shmem_destroy_inode(struct inode *inode) | |
2382 | { | |
2383 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2384 | /* only struct inode is valid if it's an inline symlink */ | |
2385 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2386 | } | |
39f0247d | 2387 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2388 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2389 | } | |
2390 | ||
4ba9b9d0 | 2391 | static void init_once(struct kmem_cache *cachep, void *foo) |
1da177e4 LT |
2392 | { |
2393 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2394 | ||
a35afb83 | 2395 | inode_init_once(&p->vfs_inode); |
39f0247d | 2396 | #ifdef CONFIG_TMPFS_POSIX_ACL |
a35afb83 CL |
2397 | p->i_acl = NULL; |
2398 | p->i_default_acl = NULL; | |
39f0247d | 2399 | #endif |
1da177e4 LT |
2400 | } |
2401 | ||
2402 | static int init_inodecache(void) | |
2403 | { | |
2404 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2405 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2406 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2407 | return 0; |
2408 | } | |
2409 | ||
2410 | static void destroy_inodecache(void) | |
2411 | { | |
1a1d92c1 | 2412 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2413 | } |
2414 | ||
f5e54d6e | 2415 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2416 | .writepage = shmem_writepage, |
76719325 | 2417 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2418 | #ifdef CONFIG_TMPFS |
ae976416 | 2419 | .readpage = shmem_readpage, |
800d15a5 NP |
2420 | .write_begin = shmem_write_begin, |
2421 | .write_end = shmem_write_end, | |
1da177e4 | 2422 | #endif |
304dbdb7 | 2423 | .migratepage = migrate_page, |
1da177e4 LT |
2424 | }; |
2425 | ||
15ad7cdc | 2426 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2427 | .mmap = shmem_mmap, |
2428 | #ifdef CONFIG_TMPFS | |
2429 | .llseek = generic_file_llseek, | |
2430 | .read = shmem_file_read, | |
5402b976 HD |
2431 | .write = do_sync_write, |
2432 | .aio_write = generic_file_aio_write, | |
1da177e4 | 2433 | .fsync = simple_sync_file, |
ae976416 HD |
2434 | .splice_read = generic_file_splice_read, |
2435 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2436 | #endif |
2437 | }; | |
2438 | ||
92e1d5be | 2439 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2440 | .truncate = shmem_truncate, |
2441 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2442 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2443 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2444 | .setxattr = generic_setxattr, | |
2445 | .getxattr = generic_getxattr, | |
2446 | .listxattr = generic_listxattr, | |
2447 | .removexattr = generic_removexattr, | |
2448 | .permission = shmem_permission, | |
2449 | #endif | |
2450 | ||
1da177e4 LT |
2451 | }; |
2452 | ||
92e1d5be | 2453 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2454 | #ifdef CONFIG_TMPFS |
2455 | .create = shmem_create, | |
2456 | .lookup = simple_lookup, | |
2457 | .link = shmem_link, | |
2458 | .unlink = shmem_unlink, | |
2459 | .symlink = shmem_symlink, | |
2460 | .mkdir = shmem_mkdir, | |
2461 | .rmdir = shmem_rmdir, | |
2462 | .mknod = shmem_mknod, | |
2463 | .rename = shmem_rename, | |
1da177e4 | 2464 | #endif |
39f0247d AG |
2465 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2466 | .setattr = shmem_notify_change, | |
2467 | .setxattr = generic_setxattr, | |
2468 | .getxattr = generic_getxattr, | |
2469 | .listxattr = generic_listxattr, | |
2470 | .removexattr = generic_removexattr, | |
2471 | .permission = shmem_permission, | |
2472 | #endif | |
2473 | }; | |
2474 | ||
92e1d5be | 2475 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2476 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2477 | .setattr = shmem_notify_change, | |
2478 | .setxattr = generic_setxattr, | |
2479 | .getxattr = generic_getxattr, | |
2480 | .listxattr = generic_listxattr, | |
2481 | .removexattr = generic_removexattr, | |
2482 | .permission = shmem_permission, | |
2483 | #endif | |
1da177e4 LT |
2484 | }; |
2485 | ||
759b9775 | 2486 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2487 | .alloc_inode = shmem_alloc_inode, |
2488 | .destroy_inode = shmem_destroy_inode, | |
2489 | #ifdef CONFIG_TMPFS | |
2490 | .statfs = shmem_statfs, | |
2491 | .remount_fs = shmem_remount_fs, | |
680d794b | 2492 | .show_options = shmem_show_options, |
1da177e4 LT |
2493 | #endif |
2494 | .delete_inode = shmem_delete_inode, | |
2495 | .drop_inode = generic_delete_inode, | |
2496 | .put_super = shmem_put_super, | |
2497 | }; | |
2498 | ||
2499 | static struct vm_operations_struct shmem_vm_ops = { | |
54cb8821 | 2500 | .fault = shmem_fault, |
1da177e4 LT |
2501 | #ifdef CONFIG_NUMA |
2502 | .set_policy = shmem_set_policy, | |
2503 | .get_policy = shmem_get_policy, | |
2504 | #endif | |
2505 | }; | |
2506 | ||
2507 | ||
454e2398 DH |
2508 | static int shmem_get_sb(struct file_system_type *fs_type, |
2509 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2510 | { |
454e2398 | 2511 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2512 | } |
2513 | ||
2514 | static struct file_system_type tmpfs_fs_type = { | |
2515 | .owner = THIS_MODULE, | |
2516 | .name = "tmpfs", | |
2517 | .get_sb = shmem_get_sb, | |
2518 | .kill_sb = kill_litter_super, | |
2519 | }; | |
2520 | static struct vfsmount *shm_mnt; | |
2521 | ||
2522 | static int __init init_tmpfs(void) | |
2523 | { | |
2524 | int error; | |
2525 | ||
e0bf68dd PZ |
2526 | error = bdi_init(&shmem_backing_dev_info); |
2527 | if (error) | |
2528 | goto out4; | |
2529 | ||
1da177e4 LT |
2530 | error = init_inodecache(); |
2531 | if (error) | |
2532 | goto out3; | |
2533 | ||
2534 | error = register_filesystem(&tmpfs_fs_type); | |
2535 | if (error) { | |
2536 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2537 | goto out2; | |
2538 | } | |
95dc112a | 2539 | |
1f5ce9e9 | 2540 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2541 | tmpfs_fs_type.name, NULL); |
2542 | if (IS_ERR(shm_mnt)) { | |
2543 | error = PTR_ERR(shm_mnt); | |
2544 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2545 | goto out1; | |
2546 | } | |
2547 | return 0; | |
2548 | ||
2549 | out1: | |
2550 | unregister_filesystem(&tmpfs_fs_type); | |
2551 | out2: | |
2552 | destroy_inodecache(); | |
2553 | out3: | |
e0bf68dd PZ |
2554 | bdi_destroy(&shmem_backing_dev_info); |
2555 | out4: | |
1da177e4 LT |
2556 | shm_mnt = ERR_PTR(error); |
2557 | return error; | |
2558 | } | |
2559 | module_init(init_tmpfs) | |
2560 | ||
2561 | /* | |
2562 | * shmem_file_setup - get an unlinked file living in tmpfs | |
2563 | * | |
2564 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
2565 | * @size: size to be set for the file | |
2566 | * | |
2567 | */ | |
2568 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2569 | { | |
2570 | int error; | |
2571 | struct file *file; | |
2572 | struct inode *inode; | |
2573 | struct dentry *dentry, *root; | |
2574 | struct qstr this; | |
2575 | ||
2576 | if (IS_ERR(shm_mnt)) | |
2577 | return (void *)shm_mnt; | |
2578 | ||
2579 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2580 | return ERR_PTR(-EINVAL); | |
2581 | ||
2582 | if (shmem_acct_size(flags, size)) | |
2583 | return ERR_PTR(-ENOMEM); | |
2584 | ||
2585 | error = -ENOMEM; | |
2586 | this.name = name; | |
2587 | this.len = strlen(name); | |
2588 | this.hash = 0; /* will go */ | |
2589 | root = shm_mnt->mnt_root; | |
2590 | dentry = d_alloc(root, &this); | |
2591 | if (!dentry) | |
2592 | goto put_memory; | |
2593 | ||
2594 | error = -ENFILE; | |
2595 | file = get_empty_filp(); | |
2596 | if (!file) | |
2597 | goto put_dentry; | |
2598 | ||
2599 | error = -ENOSPC; | |
2600 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0); | |
2601 | if (!inode) | |
2602 | goto close_file; | |
2603 | ||
2604 | SHMEM_I(inode)->flags = flags & VM_ACCOUNT; | |
2605 | d_instantiate(dentry, inode); | |
2606 | inode->i_size = size; | |
2607 | inode->i_nlink = 0; /* It is unlinked */ | |
ce8d2cdf DH |
2608 | init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ, |
2609 | &shmem_file_operations); | |
1da177e4 LT |
2610 | return file; |
2611 | ||
2612 | close_file: | |
2613 | put_filp(file); | |
2614 | put_dentry: | |
2615 | dput(dentry); | |
2616 | put_memory: | |
2617 | shmem_unacct_size(flags, size); | |
2618 | return ERR_PTR(error); | |
2619 | } | |
2620 | ||
2621 | /* | |
2622 | * shmem_zero_setup - setup a shared anonymous mapping | |
2623 | * | |
2624 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
2625 | */ | |
2626 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2627 | { | |
2628 | struct file *file; | |
2629 | loff_t size = vma->vm_end - vma->vm_start; | |
2630 | ||
2631 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2632 | if (IS_ERR(file)) | |
2633 | return PTR_ERR(file); | |
2634 | ||
2635 | if (vma->vm_file) | |
2636 | fput(vma->vm_file); | |
2637 | vma->vm_file = file; | |
2638 | vma->vm_ops = &shmem_vm_ops; | |
2639 | return 0; | |
2640 | } |