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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
0edd73b3 HD |
9 | * Copyright (C) 2002-2005 Hugh Dickins. |
10 | * Copyright (C) 2002-2005 VERITAS Software Corporation. | |
1da177e4 LT |
11 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
12 | * | |
13 | * Extended attribute support for tmpfs: | |
14 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
15 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
16 | * | |
853ac43a MM |
17 | * tiny-shmem: |
18 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
19 | * | |
1da177e4 LT |
20 | * This file is released under the GPL. |
21 | */ | |
22 | ||
853ac43a MM |
23 | #include <linux/fs.h> |
24 | #include <linux/init.h> | |
25 | #include <linux/vfs.h> | |
26 | #include <linux/mount.h> | |
27 | #include <linux/file.h> | |
28 | #include <linux/mm.h> | |
29 | #include <linux/module.h> | |
30 | #include <linux/swap.h> | |
ed850a52 | 31 | #include <linux/ima.h> |
853ac43a MM |
32 | |
33 | static struct vfsmount *shm_mnt; | |
34 | ||
35 | #ifdef CONFIG_SHMEM | |
1da177e4 LT |
36 | /* |
37 | * This virtual memory filesystem is heavily based on the ramfs. It | |
38 | * extends ramfs by the ability to use swap and honor resource limits | |
39 | * which makes it a completely usable filesystem. | |
40 | */ | |
41 | ||
39f0247d | 42 | #include <linux/xattr.h> |
a5694255 | 43 | #include <linux/exportfs.h> |
39f0247d | 44 | #include <linux/generic_acl.h> |
1da177e4 | 45 | #include <linux/mman.h> |
1da177e4 LT |
46 | #include <linux/pagemap.h> |
47 | #include <linux/string.h> | |
48 | #include <linux/slab.h> | |
49 | #include <linux/backing-dev.h> | |
50 | #include <linux/shmem_fs.h> | |
1da177e4 LT |
51 | #include <linux/writeback.h> |
52 | #include <linux/vfs.h> | |
53 | #include <linux/blkdev.h> | |
54 | #include <linux/security.h> | |
55 | #include <linux/swapops.h> | |
56 | #include <linux/mempolicy.h> | |
57 | #include <linux/namei.h> | |
b00dc3ad | 58 | #include <linux/ctype.h> |
304dbdb7 | 59 | #include <linux/migrate.h> |
c1f60a5a | 60 | #include <linux/highmem.h> |
680d794b | 61 | #include <linux/seq_file.h> |
92562927 | 62 | #include <linux/magic.h> |
304dbdb7 | 63 | |
1da177e4 LT |
64 | #include <asm/uaccess.h> |
65 | #include <asm/div64.h> | |
66 | #include <asm/pgtable.h> | |
67 | ||
1da177e4 LT |
68 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) |
69 | #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) | |
70 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
71 | ||
72 | #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) | |
73 | #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT) | |
74 | ||
75 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) | |
76 | ||
77 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
78 | #define SHMEM_PAGEIN VM_READ | |
79 | #define SHMEM_TRUNCATE VM_WRITE | |
80 | ||
81 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
82 | #define LATENCY_LIMIT 64 | |
83 | ||
84 | /* Pretend that each entry is of this size in directory's i_size */ | |
85 | #define BOGO_DIRENT_SIZE 20 | |
86 | ||
1da177e4 LT |
87 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
88 | enum sgp_type { | |
1da177e4 LT |
89 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
90 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 91 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
92 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
93 | }; | |
94 | ||
b76db735 | 95 | #ifdef CONFIG_TMPFS |
680d794b AM |
96 | static unsigned long shmem_default_max_blocks(void) |
97 | { | |
98 | return totalram_pages / 2; | |
99 | } | |
100 | ||
101 | static unsigned long shmem_default_max_inodes(void) | |
102 | { | |
103 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
104 | } | |
b76db735 | 105 | #endif |
680d794b | 106 | |
1da177e4 LT |
107 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
108 | struct page **pagep, enum sgp_type sgp, int *type); | |
109 | ||
6daa0e28 | 110 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
111 | { |
112 | /* | |
113 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
114 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
115 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 | 116 | * |
e12ba74d | 117 | * Mobility flags are masked out as swap vectors cannot move |
1da177e4 | 118 | */ |
e12ba74d | 119 | return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO, |
769848c0 | 120 | PAGE_CACHE_SHIFT-PAGE_SHIFT); |
1da177e4 LT |
121 | } |
122 | ||
123 | static inline void shmem_dir_free(struct page *page) | |
124 | { | |
125 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
126 | } | |
127 | ||
128 | static struct page **shmem_dir_map(struct page *page) | |
129 | { | |
130 | return (struct page **)kmap_atomic(page, KM_USER0); | |
131 | } | |
132 | ||
133 | static inline void shmem_dir_unmap(struct page **dir) | |
134 | { | |
135 | kunmap_atomic(dir, KM_USER0); | |
136 | } | |
137 | ||
138 | static swp_entry_t *shmem_swp_map(struct page *page) | |
139 | { | |
140 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
141 | } | |
142 | ||
143 | static inline void shmem_swp_balance_unmap(void) | |
144 | { | |
145 | /* | |
146 | * When passing a pointer to an i_direct entry, to code which | |
147 | * also handles indirect entries and so will shmem_swp_unmap, | |
148 | * we must arrange for the preempt count to remain in balance. | |
149 | * What kmap_atomic of a lowmem page does depends on config | |
150 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
151 | */ | |
152 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
153 | } | |
154 | ||
155 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
156 | { | |
157 | kunmap_atomic(entry, KM_USER1); | |
158 | } | |
159 | ||
160 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
161 | { | |
162 | return sb->s_fs_info; | |
163 | } | |
164 | ||
165 | /* | |
166 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
167 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
168 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
169 | * consistent with the pre-accounting of private mappings ... | |
170 | */ | |
171 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
172 | { | |
0b0a0806 HD |
173 | return (flags & VM_NORESERVE) ? |
174 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
175 | } |
176 | ||
177 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
178 | { | |
0b0a0806 | 179 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
180 | vm_unacct_memory(VM_ACCT(size)); |
181 | } | |
182 | ||
183 | /* | |
184 | * ... whereas tmpfs objects are accounted incrementally as | |
185 | * pages are allocated, in order to allow huge sparse files. | |
186 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
187 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
188 | */ | |
189 | static inline int shmem_acct_block(unsigned long flags) | |
190 | { | |
0b0a0806 HD |
191 | return (flags & VM_NORESERVE) ? |
192 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
193 | } |
194 | ||
195 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
196 | { | |
0b0a0806 | 197 | if (flags & VM_NORESERVE) |
1da177e4 LT |
198 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
199 | } | |
200 | ||
759b9775 | 201 | static const struct super_operations shmem_ops; |
f5e54d6e | 202 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 203 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
204 | static const struct inode_operations shmem_inode_operations; |
205 | static const struct inode_operations shmem_dir_inode_operations; | |
206 | static const struct inode_operations shmem_special_inode_operations; | |
1da177e4 LT |
207 | static struct vm_operations_struct shmem_vm_ops; |
208 | ||
6c231b7b | 209 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 210 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 211 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
212 | .unplug_io_fn = default_unplug_io_fn, |
213 | }; | |
214 | ||
215 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 216 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 LT |
217 | |
218 | static void shmem_free_blocks(struct inode *inode, long pages) | |
219 | { | |
220 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 221 | if (sbinfo->max_blocks) { |
1da177e4 LT |
222 | spin_lock(&sbinfo->stat_lock); |
223 | sbinfo->free_blocks += pages; | |
224 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
225 | spin_unlock(&sbinfo->stat_lock); | |
226 | } | |
227 | } | |
228 | ||
5b04c689 PE |
229 | static int shmem_reserve_inode(struct super_block *sb) |
230 | { | |
231 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
232 | if (sbinfo->max_inodes) { | |
233 | spin_lock(&sbinfo->stat_lock); | |
234 | if (!sbinfo->free_inodes) { | |
235 | spin_unlock(&sbinfo->stat_lock); | |
236 | return -ENOSPC; | |
237 | } | |
238 | sbinfo->free_inodes--; | |
239 | spin_unlock(&sbinfo->stat_lock); | |
240 | } | |
241 | return 0; | |
242 | } | |
243 | ||
244 | static void shmem_free_inode(struct super_block *sb) | |
245 | { | |
246 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
247 | if (sbinfo->max_inodes) { | |
248 | spin_lock(&sbinfo->stat_lock); | |
249 | sbinfo->free_inodes++; | |
250 | spin_unlock(&sbinfo->stat_lock); | |
251 | } | |
252 | } | |
253 | ||
46711810 | 254 | /** |
1da177e4 | 255 | * shmem_recalc_inode - recalculate the size of an inode |
1da177e4 LT |
256 | * @inode: inode to recalc |
257 | * | |
258 | * We have to calculate the free blocks since the mm can drop | |
259 | * undirtied hole pages behind our back. | |
260 | * | |
261 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
262 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
263 | * | |
264 | * It has to be called with the spinlock held. | |
265 | */ | |
266 | static void shmem_recalc_inode(struct inode *inode) | |
267 | { | |
268 | struct shmem_inode_info *info = SHMEM_I(inode); | |
269 | long freed; | |
270 | ||
271 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
272 | if (freed > 0) { | |
273 | info->alloced -= freed; | |
274 | shmem_unacct_blocks(info->flags, freed); | |
275 | shmem_free_blocks(inode, freed); | |
276 | } | |
277 | } | |
278 | ||
46711810 | 279 | /** |
1da177e4 | 280 | * shmem_swp_entry - find the swap vector position in the info structure |
1da177e4 LT |
281 | * @info: info structure for the inode |
282 | * @index: index of the page to find | |
283 | * @page: optional page to add to the structure. Has to be preset to | |
284 | * all zeros | |
285 | * | |
286 | * If there is no space allocated yet it will return NULL when | |
287 | * page is NULL, else it will use the page for the needed block, | |
288 | * setting it to NULL on return to indicate that it has been used. | |
289 | * | |
290 | * The swap vector is organized the following way: | |
291 | * | |
292 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
293 | * shmem_inode_info structure. So small files do not need an addional | |
294 | * allocation. | |
295 | * | |
296 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
297 | * i_indirect which points to a page which holds in the first half | |
298 | * doubly indirect blocks, in the second half triple indirect blocks: | |
299 | * | |
300 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
301 | * following layout (for SHMEM_NR_DIRECT == 16): | |
302 | * | |
303 | * i_indirect -> dir --> 16-19 | |
304 | * | +-> 20-23 | |
305 | * | | |
306 | * +-->dir2 --> 24-27 | |
307 | * | +-> 28-31 | |
308 | * | +-> 32-35 | |
309 | * | +-> 36-39 | |
310 | * | | |
311 | * +-->dir3 --> 40-43 | |
312 | * +-> 44-47 | |
313 | * +-> 48-51 | |
314 | * +-> 52-55 | |
315 | */ | |
316 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
317 | { | |
318 | unsigned long offset; | |
319 | struct page **dir; | |
320 | struct page *subdir; | |
321 | ||
322 | if (index < SHMEM_NR_DIRECT) { | |
323 | shmem_swp_balance_unmap(); | |
324 | return info->i_direct+index; | |
325 | } | |
326 | if (!info->i_indirect) { | |
327 | if (page) { | |
328 | info->i_indirect = *page; | |
329 | *page = NULL; | |
330 | } | |
331 | return NULL; /* need another page */ | |
332 | } | |
333 | ||
334 | index -= SHMEM_NR_DIRECT; | |
335 | offset = index % ENTRIES_PER_PAGE; | |
336 | index /= ENTRIES_PER_PAGE; | |
337 | dir = shmem_dir_map(info->i_indirect); | |
338 | ||
339 | if (index >= ENTRIES_PER_PAGE/2) { | |
340 | index -= ENTRIES_PER_PAGE/2; | |
341 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
342 | index %= ENTRIES_PER_PAGE; | |
343 | subdir = *dir; | |
344 | if (!subdir) { | |
345 | if (page) { | |
346 | *dir = *page; | |
347 | *page = NULL; | |
348 | } | |
349 | shmem_dir_unmap(dir); | |
350 | return NULL; /* need another page */ | |
351 | } | |
352 | shmem_dir_unmap(dir); | |
353 | dir = shmem_dir_map(subdir); | |
354 | } | |
355 | ||
356 | dir += index; | |
357 | subdir = *dir; | |
358 | if (!subdir) { | |
359 | if (!page || !(subdir = *page)) { | |
360 | shmem_dir_unmap(dir); | |
361 | return NULL; /* need a page */ | |
362 | } | |
363 | *dir = subdir; | |
364 | *page = NULL; | |
365 | } | |
366 | shmem_dir_unmap(dir); | |
367 | return shmem_swp_map(subdir) + offset; | |
368 | } | |
369 | ||
370 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
371 | { | |
372 | long incdec = value? 1: -1; | |
373 | ||
374 | entry->val = value; | |
375 | info->swapped += incdec; | |
4c21e2f2 HD |
376 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
377 | struct page *page = kmap_atomic_to_page(entry); | |
378 | set_page_private(page, page_private(page) + incdec); | |
379 | } | |
1da177e4 LT |
380 | } |
381 | ||
46711810 | 382 | /** |
1da177e4 | 383 | * shmem_swp_alloc - get the position of the swap entry for the page. |
1da177e4 LT |
384 | * @info: info structure for the inode |
385 | * @index: index of the page to find | |
386 | * @sgp: check and recheck i_size? skip allocation? | |
46711810 RD |
387 | * |
388 | * If the entry does not exist, allocate it. | |
1da177e4 LT |
389 | */ |
390 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
391 | { | |
392 | struct inode *inode = &info->vfs_inode; | |
393 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
394 | struct page *page = NULL; | |
395 | swp_entry_t *entry; | |
396 | ||
397 | if (sgp != SGP_WRITE && | |
398 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
399 | return ERR_PTR(-EINVAL); | |
400 | ||
401 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
402 | if (sgp == SGP_READ) | |
403 | return shmem_swp_map(ZERO_PAGE(0)); | |
404 | /* | |
405 | * Test free_blocks against 1 not 0, since we have 1 data | |
406 | * page (and perhaps indirect index pages) yet to allocate: | |
407 | * a waste to allocate index if we cannot allocate data. | |
408 | */ | |
0edd73b3 | 409 | if (sbinfo->max_blocks) { |
1da177e4 LT |
410 | spin_lock(&sbinfo->stat_lock); |
411 | if (sbinfo->free_blocks <= 1) { | |
412 | spin_unlock(&sbinfo->stat_lock); | |
413 | return ERR_PTR(-ENOSPC); | |
414 | } | |
415 | sbinfo->free_blocks--; | |
416 | inode->i_blocks += BLOCKS_PER_PAGE; | |
417 | spin_unlock(&sbinfo->stat_lock); | |
418 | } | |
419 | ||
420 | spin_unlock(&info->lock); | |
769848c0 | 421 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
4c21e2f2 HD |
422 | if (page) |
423 | set_page_private(page, 0); | |
1da177e4 LT |
424 | spin_lock(&info->lock); |
425 | ||
426 | if (!page) { | |
427 | shmem_free_blocks(inode, 1); | |
428 | return ERR_PTR(-ENOMEM); | |
429 | } | |
430 | if (sgp != SGP_WRITE && | |
431 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
432 | entry = ERR_PTR(-EINVAL); | |
433 | break; | |
434 | } | |
435 | if (info->next_index <= index) | |
436 | info->next_index = index + 1; | |
437 | } | |
438 | if (page) { | |
439 | /* another task gave its page, or truncated the file */ | |
440 | shmem_free_blocks(inode, 1); | |
441 | shmem_dir_free(page); | |
442 | } | |
443 | if (info->next_index <= index && !IS_ERR(entry)) | |
444 | info->next_index = index + 1; | |
445 | return entry; | |
446 | } | |
447 | ||
46711810 | 448 | /** |
1da177e4 | 449 | * shmem_free_swp - free some swap entries in a directory |
1ae70006 HD |
450 | * @dir: pointer to the directory |
451 | * @edir: pointer after last entry of the directory | |
452 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 453 | */ |
1ae70006 HD |
454 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
455 | spinlock_t *punch_lock) | |
1da177e4 | 456 | { |
1ae70006 | 457 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
458 | swp_entry_t *ptr; |
459 | int freed = 0; | |
460 | ||
461 | for (ptr = dir; ptr < edir; ptr++) { | |
462 | if (ptr->val) { | |
1ae70006 HD |
463 | if (unlikely(punch_lock)) { |
464 | punch_unlock = punch_lock; | |
465 | punch_lock = NULL; | |
466 | spin_lock(punch_unlock); | |
467 | if (!ptr->val) | |
468 | continue; | |
469 | } | |
1da177e4 LT |
470 | free_swap_and_cache(*ptr); |
471 | *ptr = (swp_entry_t){0}; | |
472 | freed++; | |
473 | } | |
474 | } | |
1ae70006 HD |
475 | if (punch_unlock) |
476 | spin_unlock(punch_unlock); | |
1da177e4 LT |
477 | return freed; |
478 | } | |
479 | ||
1ae70006 HD |
480 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
481 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
482 | { |
483 | swp_entry_t *ptr; | |
484 | int freed = 0; | |
485 | ||
486 | ptr = shmem_swp_map(subdir); | |
487 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
488 | int size = limit - offset; | |
489 | if (size > LATENCY_LIMIT) | |
490 | size = LATENCY_LIMIT; | |
1ae70006 HD |
491 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
492 | punch_lock); | |
1da177e4 LT |
493 | if (need_resched()) { |
494 | shmem_swp_unmap(ptr); | |
495 | if (*dir) { | |
496 | shmem_dir_unmap(*dir); | |
497 | *dir = NULL; | |
498 | } | |
499 | cond_resched(); | |
500 | ptr = shmem_swp_map(subdir); | |
501 | } | |
502 | } | |
503 | shmem_swp_unmap(ptr); | |
504 | return freed; | |
505 | } | |
506 | ||
507 | static void shmem_free_pages(struct list_head *next) | |
508 | { | |
509 | struct page *page; | |
510 | int freed = 0; | |
511 | ||
512 | do { | |
513 | page = container_of(next, struct page, lru); | |
514 | next = next->next; | |
515 | shmem_dir_free(page); | |
516 | freed++; | |
517 | if (freed >= LATENCY_LIMIT) { | |
518 | cond_resched(); | |
519 | freed = 0; | |
520 | } | |
521 | } while (next); | |
522 | } | |
523 | ||
f6b3ec23 | 524 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
525 | { |
526 | struct shmem_inode_info *info = SHMEM_I(inode); | |
527 | unsigned long idx; | |
528 | unsigned long size; | |
529 | unsigned long limit; | |
530 | unsigned long stage; | |
531 | unsigned long diroff; | |
532 | struct page **dir; | |
533 | struct page *topdir; | |
534 | struct page *middir; | |
535 | struct page *subdir; | |
536 | swp_entry_t *ptr; | |
537 | LIST_HEAD(pages_to_free); | |
538 | long nr_pages_to_free = 0; | |
539 | long nr_swaps_freed = 0; | |
540 | int offset; | |
541 | int freed; | |
a2646d1e | 542 | int punch_hole; |
1ae70006 HD |
543 | spinlock_t *needs_lock; |
544 | spinlock_t *punch_lock; | |
a2646d1e | 545 | unsigned long upper_limit; |
1da177e4 LT |
546 | |
547 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 548 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
549 | if (idx >= info->next_index) |
550 | return; | |
551 | ||
552 | spin_lock(&info->lock); | |
553 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
554 | if (likely(end == (loff_t) -1)) { |
555 | limit = info->next_index; | |
a2646d1e | 556 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 557 | info->next_index = idx; |
1ae70006 | 558 | needs_lock = NULL; |
a2646d1e | 559 | punch_hole = 0; |
f6b3ec23 | 560 | } else { |
a2646d1e HD |
561 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
562 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
563 | PAGE_CACHE_SHIFT; | |
564 | upper_limit = SHMEM_MAX_INDEX; | |
565 | } else { | |
566 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
567 | upper_limit = limit; | |
568 | } | |
1ae70006 | 569 | needs_lock = &info->lock; |
f6b3ec23 BP |
570 | punch_hole = 1; |
571 | } | |
572 | ||
1da177e4 | 573 | topdir = info->i_indirect; |
f6b3ec23 | 574 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
575 | info->i_indirect = NULL; |
576 | nr_pages_to_free++; | |
577 | list_add(&topdir->lru, &pages_to_free); | |
578 | } | |
579 | spin_unlock(&info->lock); | |
580 | ||
581 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
582 | ptr = info->i_direct; | |
583 | size = limit; | |
584 | if (size > SHMEM_NR_DIRECT) | |
585 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 586 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 587 | } |
92a3d03a BP |
588 | |
589 | /* | |
590 | * If there are no indirect blocks or we are punching a hole | |
591 | * below indirect blocks, nothing to be done. | |
592 | */ | |
a2646d1e | 593 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
594 | goto done2; |
595 | ||
1ae70006 HD |
596 | /* |
597 | * The truncation case has already dropped info->lock, and we're safe | |
598 | * because i_size and next_index have already been lowered, preventing | |
599 | * access beyond. But in the punch_hole case, we still need to take | |
600 | * the lock when updating the swap directory, because there might be | |
601 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
602 | * shmem_writepage. However, whenever we find we can remove a whole | |
603 | * directory page (not at the misaligned start or end of the range), | |
604 | * we first NULLify its pointer in the level above, and then have no | |
605 | * need to take the lock when updating its contents: needs_lock and | |
606 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
607 | */ | |
608 | ||
a2646d1e | 609 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
610 | limit -= SHMEM_NR_DIRECT; |
611 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
612 | offset = idx % ENTRIES_PER_PAGE; | |
613 | idx -= offset; | |
614 | ||
615 | dir = shmem_dir_map(topdir); | |
616 | stage = ENTRIES_PER_PAGEPAGE/2; | |
617 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
618 | middir = topdir; | |
619 | diroff = idx/ENTRIES_PER_PAGE; | |
620 | } else { | |
621 | dir += ENTRIES_PER_PAGE/2; | |
622 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
623 | while (stage <= idx) | |
624 | stage += ENTRIES_PER_PAGEPAGE; | |
625 | middir = *dir; | |
626 | if (*dir) { | |
627 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
628 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 629 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
630 | if (needs_lock) { |
631 | spin_lock(needs_lock); | |
632 | *dir = NULL; | |
633 | spin_unlock(needs_lock); | |
634 | needs_lock = NULL; | |
635 | } else | |
636 | *dir = NULL; | |
1da177e4 LT |
637 | nr_pages_to_free++; |
638 | list_add(&middir->lru, &pages_to_free); | |
639 | } | |
640 | shmem_dir_unmap(dir); | |
641 | dir = shmem_dir_map(middir); | |
642 | } else { | |
643 | diroff = 0; | |
644 | offset = 0; | |
645 | idx = stage; | |
646 | } | |
647 | } | |
648 | ||
649 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
650 | if (unlikely(idx == stage)) { | |
651 | shmem_dir_unmap(dir); | |
652 | dir = shmem_dir_map(topdir) + | |
653 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
654 | while (!*dir) { | |
655 | dir++; | |
656 | idx += ENTRIES_PER_PAGEPAGE; | |
657 | if (idx >= limit) | |
658 | goto done1; | |
659 | } | |
660 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
661 | middir = *dir; | |
1ae70006 HD |
662 | if (punch_hole) |
663 | needs_lock = &info->lock; | |
a2646d1e | 664 | if (upper_limit >= stage) { |
1ae70006 HD |
665 | if (needs_lock) { |
666 | spin_lock(needs_lock); | |
667 | *dir = NULL; | |
668 | spin_unlock(needs_lock); | |
669 | needs_lock = NULL; | |
670 | } else | |
671 | *dir = NULL; | |
a2646d1e HD |
672 | nr_pages_to_free++; |
673 | list_add(&middir->lru, &pages_to_free); | |
674 | } | |
1da177e4 LT |
675 | shmem_dir_unmap(dir); |
676 | cond_resched(); | |
677 | dir = shmem_dir_map(middir); | |
678 | diroff = 0; | |
679 | } | |
1ae70006 | 680 | punch_lock = needs_lock; |
1da177e4 | 681 | subdir = dir[diroff]; |
1ae70006 HD |
682 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
683 | if (needs_lock) { | |
684 | spin_lock(needs_lock); | |
685 | dir[diroff] = NULL; | |
686 | spin_unlock(needs_lock); | |
687 | punch_lock = NULL; | |
688 | } else | |
689 | dir[diroff] = NULL; | |
690 | nr_pages_to_free++; | |
691 | list_add(&subdir->lru, &pages_to_free); | |
692 | } | |
693 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
694 | size = limit - idx; |
695 | if (size > ENTRIES_PER_PAGE) | |
696 | size = ENTRIES_PER_PAGE; | |
697 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 698 | offset, size, &dir, punch_lock); |
1da177e4 LT |
699 | if (!dir) |
700 | dir = shmem_dir_map(middir); | |
701 | nr_swaps_freed += freed; | |
1ae70006 | 702 | if (offset || punch_lock) { |
1da177e4 | 703 | spin_lock(&info->lock); |
1ae70006 HD |
704 | set_page_private(subdir, |
705 | page_private(subdir) - freed); | |
1da177e4 | 706 | spin_unlock(&info->lock); |
1ae70006 HD |
707 | } else |
708 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 709 | } |
1ae70006 | 710 | offset = 0; |
1da177e4 LT |
711 | } |
712 | done1: | |
713 | shmem_dir_unmap(dir); | |
714 | done2: | |
715 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
716 | /* | |
717 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
718 | * may have swizzled a page in from swap since vmtruncate or | |
719 | * generic_delete_inode did it, before we lowered next_index. | |
720 | * Also, though shmem_getpage checks i_size before adding to | |
721 | * cache, no recheck after: so fix the narrow window there too. | |
16a10019 HD |
722 | * |
723 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
724 | * every time for punch_hole (which never got a chance to clear | |
725 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
726 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 727 | */ |
f6b3ec23 | 728 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
729 | if (punch_hole) |
730 | unmap_mapping_range(inode->i_mapping, start, | |
731 | end - start, 1); | |
1da177e4 LT |
732 | } |
733 | ||
734 | spin_lock(&info->lock); | |
735 | info->flags &= ~SHMEM_TRUNCATE; | |
736 | info->swapped -= nr_swaps_freed; | |
737 | if (nr_pages_to_free) | |
738 | shmem_free_blocks(inode, nr_pages_to_free); | |
739 | shmem_recalc_inode(inode); | |
740 | spin_unlock(&info->lock); | |
741 | ||
742 | /* | |
743 | * Empty swap vector directory pages to be freed? | |
744 | */ | |
745 | if (!list_empty(&pages_to_free)) { | |
746 | pages_to_free.prev->next = NULL; | |
747 | shmem_free_pages(pages_to_free.next); | |
748 | } | |
749 | } | |
750 | ||
f6b3ec23 BP |
751 | static void shmem_truncate(struct inode *inode) |
752 | { | |
753 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
754 | } | |
755 | ||
1da177e4 LT |
756 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
757 | { | |
758 | struct inode *inode = dentry->d_inode; | |
759 | struct page *page = NULL; | |
760 | int error; | |
761 | ||
39f0247d | 762 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
763 | if (attr->ia_size < inode->i_size) { |
764 | /* | |
765 | * If truncating down to a partial page, then | |
766 | * if that page is already allocated, hold it | |
767 | * in memory until the truncation is over, so | |
768 | * truncate_partial_page cannnot miss it were | |
769 | * it assigned to swap. | |
770 | */ | |
771 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
772 | (void) shmem_getpage(inode, | |
773 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
774 | &page, SGP_READ, NULL); | |
d3602444 HD |
775 | if (page) |
776 | unlock_page(page); | |
1da177e4 LT |
777 | } |
778 | /* | |
779 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
780 | * detect if any pages might have been added to cache | |
781 | * after truncate_inode_pages. But we needn't bother | |
782 | * if it's being fully truncated to zero-length: the | |
783 | * nrpages check is efficient enough in that case. | |
784 | */ | |
785 | if (attr->ia_size) { | |
786 | struct shmem_inode_info *info = SHMEM_I(inode); | |
787 | spin_lock(&info->lock); | |
788 | info->flags &= ~SHMEM_PAGEIN; | |
789 | spin_unlock(&info->lock); | |
790 | } | |
791 | } | |
792 | } | |
793 | ||
794 | error = inode_change_ok(inode, attr); | |
795 | if (!error) | |
796 | error = inode_setattr(inode, attr); | |
39f0247d AG |
797 | #ifdef CONFIG_TMPFS_POSIX_ACL |
798 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
799 | error = generic_acl_chmod(inode, &shmem_acl_ops); | |
800 | #endif | |
1da177e4 LT |
801 | if (page) |
802 | page_cache_release(page); | |
803 | return error; | |
804 | } | |
805 | ||
806 | static void shmem_delete_inode(struct inode *inode) | |
807 | { | |
1da177e4 LT |
808 | struct shmem_inode_info *info = SHMEM_I(inode); |
809 | ||
810 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 811 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
812 | shmem_unacct_size(info->flags, inode->i_size); |
813 | inode->i_size = 0; | |
814 | shmem_truncate(inode); | |
815 | if (!list_empty(&info->swaplist)) { | |
cb5f7b9a | 816 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 817 | list_del_init(&info->swaplist); |
cb5f7b9a | 818 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
819 | } |
820 | } | |
0edd73b3 | 821 | BUG_ON(inode->i_blocks); |
5b04c689 | 822 | shmem_free_inode(inode->i_sb); |
1da177e4 LT |
823 | clear_inode(inode); |
824 | } | |
825 | ||
826 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
827 | { | |
828 | swp_entry_t *ptr; | |
829 | ||
830 | for (ptr = dir; ptr < edir; ptr++) { | |
831 | if (ptr->val == entry.val) | |
832 | return ptr - dir; | |
833 | } | |
834 | return -1; | |
835 | } | |
836 | ||
837 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
838 | { | |
839 | struct inode *inode; | |
840 | unsigned long idx; | |
841 | unsigned long size; | |
842 | unsigned long limit; | |
843 | unsigned long stage; | |
844 | struct page **dir; | |
845 | struct page *subdir; | |
846 | swp_entry_t *ptr; | |
847 | int offset; | |
d9fe526a | 848 | int error; |
1da177e4 LT |
849 | |
850 | idx = 0; | |
851 | ptr = info->i_direct; | |
852 | spin_lock(&info->lock); | |
1b1b32f2 HD |
853 | if (!info->swapped) { |
854 | list_del_init(&info->swaplist); | |
855 | goto lost2; | |
856 | } | |
1da177e4 LT |
857 | limit = info->next_index; |
858 | size = limit; | |
859 | if (size > SHMEM_NR_DIRECT) | |
860 | size = SHMEM_NR_DIRECT; | |
861 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 862 | if (offset >= 0) |
1da177e4 | 863 | goto found; |
1da177e4 LT |
864 | if (!info->i_indirect) |
865 | goto lost2; | |
866 | ||
867 | dir = shmem_dir_map(info->i_indirect); | |
868 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
869 | ||
870 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
871 | if (unlikely(idx == stage)) { | |
872 | shmem_dir_unmap(dir-1); | |
cb5f7b9a HD |
873 | if (cond_resched_lock(&info->lock)) { |
874 | /* check it has not been truncated */ | |
875 | if (limit > info->next_index) { | |
876 | limit = info->next_index; | |
877 | if (idx >= limit) | |
878 | goto lost2; | |
879 | } | |
880 | } | |
1da177e4 LT |
881 | dir = shmem_dir_map(info->i_indirect) + |
882 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
883 | while (!*dir) { | |
884 | dir++; | |
885 | idx += ENTRIES_PER_PAGEPAGE; | |
886 | if (idx >= limit) | |
887 | goto lost1; | |
888 | } | |
889 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
890 | subdir = *dir; | |
891 | shmem_dir_unmap(dir); | |
892 | dir = shmem_dir_map(subdir); | |
893 | } | |
894 | subdir = *dir; | |
4c21e2f2 | 895 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
896 | ptr = shmem_swp_map(subdir); |
897 | size = limit - idx; | |
898 | if (size > ENTRIES_PER_PAGE) | |
899 | size = ENTRIES_PER_PAGE; | |
900 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 901 | shmem_swp_unmap(ptr); |
1da177e4 LT |
902 | if (offset >= 0) { |
903 | shmem_dir_unmap(dir); | |
904 | goto found; | |
905 | } | |
1da177e4 LT |
906 | } |
907 | } | |
908 | lost1: | |
909 | shmem_dir_unmap(dir-1); | |
910 | lost2: | |
911 | spin_unlock(&info->lock); | |
912 | return 0; | |
913 | found: | |
914 | idx += offset; | |
2e0e26c7 HD |
915 | inode = igrab(&info->vfs_inode); |
916 | spin_unlock(&info->lock); | |
917 | ||
1b1b32f2 HD |
918 | /* |
919 | * Move _head_ to start search for next from here. | |
920 | * But be careful: shmem_delete_inode checks list_empty without taking | |
921 | * mutex, and there's an instant in list_move_tail when info->swaplist | |
922 | * would appear empty, if it were the only one on shmem_swaplist. We | |
923 | * could avoid doing it if inode NULL; or use this minor optimization. | |
924 | */ | |
925 | if (shmem_swaplist.next != &info->swaplist) | |
926 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 HD |
927 | mutex_unlock(&shmem_swaplist_mutex); |
928 | ||
929 | error = 1; | |
930 | if (!inode) | |
931 | goto out; | |
d13d1443 | 932 | /* |
b5a84319 KH |
933 | * Charge page using GFP_KERNEL while we can wait. |
934 | * Charged back to the user(not to caller) when swap account is used. | |
935 | * add_to_page_cache() will be called with GFP_NOWAIT. | |
d13d1443 | 936 | */ |
82369553 | 937 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); |
b409f9fc HD |
938 | if (error) |
939 | goto out; | |
82369553 | 940 | error = radix_tree_preload(GFP_KERNEL); |
69029cd5 KH |
941 | if (error) { |
942 | mem_cgroup_uncharge_cache_page(page); | |
943 | goto out; | |
944 | } | |
b409f9fc | 945 | error = 1; |
2e0e26c7 HD |
946 | |
947 | spin_lock(&info->lock); | |
948 | ptr = shmem_swp_entry(info, idx, NULL); | |
69029cd5 | 949 | if (ptr && ptr->val == entry.val) { |
e286781d | 950 | error = add_to_page_cache_locked(page, inode->i_mapping, |
b409f9fc | 951 | idx, GFP_NOWAIT); |
69029cd5 KH |
952 | /* does mem_cgroup_uncharge_cache_page on error */ |
953 | } else /* we must compensate for our precharge above */ | |
954 | mem_cgroup_uncharge_cache_page(page); | |
955 | ||
d9fe526a HD |
956 | if (error == -EEXIST) { |
957 | struct page *filepage = find_get_page(inode->i_mapping, idx); | |
2e0e26c7 | 958 | error = 1; |
d9fe526a HD |
959 | if (filepage) { |
960 | /* | |
961 | * There might be a more uptodate page coming down | |
962 | * from a stacked writepage: forget our swappage if so. | |
963 | */ | |
964 | if (PageUptodate(filepage)) | |
965 | error = 0; | |
966 | page_cache_release(filepage); | |
967 | } | |
968 | } | |
969 | if (!error) { | |
73b1262f HD |
970 | delete_from_swap_cache(page); |
971 | set_page_dirty(page); | |
1da177e4 | 972 | info->flags |= SHMEM_PAGEIN; |
2e0e26c7 HD |
973 | shmem_swp_set(info, ptr, 0); |
974 | swap_free(entry); | |
975 | error = 1; /* not an error, but entry was found */ | |
1da177e4 | 976 | } |
2e0e26c7 HD |
977 | if (ptr) |
978 | shmem_swp_unmap(ptr); | |
1da177e4 | 979 | spin_unlock(&info->lock); |
b409f9fc | 980 | radix_tree_preload_end(); |
2e0e26c7 HD |
981 | out: |
982 | unlock_page(page); | |
983 | page_cache_release(page); | |
984 | iput(inode); /* allows for NULL */ | |
985 | return error; | |
1da177e4 LT |
986 | } |
987 | ||
988 | /* | |
989 | * shmem_unuse() search for an eventually swapped out shmem page. | |
990 | */ | |
991 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
992 | { | |
993 | struct list_head *p, *next; | |
994 | struct shmem_inode_info *info; | |
995 | int found = 0; | |
996 | ||
cb5f7b9a | 997 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 LT |
998 | list_for_each_safe(p, next, &shmem_swaplist) { |
999 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
1b1b32f2 | 1000 | found = shmem_unuse_inode(info, entry, page); |
cb5f7b9a | 1001 | cond_resched(); |
2e0e26c7 HD |
1002 | if (found) |
1003 | goto out; | |
1da177e4 | 1004 | } |
cb5f7b9a | 1005 | mutex_unlock(&shmem_swaplist_mutex); |
2e0e26c7 | 1006 | out: return found; /* 0 or 1 or -ENOMEM */ |
1da177e4 LT |
1007 | } |
1008 | ||
1009 | /* | |
1010 | * Move the page from the page cache to the swap cache. | |
1011 | */ | |
1012 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
1013 | { | |
1014 | struct shmem_inode_info *info; | |
1015 | swp_entry_t *entry, swap; | |
1016 | struct address_space *mapping; | |
1017 | unsigned long index; | |
1018 | struct inode *inode; | |
1019 | ||
1020 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
1021 | mapping = page->mapping; |
1022 | index = page->index; | |
1023 | inode = mapping->host; | |
1024 | info = SHMEM_I(inode); | |
1025 | if (info->flags & VM_LOCKED) | |
1026 | goto redirty; | |
d9fe526a | 1027 | if (!total_swap_pages) |
1da177e4 LT |
1028 | goto redirty; |
1029 | ||
d9fe526a HD |
1030 | /* |
1031 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
1032 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
1033 | * may use the ->writepage of its underlying filesystem, in which case | |
1034 | * tmpfs should write out to swap only in response to memory pressure, | |
1035 | * and not for pdflush or sync. However, in those cases, we do still | |
1036 | * want to check if there's a redundant swappage to be discarded. | |
1037 | */ | |
1038 | if (wbc->for_reclaim) | |
1039 | swap = get_swap_page(); | |
1040 | else | |
1041 | swap.val = 0; | |
1042 | ||
1da177e4 | 1043 | spin_lock(&info->lock); |
1da177e4 LT |
1044 | if (index >= info->next_index) { |
1045 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
1046 | goto unlock; | |
1047 | } | |
1048 | entry = shmem_swp_entry(info, index, NULL); | |
d9fe526a HD |
1049 | if (entry->val) { |
1050 | /* | |
1051 | * The more uptodate page coming down from a stacked | |
1052 | * writepage should replace our old swappage. | |
1053 | */ | |
1054 | free_swap_and_cache(*entry); | |
1055 | shmem_swp_set(info, entry, 0); | |
1056 | } | |
1057 | shmem_recalc_inode(inode); | |
1da177e4 | 1058 | |
d9fe526a | 1059 | if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
73b1262f | 1060 | remove_from_page_cache(page); |
1da177e4 LT |
1061 | shmem_swp_set(info, entry, swap.val); |
1062 | shmem_swp_unmap(entry); | |
1b1b32f2 HD |
1063 | if (list_empty(&info->swaplist)) |
1064 | inode = igrab(inode); | |
1065 | else | |
1066 | inode = NULL; | |
1da177e4 | 1067 | spin_unlock(&info->lock); |
73b1262f | 1068 | swap_duplicate(swap); |
d9fe526a | 1069 | BUG_ON(page_mapped(page)); |
73b1262f | 1070 | page_cache_release(page); /* pagecache ref */ |
9fab5619 | 1071 | swap_writepage(page, wbc); |
1b1b32f2 HD |
1072 | if (inode) { |
1073 | mutex_lock(&shmem_swaplist_mutex); | |
1074 | /* move instead of add in case we're racing */ | |
1075 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
1076 | mutex_unlock(&shmem_swaplist_mutex); | |
1077 | iput(inode); | |
1078 | } | |
1da177e4 LT |
1079 | return 0; |
1080 | } | |
1081 | ||
1082 | shmem_swp_unmap(entry); | |
1083 | unlock: | |
1084 | spin_unlock(&info->lock); | |
1085 | swap_free(swap); | |
1086 | redirty: | |
1087 | set_page_dirty(page); | |
d9fe526a HD |
1088 | if (wbc->for_reclaim) |
1089 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1090 | unlock_page(page); | |
1091 | return 0; | |
1da177e4 LT |
1092 | } |
1093 | ||
1094 | #ifdef CONFIG_NUMA | |
680d794b | 1095 | #ifdef CONFIG_TMPFS |
71fe804b | 1096 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 1097 | { |
095f1fc4 | 1098 | char buffer[64]; |
680d794b | 1099 | |
71fe804b | 1100 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 1101 | return; /* show nothing */ |
680d794b | 1102 | |
71fe804b | 1103 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
1104 | |
1105 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 1106 | } |
71fe804b LS |
1107 | |
1108 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1109 | { | |
1110 | struct mempolicy *mpol = NULL; | |
1111 | if (sbinfo->mpol) { | |
1112 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
1113 | mpol = sbinfo->mpol; | |
1114 | mpol_get(mpol); | |
1115 | spin_unlock(&sbinfo->stat_lock); | |
1116 | } | |
1117 | return mpol; | |
1118 | } | |
680d794b AM |
1119 | #endif /* CONFIG_TMPFS */ |
1120 | ||
02098fea HD |
1121 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1122 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1123 | { |
52cd3b07 | 1124 | struct mempolicy mpol, *spol; |
1da177e4 | 1125 | struct vm_area_struct pvma; |
c4cc6d07 | 1126 | struct page *page; |
1da177e4 | 1127 | |
52cd3b07 LS |
1128 | spol = mpol_cond_copy(&mpol, |
1129 | mpol_shared_policy_lookup(&info->policy, idx)); | |
1130 | ||
1da177e4 | 1131 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 1132 | pvma.vm_start = 0; |
1da177e4 | 1133 | pvma.vm_pgoff = idx; |
c4cc6d07 | 1134 | pvma.vm_ops = NULL; |
52cd3b07 | 1135 | pvma.vm_policy = spol; |
02098fea | 1136 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1137 | return page; |
1138 | } | |
1139 | ||
02098fea HD |
1140 | static struct page *shmem_alloc_page(gfp_t gfp, |
1141 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1142 | { |
1143 | struct vm_area_struct pvma; | |
1da177e4 | 1144 | |
c4cc6d07 HD |
1145 | /* Create a pseudo vma that just contains the policy */ |
1146 | pvma.vm_start = 0; | |
1da177e4 | 1147 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1148 | pvma.vm_ops = NULL; |
1149 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
52cd3b07 LS |
1150 | |
1151 | /* | |
1152 | * alloc_page_vma() will drop the shared policy reference | |
1153 | */ | |
1154 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 1155 | } |
680d794b AM |
1156 | #else /* !CONFIG_NUMA */ |
1157 | #ifdef CONFIG_TMPFS | |
71fe804b | 1158 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p) |
680d794b AM |
1159 | { |
1160 | } | |
1161 | #endif /* CONFIG_TMPFS */ | |
1162 | ||
02098fea HD |
1163 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1164 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1165 | { |
02098fea | 1166 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1167 | } |
1168 | ||
02098fea HD |
1169 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1170 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1171 | { |
e84e2e13 | 1172 | return alloc_page(gfp); |
1da177e4 | 1173 | } |
680d794b | 1174 | #endif /* CONFIG_NUMA */ |
1da177e4 | 1175 | |
71fe804b LS |
1176 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
1177 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1178 | { | |
1179 | return NULL; | |
1180 | } | |
1181 | #endif | |
1182 | ||
1da177e4 LT |
1183 | /* |
1184 | * shmem_getpage - either get the page from swap or allocate a new one | |
1185 | * | |
1186 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1187 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1188 | * entry since a page cannot live in both the swap and page cache | |
1189 | */ | |
1190 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1191 | struct page **pagep, enum sgp_type sgp, int *type) | |
1192 | { | |
1193 | struct address_space *mapping = inode->i_mapping; | |
1194 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1195 | struct shmem_sb_info *sbinfo; | |
1196 | struct page *filepage = *pagep; | |
1197 | struct page *swappage; | |
1198 | swp_entry_t *entry; | |
1199 | swp_entry_t swap; | |
02098fea | 1200 | gfp_t gfp; |
1da177e4 LT |
1201 | int error; |
1202 | ||
1203 | if (idx >= SHMEM_MAX_INDEX) | |
1204 | return -EFBIG; | |
54cb8821 NP |
1205 | |
1206 | if (type) | |
83c54070 | 1207 | *type = 0; |
54cb8821 | 1208 | |
1da177e4 LT |
1209 | /* |
1210 | * Normally, filepage is NULL on entry, and either found | |
1211 | * uptodate immediately, or allocated and zeroed, or read | |
1212 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1213 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1214 | * filepage, which may be found not uptodate by other callers |
1215 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1216 | */ |
1217 | repeat: | |
1218 | if (!filepage) | |
1219 | filepage = find_lock_page(mapping, idx); | |
1220 | if (filepage && PageUptodate(filepage)) | |
1221 | goto done; | |
1222 | error = 0; | |
02098fea | 1223 | gfp = mapping_gfp_mask(mapping); |
b409f9fc HD |
1224 | if (!filepage) { |
1225 | /* | |
1226 | * Try to preload while we can wait, to not make a habit of | |
1227 | * draining atomic reserves; but don't latch on to this cpu. | |
1228 | */ | |
1229 | error = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
1230 | if (error) | |
1231 | goto failed; | |
1232 | radix_tree_preload_end(); | |
1233 | } | |
1da177e4 LT |
1234 | |
1235 | spin_lock(&info->lock); | |
1236 | shmem_recalc_inode(inode); | |
1237 | entry = shmem_swp_alloc(info, idx, sgp); | |
1238 | if (IS_ERR(entry)) { | |
1239 | spin_unlock(&info->lock); | |
1240 | error = PTR_ERR(entry); | |
1241 | goto failed; | |
1242 | } | |
1243 | swap = *entry; | |
1244 | ||
1245 | if (swap.val) { | |
1246 | /* Look it up and read it in.. */ | |
1247 | swappage = lookup_swap_cache(swap); | |
1248 | if (!swappage) { | |
1249 | shmem_swp_unmap(entry); | |
1da177e4 | 1250 | /* here we actually do the io */ |
83c54070 | 1251 | if (type && !(*type & VM_FAULT_MAJOR)) { |
f8891e5e | 1252 | __count_vm_event(PGMAJFAULT); |
83c54070 | 1253 | *type |= VM_FAULT_MAJOR; |
1da177e4 | 1254 | } |
f8891e5e | 1255 | spin_unlock(&info->lock); |
02098fea | 1256 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1257 | if (!swappage) { |
1258 | spin_lock(&info->lock); | |
1259 | entry = shmem_swp_alloc(info, idx, sgp); | |
1260 | if (IS_ERR(entry)) | |
1261 | error = PTR_ERR(entry); | |
1262 | else { | |
1263 | if (entry->val == swap.val) | |
1264 | error = -ENOMEM; | |
1265 | shmem_swp_unmap(entry); | |
1266 | } | |
1267 | spin_unlock(&info->lock); | |
1268 | if (error) | |
1269 | goto failed; | |
1270 | goto repeat; | |
1271 | } | |
1272 | wait_on_page_locked(swappage); | |
1273 | page_cache_release(swappage); | |
1274 | goto repeat; | |
1275 | } | |
1276 | ||
1277 | /* We have to do this with page locked to prevent races */ | |
529ae9aa | 1278 | if (!trylock_page(swappage)) { |
1da177e4 LT |
1279 | shmem_swp_unmap(entry); |
1280 | spin_unlock(&info->lock); | |
1281 | wait_on_page_locked(swappage); | |
1282 | page_cache_release(swappage); | |
1283 | goto repeat; | |
1284 | } | |
1285 | if (PageWriteback(swappage)) { | |
1286 | shmem_swp_unmap(entry); | |
1287 | spin_unlock(&info->lock); | |
1288 | wait_on_page_writeback(swappage); | |
1289 | unlock_page(swappage); | |
1290 | page_cache_release(swappage); | |
1291 | goto repeat; | |
1292 | } | |
1293 | if (!PageUptodate(swappage)) { | |
1294 | shmem_swp_unmap(entry); | |
1295 | spin_unlock(&info->lock); | |
1296 | unlock_page(swappage); | |
1297 | page_cache_release(swappage); | |
1298 | error = -EIO; | |
1299 | goto failed; | |
1300 | } | |
1301 | ||
1302 | if (filepage) { | |
1303 | shmem_swp_set(info, entry, 0); | |
1304 | shmem_swp_unmap(entry); | |
1305 | delete_from_swap_cache(swappage); | |
1306 | spin_unlock(&info->lock); | |
1307 | copy_highpage(filepage, swappage); | |
1308 | unlock_page(swappage); | |
1309 | page_cache_release(swappage); | |
1310 | flush_dcache_page(filepage); | |
1311 | SetPageUptodate(filepage); | |
1312 | set_page_dirty(filepage); | |
1313 | swap_free(swap); | |
e286781d NP |
1314 | } else if (!(error = add_to_page_cache_locked(swappage, mapping, |
1315 | idx, GFP_NOWAIT))) { | |
1da177e4 LT |
1316 | info->flags |= SHMEM_PAGEIN; |
1317 | shmem_swp_set(info, entry, 0); | |
1318 | shmem_swp_unmap(entry); | |
73b1262f | 1319 | delete_from_swap_cache(swappage); |
1da177e4 LT |
1320 | spin_unlock(&info->lock); |
1321 | filepage = swappage; | |
73b1262f | 1322 | set_page_dirty(filepage); |
1da177e4 LT |
1323 | swap_free(swap); |
1324 | } else { | |
1325 | shmem_swp_unmap(entry); | |
1326 | spin_unlock(&info->lock); | |
82369553 HD |
1327 | if (error == -ENOMEM) { |
1328 | /* allow reclaim from this memory cgroup */ | |
b5a84319 KH |
1329 | error = mem_cgroup_shrink_usage(swappage, |
1330 | current->mm, | |
c9b0ed51 | 1331 | gfp); |
b5a84319 KH |
1332 | if (error) { |
1333 | unlock_page(swappage); | |
1334 | page_cache_release(swappage); | |
82369553 | 1335 | goto failed; |
b5a84319 | 1336 | } |
82369553 | 1337 | } |
b5a84319 KH |
1338 | unlock_page(swappage); |
1339 | page_cache_release(swappage); | |
1da177e4 LT |
1340 | goto repeat; |
1341 | } | |
1342 | } else if (sgp == SGP_READ && !filepage) { | |
1343 | shmem_swp_unmap(entry); | |
1344 | filepage = find_get_page(mapping, idx); | |
1345 | if (filepage && | |
529ae9aa | 1346 | (!PageUptodate(filepage) || !trylock_page(filepage))) { |
1da177e4 LT |
1347 | spin_unlock(&info->lock); |
1348 | wait_on_page_locked(filepage); | |
1349 | page_cache_release(filepage); | |
1350 | filepage = NULL; | |
1351 | goto repeat; | |
1352 | } | |
1353 | spin_unlock(&info->lock); | |
1354 | } else { | |
1355 | shmem_swp_unmap(entry); | |
1356 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1357 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1358 | spin_lock(&sbinfo->stat_lock); |
1359 | if (sbinfo->free_blocks == 0 || | |
1360 | shmem_acct_block(info->flags)) { | |
1361 | spin_unlock(&sbinfo->stat_lock); | |
1362 | spin_unlock(&info->lock); | |
1363 | error = -ENOSPC; | |
1364 | goto failed; | |
1365 | } | |
1366 | sbinfo->free_blocks--; | |
1367 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1368 | spin_unlock(&sbinfo->stat_lock); | |
1369 | } else if (shmem_acct_block(info->flags)) { | |
1370 | spin_unlock(&info->lock); | |
1371 | error = -ENOSPC; | |
1372 | goto failed; | |
1373 | } | |
1374 | ||
1375 | if (!filepage) { | |
69029cd5 KH |
1376 | int ret; |
1377 | ||
1da177e4 | 1378 | spin_unlock(&info->lock); |
02098fea | 1379 | filepage = shmem_alloc_page(gfp, info, idx); |
1da177e4 LT |
1380 | if (!filepage) { |
1381 | shmem_unacct_blocks(info->flags, 1); | |
1382 | shmem_free_blocks(inode, 1); | |
1383 | error = -ENOMEM; | |
1384 | goto failed; | |
1385 | } | |
b2e18538 | 1386 | SetPageSwapBacked(filepage); |
1da177e4 | 1387 | |
82369553 HD |
1388 | /* Precharge page while we can wait, compensate after */ |
1389 | error = mem_cgroup_cache_charge(filepage, current->mm, | |
2c26fdd7 | 1390 | GFP_KERNEL); |
82369553 HD |
1391 | if (error) { |
1392 | page_cache_release(filepage); | |
1393 | shmem_unacct_blocks(info->flags, 1); | |
1394 | shmem_free_blocks(inode, 1); | |
1395 | filepage = NULL; | |
1396 | goto failed; | |
1397 | } | |
1398 | ||
1da177e4 LT |
1399 | spin_lock(&info->lock); |
1400 | entry = shmem_swp_alloc(info, idx, sgp); | |
1401 | if (IS_ERR(entry)) | |
1402 | error = PTR_ERR(entry); | |
1403 | else { | |
1404 | swap = *entry; | |
1405 | shmem_swp_unmap(entry); | |
1406 | } | |
69029cd5 KH |
1407 | ret = error || swap.val; |
1408 | if (ret) | |
1409 | mem_cgroup_uncharge_cache_page(filepage); | |
1410 | else | |
1411 | ret = add_to_page_cache_lru(filepage, mapping, | |
1412 | idx, GFP_NOWAIT); | |
1413 | /* | |
1414 | * At add_to_page_cache_lru() failure, uncharge will | |
1415 | * be done automatically. | |
1416 | */ | |
1417 | if (ret) { | |
1da177e4 LT |
1418 | spin_unlock(&info->lock); |
1419 | page_cache_release(filepage); | |
1420 | shmem_unacct_blocks(info->flags, 1); | |
1421 | shmem_free_blocks(inode, 1); | |
1422 | filepage = NULL; | |
1423 | if (error) | |
1424 | goto failed; | |
1425 | goto repeat; | |
1426 | } | |
1427 | info->flags |= SHMEM_PAGEIN; | |
1428 | } | |
1429 | ||
1430 | info->alloced++; | |
1431 | spin_unlock(&info->lock); | |
e84e2e13 | 1432 | clear_highpage(filepage); |
1da177e4 LT |
1433 | flush_dcache_page(filepage); |
1434 | SetPageUptodate(filepage); | |
a0ee5ec5 HD |
1435 | if (sgp == SGP_DIRTY) |
1436 | set_page_dirty(filepage); | |
1da177e4 LT |
1437 | } |
1438 | done: | |
d3602444 | 1439 | *pagep = filepage; |
1da177e4 LT |
1440 | return 0; |
1441 | ||
1442 | failed: | |
1443 | if (*pagep != filepage) { | |
1444 | unlock_page(filepage); | |
1445 | page_cache_release(filepage); | |
1446 | } | |
1447 | return error; | |
1448 | } | |
1449 | ||
d0217ac0 | 1450 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1451 | { |
d3ac7f89 | 1452 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1453 | int error; |
d0217ac0 | 1454 | int ret; |
1da177e4 | 1455 | |
d0217ac0 NP |
1456 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1457 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1458 | |
27d54b39 | 1459 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1460 | if (error) |
1461 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1da177e4 | 1462 | |
83c54070 | 1463 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1464 | } |
1465 | ||
1da177e4 | 1466 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1467 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1468 | { |
d3ac7f89 | 1469 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1470 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1471 | } | |
1472 | ||
d8dc74f2 AB |
1473 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1474 | unsigned long addr) | |
1da177e4 | 1475 | { |
d3ac7f89 | 1476 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1477 | unsigned long idx; |
1478 | ||
1479 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1480 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1481 | } | |
1482 | #endif | |
1483 | ||
1484 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1485 | { | |
d3ac7f89 | 1486 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1487 | struct shmem_inode_info *info = SHMEM_I(inode); |
1488 | int retval = -ENOMEM; | |
1489 | ||
1490 | spin_lock(&info->lock); | |
1491 | if (lock && !(info->flags & VM_LOCKED)) { | |
1492 | if (!user_shm_lock(inode->i_size, user)) | |
1493 | goto out_nomem; | |
1494 | info->flags |= VM_LOCKED; | |
89e004ea | 1495 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1496 | } |
1497 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1498 | user_shm_unlock(inode->i_size, user); | |
1499 | info->flags &= ~VM_LOCKED; | |
89e004ea LS |
1500 | mapping_clear_unevictable(file->f_mapping); |
1501 | scan_mapping_unevictable_pages(file->f_mapping); | |
1da177e4 LT |
1502 | } |
1503 | retval = 0; | |
89e004ea | 1504 | |
1da177e4 LT |
1505 | out_nomem: |
1506 | spin_unlock(&info->lock); | |
1507 | return retval; | |
1508 | } | |
1509 | ||
9b83a6a8 | 1510 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1511 | { |
1512 | file_accessed(file); | |
1513 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1514 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1515 | return 0; |
1516 | } | |
1517 | ||
0b0a0806 HD |
1518 | static struct inode *shmem_get_inode(struct super_block *sb, int mode, |
1519 | dev_t dev, unsigned long flags) | |
1da177e4 LT |
1520 | { |
1521 | struct inode *inode; | |
1522 | struct shmem_inode_info *info; | |
1523 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1524 | ||
5b04c689 PE |
1525 | if (shmem_reserve_inode(sb)) |
1526 | return NULL; | |
1da177e4 LT |
1527 | |
1528 | inode = new_inode(sb); | |
1529 | if (inode) { | |
1530 | inode->i_mode = mode; | |
76aac0e9 DH |
1531 | inode->i_uid = current_fsuid(); |
1532 | inode->i_gid = current_fsgid(); | |
1da177e4 | 1533 | inode->i_blocks = 0; |
1da177e4 LT |
1534 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1535 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1536 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1537 | info = SHMEM_I(inode); |
1538 | memset(info, 0, (char *)inode - (char *)info); | |
1539 | spin_lock_init(&info->lock); | |
0b0a0806 | 1540 | info->flags = flags & VM_NORESERVE; |
1da177e4 LT |
1541 | INIT_LIST_HEAD(&info->swaplist); |
1542 | ||
1543 | switch (mode & S_IFMT) { | |
1544 | default: | |
39f0247d | 1545 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1546 | init_special_inode(inode, mode, dev); |
1547 | break; | |
1548 | case S_IFREG: | |
14fcc23f | 1549 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1550 | inode->i_op = &shmem_inode_operations; |
1551 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1552 | mpol_shared_policy_init(&info->policy, |
1553 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1554 | break; |
1555 | case S_IFDIR: | |
d8c76e6f | 1556 | inc_nlink(inode); |
1da177e4 LT |
1557 | /* Some things misbehave if size == 0 on a directory */ |
1558 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1559 | inode->i_op = &shmem_dir_inode_operations; | |
1560 | inode->i_fop = &simple_dir_operations; | |
1561 | break; | |
1562 | case S_IFLNK: | |
1563 | /* | |
1564 | * Must not load anything in the rbtree, | |
1565 | * mpol_free_shared_policy will not be called. | |
1566 | */ | |
71fe804b | 1567 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1568 | break; |
1569 | } | |
5b04c689 PE |
1570 | } else |
1571 | shmem_free_inode(sb); | |
1da177e4 LT |
1572 | return inode; |
1573 | } | |
1574 | ||
1575 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1576 | static const struct inode_operations shmem_symlink_inode_operations; |
1577 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1578 | |
1579 | /* | |
800d15a5 | 1580 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1581 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1582 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1583 | */ |
ae976416 HD |
1584 | static int shmem_readpage(struct file *file, struct page *page) |
1585 | { | |
1586 | struct inode *inode = page->mapping->host; | |
1587 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1588 | unlock_page(page); | |
1589 | return error; | |
1590 | } | |
1591 | ||
1da177e4 | 1592 | static int |
800d15a5 NP |
1593 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1594 | loff_t pos, unsigned len, unsigned flags, | |
1595 | struct page **pagep, void **fsdata) | |
1da177e4 | 1596 | { |
800d15a5 NP |
1597 | struct inode *inode = mapping->host; |
1598 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1599 | *pagep = NULL; | |
1600 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1601 | } | |
1602 | ||
1603 | static int | |
1604 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1605 | loff_t pos, unsigned len, unsigned copied, | |
1606 | struct page *page, void *fsdata) | |
1607 | { | |
1608 | struct inode *inode = mapping->host; | |
1609 | ||
d3602444 HD |
1610 | if (pos + copied > inode->i_size) |
1611 | i_size_write(inode, pos + copied); | |
1612 | ||
1613 | unlock_page(page); | |
800d15a5 NP |
1614 | set_page_dirty(page); |
1615 | page_cache_release(page); | |
1616 | ||
800d15a5 | 1617 | return copied; |
1da177e4 LT |
1618 | } |
1619 | ||
1da177e4 LT |
1620 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1621 | { | |
d3ac7f89 | 1622 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1623 | struct address_space *mapping = inode->i_mapping; |
1624 | unsigned long index, offset; | |
a0ee5ec5 HD |
1625 | enum sgp_type sgp = SGP_READ; |
1626 | ||
1627 | /* | |
1628 | * Might this read be for a stacking filesystem? Then when reading | |
1629 | * holes of a sparse file, we actually need to allocate those pages, | |
1630 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1631 | */ | |
1632 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1633 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1634 | |
1635 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1636 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1637 | ||
1638 | for (;;) { | |
1639 | struct page *page = NULL; | |
1640 | unsigned long end_index, nr, ret; | |
1641 | loff_t i_size = i_size_read(inode); | |
1642 | ||
1643 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1644 | if (index > end_index) | |
1645 | break; | |
1646 | if (index == end_index) { | |
1647 | nr = i_size & ~PAGE_CACHE_MASK; | |
1648 | if (nr <= offset) | |
1649 | break; | |
1650 | } | |
1651 | ||
a0ee5ec5 | 1652 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1653 | if (desc->error) { |
1654 | if (desc->error == -EINVAL) | |
1655 | desc->error = 0; | |
1656 | break; | |
1657 | } | |
d3602444 HD |
1658 | if (page) |
1659 | unlock_page(page); | |
1da177e4 LT |
1660 | |
1661 | /* | |
1662 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1663 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1664 | */ |
1665 | nr = PAGE_CACHE_SIZE; | |
1666 | i_size = i_size_read(inode); | |
1667 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1668 | if (index == end_index) { | |
1669 | nr = i_size & ~PAGE_CACHE_MASK; | |
1670 | if (nr <= offset) { | |
1671 | if (page) | |
1672 | page_cache_release(page); | |
1673 | break; | |
1674 | } | |
1675 | } | |
1676 | nr -= offset; | |
1677 | ||
1678 | if (page) { | |
1679 | /* | |
1680 | * If users can be writing to this page using arbitrary | |
1681 | * virtual addresses, take care about potential aliasing | |
1682 | * before reading the page on the kernel side. | |
1683 | */ | |
1684 | if (mapping_writably_mapped(mapping)) | |
1685 | flush_dcache_page(page); | |
1686 | /* | |
1687 | * Mark the page accessed if we read the beginning. | |
1688 | */ | |
1689 | if (!offset) | |
1690 | mark_page_accessed(page); | |
b5810039 | 1691 | } else { |
1da177e4 | 1692 | page = ZERO_PAGE(0); |
b5810039 NP |
1693 | page_cache_get(page); |
1694 | } | |
1da177e4 LT |
1695 | |
1696 | /* | |
1697 | * Ok, we have the page, and it's up-to-date, so | |
1698 | * now we can copy it to user space... | |
1699 | * | |
1700 | * The actor routine returns how many bytes were actually used.. | |
1701 | * NOTE! This may not be the same as how much of a user buffer | |
1702 | * we filled up (we may be padding etc), so we can only update | |
1703 | * "pos" here (the actor routine has to update the user buffer | |
1704 | * pointers and the remaining count). | |
1705 | */ | |
1706 | ret = actor(desc, page, offset, nr); | |
1707 | offset += ret; | |
1708 | index += offset >> PAGE_CACHE_SHIFT; | |
1709 | offset &= ~PAGE_CACHE_MASK; | |
1710 | ||
1711 | page_cache_release(page); | |
1712 | if (ret != nr || !desc->count) | |
1713 | break; | |
1714 | ||
1715 | cond_resched(); | |
1716 | } | |
1717 | ||
1718 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1719 | file_accessed(filp); | |
1720 | } | |
1721 | ||
bcd78e49 HD |
1722 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1723 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1724 | { | |
1725 | struct file *filp = iocb->ki_filp; | |
1726 | ssize_t retval; | |
1727 | unsigned long seg; | |
1728 | size_t count; | |
1729 | loff_t *ppos = &iocb->ki_pos; | |
1730 | ||
1731 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1732 | if (retval) | |
1733 | return retval; | |
1734 | ||
1735 | for (seg = 0; seg < nr_segs; seg++) { | |
1736 | read_descriptor_t desc; | |
1737 | ||
1738 | desc.written = 0; | |
1739 | desc.arg.buf = iov[seg].iov_base; | |
1740 | desc.count = iov[seg].iov_len; | |
1741 | if (desc.count == 0) | |
1742 | continue; | |
1743 | desc.error = 0; | |
1744 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1745 | retval += desc.written; | |
1746 | if (desc.error) { | |
1747 | retval = retval ?: desc.error; | |
1748 | break; | |
1749 | } | |
1750 | if (desc.count > 0) | |
1751 | break; | |
1752 | } | |
1753 | return retval; | |
1da177e4 LT |
1754 | } |
1755 | ||
726c3342 | 1756 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1757 | { |
726c3342 | 1758 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1759 | |
1760 | buf->f_type = TMPFS_MAGIC; | |
1761 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1762 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1763 | spin_lock(&sbinfo->stat_lock); |
1764 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1765 | buf->f_blocks = sbinfo->max_blocks; |
1766 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1767 | } |
1768 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1769 | buf->f_files = sbinfo->max_inodes; |
1770 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1771 | } |
1772 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1773 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1774 | return 0; |
1775 | } | |
1776 | ||
1777 | /* | |
1778 | * File creation. Allocate an inode, and we're done.. | |
1779 | */ | |
1780 | static int | |
1781 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1782 | { | |
0b0a0806 | 1783 | struct inode *inode; |
1da177e4 LT |
1784 | int error = -ENOSPC; |
1785 | ||
0b0a0806 | 1786 | inode = shmem_get_inode(dir->i_sb, mode, dev, VM_NORESERVE); |
1da177e4 | 1787 | if (inode) { |
570bc1c2 SS |
1788 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1789 | NULL); | |
1790 | if (error) { | |
1791 | if (error != -EOPNOTSUPP) { | |
1792 | iput(inode); | |
1793 | return error; | |
1794 | } | |
39f0247d AG |
1795 | } |
1796 | error = shmem_acl_init(inode, dir); | |
1797 | if (error) { | |
1798 | iput(inode); | |
1799 | return error; | |
570bc1c2 | 1800 | } |
1da177e4 LT |
1801 | if (dir->i_mode & S_ISGID) { |
1802 | inode->i_gid = dir->i_gid; | |
1803 | if (S_ISDIR(mode)) | |
1804 | inode->i_mode |= S_ISGID; | |
1805 | } | |
1806 | dir->i_size += BOGO_DIRENT_SIZE; | |
1807 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1808 | d_instantiate(dentry, inode); | |
1809 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1810 | } |
1811 | return error; | |
1812 | } | |
1813 | ||
1814 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1815 | { | |
1816 | int error; | |
1817 | ||
1818 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1819 | return error; | |
d8c76e6f | 1820 | inc_nlink(dir); |
1da177e4 LT |
1821 | return 0; |
1822 | } | |
1823 | ||
1824 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1825 | struct nameidata *nd) | |
1826 | { | |
1827 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1828 | } | |
1829 | ||
1830 | /* | |
1831 | * Link a file.. | |
1832 | */ | |
1833 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1834 | { | |
1835 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1836 | int ret; |
1da177e4 LT |
1837 | |
1838 | /* | |
1839 | * No ordinary (disk based) filesystem counts links as inodes; | |
1840 | * but each new link needs a new dentry, pinning lowmem, and | |
1841 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1842 | */ | |
5b04c689 PE |
1843 | ret = shmem_reserve_inode(inode->i_sb); |
1844 | if (ret) | |
1845 | goto out; | |
1da177e4 LT |
1846 | |
1847 | dir->i_size += BOGO_DIRENT_SIZE; | |
1848 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1849 | inc_nlink(inode); |
1da177e4 LT |
1850 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1851 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1852 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1853 | out: |
1854 | return ret; | |
1da177e4 LT |
1855 | } |
1856 | ||
1857 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1858 | { | |
1859 | struct inode *inode = dentry->d_inode; | |
1860 | ||
5b04c689 PE |
1861 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1862 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1863 | |
1864 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1865 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1866 | drop_nlink(inode); |
1da177e4 LT |
1867 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1868 | return 0; | |
1869 | } | |
1870 | ||
1871 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1872 | { | |
1873 | if (!simple_empty(dentry)) | |
1874 | return -ENOTEMPTY; | |
1875 | ||
9a53c3a7 DH |
1876 | drop_nlink(dentry->d_inode); |
1877 | drop_nlink(dir); | |
1da177e4 LT |
1878 | return shmem_unlink(dir, dentry); |
1879 | } | |
1880 | ||
1881 | /* | |
1882 | * The VFS layer already does all the dentry stuff for rename, | |
1883 | * we just have to decrement the usage count for the target if | |
1884 | * it exists so that the VFS layer correctly free's it when it | |
1885 | * gets overwritten. | |
1886 | */ | |
1887 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1888 | { | |
1889 | struct inode *inode = old_dentry->d_inode; | |
1890 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1891 | ||
1892 | if (!simple_empty(new_dentry)) | |
1893 | return -ENOTEMPTY; | |
1894 | ||
1895 | if (new_dentry->d_inode) { | |
1896 | (void) shmem_unlink(new_dir, new_dentry); | |
1897 | if (they_are_dirs) | |
9a53c3a7 | 1898 | drop_nlink(old_dir); |
1da177e4 | 1899 | } else if (they_are_dirs) { |
9a53c3a7 | 1900 | drop_nlink(old_dir); |
d8c76e6f | 1901 | inc_nlink(new_dir); |
1da177e4 LT |
1902 | } |
1903 | ||
1904 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1905 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1906 | old_dir->i_ctime = old_dir->i_mtime = | |
1907 | new_dir->i_ctime = new_dir->i_mtime = | |
1908 | inode->i_ctime = CURRENT_TIME; | |
1909 | return 0; | |
1910 | } | |
1911 | ||
1912 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1913 | { | |
1914 | int error; | |
1915 | int len; | |
1916 | struct inode *inode; | |
1917 | struct page *page = NULL; | |
1918 | char *kaddr; | |
1919 | struct shmem_inode_info *info; | |
1920 | ||
1921 | len = strlen(symname) + 1; | |
1922 | if (len > PAGE_CACHE_SIZE) | |
1923 | return -ENAMETOOLONG; | |
1924 | ||
0b0a0806 | 1925 | inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
1926 | if (!inode) |
1927 | return -ENOSPC; | |
1928 | ||
570bc1c2 SS |
1929 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1930 | NULL); | |
1931 | if (error) { | |
1932 | if (error != -EOPNOTSUPP) { | |
1933 | iput(inode); | |
1934 | return error; | |
1935 | } | |
1936 | error = 0; | |
1937 | } | |
1938 | ||
1da177e4 LT |
1939 | info = SHMEM_I(inode); |
1940 | inode->i_size = len-1; | |
1941 | if (len <= (char *)inode - (char *)info) { | |
1942 | /* do it inline */ | |
1943 | memcpy(info, symname, len); | |
1944 | inode->i_op = &shmem_symlink_inline_operations; | |
1945 | } else { | |
1946 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1947 | if (error) { | |
1948 | iput(inode); | |
1949 | return error; | |
1950 | } | |
d3602444 | 1951 | unlock_page(page); |
14fcc23f | 1952 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1953 | inode->i_op = &shmem_symlink_inode_operations; |
1954 | kaddr = kmap_atomic(page, KM_USER0); | |
1955 | memcpy(kaddr, symname, len); | |
1956 | kunmap_atomic(kaddr, KM_USER0); | |
1957 | set_page_dirty(page); | |
1958 | page_cache_release(page); | |
1959 | } | |
1960 | if (dir->i_mode & S_ISGID) | |
1961 | inode->i_gid = dir->i_gid; | |
1962 | dir->i_size += BOGO_DIRENT_SIZE; | |
1963 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1964 | d_instantiate(dentry, inode); | |
1965 | dget(dentry); | |
1966 | return 0; | |
1967 | } | |
1968 | ||
cc314eef | 1969 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1970 | { |
1971 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1972 | return NULL; |
1da177e4 LT |
1973 | } |
1974 | ||
cc314eef | 1975 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1976 | { |
1977 | struct page *page = NULL; | |
1978 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1979 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
1980 | if (page) |
1981 | unlock_page(page); | |
cc314eef | 1982 | return page; |
1da177e4 LT |
1983 | } |
1984 | ||
cc314eef | 1985 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1986 | { |
1987 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1988 | struct page *page = cookie; |
1da177e4 LT |
1989 | kunmap(page); |
1990 | mark_page_accessed(page); | |
1991 | page_cache_release(page); | |
1da177e4 LT |
1992 | } |
1993 | } | |
1994 | ||
92e1d5be | 1995 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
1996 | .readlink = generic_readlink, |
1997 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
1998 | }; |
1999 | ||
92e1d5be | 2000 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
2001 | .truncate = shmem_truncate, |
2002 | .readlink = generic_readlink, | |
2003 | .follow_link = shmem_follow_link, | |
2004 | .put_link = shmem_put_link, | |
1da177e4 LT |
2005 | }; |
2006 | ||
39f0247d | 2007 | #ifdef CONFIG_TMPFS_POSIX_ACL |
46711810 | 2008 | /* |
39f0247d AG |
2009 | * Superblocks without xattr inode operations will get security.* xattr |
2010 | * support from the VFS "for free". As soon as we have any other xattrs | |
2011 | * like ACLs, we also need to implement the security.* handlers at | |
2012 | * filesystem level, though. | |
2013 | */ | |
2014 | ||
2015 | static size_t shmem_xattr_security_list(struct inode *inode, char *list, | |
2016 | size_t list_len, const char *name, | |
2017 | size_t name_len) | |
2018 | { | |
2019 | return security_inode_listsecurity(inode, list, list_len); | |
2020 | } | |
2021 | ||
2022 | static int shmem_xattr_security_get(struct inode *inode, const char *name, | |
2023 | void *buffer, size_t size) | |
2024 | { | |
2025 | if (strcmp(name, "") == 0) | |
2026 | return -EINVAL; | |
42492594 | 2027 | return xattr_getsecurity(inode, name, buffer, size); |
39f0247d AG |
2028 | } |
2029 | ||
2030 | static int shmem_xattr_security_set(struct inode *inode, const char *name, | |
2031 | const void *value, size_t size, int flags) | |
2032 | { | |
2033 | if (strcmp(name, "") == 0) | |
2034 | return -EINVAL; | |
2035 | return security_inode_setsecurity(inode, name, value, size, flags); | |
2036 | } | |
2037 | ||
1f370a23 | 2038 | static struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
2039 | .prefix = XATTR_SECURITY_PREFIX, |
2040 | .list = shmem_xattr_security_list, | |
2041 | .get = shmem_xattr_security_get, | |
2042 | .set = shmem_xattr_security_set, | |
2043 | }; | |
2044 | ||
2045 | static struct xattr_handler *shmem_xattr_handlers[] = { | |
2046 | &shmem_xattr_acl_access_handler, | |
2047 | &shmem_xattr_acl_default_handler, | |
2048 | &shmem_xattr_security_handler, | |
2049 | NULL | |
2050 | }; | |
2051 | #endif | |
2052 | ||
91828a40 DG |
2053 | static struct dentry *shmem_get_parent(struct dentry *child) |
2054 | { | |
2055 | return ERR_PTR(-ESTALE); | |
2056 | } | |
2057 | ||
2058 | static int shmem_match(struct inode *ino, void *vfh) | |
2059 | { | |
2060 | __u32 *fh = vfh; | |
2061 | __u64 inum = fh[2]; | |
2062 | inum = (inum << 32) | fh[1]; | |
2063 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2064 | } | |
2065 | ||
480b116c CH |
2066 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2067 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2068 | { |
91828a40 | 2069 | struct inode *inode; |
480b116c CH |
2070 | struct dentry *dentry = NULL; |
2071 | u64 inum = fid->raw[2]; | |
2072 | inum = (inum << 32) | fid->raw[1]; | |
2073 | ||
2074 | if (fh_len < 3) | |
2075 | return NULL; | |
91828a40 | 2076 | |
480b116c CH |
2077 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2078 | shmem_match, fid->raw); | |
91828a40 | 2079 | if (inode) { |
480b116c | 2080 | dentry = d_find_alias(inode); |
91828a40 DG |
2081 | iput(inode); |
2082 | } | |
2083 | ||
480b116c | 2084 | return dentry; |
91828a40 DG |
2085 | } |
2086 | ||
2087 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2088 | int connectable) | |
2089 | { | |
2090 | struct inode *inode = dentry->d_inode; | |
2091 | ||
2092 | if (*len < 3) | |
2093 | return 255; | |
2094 | ||
2095 | if (hlist_unhashed(&inode->i_hash)) { | |
2096 | /* Unfortunately insert_inode_hash is not idempotent, | |
2097 | * so as we hash inodes here rather than at creation | |
2098 | * time, we need a lock to ensure we only try | |
2099 | * to do it once | |
2100 | */ | |
2101 | static DEFINE_SPINLOCK(lock); | |
2102 | spin_lock(&lock); | |
2103 | if (hlist_unhashed(&inode->i_hash)) | |
2104 | __insert_inode_hash(inode, | |
2105 | inode->i_ino + inode->i_generation); | |
2106 | spin_unlock(&lock); | |
2107 | } | |
2108 | ||
2109 | fh[0] = inode->i_generation; | |
2110 | fh[1] = inode->i_ino; | |
2111 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2112 | ||
2113 | *len = 3; | |
2114 | return 1; | |
2115 | } | |
2116 | ||
39655164 | 2117 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2118 | .get_parent = shmem_get_parent, |
91828a40 | 2119 | .encode_fh = shmem_encode_fh, |
480b116c | 2120 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2121 | }; |
2122 | ||
680d794b AM |
2123 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2124 | bool remount) | |
1da177e4 LT |
2125 | { |
2126 | char *this_char, *value, *rest; | |
2127 | ||
b00dc3ad HD |
2128 | while (options != NULL) { |
2129 | this_char = options; | |
2130 | for (;;) { | |
2131 | /* | |
2132 | * NUL-terminate this option: unfortunately, | |
2133 | * mount options form a comma-separated list, | |
2134 | * but mpol's nodelist may also contain commas. | |
2135 | */ | |
2136 | options = strchr(options, ','); | |
2137 | if (options == NULL) | |
2138 | break; | |
2139 | options++; | |
2140 | if (!isdigit(*options)) { | |
2141 | options[-1] = '\0'; | |
2142 | break; | |
2143 | } | |
2144 | } | |
1da177e4 LT |
2145 | if (!*this_char) |
2146 | continue; | |
2147 | if ((value = strchr(this_char,'=')) != NULL) { | |
2148 | *value++ = 0; | |
2149 | } else { | |
2150 | printk(KERN_ERR | |
2151 | "tmpfs: No value for mount option '%s'\n", | |
2152 | this_char); | |
2153 | return 1; | |
2154 | } | |
2155 | ||
2156 | if (!strcmp(this_char,"size")) { | |
2157 | unsigned long long size; | |
2158 | size = memparse(value,&rest); | |
2159 | if (*rest == '%') { | |
2160 | size <<= PAGE_SHIFT; | |
2161 | size *= totalram_pages; | |
2162 | do_div(size, 100); | |
2163 | rest++; | |
2164 | } | |
2165 | if (*rest) | |
2166 | goto bad_val; | |
680d794b AM |
2167 | sbinfo->max_blocks = |
2168 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2169 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2170 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2171 | if (*rest) |
2172 | goto bad_val; | |
2173 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2174 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2175 | if (*rest) |
2176 | goto bad_val; | |
2177 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2178 | if (remount) |
1da177e4 | 2179 | continue; |
680d794b | 2180 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2181 | if (*rest) |
2182 | goto bad_val; | |
2183 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2184 | if (remount) |
1da177e4 | 2185 | continue; |
680d794b | 2186 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2187 | if (*rest) |
2188 | goto bad_val; | |
2189 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2190 | if (remount) |
1da177e4 | 2191 | continue; |
680d794b | 2192 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2193 | if (*rest) |
2194 | goto bad_val; | |
7339ff83 | 2195 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2196 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2197 | goto bad_val; |
1da177e4 LT |
2198 | } else { |
2199 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2200 | this_char); | |
2201 | return 1; | |
2202 | } | |
2203 | } | |
2204 | return 0; | |
2205 | ||
2206 | bad_val: | |
2207 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2208 | value, this_char); | |
2209 | return 1; | |
2210 | ||
2211 | } | |
2212 | ||
2213 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2214 | { | |
2215 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2216 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2217 | unsigned long blocks; |
2218 | unsigned long inodes; | |
2219 | int error = -EINVAL; | |
2220 | ||
680d794b | 2221 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2222 | return error; |
1da177e4 | 2223 | |
0edd73b3 HD |
2224 | spin_lock(&sbinfo->stat_lock); |
2225 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2226 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
680d794b | 2227 | if (config.max_blocks < blocks) |
0edd73b3 | 2228 | goto out; |
680d794b | 2229 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2230 | goto out; |
2231 | /* | |
2232 | * Those tests also disallow limited->unlimited while any are in | |
2233 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2234 | * but we must separately disallow unlimited->limited, because | |
2235 | * in that case we have no record of how much is already in use. | |
2236 | */ | |
680d794b | 2237 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2238 | goto out; |
680d794b | 2239 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2240 | goto out; |
2241 | ||
2242 | error = 0; | |
680d794b AM |
2243 | sbinfo->max_blocks = config.max_blocks; |
2244 | sbinfo->free_blocks = config.max_blocks - blocks; | |
2245 | sbinfo->max_inodes = config.max_inodes; | |
2246 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2247 | |
2248 | mpol_put(sbinfo->mpol); | |
2249 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2250 | out: |
2251 | spin_unlock(&sbinfo->stat_lock); | |
2252 | return error; | |
1da177e4 | 2253 | } |
680d794b AM |
2254 | |
2255 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
2256 | { | |
2257 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
2258 | ||
2259 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2260 | seq_printf(seq, ",size=%luk", | |
2261 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2262 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2263 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2264 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
2265 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
2266 | if (sbinfo->uid != 0) | |
2267 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2268 | if (sbinfo->gid != 0) | |
2269 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 2270 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b AM |
2271 | return 0; |
2272 | } | |
2273 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2274 | |
2275 | static void shmem_put_super(struct super_block *sb) | |
2276 | { | |
2277 | kfree(sb->s_fs_info); | |
2278 | sb->s_fs_info = NULL; | |
2279 | } | |
2280 | ||
1da177e4 LT |
2281 | static int shmem_fill_super(struct super_block *sb, |
2282 | void *data, int silent) | |
2283 | { | |
2284 | struct inode *inode; | |
2285 | struct dentry *root; | |
0edd73b3 | 2286 | struct shmem_sb_info *sbinfo; |
680d794b AM |
2287 | int err = -ENOMEM; |
2288 | ||
2289 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
2290 | sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info), | |
2291 | L1_CACHE_BYTES), GFP_KERNEL); | |
2292 | if (!sbinfo) | |
2293 | return -ENOMEM; | |
2294 | ||
2295 | sbinfo->max_blocks = 0; | |
2296 | sbinfo->max_inodes = 0; | |
2297 | sbinfo->mode = S_IRWXUGO | S_ISVTX; | |
76aac0e9 DH |
2298 | sbinfo->uid = current_fsuid(); |
2299 | sbinfo->gid = current_fsgid(); | |
71fe804b | 2300 | sbinfo->mpol = NULL; |
680d794b | 2301 | sb->s_fs_info = sbinfo; |
1da177e4 | 2302 | |
0edd73b3 | 2303 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2304 | /* |
2305 | * Per default we only allow half of the physical ram per | |
2306 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2307 | * but the internal instance is left unlimited. | |
2308 | */ | |
2309 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b AM |
2310 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2311 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2312 | if (shmem_parse_options(data, sbinfo, false)) { | |
2313 | err = -EINVAL; | |
2314 | goto failed; | |
2315 | } | |
1da177e4 | 2316 | } |
91828a40 | 2317 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2318 | #else |
2319 | sb->s_flags |= MS_NOUSER; | |
2320 | #endif | |
2321 | ||
0edd73b3 | 2322 | spin_lock_init(&sbinfo->stat_lock); |
680d794b AM |
2323 | sbinfo->free_blocks = sbinfo->max_blocks; |
2324 | sbinfo->free_inodes = sbinfo->max_inodes; | |
0edd73b3 | 2325 | |
1da177e4 LT |
2326 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2327 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2328 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2329 | sb->s_magic = TMPFS_MAGIC; | |
2330 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2331 | sb->s_time_gran = 1; |
39f0247d AG |
2332 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2333 | sb->s_xattr = shmem_xattr_handlers; | |
2334 | sb->s_flags |= MS_POSIXACL; | |
2335 | #endif | |
0edd73b3 | 2336 | |
0b0a0806 | 2337 | inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2338 | if (!inode) |
2339 | goto failed; | |
680d794b AM |
2340 | inode->i_uid = sbinfo->uid; |
2341 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2342 | root = d_alloc_root(inode); |
2343 | if (!root) | |
2344 | goto failed_iput; | |
2345 | sb->s_root = root; | |
2346 | return 0; | |
2347 | ||
2348 | failed_iput: | |
2349 | iput(inode); | |
2350 | failed: | |
2351 | shmem_put_super(sb); | |
2352 | return err; | |
2353 | } | |
2354 | ||
fcc234f8 | 2355 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2356 | |
2357 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2358 | { | |
2359 | struct shmem_inode_info *p; | |
e94b1766 | 2360 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2361 | if (!p) |
2362 | return NULL; | |
2363 | return &p->vfs_inode; | |
2364 | } | |
2365 | ||
2366 | static void shmem_destroy_inode(struct inode *inode) | |
2367 | { | |
2368 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2369 | /* only struct inode is valid if it's an inline symlink */ | |
2370 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2371 | } | |
39f0247d | 2372 | shmem_acl_destroy_inode(inode); |
1da177e4 LT |
2373 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
2374 | } | |
2375 | ||
51cc5068 | 2376 | static void init_once(void *foo) |
1da177e4 LT |
2377 | { |
2378 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2379 | ||
a35afb83 | 2380 | inode_init_once(&p->vfs_inode); |
39f0247d | 2381 | #ifdef CONFIG_TMPFS_POSIX_ACL |
a35afb83 CL |
2382 | p->i_acl = NULL; |
2383 | p->i_default_acl = NULL; | |
39f0247d | 2384 | #endif |
1da177e4 LT |
2385 | } |
2386 | ||
2387 | static int init_inodecache(void) | |
2388 | { | |
2389 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2390 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2391 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2392 | return 0; |
2393 | } | |
2394 | ||
2395 | static void destroy_inodecache(void) | |
2396 | { | |
1a1d92c1 | 2397 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2398 | } |
2399 | ||
f5e54d6e | 2400 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2401 | .writepage = shmem_writepage, |
76719325 | 2402 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2403 | #ifdef CONFIG_TMPFS |
ae976416 | 2404 | .readpage = shmem_readpage, |
800d15a5 NP |
2405 | .write_begin = shmem_write_begin, |
2406 | .write_end = shmem_write_end, | |
1da177e4 | 2407 | #endif |
304dbdb7 | 2408 | .migratepage = migrate_page, |
1da177e4 LT |
2409 | }; |
2410 | ||
15ad7cdc | 2411 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2412 | .mmap = shmem_mmap, |
2413 | #ifdef CONFIG_TMPFS | |
2414 | .llseek = generic_file_llseek, | |
bcd78e49 | 2415 | .read = do_sync_read, |
5402b976 | 2416 | .write = do_sync_write, |
bcd78e49 | 2417 | .aio_read = shmem_file_aio_read, |
5402b976 | 2418 | .aio_write = generic_file_aio_write, |
1da177e4 | 2419 | .fsync = simple_sync_file, |
ae976416 HD |
2420 | .splice_read = generic_file_splice_read, |
2421 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2422 | #endif |
2423 | }; | |
2424 | ||
92e1d5be | 2425 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2426 | .truncate = shmem_truncate, |
2427 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2428 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2429 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2430 | .setxattr = generic_setxattr, | |
2431 | .getxattr = generic_getxattr, | |
2432 | .listxattr = generic_listxattr, | |
2433 | .removexattr = generic_removexattr, | |
2434 | .permission = shmem_permission, | |
2435 | #endif | |
2436 | ||
1da177e4 LT |
2437 | }; |
2438 | ||
92e1d5be | 2439 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2440 | #ifdef CONFIG_TMPFS |
2441 | .create = shmem_create, | |
2442 | .lookup = simple_lookup, | |
2443 | .link = shmem_link, | |
2444 | .unlink = shmem_unlink, | |
2445 | .symlink = shmem_symlink, | |
2446 | .mkdir = shmem_mkdir, | |
2447 | .rmdir = shmem_rmdir, | |
2448 | .mknod = shmem_mknod, | |
2449 | .rename = shmem_rename, | |
1da177e4 | 2450 | #endif |
39f0247d AG |
2451 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2452 | .setattr = shmem_notify_change, | |
2453 | .setxattr = generic_setxattr, | |
2454 | .getxattr = generic_getxattr, | |
2455 | .listxattr = generic_listxattr, | |
2456 | .removexattr = generic_removexattr, | |
2457 | .permission = shmem_permission, | |
2458 | #endif | |
2459 | }; | |
2460 | ||
92e1d5be | 2461 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2462 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2463 | .setattr = shmem_notify_change, | |
2464 | .setxattr = generic_setxattr, | |
2465 | .getxattr = generic_getxattr, | |
2466 | .listxattr = generic_listxattr, | |
2467 | .removexattr = generic_removexattr, | |
2468 | .permission = shmem_permission, | |
2469 | #endif | |
1da177e4 LT |
2470 | }; |
2471 | ||
759b9775 | 2472 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2473 | .alloc_inode = shmem_alloc_inode, |
2474 | .destroy_inode = shmem_destroy_inode, | |
2475 | #ifdef CONFIG_TMPFS | |
2476 | .statfs = shmem_statfs, | |
2477 | .remount_fs = shmem_remount_fs, | |
680d794b | 2478 | .show_options = shmem_show_options, |
1da177e4 LT |
2479 | #endif |
2480 | .delete_inode = shmem_delete_inode, | |
2481 | .drop_inode = generic_delete_inode, | |
2482 | .put_super = shmem_put_super, | |
2483 | }; | |
2484 | ||
2485 | static struct vm_operations_struct shmem_vm_ops = { | |
54cb8821 | 2486 | .fault = shmem_fault, |
1da177e4 LT |
2487 | #ifdef CONFIG_NUMA |
2488 | .set_policy = shmem_set_policy, | |
2489 | .get_policy = shmem_get_policy, | |
2490 | #endif | |
2491 | }; | |
2492 | ||
2493 | ||
454e2398 DH |
2494 | static int shmem_get_sb(struct file_system_type *fs_type, |
2495 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2496 | { |
454e2398 | 2497 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2498 | } |
2499 | ||
2500 | static struct file_system_type tmpfs_fs_type = { | |
2501 | .owner = THIS_MODULE, | |
2502 | .name = "tmpfs", | |
2503 | .get_sb = shmem_get_sb, | |
2504 | .kill_sb = kill_litter_super, | |
2505 | }; | |
1da177e4 LT |
2506 | |
2507 | static int __init init_tmpfs(void) | |
2508 | { | |
2509 | int error; | |
2510 | ||
e0bf68dd PZ |
2511 | error = bdi_init(&shmem_backing_dev_info); |
2512 | if (error) | |
2513 | goto out4; | |
2514 | ||
1da177e4 LT |
2515 | error = init_inodecache(); |
2516 | if (error) | |
2517 | goto out3; | |
2518 | ||
2519 | error = register_filesystem(&tmpfs_fs_type); | |
2520 | if (error) { | |
2521 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2522 | goto out2; | |
2523 | } | |
95dc112a | 2524 | |
1f5ce9e9 | 2525 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2526 | tmpfs_fs_type.name, NULL); |
2527 | if (IS_ERR(shm_mnt)) { | |
2528 | error = PTR_ERR(shm_mnt); | |
2529 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2530 | goto out1; | |
2531 | } | |
2532 | return 0; | |
2533 | ||
2534 | out1: | |
2535 | unregister_filesystem(&tmpfs_fs_type); | |
2536 | out2: | |
2537 | destroy_inodecache(); | |
2538 | out3: | |
e0bf68dd PZ |
2539 | bdi_destroy(&shmem_backing_dev_info); |
2540 | out4: | |
1da177e4 LT |
2541 | shm_mnt = ERR_PTR(error); |
2542 | return error; | |
2543 | } | |
853ac43a MM |
2544 | |
2545 | #else /* !CONFIG_SHMEM */ | |
2546 | ||
2547 | /* | |
2548 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2549 | * | |
2550 | * This is intended for small system where the benefits of the full | |
2551 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2552 | * their complexity. On systems without swap this code should be | |
2553 | * effectively equivalent, but much lighter weight. | |
2554 | */ | |
2555 | ||
2556 | #include <linux/ramfs.h> | |
2557 | ||
2558 | static struct file_system_type tmpfs_fs_type = { | |
2559 | .name = "tmpfs", | |
2560 | .get_sb = ramfs_get_sb, | |
2561 | .kill_sb = kill_litter_super, | |
2562 | }; | |
2563 | ||
2564 | static int __init init_tmpfs(void) | |
2565 | { | |
2566 | BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); | |
2567 | ||
2568 | shm_mnt = kern_mount(&tmpfs_fs_type); | |
2569 | BUG_ON(IS_ERR(shm_mnt)); | |
2570 | ||
2571 | return 0; | |
2572 | } | |
2573 | ||
2574 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
2575 | { | |
2576 | return 0; | |
2577 | } | |
2578 | ||
0b0a0806 HD |
2579 | #define shmem_vm_ops generic_file_vm_ops |
2580 | #define shmem_file_operations ramfs_file_operations | |
2581 | #define shmem_get_inode(sb, mode, dev, flags) ramfs_get_inode(sb, mode, dev) | |
2582 | #define shmem_acct_size(flags, size) 0 | |
2583 | #define shmem_unacct_size(flags, size) do {} while (0) | |
2584 | #define SHMEM_MAX_BYTES LLONG_MAX | |
853ac43a MM |
2585 | |
2586 | #endif /* CONFIG_SHMEM */ | |
2587 | ||
2588 | /* common code */ | |
1da177e4 | 2589 | |
46711810 | 2590 | /** |
1da177e4 | 2591 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2592 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2593 | * @size: size to be set for the file | |
0b0a0806 | 2594 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 LT |
2595 | */ |
2596 | struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags) | |
2597 | { | |
2598 | int error; | |
2599 | struct file *file; | |
2600 | struct inode *inode; | |
2601 | struct dentry *dentry, *root; | |
2602 | struct qstr this; | |
2603 | ||
2604 | if (IS_ERR(shm_mnt)) | |
2605 | return (void *)shm_mnt; | |
2606 | ||
2607 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2608 | return ERR_PTR(-EINVAL); | |
2609 | ||
2610 | if (shmem_acct_size(flags, size)) | |
2611 | return ERR_PTR(-ENOMEM); | |
2612 | ||
2613 | error = -ENOMEM; | |
2614 | this.name = name; | |
2615 | this.len = strlen(name); | |
2616 | this.hash = 0; /* will go */ | |
2617 | root = shm_mnt->mnt_root; | |
2618 | dentry = d_alloc(root, &this); | |
2619 | if (!dentry) | |
2620 | goto put_memory; | |
2621 | ||
2622 | error = -ENFILE; | |
2623 | file = get_empty_filp(); | |
2624 | if (!file) | |
2625 | goto put_dentry; | |
2626 | ||
2627 | error = -ENOSPC; | |
0b0a0806 | 2628 | inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 LT |
2629 | if (!inode) |
2630 | goto close_file; | |
2631 | ||
1da177e4 LT |
2632 | d_instantiate(dentry, inode); |
2633 | inode->i_size = size; | |
2634 | inode->i_nlink = 0; /* It is unlinked */ | |
ce8d2cdf | 2635 | init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ, |
853ac43a MM |
2636 | &shmem_file_operations); |
2637 | ||
2638 | #ifndef CONFIG_MMU | |
2639 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2640 | if (error) | |
2641 | goto close_file; | |
2642 | #endif | |
1da177e4 LT |
2643 | return file; |
2644 | ||
2645 | close_file: | |
2646 | put_filp(file); | |
2647 | put_dentry: | |
2648 | dput(dentry); | |
2649 | put_memory: | |
2650 | shmem_unacct_size(flags, size); | |
2651 | return ERR_PTR(error); | |
2652 | } | |
395e0ddc | 2653 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2654 | |
46711810 | 2655 | /** |
1da177e4 | 2656 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2657 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2658 | */ | |
2659 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2660 | { | |
2661 | struct file *file; | |
2662 | loff_t size = vma->vm_end - vma->vm_start; | |
2663 | ||
2664 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2665 | if (IS_ERR(file)) | |
2666 | return PTR_ERR(file); | |
2667 | ||
1df9f0a7 | 2668 | ima_shm_check(file); |
1da177e4 LT |
2669 | if (vma->vm_file) |
2670 | fput(vma->vm_file); | |
2671 | vma->vm_file = file; | |
2672 | vma->vm_ops = &shmem_vm_ops; | |
2673 | return 0; | |
2674 | } | |
853ac43a MM |
2675 | |
2676 | module_init(init_tmpfs) |