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> | |
caefba17 | 27 | #include <linux/pagemap.h> |
853ac43a MM |
28 | #include <linux/file.h> |
29 | #include <linux/mm.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/swap.h> | |
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> |
1c7c474c | 44 | #include <linux/posix_acl.h> |
39f0247d | 45 | #include <linux/generic_acl.h> |
1da177e4 | 46 | #include <linux/mman.h> |
1da177e4 LT |
47 | #include <linux/string.h> |
48 | #include <linux/slab.h> | |
49 | #include <linux/backing-dev.h> | |
50 | #include <linux/shmem_fs.h> | |
1da177e4 | 51 | #include <linux/writeback.h> |
1da177e4 LT |
52 | #include <linux/blkdev.h> |
53 | #include <linux/security.h> | |
54 | #include <linux/swapops.h> | |
55 | #include <linux/mempolicy.h> | |
56 | #include <linux/namei.h> | |
b00dc3ad | 57 | #include <linux/ctype.h> |
304dbdb7 | 58 | #include <linux/migrate.h> |
c1f60a5a | 59 | #include <linux/highmem.h> |
680d794b | 60 | #include <linux/seq_file.h> |
92562927 | 61 | #include <linux/magic.h> |
304dbdb7 | 62 | |
1da177e4 LT |
63 | #include <asm/uaccess.h> |
64 | #include <asm/div64.h> | |
65 | #include <asm/pgtable.h> | |
66 | ||
caefba17 HD |
67 | /* |
68 | * The maximum size of a shmem/tmpfs file is limited by the maximum size of | |
69 | * its triple-indirect swap vector - see illustration at shmem_swp_entry(). | |
70 | * | |
71 | * With 4kB page size, maximum file size is just over 2TB on a 32-bit kernel, | |
72 | * but one eighth of that on a 64-bit kernel. With 8kB page size, maximum | |
73 | * file size is just over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel, | |
74 | * MAX_LFS_FILESIZE being then more restrictive than swap vector layout. | |
75 | * | |
76 | * We use / and * instead of shifts in the definitions below, so that the swap | |
77 | * vector can be tested with small even values (e.g. 20) for ENTRIES_PER_PAGE. | |
78 | */ | |
1da177e4 | 79 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) |
61609d01 | 80 | #define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) |
1da177e4 | 81 | |
caefba17 HD |
82 | #define SHMSWP_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) |
83 | #define SHMSWP_MAX_BYTES (SHMSWP_MAX_INDEX << PAGE_CACHE_SHIFT) | |
1da177e4 | 84 | |
caefba17 HD |
85 | #define SHMEM_MAX_BYTES min_t(unsigned long long, SHMSWP_MAX_BYTES, MAX_LFS_FILESIZE) |
86 | #define SHMEM_MAX_INDEX ((unsigned long)((SHMEM_MAX_BYTES+1) >> PAGE_CACHE_SHIFT)) | |
87 | ||
88 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
1da177e4 LT |
89 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
90 | ||
91 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
92 | #define SHMEM_PAGEIN VM_READ | |
93 | #define SHMEM_TRUNCATE VM_WRITE | |
94 | ||
95 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
96 | #define LATENCY_LIMIT 64 | |
97 | ||
98 | /* Pretend that each entry is of this size in directory's i_size */ | |
99 | #define BOGO_DIRENT_SIZE 20 | |
100 | ||
1da177e4 LT |
101 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
102 | enum sgp_type { | |
1da177e4 LT |
103 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
104 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 105 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
106 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
107 | }; | |
108 | ||
b76db735 | 109 | #ifdef CONFIG_TMPFS |
680d794b | 110 | static unsigned long shmem_default_max_blocks(void) |
111 | { | |
112 | return totalram_pages / 2; | |
113 | } | |
114 | ||
115 | static unsigned long shmem_default_max_inodes(void) | |
116 | { | |
117 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
118 | } | |
b76db735 | 119 | #endif |
680d794b | 120 | |
1da177e4 LT |
121 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
122 | struct page **pagep, enum sgp_type sgp, int *type); | |
123 | ||
6daa0e28 | 124 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
125 | { |
126 | /* | |
127 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
128 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
129 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 | 130 | * |
e12ba74d | 131 | * Mobility flags are masked out as swap vectors cannot move |
1da177e4 | 132 | */ |
e12ba74d | 133 | return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO, |
769848c0 | 134 | PAGE_CACHE_SHIFT-PAGE_SHIFT); |
1da177e4 LT |
135 | } |
136 | ||
137 | static inline void shmem_dir_free(struct page *page) | |
138 | { | |
139 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
140 | } | |
141 | ||
142 | static struct page **shmem_dir_map(struct page *page) | |
143 | { | |
144 | return (struct page **)kmap_atomic(page, KM_USER0); | |
145 | } | |
146 | ||
147 | static inline void shmem_dir_unmap(struct page **dir) | |
148 | { | |
149 | kunmap_atomic(dir, KM_USER0); | |
150 | } | |
151 | ||
152 | static swp_entry_t *shmem_swp_map(struct page *page) | |
153 | { | |
154 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
155 | } | |
156 | ||
157 | static inline void shmem_swp_balance_unmap(void) | |
158 | { | |
159 | /* | |
160 | * When passing a pointer to an i_direct entry, to code which | |
161 | * also handles indirect entries and so will shmem_swp_unmap, | |
162 | * we must arrange for the preempt count to remain in balance. | |
163 | * What kmap_atomic of a lowmem page does depends on config | |
164 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
165 | */ | |
166 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
167 | } | |
168 | ||
169 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
170 | { | |
171 | kunmap_atomic(entry, KM_USER1); | |
172 | } | |
173 | ||
174 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
175 | { | |
176 | return sb->s_fs_info; | |
177 | } | |
178 | ||
179 | /* | |
180 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
181 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
182 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
183 | * consistent with the pre-accounting of private mappings ... | |
184 | */ | |
185 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
186 | { | |
0b0a0806 HD |
187 | return (flags & VM_NORESERVE) ? |
188 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
189 | } |
190 | ||
191 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
192 | { | |
0b0a0806 | 193 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
194 | vm_unacct_memory(VM_ACCT(size)); |
195 | } | |
196 | ||
197 | /* | |
198 | * ... whereas tmpfs objects are accounted incrementally as | |
199 | * pages are allocated, in order to allow huge sparse files. | |
200 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
201 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
202 | */ | |
203 | static inline int shmem_acct_block(unsigned long flags) | |
204 | { | |
0b0a0806 HD |
205 | return (flags & VM_NORESERVE) ? |
206 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
207 | } |
208 | ||
209 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
210 | { | |
0b0a0806 | 211 | if (flags & VM_NORESERVE) |
1da177e4 LT |
212 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
213 | } | |
214 | ||
759b9775 | 215 | static const struct super_operations shmem_ops; |
f5e54d6e | 216 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 217 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
218 | static const struct inode_operations shmem_inode_operations; |
219 | static const struct inode_operations shmem_dir_inode_operations; | |
220 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 221 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 222 | |
6c231b7b | 223 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 224 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 225 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
226 | .unplug_io_fn = default_unplug_io_fn, |
227 | }; | |
228 | ||
229 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 230 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 LT |
231 | |
232 | static void shmem_free_blocks(struct inode *inode, long pages) | |
233 | { | |
234 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 235 | if (sbinfo->max_blocks) { |
1da177e4 LT |
236 | spin_lock(&sbinfo->stat_lock); |
237 | sbinfo->free_blocks += pages; | |
238 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; | |
239 | spin_unlock(&sbinfo->stat_lock); | |
240 | } | |
241 | } | |
242 | ||
5b04c689 PE |
243 | static int shmem_reserve_inode(struct super_block *sb) |
244 | { | |
245 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
246 | if (sbinfo->max_inodes) { | |
247 | spin_lock(&sbinfo->stat_lock); | |
248 | if (!sbinfo->free_inodes) { | |
249 | spin_unlock(&sbinfo->stat_lock); | |
250 | return -ENOSPC; | |
251 | } | |
252 | sbinfo->free_inodes--; | |
253 | spin_unlock(&sbinfo->stat_lock); | |
254 | } | |
255 | return 0; | |
256 | } | |
257 | ||
258 | static void shmem_free_inode(struct super_block *sb) | |
259 | { | |
260 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
261 | if (sbinfo->max_inodes) { | |
262 | spin_lock(&sbinfo->stat_lock); | |
263 | sbinfo->free_inodes++; | |
264 | spin_unlock(&sbinfo->stat_lock); | |
265 | } | |
266 | } | |
267 | ||
46711810 | 268 | /** |
1da177e4 | 269 | * shmem_recalc_inode - recalculate the size of an inode |
1da177e4 LT |
270 | * @inode: inode to recalc |
271 | * | |
272 | * We have to calculate the free blocks since the mm can drop | |
273 | * undirtied hole pages behind our back. | |
274 | * | |
275 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
276 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
277 | * | |
278 | * It has to be called with the spinlock held. | |
279 | */ | |
280 | static void shmem_recalc_inode(struct inode *inode) | |
281 | { | |
282 | struct shmem_inode_info *info = SHMEM_I(inode); | |
283 | long freed; | |
284 | ||
285 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
286 | if (freed > 0) { | |
287 | info->alloced -= freed; | |
288 | shmem_unacct_blocks(info->flags, freed); | |
289 | shmem_free_blocks(inode, freed); | |
290 | } | |
291 | } | |
292 | ||
46711810 | 293 | /** |
1da177e4 | 294 | * shmem_swp_entry - find the swap vector position in the info structure |
1da177e4 LT |
295 | * @info: info structure for the inode |
296 | * @index: index of the page to find | |
297 | * @page: optional page to add to the structure. Has to be preset to | |
298 | * all zeros | |
299 | * | |
300 | * If there is no space allocated yet it will return NULL when | |
301 | * page is NULL, else it will use the page for the needed block, | |
302 | * setting it to NULL on return to indicate that it has been used. | |
303 | * | |
304 | * The swap vector is organized the following way: | |
305 | * | |
306 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
307 | * shmem_inode_info structure. So small files do not need an addional | |
308 | * allocation. | |
309 | * | |
310 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
311 | * i_indirect which points to a page which holds in the first half | |
312 | * doubly indirect blocks, in the second half triple indirect blocks: | |
313 | * | |
314 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
315 | * following layout (for SHMEM_NR_DIRECT == 16): | |
316 | * | |
317 | * i_indirect -> dir --> 16-19 | |
318 | * | +-> 20-23 | |
319 | * | | |
320 | * +-->dir2 --> 24-27 | |
321 | * | +-> 28-31 | |
322 | * | +-> 32-35 | |
323 | * | +-> 36-39 | |
324 | * | | |
325 | * +-->dir3 --> 40-43 | |
326 | * +-> 44-47 | |
327 | * +-> 48-51 | |
328 | * +-> 52-55 | |
329 | */ | |
330 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
331 | { | |
332 | unsigned long offset; | |
333 | struct page **dir; | |
334 | struct page *subdir; | |
335 | ||
336 | if (index < SHMEM_NR_DIRECT) { | |
337 | shmem_swp_balance_unmap(); | |
338 | return info->i_direct+index; | |
339 | } | |
340 | if (!info->i_indirect) { | |
341 | if (page) { | |
342 | info->i_indirect = *page; | |
343 | *page = NULL; | |
344 | } | |
345 | return NULL; /* need another page */ | |
346 | } | |
347 | ||
348 | index -= SHMEM_NR_DIRECT; | |
349 | offset = index % ENTRIES_PER_PAGE; | |
350 | index /= ENTRIES_PER_PAGE; | |
351 | dir = shmem_dir_map(info->i_indirect); | |
352 | ||
353 | if (index >= ENTRIES_PER_PAGE/2) { | |
354 | index -= ENTRIES_PER_PAGE/2; | |
355 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
356 | index %= ENTRIES_PER_PAGE; | |
357 | subdir = *dir; | |
358 | if (!subdir) { | |
359 | if (page) { | |
360 | *dir = *page; | |
361 | *page = NULL; | |
362 | } | |
363 | shmem_dir_unmap(dir); | |
364 | return NULL; /* need another page */ | |
365 | } | |
366 | shmem_dir_unmap(dir); | |
367 | dir = shmem_dir_map(subdir); | |
368 | } | |
369 | ||
370 | dir += index; | |
371 | subdir = *dir; | |
372 | if (!subdir) { | |
373 | if (!page || !(subdir = *page)) { | |
374 | shmem_dir_unmap(dir); | |
375 | return NULL; /* need a page */ | |
376 | } | |
377 | *dir = subdir; | |
378 | *page = NULL; | |
379 | } | |
380 | shmem_dir_unmap(dir); | |
381 | return shmem_swp_map(subdir) + offset; | |
382 | } | |
383 | ||
384 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
385 | { | |
386 | long incdec = value? 1: -1; | |
387 | ||
388 | entry->val = value; | |
389 | info->swapped += incdec; | |
4c21e2f2 HD |
390 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
391 | struct page *page = kmap_atomic_to_page(entry); | |
392 | set_page_private(page, page_private(page) + incdec); | |
393 | } | |
1da177e4 LT |
394 | } |
395 | ||
46711810 | 396 | /** |
1da177e4 | 397 | * shmem_swp_alloc - get the position of the swap entry for the page. |
1da177e4 LT |
398 | * @info: info structure for the inode |
399 | * @index: index of the page to find | |
400 | * @sgp: check and recheck i_size? skip allocation? | |
46711810 RD |
401 | * |
402 | * If the entry does not exist, allocate it. | |
1da177e4 LT |
403 | */ |
404 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
405 | { | |
406 | struct inode *inode = &info->vfs_inode; | |
407 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
408 | struct page *page = NULL; | |
409 | swp_entry_t *entry; | |
410 | ||
411 | if (sgp != SGP_WRITE && | |
412 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
413 | return ERR_PTR(-EINVAL); | |
414 | ||
415 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
416 | if (sgp == SGP_READ) | |
417 | return shmem_swp_map(ZERO_PAGE(0)); | |
418 | /* | |
419 | * Test free_blocks against 1 not 0, since we have 1 data | |
420 | * page (and perhaps indirect index pages) yet to allocate: | |
421 | * a waste to allocate index if we cannot allocate data. | |
422 | */ | |
0edd73b3 | 423 | if (sbinfo->max_blocks) { |
1da177e4 LT |
424 | spin_lock(&sbinfo->stat_lock); |
425 | if (sbinfo->free_blocks <= 1) { | |
426 | spin_unlock(&sbinfo->stat_lock); | |
427 | return ERR_PTR(-ENOSPC); | |
428 | } | |
429 | sbinfo->free_blocks--; | |
430 | inode->i_blocks += BLOCKS_PER_PAGE; | |
431 | spin_unlock(&sbinfo->stat_lock); | |
432 | } | |
433 | ||
434 | spin_unlock(&info->lock); | |
769848c0 | 435 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
1da177e4 LT |
436 | spin_lock(&info->lock); |
437 | ||
438 | if (!page) { | |
439 | shmem_free_blocks(inode, 1); | |
440 | return ERR_PTR(-ENOMEM); | |
441 | } | |
442 | if (sgp != SGP_WRITE && | |
443 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
444 | entry = ERR_PTR(-EINVAL); | |
445 | break; | |
446 | } | |
447 | if (info->next_index <= index) | |
448 | info->next_index = index + 1; | |
449 | } | |
450 | if (page) { | |
451 | /* another task gave its page, or truncated the file */ | |
452 | shmem_free_blocks(inode, 1); | |
453 | shmem_dir_free(page); | |
454 | } | |
455 | if (info->next_index <= index && !IS_ERR(entry)) | |
456 | info->next_index = index + 1; | |
457 | return entry; | |
458 | } | |
459 | ||
46711810 | 460 | /** |
1da177e4 | 461 | * shmem_free_swp - free some swap entries in a directory |
1ae70006 HD |
462 | * @dir: pointer to the directory |
463 | * @edir: pointer after last entry of the directory | |
464 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 465 | */ |
1ae70006 HD |
466 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
467 | spinlock_t *punch_lock) | |
1da177e4 | 468 | { |
1ae70006 | 469 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
470 | swp_entry_t *ptr; |
471 | int freed = 0; | |
472 | ||
473 | for (ptr = dir; ptr < edir; ptr++) { | |
474 | if (ptr->val) { | |
1ae70006 HD |
475 | if (unlikely(punch_lock)) { |
476 | punch_unlock = punch_lock; | |
477 | punch_lock = NULL; | |
478 | spin_lock(punch_unlock); | |
479 | if (!ptr->val) | |
480 | continue; | |
481 | } | |
1da177e4 LT |
482 | free_swap_and_cache(*ptr); |
483 | *ptr = (swp_entry_t){0}; | |
484 | freed++; | |
485 | } | |
486 | } | |
1ae70006 HD |
487 | if (punch_unlock) |
488 | spin_unlock(punch_unlock); | |
1da177e4 LT |
489 | return freed; |
490 | } | |
491 | ||
1ae70006 HD |
492 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
493 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
494 | { |
495 | swp_entry_t *ptr; | |
496 | int freed = 0; | |
497 | ||
498 | ptr = shmem_swp_map(subdir); | |
499 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
500 | int size = limit - offset; | |
501 | if (size > LATENCY_LIMIT) | |
502 | size = LATENCY_LIMIT; | |
1ae70006 HD |
503 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
504 | punch_lock); | |
1da177e4 LT |
505 | if (need_resched()) { |
506 | shmem_swp_unmap(ptr); | |
507 | if (*dir) { | |
508 | shmem_dir_unmap(*dir); | |
509 | *dir = NULL; | |
510 | } | |
511 | cond_resched(); | |
512 | ptr = shmem_swp_map(subdir); | |
513 | } | |
514 | } | |
515 | shmem_swp_unmap(ptr); | |
516 | return freed; | |
517 | } | |
518 | ||
519 | static void shmem_free_pages(struct list_head *next) | |
520 | { | |
521 | struct page *page; | |
522 | int freed = 0; | |
523 | ||
524 | do { | |
525 | page = container_of(next, struct page, lru); | |
526 | next = next->next; | |
527 | shmem_dir_free(page); | |
528 | freed++; | |
529 | if (freed >= LATENCY_LIMIT) { | |
530 | cond_resched(); | |
531 | freed = 0; | |
532 | } | |
533 | } while (next); | |
534 | } | |
535 | ||
f6b3ec23 | 536 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
537 | { |
538 | struct shmem_inode_info *info = SHMEM_I(inode); | |
539 | unsigned long idx; | |
540 | unsigned long size; | |
541 | unsigned long limit; | |
542 | unsigned long stage; | |
543 | unsigned long diroff; | |
544 | struct page **dir; | |
545 | struct page *topdir; | |
546 | struct page *middir; | |
547 | struct page *subdir; | |
548 | swp_entry_t *ptr; | |
549 | LIST_HEAD(pages_to_free); | |
550 | long nr_pages_to_free = 0; | |
551 | long nr_swaps_freed = 0; | |
552 | int offset; | |
553 | int freed; | |
a2646d1e | 554 | int punch_hole; |
1ae70006 HD |
555 | spinlock_t *needs_lock; |
556 | spinlock_t *punch_lock; | |
a2646d1e | 557 | unsigned long upper_limit; |
1da177e4 LT |
558 | |
559 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 560 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
561 | if (idx >= info->next_index) |
562 | return; | |
563 | ||
564 | spin_lock(&info->lock); | |
565 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
566 | if (likely(end == (loff_t) -1)) { |
567 | limit = info->next_index; | |
a2646d1e | 568 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 569 | info->next_index = idx; |
1ae70006 | 570 | needs_lock = NULL; |
a2646d1e | 571 | punch_hole = 0; |
f6b3ec23 | 572 | } else { |
a2646d1e HD |
573 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
574 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
575 | PAGE_CACHE_SHIFT; | |
576 | upper_limit = SHMEM_MAX_INDEX; | |
577 | } else { | |
578 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
579 | upper_limit = limit; | |
580 | } | |
1ae70006 | 581 | needs_lock = &info->lock; |
f6b3ec23 BP |
582 | punch_hole = 1; |
583 | } | |
584 | ||
1da177e4 | 585 | topdir = info->i_indirect; |
f6b3ec23 | 586 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
587 | info->i_indirect = NULL; |
588 | nr_pages_to_free++; | |
589 | list_add(&topdir->lru, &pages_to_free); | |
590 | } | |
591 | spin_unlock(&info->lock); | |
592 | ||
593 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
594 | ptr = info->i_direct; | |
595 | size = limit; | |
596 | if (size > SHMEM_NR_DIRECT) | |
597 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 598 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 599 | } |
92a3d03a BP |
600 | |
601 | /* | |
602 | * If there are no indirect blocks or we are punching a hole | |
603 | * below indirect blocks, nothing to be done. | |
604 | */ | |
a2646d1e | 605 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
606 | goto done2; |
607 | ||
1ae70006 HD |
608 | /* |
609 | * The truncation case has already dropped info->lock, and we're safe | |
610 | * because i_size and next_index have already been lowered, preventing | |
611 | * access beyond. But in the punch_hole case, we still need to take | |
612 | * the lock when updating the swap directory, because there might be | |
613 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
614 | * shmem_writepage. However, whenever we find we can remove a whole | |
615 | * directory page (not at the misaligned start or end of the range), | |
616 | * we first NULLify its pointer in the level above, and then have no | |
617 | * need to take the lock when updating its contents: needs_lock and | |
618 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
619 | */ | |
620 | ||
a2646d1e | 621 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
622 | limit -= SHMEM_NR_DIRECT; |
623 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
624 | offset = idx % ENTRIES_PER_PAGE; | |
625 | idx -= offset; | |
626 | ||
627 | dir = shmem_dir_map(topdir); | |
628 | stage = ENTRIES_PER_PAGEPAGE/2; | |
629 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
630 | middir = topdir; | |
631 | diroff = idx/ENTRIES_PER_PAGE; | |
632 | } else { | |
633 | dir += ENTRIES_PER_PAGE/2; | |
634 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
635 | while (stage <= idx) | |
636 | stage += ENTRIES_PER_PAGEPAGE; | |
637 | middir = *dir; | |
638 | if (*dir) { | |
639 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
640 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 641 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
642 | if (needs_lock) { |
643 | spin_lock(needs_lock); | |
644 | *dir = NULL; | |
645 | spin_unlock(needs_lock); | |
646 | needs_lock = NULL; | |
647 | } else | |
648 | *dir = NULL; | |
1da177e4 LT |
649 | nr_pages_to_free++; |
650 | list_add(&middir->lru, &pages_to_free); | |
651 | } | |
652 | shmem_dir_unmap(dir); | |
653 | dir = shmem_dir_map(middir); | |
654 | } else { | |
655 | diroff = 0; | |
656 | offset = 0; | |
657 | idx = stage; | |
658 | } | |
659 | } | |
660 | ||
661 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
662 | if (unlikely(idx == stage)) { | |
663 | shmem_dir_unmap(dir); | |
664 | dir = shmem_dir_map(topdir) + | |
665 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
666 | while (!*dir) { | |
667 | dir++; | |
668 | idx += ENTRIES_PER_PAGEPAGE; | |
669 | if (idx >= limit) | |
670 | goto done1; | |
671 | } | |
672 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
673 | middir = *dir; | |
1ae70006 HD |
674 | if (punch_hole) |
675 | needs_lock = &info->lock; | |
a2646d1e | 676 | if (upper_limit >= stage) { |
1ae70006 HD |
677 | if (needs_lock) { |
678 | spin_lock(needs_lock); | |
679 | *dir = NULL; | |
680 | spin_unlock(needs_lock); | |
681 | needs_lock = NULL; | |
682 | } else | |
683 | *dir = NULL; | |
a2646d1e HD |
684 | nr_pages_to_free++; |
685 | list_add(&middir->lru, &pages_to_free); | |
686 | } | |
1da177e4 LT |
687 | shmem_dir_unmap(dir); |
688 | cond_resched(); | |
689 | dir = shmem_dir_map(middir); | |
690 | diroff = 0; | |
691 | } | |
1ae70006 | 692 | punch_lock = needs_lock; |
1da177e4 | 693 | subdir = dir[diroff]; |
1ae70006 HD |
694 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
695 | if (needs_lock) { | |
696 | spin_lock(needs_lock); | |
697 | dir[diroff] = NULL; | |
698 | spin_unlock(needs_lock); | |
699 | punch_lock = NULL; | |
700 | } else | |
701 | dir[diroff] = NULL; | |
702 | nr_pages_to_free++; | |
703 | list_add(&subdir->lru, &pages_to_free); | |
704 | } | |
705 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
706 | size = limit - idx; |
707 | if (size > ENTRIES_PER_PAGE) | |
708 | size = ENTRIES_PER_PAGE; | |
709 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 710 | offset, size, &dir, punch_lock); |
1da177e4 LT |
711 | if (!dir) |
712 | dir = shmem_dir_map(middir); | |
713 | nr_swaps_freed += freed; | |
1ae70006 | 714 | if (offset || punch_lock) { |
1da177e4 | 715 | spin_lock(&info->lock); |
1ae70006 HD |
716 | set_page_private(subdir, |
717 | page_private(subdir) - freed); | |
1da177e4 | 718 | spin_unlock(&info->lock); |
1ae70006 HD |
719 | } else |
720 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 721 | } |
1ae70006 | 722 | offset = 0; |
1da177e4 LT |
723 | } |
724 | done1: | |
725 | shmem_dir_unmap(dir); | |
726 | done2: | |
727 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
728 | /* | |
729 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
730 | * may have swizzled a page in from swap since vmtruncate or | |
731 | * generic_delete_inode did it, before we lowered next_index. | |
732 | * Also, though shmem_getpage checks i_size before adding to | |
733 | * cache, no recheck after: so fix the narrow window there too. | |
16a10019 HD |
734 | * |
735 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
736 | * every time for punch_hole (which never got a chance to clear | |
737 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
738 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 739 | */ |
f6b3ec23 | 740 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
741 | if (punch_hole) |
742 | unmap_mapping_range(inode->i_mapping, start, | |
743 | end - start, 1); | |
1da177e4 LT |
744 | } |
745 | ||
746 | spin_lock(&info->lock); | |
747 | info->flags &= ~SHMEM_TRUNCATE; | |
748 | info->swapped -= nr_swaps_freed; | |
749 | if (nr_pages_to_free) | |
750 | shmem_free_blocks(inode, nr_pages_to_free); | |
751 | shmem_recalc_inode(inode); | |
752 | spin_unlock(&info->lock); | |
753 | ||
754 | /* | |
755 | * Empty swap vector directory pages to be freed? | |
756 | */ | |
757 | if (!list_empty(&pages_to_free)) { | |
758 | pages_to_free.prev->next = NULL; | |
759 | shmem_free_pages(pages_to_free.next); | |
760 | } | |
761 | } | |
762 | ||
f6b3ec23 BP |
763 | static void shmem_truncate(struct inode *inode) |
764 | { | |
765 | shmem_truncate_range(inode, inode->i_size, (loff_t)-1); | |
766 | } | |
767 | ||
1da177e4 LT |
768 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) |
769 | { | |
770 | struct inode *inode = dentry->d_inode; | |
771 | struct page *page = NULL; | |
772 | int error; | |
773 | ||
39f0247d | 774 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
1da177e4 LT |
775 | if (attr->ia_size < inode->i_size) { |
776 | /* | |
777 | * If truncating down to a partial page, then | |
778 | * if that page is already allocated, hold it | |
779 | * in memory until the truncation is over, so | |
780 | * truncate_partial_page cannnot miss it were | |
781 | * it assigned to swap. | |
782 | */ | |
783 | if (attr->ia_size & (PAGE_CACHE_SIZE-1)) { | |
784 | (void) shmem_getpage(inode, | |
785 | attr->ia_size>>PAGE_CACHE_SHIFT, | |
786 | &page, SGP_READ, NULL); | |
d3602444 HD |
787 | if (page) |
788 | unlock_page(page); | |
1da177e4 LT |
789 | } |
790 | /* | |
791 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
792 | * detect if any pages might have been added to cache | |
793 | * after truncate_inode_pages. But we needn't bother | |
794 | * if it's being fully truncated to zero-length: the | |
795 | * nrpages check is efficient enough in that case. | |
796 | */ | |
797 | if (attr->ia_size) { | |
798 | struct shmem_inode_info *info = SHMEM_I(inode); | |
799 | spin_lock(&info->lock); | |
800 | info->flags &= ~SHMEM_PAGEIN; | |
801 | spin_unlock(&info->lock); | |
802 | } | |
803 | } | |
804 | } | |
805 | ||
806 | error = inode_change_ok(inode, attr); | |
807 | if (!error) | |
808 | error = inode_setattr(inode, attr); | |
39f0247d AG |
809 | #ifdef CONFIG_TMPFS_POSIX_ACL |
810 | if (!error && (attr->ia_valid & ATTR_MODE)) | |
1c7c474c | 811 | error = generic_acl_chmod(inode); |
39f0247d | 812 | #endif |
1da177e4 LT |
813 | if (page) |
814 | page_cache_release(page); | |
815 | return error; | |
816 | } | |
817 | ||
818 | static void shmem_delete_inode(struct inode *inode) | |
819 | { | |
1da177e4 LT |
820 | struct shmem_inode_info *info = SHMEM_I(inode); |
821 | ||
822 | if (inode->i_op->truncate == shmem_truncate) { | |
fef26658 | 823 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
824 | shmem_unacct_size(info->flags, inode->i_size); |
825 | inode->i_size = 0; | |
826 | shmem_truncate(inode); | |
827 | if (!list_empty(&info->swaplist)) { | |
cb5f7b9a | 828 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 829 | list_del_init(&info->swaplist); |
cb5f7b9a | 830 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
831 | } |
832 | } | |
0edd73b3 | 833 | BUG_ON(inode->i_blocks); |
5b04c689 | 834 | shmem_free_inode(inode->i_sb); |
1da177e4 LT |
835 | clear_inode(inode); |
836 | } | |
837 | ||
838 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
839 | { | |
840 | swp_entry_t *ptr; | |
841 | ||
842 | for (ptr = dir; ptr < edir; ptr++) { | |
843 | if (ptr->val == entry.val) | |
844 | return ptr - dir; | |
845 | } | |
846 | return -1; | |
847 | } | |
848 | ||
849 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
850 | { | |
851 | struct inode *inode; | |
852 | unsigned long idx; | |
853 | unsigned long size; | |
854 | unsigned long limit; | |
855 | unsigned long stage; | |
856 | struct page **dir; | |
857 | struct page *subdir; | |
858 | swp_entry_t *ptr; | |
859 | int offset; | |
d9fe526a | 860 | int error; |
1da177e4 LT |
861 | |
862 | idx = 0; | |
863 | ptr = info->i_direct; | |
864 | spin_lock(&info->lock); | |
1b1b32f2 HD |
865 | if (!info->swapped) { |
866 | list_del_init(&info->swaplist); | |
867 | goto lost2; | |
868 | } | |
1da177e4 LT |
869 | limit = info->next_index; |
870 | size = limit; | |
871 | if (size > SHMEM_NR_DIRECT) | |
872 | size = SHMEM_NR_DIRECT; | |
873 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 874 | if (offset >= 0) |
1da177e4 | 875 | goto found; |
1da177e4 LT |
876 | if (!info->i_indirect) |
877 | goto lost2; | |
878 | ||
879 | dir = shmem_dir_map(info->i_indirect); | |
880 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
881 | ||
882 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
883 | if (unlikely(idx == stage)) { | |
884 | shmem_dir_unmap(dir-1); | |
cb5f7b9a HD |
885 | if (cond_resched_lock(&info->lock)) { |
886 | /* check it has not been truncated */ | |
887 | if (limit > info->next_index) { | |
888 | limit = info->next_index; | |
889 | if (idx >= limit) | |
890 | goto lost2; | |
891 | } | |
892 | } | |
1da177e4 LT |
893 | dir = shmem_dir_map(info->i_indirect) + |
894 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
895 | while (!*dir) { | |
896 | dir++; | |
897 | idx += ENTRIES_PER_PAGEPAGE; | |
898 | if (idx >= limit) | |
899 | goto lost1; | |
900 | } | |
901 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
902 | subdir = *dir; | |
903 | shmem_dir_unmap(dir); | |
904 | dir = shmem_dir_map(subdir); | |
905 | } | |
906 | subdir = *dir; | |
4c21e2f2 | 907 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
908 | ptr = shmem_swp_map(subdir); |
909 | size = limit - idx; | |
910 | if (size > ENTRIES_PER_PAGE) | |
911 | size = ENTRIES_PER_PAGE; | |
912 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
2e0e26c7 | 913 | shmem_swp_unmap(ptr); |
1da177e4 LT |
914 | if (offset >= 0) { |
915 | shmem_dir_unmap(dir); | |
916 | goto found; | |
917 | } | |
1da177e4 LT |
918 | } |
919 | } | |
920 | lost1: | |
921 | shmem_dir_unmap(dir-1); | |
922 | lost2: | |
923 | spin_unlock(&info->lock); | |
924 | return 0; | |
925 | found: | |
926 | idx += offset; | |
2e0e26c7 HD |
927 | inode = igrab(&info->vfs_inode); |
928 | spin_unlock(&info->lock); | |
929 | ||
1b1b32f2 HD |
930 | /* |
931 | * Move _head_ to start search for next from here. | |
932 | * But be careful: shmem_delete_inode checks list_empty without taking | |
933 | * mutex, and there's an instant in list_move_tail when info->swaplist | |
934 | * would appear empty, if it were the only one on shmem_swaplist. We | |
935 | * could avoid doing it if inode NULL; or use this minor optimization. | |
936 | */ | |
937 | if (shmem_swaplist.next != &info->swaplist) | |
938 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 HD |
939 | mutex_unlock(&shmem_swaplist_mutex); |
940 | ||
941 | error = 1; | |
942 | if (!inode) | |
943 | goto out; | |
d13d1443 | 944 | /* |
b5a84319 KH |
945 | * Charge page using GFP_KERNEL while we can wait. |
946 | * Charged back to the user(not to caller) when swap account is used. | |
947 | * add_to_page_cache() will be called with GFP_NOWAIT. | |
d13d1443 | 948 | */ |
82369553 | 949 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); |
b409f9fc HD |
950 | if (error) |
951 | goto out; | |
82369553 | 952 | error = radix_tree_preload(GFP_KERNEL); |
69029cd5 KH |
953 | if (error) { |
954 | mem_cgroup_uncharge_cache_page(page); | |
955 | goto out; | |
956 | } | |
b409f9fc | 957 | error = 1; |
2e0e26c7 HD |
958 | |
959 | spin_lock(&info->lock); | |
960 | ptr = shmem_swp_entry(info, idx, NULL); | |
69029cd5 | 961 | if (ptr && ptr->val == entry.val) { |
e286781d | 962 | error = add_to_page_cache_locked(page, inode->i_mapping, |
b409f9fc | 963 | idx, GFP_NOWAIT); |
69029cd5 KH |
964 | /* does mem_cgroup_uncharge_cache_page on error */ |
965 | } else /* we must compensate for our precharge above */ | |
966 | mem_cgroup_uncharge_cache_page(page); | |
967 | ||
d9fe526a HD |
968 | if (error == -EEXIST) { |
969 | struct page *filepage = find_get_page(inode->i_mapping, idx); | |
2e0e26c7 | 970 | error = 1; |
d9fe526a HD |
971 | if (filepage) { |
972 | /* | |
973 | * There might be a more uptodate page coming down | |
974 | * from a stacked writepage: forget our swappage if so. | |
975 | */ | |
976 | if (PageUptodate(filepage)) | |
977 | error = 0; | |
978 | page_cache_release(filepage); | |
979 | } | |
980 | } | |
981 | if (!error) { | |
73b1262f HD |
982 | delete_from_swap_cache(page); |
983 | set_page_dirty(page); | |
1da177e4 | 984 | info->flags |= SHMEM_PAGEIN; |
2e0e26c7 HD |
985 | shmem_swp_set(info, ptr, 0); |
986 | swap_free(entry); | |
987 | error = 1; /* not an error, but entry was found */ | |
1da177e4 | 988 | } |
2e0e26c7 HD |
989 | if (ptr) |
990 | shmem_swp_unmap(ptr); | |
1da177e4 | 991 | spin_unlock(&info->lock); |
b409f9fc | 992 | radix_tree_preload_end(); |
2e0e26c7 HD |
993 | out: |
994 | unlock_page(page); | |
995 | page_cache_release(page); | |
996 | iput(inode); /* allows for NULL */ | |
997 | return error; | |
1da177e4 LT |
998 | } |
999 | ||
1000 | /* | |
1001 | * shmem_unuse() search for an eventually swapped out shmem page. | |
1002 | */ | |
1003 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
1004 | { | |
1005 | struct list_head *p, *next; | |
1006 | struct shmem_inode_info *info; | |
1007 | int found = 0; | |
1008 | ||
cb5f7b9a | 1009 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 LT |
1010 | list_for_each_safe(p, next, &shmem_swaplist) { |
1011 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
1b1b32f2 | 1012 | found = shmem_unuse_inode(info, entry, page); |
cb5f7b9a | 1013 | cond_resched(); |
2e0e26c7 HD |
1014 | if (found) |
1015 | goto out; | |
1da177e4 | 1016 | } |
cb5f7b9a | 1017 | mutex_unlock(&shmem_swaplist_mutex); |
aaa46865 HD |
1018 | /* |
1019 | * Can some race bring us here? We've been holding page lock, | |
1020 | * so I think not; but would rather try again later than BUG() | |
1021 | */ | |
1022 | unlock_page(page); | |
1023 | page_cache_release(page); | |
1024 | out: | |
1025 | return (found < 0) ? found : 0; | |
1da177e4 LT |
1026 | } |
1027 | ||
1028 | /* | |
1029 | * Move the page from the page cache to the swap cache. | |
1030 | */ | |
1031 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
1032 | { | |
1033 | struct shmem_inode_info *info; | |
1034 | swp_entry_t *entry, swap; | |
1035 | struct address_space *mapping; | |
1036 | unsigned long index; | |
1037 | struct inode *inode; | |
1038 | ||
1039 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
1040 | mapping = page->mapping; |
1041 | index = page->index; | |
1042 | inode = mapping->host; | |
1043 | info = SHMEM_I(inode); | |
1044 | if (info->flags & VM_LOCKED) | |
1045 | goto redirty; | |
d9fe526a | 1046 | if (!total_swap_pages) |
1da177e4 LT |
1047 | goto redirty; |
1048 | ||
d9fe526a HD |
1049 | /* |
1050 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
1051 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
1052 | * may use the ->writepage of its underlying filesystem, in which case | |
1053 | * tmpfs should write out to swap only in response to memory pressure, | |
5b0830cb JA |
1054 | * and not for the writeback threads or sync. However, in those cases, |
1055 | * we do still want to check if there's a redundant swappage to be | |
1056 | * discarded. | |
d9fe526a HD |
1057 | */ |
1058 | if (wbc->for_reclaim) | |
1059 | swap = get_swap_page(); | |
1060 | else | |
1061 | swap.val = 0; | |
1062 | ||
1da177e4 | 1063 | spin_lock(&info->lock); |
1da177e4 LT |
1064 | if (index >= info->next_index) { |
1065 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
1066 | goto unlock; | |
1067 | } | |
1068 | entry = shmem_swp_entry(info, index, NULL); | |
d9fe526a HD |
1069 | if (entry->val) { |
1070 | /* | |
1071 | * The more uptodate page coming down from a stacked | |
1072 | * writepage should replace our old swappage. | |
1073 | */ | |
1074 | free_swap_and_cache(*entry); | |
1075 | shmem_swp_set(info, entry, 0); | |
1076 | } | |
1077 | shmem_recalc_inode(inode); | |
1da177e4 | 1078 | |
d9fe526a | 1079 | if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
73b1262f | 1080 | remove_from_page_cache(page); |
1da177e4 LT |
1081 | shmem_swp_set(info, entry, swap.val); |
1082 | shmem_swp_unmap(entry); | |
1b1b32f2 HD |
1083 | if (list_empty(&info->swaplist)) |
1084 | inode = igrab(inode); | |
1085 | else | |
1086 | inode = NULL; | |
1da177e4 | 1087 | spin_unlock(&info->lock); |
aaa46865 | 1088 | swap_shmem_alloc(swap); |
d9fe526a | 1089 | BUG_ON(page_mapped(page)); |
73b1262f | 1090 | page_cache_release(page); /* pagecache ref */ |
9fab5619 | 1091 | swap_writepage(page, wbc); |
1b1b32f2 HD |
1092 | if (inode) { |
1093 | mutex_lock(&shmem_swaplist_mutex); | |
1094 | /* move instead of add in case we're racing */ | |
1095 | list_move_tail(&info->swaplist, &shmem_swaplist); | |
1096 | mutex_unlock(&shmem_swaplist_mutex); | |
1097 | iput(inode); | |
1098 | } | |
1da177e4 LT |
1099 | return 0; |
1100 | } | |
1101 | ||
1102 | shmem_swp_unmap(entry); | |
1103 | unlock: | |
1104 | spin_unlock(&info->lock); | |
2ca4532a DN |
1105 | /* |
1106 | * add_to_swap_cache() doesn't return -EEXIST, so we can safely | |
1107 | * clear SWAP_HAS_CACHE flag. | |
1108 | */ | |
cb4b86ba | 1109 | swapcache_free(swap, NULL); |
1da177e4 LT |
1110 | redirty: |
1111 | set_page_dirty(page); | |
d9fe526a HD |
1112 | if (wbc->for_reclaim) |
1113 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1114 | unlock_page(page); | |
1115 | return 0; | |
1da177e4 LT |
1116 | } |
1117 | ||
1118 | #ifdef CONFIG_NUMA | |
680d794b | 1119 | #ifdef CONFIG_TMPFS |
71fe804b | 1120 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 1121 | { |
095f1fc4 | 1122 | char buffer[64]; |
680d794b | 1123 | |
71fe804b | 1124 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 1125 | return; /* show nothing */ |
680d794b | 1126 | |
71fe804b | 1127 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
1128 | |
1129 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 1130 | } |
71fe804b LS |
1131 | |
1132 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1133 | { | |
1134 | struct mempolicy *mpol = NULL; | |
1135 | if (sbinfo->mpol) { | |
1136 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
1137 | mpol = sbinfo->mpol; | |
1138 | mpol_get(mpol); | |
1139 | spin_unlock(&sbinfo->stat_lock); | |
1140 | } | |
1141 | return mpol; | |
1142 | } | |
680d794b | 1143 | #endif /* CONFIG_TMPFS */ |
1144 | ||
02098fea HD |
1145 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1146 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1147 | { |
52cd3b07 | 1148 | struct mempolicy mpol, *spol; |
1da177e4 | 1149 | struct vm_area_struct pvma; |
c4cc6d07 | 1150 | struct page *page; |
1da177e4 | 1151 | |
52cd3b07 LS |
1152 | spol = mpol_cond_copy(&mpol, |
1153 | mpol_shared_policy_lookup(&info->policy, idx)); | |
1154 | ||
1da177e4 | 1155 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 1156 | pvma.vm_start = 0; |
1da177e4 | 1157 | pvma.vm_pgoff = idx; |
c4cc6d07 | 1158 | pvma.vm_ops = NULL; |
52cd3b07 | 1159 | pvma.vm_policy = spol; |
02098fea | 1160 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1161 | return page; |
1162 | } | |
1163 | ||
02098fea HD |
1164 | static struct page *shmem_alloc_page(gfp_t gfp, |
1165 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1166 | { |
1167 | struct vm_area_struct pvma; | |
1da177e4 | 1168 | |
c4cc6d07 HD |
1169 | /* Create a pseudo vma that just contains the policy */ |
1170 | pvma.vm_start = 0; | |
1da177e4 | 1171 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1172 | pvma.vm_ops = NULL; |
1173 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
52cd3b07 LS |
1174 | |
1175 | /* | |
1176 | * alloc_page_vma() will drop the shared policy reference | |
1177 | */ | |
1178 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 1179 | } |
680d794b | 1180 | #else /* !CONFIG_NUMA */ |
1181 | #ifdef CONFIG_TMPFS | |
71fe804b | 1182 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p) |
680d794b | 1183 | { |
1184 | } | |
1185 | #endif /* CONFIG_TMPFS */ | |
1186 | ||
02098fea HD |
1187 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1188 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1189 | { |
02098fea | 1190 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1191 | } |
1192 | ||
02098fea HD |
1193 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1194 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1195 | { |
e84e2e13 | 1196 | return alloc_page(gfp); |
1da177e4 | 1197 | } |
680d794b | 1198 | #endif /* CONFIG_NUMA */ |
1da177e4 | 1199 | |
71fe804b LS |
1200 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
1201 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1202 | { | |
1203 | return NULL; | |
1204 | } | |
1205 | #endif | |
1206 | ||
1da177e4 LT |
1207 | /* |
1208 | * shmem_getpage - either get the page from swap or allocate a new one | |
1209 | * | |
1210 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1211 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1212 | * entry since a page cannot live in both the swap and page cache | |
1213 | */ | |
1214 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1215 | struct page **pagep, enum sgp_type sgp, int *type) | |
1216 | { | |
1217 | struct address_space *mapping = inode->i_mapping; | |
1218 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1219 | struct shmem_sb_info *sbinfo; | |
1220 | struct page *filepage = *pagep; | |
1221 | struct page *swappage; | |
1222 | swp_entry_t *entry; | |
1223 | swp_entry_t swap; | |
02098fea | 1224 | gfp_t gfp; |
1da177e4 LT |
1225 | int error; |
1226 | ||
1227 | if (idx >= SHMEM_MAX_INDEX) | |
1228 | return -EFBIG; | |
54cb8821 NP |
1229 | |
1230 | if (type) | |
83c54070 | 1231 | *type = 0; |
54cb8821 | 1232 | |
1da177e4 LT |
1233 | /* |
1234 | * Normally, filepage is NULL on entry, and either found | |
1235 | * uptodate immediately, or allocated and zeroed, or read | |
1236 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1237 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1238 | * filepage, which may be found not uptodate by other callers |
1239 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1240 | */ |
1241 | repeat: | |
1242 | if (!filepage) | |
1243 | filepage = find_lock_page(mapping, idx); | |
1244 | if (filepage && PageUptodate(filepage)) | |
1245 | goto done; | |
1246 | error = 0; | |
02098fea | 1247 | gfp = mapping_gfp_mask(mapping); |
b409f9fc HD |
1248 | if (!filepage) { |
1249 | /* | |
1250 | * Try to preload while we can wait, to not make a habit of | |
1251 | * draining atomic reserves; but don't latch on to this cpu. | |
1252 | */ | |
1253 | error = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
1254 | if (error) | |
1255 | goto failed; | |
1256 | radix_tree_preload_end(); | |
1257 | } | |
1da177e4 LT |
1258 | |
1259 | spin_lock(&info->lock); | |
1260 | shmem_recalc_inode(inode); | |
1261 | entry = shmem_swp_alloc(info, idx, sgp); | |
1262 | if (IS_ERR(entry)) { | |
1263 | spin_unlock(&info->lock); | |
1264 | error = PTR_ERR(entry); | |
1265 | goto failed; | |
1266 | } | |
1267 | swap = *entry; | |
1268 | ||
1269 | if (swap.val) { | |
1270 | /* Look it up and read it in.. */ | |
1271 | swappage = lookup_swap_cache(swap); | |
1272 | if (!swappage) { | |
1273 | shmem_swp_unmap(entry); | |
1da177e4 | 1274 | /* here we actually do the io */ |
83c54070 | 1275 | if (type && !(*type & VM_FAULT_MAJOR)) { |
f8891e5e | 1276 | __count_vm_event(PGMAJFAULT); |
83c54070 | 1277 | *type |= VM_FAULT_MAJOR; |
1da177e4 | 1278 | } |
f8891e5e | 1279 | spin_unlock(&info->lock); |
02098fea | 1280 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1281 | if (!swappage) { |
1282 | spin_lock(&info->lock); | |
1283 | entry = shmem_swp_alloc(info, idx, sgp); | |
1284 | if (IS_ERR(entry)) | |
1285 | error = PTR_ERR(entry); | |
1286 | else { | |
1287 | if (entry->val == swap.val) | |
1288 | error = -ENOMEM; | |
1289 | shmem_swp_unmap(entry); | |
1290 | } | |
1291 | spin_unlock(&info->lock); | |
1292 | if (error) | |
1293 | goto failed; | |
1294 | goto repeat; | |
1295 | } | |
1296 | wait_on_page_locked(swappage); | |
1297 | page_cache_release(swappage); | |
1298 | goto repeat; | |
1299 | } | |
1300 | ||
1301 | /* We have to do this with page locked to prevent races */ | |
529ae9aa | 1302 | if (!trylock_page(swappage)) { |
1da177e4 LT |
1303 | shmem_swp_unmap(entry); |
1304 | spin_unlock(&info->lock); | |
1305 | wait_on_page_locked(swappage); | |
1306 | page_cache_release(swappage); | |
1307 | goto repeat; | |
1308 | } | |
1309 | if (PageWriteback(swappage)) { | |
1310 | shmem_swp_unmap(entry); | |
1311 | spin_unlock(&info->lock); | |
1312 | wait_on_page_writeback(swappage); | |
1313 | unlock_page(swappage); | |
1314 | page_cache_release(swappage); | |
1315 | goto repeat; | |
1316 | } | |
1317 | if (!PageUptodate(swappage)) { | |
1318 | shmem_swp_unmap(entry); | |
1319 | spin_unlock(&info->lock); | |
1320 | unlock_page(swappage); | |
1321 | page_cache_release(swappage); | |
1322 | error = -EIO; | |
1323 | goto failed; | |
1324 | } | |
1325 | ||
1326 | if (filepage) { | |
1327 | shmem_swp_set(info, entry, 0); | |
1328 | shmem_swp_unmap(entry); | |
1329 | delete_from_swap_cache(swappage); | |
1330 | spin_unlock(&info->lock); | |
1331 | copy_highpage(filepage, swappage); | |
1332 | unlock_page(swappage); | |
1333 | page_cache_release(swappage); | |
1334 | flush_dcache_page(filepage); | |
1335 | SetPageUptodate(filepage); | |
1336 | set_page_dirty(filepage); | |
1337 | swap_free(swap); | |
e286781d NP |
1338 | } else if (!(error = add_to_page_cache_locked(swappage, mapping, |
1339 | idx, GFP_NOWAIT))) { | |
1da177e4 LT |
1340 | info->flags |= SHMEM_PAGEIN; |
1341 | shmem_swp_set(info, entry, 0); | |
1342 | shmem_swp_unmap(entry); | |
73b1262f | 1343 | delete_from_swap_cache(swappage); |
1da177e4 LT |
1344 | spin_unlock(&info->lock); |
1345 | filepage = swappage; | |
73b1262f | 1346 | set_page_dirty(filepage); |
1da177e4 LT |
1347 | swap_free(swap); |
1348 | } else { | |
1349 | shmem_swp_unmap(entry); | |
1350 | spin_unlock(&info->lock); | |
82369553 | 1351 | if (error == -ENOMEM) { |
ae3abae6 DN |
1352 | /* |
1353 | * reclaim from proper memory cgroup and | |
1354 | * call memcg's OOM if needed. | |
1355 | */ | |
1356 | error = mem_cgroup_shmem_charge_fallback( | |
1357 | swappage, | |
b5a84319 | 1358 | current->mm, |
c9b0ed51 | 1359 | gfp); |
b5a84319 KH |
1360 | if (error) { |
1361 | unlock_page(swappage); | |
1362 | page_cache_release(swappage); | |
82369553 | 1363 | goto failed; |
b5a84319 | 1364 | } |
82369553 | 1365 | } |
b5a84319 KH |
1366 | unlock_page(swappage); |
1367 | page_cache_release(swappage); | |
1da177e4 LT |
1368 | goto repeat; |
1369 | } | |
1370 | } else if (sgp == SGP_READ && !filepage) { | |
1371 | shmem_swp_unmap(entry); | |
1372 | filepage = find_get_page(mapping, idx); | |
1373 | if (filepage && | |
529ae9aa | 1374 | (!PageUptodate(filepage) || !trylock_page(filepage))) { |
1da177e4 LT |
1375 | spin_unlock(&info->lock); |
1376 | wait_on_page_locked(filepage); | |
1377 | page_cache_release(filepage); | |
1378 | filepage = NULL; | |
1379 | goto repeat; | |
1380 | } | |
1381 | spin_unlock(&info->lock); | |
1382 | } else { | |
1383 | shmem_swp_unmap(entry); | |
1384 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1385 | if (sbinfo->max_blocks) { |
1da177e4 LT |
1386 | spin_lock(&sbinfo->stat_lock); |
1387 | if (sbinfo->free_blocks == 0 || | |
1388 | shmem_acct_block(info->flags)) { | |
1389 | spin_unlock(&sbinfo->stat_lock); | |
1390 | spin_unlock(&info->lock); | |
1391 | error = -ENOSPC; | |
1392 | goto failed; | |
1393 | } | |
1394 | sbinfo->free_blocks--; | |
1395 | inode->i_blocks += BLOCKS_PER_PAGE; | |
1396 | spin_unlock(&sbinfo->stat_lock); | |
1397 | } else if (shmem_acct_block(info->flags)) { | |
1398 | spin_unlock(&info->lock); | |
1399 | error = -ENOSPC; | |
1400 | goto failed; | |
1401 | } | |
1402 | ||
1403 | if (!filepage) { | |
69029cd5 KH |
1404 | int ret; |
1405 | ||
1da177e4 | 1406 | spin_unlock(&info->lock); |
02098fea | 1407 | filepage = shmem_alloc_page(gfp, info, idx); |
1da177e4 LT |
1408 | if (!filepage) { |
1409 | shmem_unacct_blocks(info->flags, 1); | |
1410 | shmem_free_blocks(inode, 1); | |
1411 | error = -ENOMEM; | |
1412 | goto failed; | |
1413 | } | |
b2e18538 | 1414 | SetPageSwapBacked(filepage); |
1da177e4 | 1415 | |
82369553 HD |
1416 | /* Precharge page while we can wait, compensate after */ |
1417 | error = mem_cgroup_cache_charge(filepage, current->mm, | |
2c26fdd7 | 1418 | GFP_KERNEL); |
82369553 HD |
1419 | if (error) { |
1420 | page_cache_release(filepage); | |
1421 | shmem_unacct_blocks(info->flags, 1); | |
1422 | shmem_free_blocks(inode, 1); | |
1423 | filepage = NULL; | |
1424 | goto failed; | |
1425 | } | |
1426 | ||
1da177e4 LT |
1427 | spin_lock(&info->lock); |
1428 | entry = shmem_swp_alloc(info, idx, sgp); | |
1429 | if (IS_ERR(entry)) | |
1430 | error = PTR_ERR(entry); | |
1431 | else { | |
1432 | swap = *entry; | |
1433 | shmem_swp_unmap(entry); | |
1434 | } | |
69029cd5 KH |
1435 | ret = error || swap.val; |
1436 | if (ret) | |
1437 | mem_cgroup_uncharge_cache_page(filepage); | |
1438 | else | |
1439 | ret = add_to_page_cache_lru(filepage, mapping, | |
1440 | idx, GFP_NOWAIT); | |
1441 | /* | |
1442 | * At add_to_page_cache_lru() failure, uncharge will | |
1443 | * be done automatically. | |
1444 | */ | |
1445 | if (ret) { | |
1da177e4 LT |
1446 | spin_unlock(&info->lock); |
1447 | page_cache_release(filepage); | |
1448 | shmem_unacct_blocks(info->flags, 1); | |
1449 | shmem_free_blocks(inode, 1); | |
1450 | filepage = NULL; | |
1451 | if (error) | |
1452 | goto failed; | |
1453 | goto repeat; | |
1454 | } | |
1455 | info->flags |= SHMEM_PAGEIN; | |
1456 | } | |
1457 | ||
1458 | info->alloced++; | |
1459 | spin_unlock(&info->lock); | |
e84e2e13 | 1460 | clear_highpage(filepage); |
1da177e4 LT |
1461 | flush_dcache_page(filepage); |
1462 | SetPageUptodate(filepage); | |
a0ee5ec5 HD |
1463 | if (sgp == SGP_DIRTY) |
1464 | set_page_dirty(filepage); | |
1da177e4 LT |
1465 | } |
1466 | done: | |
d3602444 | 1467 | *pagep = filepage; |
1da177e4 LT |
1468 | return 0; |
1469 | ||
1470 | failed: | |
1471 | if (*pagep != filepage) { | |
1472 | unlock_page(filepage); | |
1473 | page_cache_release(filepage); | |
1474 | } | |
1475 | return error; | |
1476 | } | |
1477 | ||
d0217ac0 | 1478 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1479 | { |
d3ac7f89 | 1480 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1481 | int error; |
d0217ac0 | 1482 | int ret; |
1da177e4 | 1483 | |
d0217ac0 NP |
1484 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1485 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1486 | |
27d54b39 | 1487 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1488 | if (error) |
1489 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1da177e4 | 1490 | |
83c54070 | 1491 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1492 | } |
1493 | ||
1da177e4 | 1494 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1495 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1496 | { |
d3ac7f89 | 1497 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1498 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1499 | } | |
1500 | ||
d8dc74f2 AB |
1501 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1502 | unsigned long addr) | |
1da177e4 | 1503 | { |
d3ac7f89 | 1504 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1505 | unsigned long idx; |
1506 | ||
1507 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1508 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1509 | } | |
1510 | #endif | |
1511 | ||
1512 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1513 | { | |
d3ac7f89 | 1514 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1515 | struct shmem_inode_info *info = SHMEM_I(inode); |
1516 | int retval = -ENOMEM; | |
1517 | ||
1518 | spin_lock(&info->lock); | |
1519 | if (lock && !(info->flags & VM_LOCKED)) { | |
1520 | if (!user_shm_lock(inode->i_size, user)) | |
1521 | goto out_nomem; | |
1522 | info->flags |= VM_LOCKED; | |
89e004ea | 1523 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1524 | } |
1525 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1526 | user_shm_unlock(inode->i_size, user); | |
1527 | info->flags &= ~VM_LOCKED; | |
89e004ea LS |
1528 | mapping_clear_unevictable(file->f_mapping); |
1529 | scan_mapping_unevictable_pages(file->f_mapping); | |
1da177e4 LT |
1530 | } |
1531 | retval = 0; | |
89e004ea | 1532 | |
1da177e4 LT |
1533 | out_nomem: |
1534 | spin_unlock(&info->lock); | |
1535 | return retval; | |
1536 | } | |
1537 | ||
9b83a6a8 | 1538 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1539 | { |
1540 | file_accessed(file); | |
1541 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1542 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1543 | return 0; |
1544 | } | |
1545 | ||
454abafe DM |
1546 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
1547 | int mode, dev_t dev, unsigned long flags) | |
1da177e4 LT |
1548 | { |
1549 | struct inode *inode; | |
1550 | struct shmem_inode_info *info; | |
1551 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1552 | ||
5b04c689 PE |
1553 | if (shmem_reserve_inode(sb)) |
1554 | return NULL; | |
1da177e4 LT |
1555 | |
1556 | inode = new_inode(sb); | |
1557 | if (inode) { | |
454abafe | 1558 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1559 | inode->i_blocks = 0; |
1da177e4 LT |
1560 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1561 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1562 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1563 | info = SHMEM_I(inode); |
1564 | memset(info, 0, (char *)inode - (char *)info); | |
1565 | spin_lock_init(&info->lock); | |
0b0a0806 | 1566 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1567 | INIT_LIST_HEAD(&info->swaplist); |
72c04902 | 1568 | cache_no_acl(inode); |
1da177e4 LT |
1569 | |
1570 | switch (mode & S_IFMT) { | |
1571 | default: | |
39f0247d | 1572 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1573 | init_special_inode(inode, mode, dev); |
1574 | break; | |
1575 | case S_IFREG: | |
14fcc23f | 1576 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1577 | inode->i_op = &shmem_inode_operations; |
1578 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1579 | mpol_shared_policy_init(&info->policy, |
1580 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1581 | break; |
1582 | case S_IFDIR: | |
d8c76e6f | 1583 | inc_nlink(inode); |
1da177e4 LT |
1584 | /* Some things misbehave if size == 0 on a directory */ |
1585 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1586 | inode->i_op = &shmem_dir_inode_operations; | |
1587 | inode->i_fop = &simple_dir_operations; | |
1588 | break; | |
1589 | case S_IFLNK: | |
1590 | /* | |
1591 | * Must not load anything in the rbtree, | |
1592 | * mpol_free_shared_policy will not be called. | |
1593 | */ | |
71fe804b | 1594 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1595 | break; |
1596 | } | |
5b04c689 PE |
1597 | } else |
1598 | shmem_free_inode(sb); | |
1da177e4 LT |
1599 | return inode; |
1600 | } | |
1601 | ||
1602 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1603 | static const struct inode_operations shmem_symlink_inode_operations; |
1604 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1605 | |
1606 | /* | |
800d15a5 | 1607 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1608 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1609 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1610 | */ |
ae976416 HD |
1611 | static int shmem_readpage(struct file *file, struct page *page) |
1612 | { | |
1613 | struct inode *inode = page->mapping->host; | |
1614 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1615 | unlock_page(page); | |
1616 | return error; | |
1617 | } | |
1618 | ||
1da177e4 | 1619 | static int |
800d15a5 NP |
1620 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1621 | loff_t pos, unsigned len, unsigned flags, | |
1622 | struct page **pagep, void **fsdata) | |
1da177e4 | 1623 | { |
800d15a5 NP |
1624 | struct inode *inode = mapping->host; |
1625 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1626 | *pagep = NULL; | |
1627 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1628 | } | |
1629 | ||
1630 | static int | |
1631 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1632 | loff_t pos, unsigned len, unsigned copied, | |
1633 | struct page *page, void *fsdata) | |
1634 | { | |
1635 | struct inode *inode = mapping->host; | |
1636 | ||
d3602444 HD |
1637 | if (pos + copied > inode->i_size) |
1638 | i_size_write(inode, pos + copied); | |
1639 | ||
800d15a5 | 1640 | set_page_dirty(page); |
6746aff7 | 1641 | unlock_page(page); |
800d15a5 NP |
1642 | page_cache_release(page); |
1643 | ||
800d15a5 | 1644 | return copied; |
1da177e4 LT |
1645 | } |
1646 | ||
1da177e4 LT |
1647 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1648 | { | |
d3ac7f89 | 1649 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1650 | struct address_space *mapping = inode->i_mapping; |
1651 | unsigned long index, offset; | |
a0ee5ec5 HD |
1652 | enum sgp_type sgp = SGP_READ; |
1653 | ||
1654 | /* | |
1655 | * Might this read be for a stacking filesystem? Then when reading | |
1656 | * holes of a sparse file, we actually need to allocate those pages, | |
1657 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1658 | */ | |
1659 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1660 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1661 | |
1662 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1663 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1664 | ||
1665 | for (;;) { | |
1666 | struct page *page = NULL; | |
1667 | unsigned long end_index, nr, ret; | |
1668 | loff_t i_size = i_size_read(inode); | |
1669 | ||
1670 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1671 | if (index > end_index) | |
1672 | break; | |
1673 | if (index == end_index) { | |
1674 | nr = i_size & ~PAGE_CACHE_MASK; | |
1675 | if (nr <= offset) | |
1676 | break; | |
1677 | } | |
1678 | ||
a0ee5ec5 | 1679 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1680 | if (desc->error) { |
1681 | if (desc->error == -EINVAL) | |
1682 | desc->error = 0; | |
1683 | break; | |
1684 | } | |
d3602444 HD |
1685 | if (page) |
1686 | unlock_page(page); | |
1da177e4 LT |
1687 | |
1688 | /* | |
1689 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1690 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1691 | */ |
1692 | nr = PAGE_CACHE_SIZE; | |
1693 | i_size = i_size_read(inode); | |
1694 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1695 | if (index == end_index) { | |
1696 | nr = i_size & ~PAGE_CACHE_MASK; | |
1697 | if (nr <= offset) { | |
1698 | if (page) | |
1699 | page_cache_release(page); | |
1700 | break; | |
1701 | } | |
1702 | } | |
1703 | nr -= offset; | |
1704 | ||
1705 | if (page) { | |
1706 | /* | |
1707 | * If users can be writing to this page using arbitrary | |
1708 | * virtual addresses, take care about potential aliasing | |
1709 | * before reading the page on the kernel side. | |
1710 | */ | |
1711 | if (mapping_writably_mapped(mapping)) | |
1712 | flush_dcache_page(page); | |
1713 | /* | |
1714 | * Mark the page accessed if we read the beginning. | |
1715 | */ | |
1716 | if (!offset) | |
1717 | mark_page_accessed(page); | |
b5810039 | 1718 | } else { |
1da177e4 | 1719 | page = ZERO_PAGE(0); |
b5810039 NP |
1720 | page_cache_get(page); |
1721 | } | |
1da177e4 LT |
1722 | |
1723 | /* | |
1724 | * Ok, we have the page, and it's up-to-date, so | |
1725 | * now we can copy it to user space... | |
1726 | * | |
1727 | * The actor routine returns how many bytes were actually used.. | |
1728 | * NOTE! This may not be the same as how much of a user buffer | |
1729 | * we filled up (we may be padding etc), so we can only update | |
1730 | * "pos" here (the actor routine has to update the user buffer | |
1731 | * pointers and the remaining count). | |
1732 | */ | |
1733 | ret = actor(desc, page, offset, nr); | |
1734 | offset += ret; | |
1735 | index += offset >> PAGE_CACHE_SHIFT; | |
1736 | offset &= ~PAGE_CACHE_MASK; | |
1737 | ||
1738 | page_cache_release(page); | |
1739 | if (ret != nr || !desc->count) | |
1740 | break; | |
1741 | ||
1742 | cond_resched(); | |
1743 | } | |
1744 | ||
1745 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1746 | file_accessed(filp); | |
1747 | } | |
1748 | ||
bcd78e49 HD |
1749 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1750 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1751 | { | |
1752 | struct file *filp = iocb->ki_filp; | |
1753 | ssize_t retval; | |
1754 | unsigned long seg; | |
1755 | size_t count; | |
1756 | loff_t *ppos = &iocb->ki_pos; | |
1757 | ||
1758 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1759 | if (retval) | |
1760 | return retval; | |
1761 | ||
1762 | for (seg = 0; seg < nr_segs; seg++) { | |
1763 | read_descriptor_t desc; | |
1764 | ||
1765 | desc.written = 0; | |
1766 | desc.arg.buf = iov[seg].iov_base; | |
1767 | desc.count = iov[seg].iov_len; | |
1768 | if (desc.count == 0) | |
1769 | continue; | |
1770 | desc.error = 0; | |
1771 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1772 | retval += desc.written; | |
1773 | if (desc.error) { | |
1774 | retval = retval ?: desc.error; | |
1775 | break; | |
1776 | } | |
1777 | if (desc.count > 0) | |
1778 | break; | |
1779 | } | |
1780 | return retval; | |
1da177e4 LT |
1781 | } |
1782 | ||
726c3342 | 1783 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1784 | { |
726c3342 | 1785 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1786 | |
1787 | buf->f_type = TMPFS_MAGIC; | |
1788 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1789 | buf->f_namelen = NAME_MAX; | |
0edd73b3 HD |
1790 | spin_lock(&sbinfo->stat_lock); |
1791 | if (sbinfo->max_blocks) { | |
1da177e4 LT |
1792 | buf->f_blocks = sbinfo->max_blocks; |
1793 | buf->f_bavail = buf->f_bfree = sbinfo->free_blocks; | |
0edd73b3 HD |
1794 | } |
1795 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1796 | buf->f_files = sbinfo->max_inodes; |
1797 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1798 | } |
1799 | /* else leave those fields 0 like simple_statfs */ | |
0edd73b3 | 1800 | spin_unlock(&sbinfo->stat_lock); |
1da177e4 LT |
1801 | return 0; |
1802 | } | |
1803 | ||
1804 | /* | |
1805 | * File creation. Allocate an inode, and we're done.. | |
1806 | */ | |
1807 | static int | |
1808 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1809 | { | |
0b0a0806 | 1810 | struct inode *inode; |
1da177e4 LT |
1811 | int error = -ENOSPC; |
1812 | ||
454abafe | 1813 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1814 | if (inode) { |
570bc1c2 SS |
1815 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1816 | NULL); | |
1817 | if (error) { | |
1818 | if (error != -EOPNOTSUPP) { | |
1819 | iput(inode); | |
1820 | return error; | |
1821 | } | |
39f0247d | 1822 | } |
1c7c474c CH |
1823 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1824 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1825 | if (error) { |
1826 | iput(inode); | |
1827 | return error; | |
570bc1c2 | 1828 | } |
718deb6b AV |
1829 | #else |
1830 | error = 0; | |
1c7c474c | 1831 | #endif |
1da177e4 LT |
1832 | dir->i_size += BOGO_DIRENT_SIZE; |
1833 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1834 | d_instantiate(dentry, inode); | |
1835 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1836 | } |
1837 | return error; | |
1838 | } | |
1839 | ||
1840 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1841 | { | |
1842 | int error; | |
1843 | ||
1844 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1845 | return error; | |
d8c76e6f | 1846 | inc_nlink(dir); |
1da177e4 LT |
1847 | return 0; |
1848 | } | |
1849 | ||
1850 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1851 | struct nameidata *nd) | |
1852 | { | |
1853 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1854 | } | |
1855 | ||
1856 | /* | |
1857 | * Link a file.. | |
1858 | */ | |
1859 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1860 | { | |
1861 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1862 | int ret; |
1da177e4 LT |
1863 | |
1864 | /* | |
1865 | * No ordinary (disk based) filesystem counts links as inodes; | |
1866 | * but each new link needs a new dentry, pinning lowmem, and | |
1867 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1868 | */ | |
5b04c689 PE |
1869 | ret = shmem_reserve_inode(inode->i_sb); |
1870 | if (ret) | |
1871 | goto out; | |
1da177e4 LT |
1872 | |
1873 | dir->i_size += BOGO_DIRENT_SIZE; | |
1874 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1875 | inc_nlink(inode); |
1da177e4 LT |
1876 | atomic_inc(&inode->i_count); /* New dentry reference */ |
1877 | dget(dentry); /* Extra pinning count for the created dentry */ | |
1878 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1879 | out: |
1880 | return ret; | |
1da177e4 LT |
1881 | } |
1882 | ||
1883 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1884 | { | |
1885 | struct inode *inode = dentry->d_inode; | |
1886 | ||
5b04c689 PE |
1887 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1888 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1889 | |
1890 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1891 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1892 | drop_nlink(inode); |
1da177e4 LT |
1893 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1894 | return 0; | |
1895 | } | |
1896 | ||
1897 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1898 | { | |
1899 | if (!simple_empty(dentry)) | |
1900 | return -ENOTEMPTY; | |
1901 | ||
9a53c3a7 DH |
1902 | drop_nlink(dentry->d_inode); |
1903 | drop_nlink(dir); | |
1da177e4 LT |
1904 | return shmem_unlink(dir, dentry); |
1905 | } | |
1906 | ||
1907 | /* | |
1908 | * The VFS layer already does all the dentry stuff for rename, | |
1909 | * we just have to decrement the usage count for the target if | |
1910 | * it exists so that the VFS layer correctly free's it when it | |
1911 | * gets overwritten. | |
1912 | */ | |
1913 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1914 | { | |
1915 | struct inode *inode = old_dentry->d_inode; | |
1916 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1917 | ||
1918 | if (!simple_empty(new_dentry)) | |
1919 | return -ENOTEMPTY; | |
1920 | ||
1921 | if (new_dentry->d_inode) { | |
1922 | (void) shmem_unlink(new_dir, new_dentry); | |
1923 | if (they_are_dirs) | |
9a53c3a7 | 1924 | drop_nlink(old_dir); |
1da177e4 | 1925 | } else if (they_are_dirs) { |
9a53c3a7 | 1926 | drop_nlink(old_dir); |
d8c76e6f | 1927 | inc_nlink(new_dir); |
1da177e4 LT |
1928 | } |
1929 | ||
1930 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1931 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1932 | old_dir->i_ctime = old_dir->i_mtime = | |
1933 | new_dir->i_ctime = new_dir->i_mtime = | |
1934 | inode->i_ctime = CURRENT_TIME; | |
1935 | return 0; | |
1936 | } | |
1937 | ||
1938 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1939 | { | |
1940 | int error; | |
1941 | int len; | |
1942 | struct inode *inode; | |
1943 | struct page *page = NULL; | |
1944 | char *kaddr; | |
1945 | struct shmem_inode_info *info; | |
1946 | ||
1947 | len = strlen(symname) + 1; | |
1948 | if (len > PAGE_CACHE_SIZE) | |
1949 | return -ENAMETOOLONG; | |
1950 | ||
454abafe | 1951 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
1952 | if (!inode) |
1953 | return -ENOSPC; | |
1954 | ||
570bc1c2 SS |
1955 | error = security_inode_init_security(inode, dir, NULL, NULL, |
1956 | NULL); | |
1957 | if (error) { | |
1958 | if (error != -EOPNOTSUPP) { | |
1959 | iput(inode); | |
1960 | return error; | |
1961 | } | |
1962 | error = 0; | |
1963 | } | |
1964 | ||
1da177e4 LT |
1965 | info = SHMEM_I(inode); |
1966 | inode->i_size = len-1; | |
1967 | if (len <= (char *)inode - (char *)info) { | |
1968 | /* do it inline */ | |
1969 | memcpy(info, symname, len); | |
1970 | inode->i_op = &shmem_symlink_inline_operations; | |
1971 | } else { | |
1972 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1973 | if (error) { | |
1974 | iput(inode); | |
1975 | return error; | |
1976 | } | |
14fcc23f | 1977 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1978 | inode->i_op = &shmem_symlink_inode_operations; |
1979 | kaddr = kmap_atomic(page, KM_USER0); | |
1980 | memcpy(kaddr, symname, len); | |
1981 | kunmap_atomic(kaddr, KM_USER0); | |
1982 | set_page_dirty(page); | |
6746aff7 | 1983 | unlock_page(page); |
1da177e4 LT |
1984 | page_cache_release(page); |
1985 | } | |
1da177e4 LT |
1986 | dir->i_size += BOGO_DIRENT_SIZE; |
1987 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1988 | d_instantiate(dentry, inode); | |
1989 | dget(dentry); | |
1990 | return 0; | |
1991 | } | |
1992 | ||
cc314eef | 1993 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1994 | { |
1995 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 1996 | return NULL; |
1da177e4 LT |
1997 | } |
1998 | ||
cc314eef | 1999 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
2000 | { |
2001 | struct page *page = NULL; | |
2002 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
2003 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
2004 | if (page) |
2005 | unlock_page(page); | |
cc314eef | 2006 | return page; |
1da177e4 LT |
2007 | } |
2008 | ||
cc314eef | 2009 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
2010 | { |
2011 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 2012 | struct page *page = cookie; |
1da177e4 LT |
2013 | kunmap(page); |
2014 | mark_page_accessed(page); | |
2015 | page_cache_release(page); | |
1da177e4 LT |
2016 | } |
2017 | } | |
2018 | ||
92e1d5be | 2019 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
2020 | .readlink = generic_readlink, |
2021 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
2022 | }; |
2023 | ||
92e1d5be | 2024 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
2025 | .truncate = shmem_truncate, |
2026 | .readlink = generic_readlink, | |
2027 | .follow_link = shmem_follow_link, | |
2028 | .put_link = shmem_put_link, | |
1da177e4 LT |
2029 | }; |
2030 | ||
39f0247d | 2031 | #ifdef CONFIG_TMPFS_POSIX_ACL |
46711810 | 2032 | /* |
39f0247d AG |
2033 | * Superblocks without xattr inode operations will get security.* xattr |
2034 | * support from the VFS "for free". As soon as we have any other xattrs | |
2035 | * like ACLs, we also need to implement the security.* handlers at | |
2036 | * filesystem level, though. | |
2037 | */ | |
2038 | ||
431547b3 | 2039 | static size_t shmem_xattr_security_list(struct dentry *dentry, char *list, |
39f0247d | 2040 | size_t list_len, const char *name, |
431547b3 | 2041 | size_t name_len, int handler_flags) |
39f0247d | 2042 | { |
431547b3 | 2043 | return security_inode_listsecurity(dentry->d_inode, list, list_len); |
39f0247d AG |
2044 | } |
2045 | ||
431547b3 CH |
2046 | static int shmem_xattr_security_get(struct dentry *dentry, const char *name, |
2047 | void *buffer, size_t size, int handler_flags) | |
39f0247d AG |
2048 | { |
2049 | if (strcmp(name, "") == 0) | |
2050 | return -EINVAL; | |
431547b3 | 2051 | return xattr_getsecurity(dentry->d_inode, name, buffer, size); |
39f0247d AG |
2052 | } |
2053 | ||
431547b3 CH |
2054 | static int shmem_xattr_security_set(struct dentry *dentry, const char *name, |
2055 | const void *value, size_t size, int flags, int handler_flags) | |
39f0247d AG |
2056 | { |
2057 | if (strcmp(name, "") == 0) | |
2058 | return -EINVAL; | |
431547b3 CH |
2059 | return security_inode_setsecurity(dentry->d_inode, name, value, |
2060 | size, flags); | |
39f0247d AG |
2061 | } |
2062 | ||
bb435453 | 2063 | static const struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
2064 | .prefix = XATTR_SECURITY_PREFIX, |
2065 | .list = shmem_xattr_security_list, | |
2066 | .get = shmem_xattr_security_get, | |
2067 | .set = shmem_xattr_security_set, | |
2068 | }; | |
2069 | ||
bb435453 | 2070 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
1c7c474c CH |
2071 | &generic_acl_access_handler, |
2072 | &generic_acl_default_handler, | |
39f0247d AG |
2073 | &shmem_xattr_security_handler, |
2074 | NULL | |
2075 | }; | |
2076 | #endif | |
2077 | ||
91828a40 DG |
2078 | static struct dentry *shmem_get_parent(struct dentry *child) |
2079 | { | |
2080 | return ERR_PTR(-ESTALE); | |
2081 | } | |
2082 | ||
2083 | static int shmem_match(struct inode *ino, void *vfh) | |
2084 | { | |
2085 | __u32 *fh = vfh; | |
2086 | __u64 inum = fh[2]; | |
2087 | inum = (inum << 32) | fh[1]; | |
2088 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2089 | } | |
2090 | ||
480b116c CH |
2091 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2092 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2093 | { |
91828a40 | 2094 | struct inode *inode; |
480b116c CH |
2095 | struct dentry *dentry = NULL; |
2096 | u64 inum = fid->raw[2]; | |
2097 | inum = (inum << 32) | fid->raw[1]; | |
2098 | ||
2099 | if (fh_len < 3) | |
2100 | return NULL; | |
91828a40 | 2101 | |
480b116c CH |
2102 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2103 | shmem_match, fid->raw); | |
91828a40 | 2104 | if (inode) { |
480b116c | 2105 | dentry = d_find_alias(inode); |
91828a40 DG |
2106 | iput(inode); |
2107 | } | |
2108 | ||
480b116c | 2109 | return dentry; |
91828a40 DG |
2110 | } |
2111 | ||
2112 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2113 | int connectable) | |
2114 | { | |
2115 | struct inode *inode = dentry->d_inode; | |
2116 | ||
2117 | if (*len < 3) | |
2118 | return 255; | |
2119 | ||
2120 | if (hlist_unhashed(&inode->i_hash)) { | |
2121 | /* Unfortunately insert_inode_hash is not idempotent, | |
2122 | * so as we hash inodes here rather than at creation | |
2123 | * time, we need a lock to ensure we only try | |
2124 | * to do it once | |
2125 | */ | |
2126 | static DEFINE_SPINLOCK(lock); | |
2127 | spin_lock(&lock); | |
2128 | if (hlist_unhashed(&inode->i_hash)) | |
2129 | __insert_inode_hash(inode, | |
2130 | inode->i_ino + inode->i_generation); | |
2131 | spin_unlock(&lock); | |
2132 | } | |
2133 | ||
2134 | fh[0] = inode->i_generation; | |
2135 | fh[1] = inode->i_ino; | |
2136 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2137 | ||
2138 | *len = 3; | |
2139 | return 1; | |
2140 | } | |
2141 | ||
39655164 | 2142 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2143 | .get_parent = shmem_get_parent, |
91828a40 | 2144 | .encode_fh = shmem_encode_fh, |
480b116c | 2145 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2146 | }; |
2147 | ||
680d794b | 2148 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2149 | bool remount) | |
1da177e4 LT |
2150 | { |
2151 | char *this_char, *value, *rest; | |
2152 | ||
b00dc3ad HD |
2153 | while (options != NULL) { |
2154 | this_char = options; | |
2155 | for (;;) { | |
2156 | /* | |
2157 | * NUL-terminate this option: unfortunately, | |
2158 | * mount options form a comma-separated list, | |
2159 | * but mpol's nodelist may also contain commas. | |
2160 | */ | |
2161 | options = strchr(options, ','); | |
2162 | if (options == NULL) | |
2163 | break; | |
2164 | options++; | |
2165 | if (!isdigit(*options)) { | |
2166 | options[-1] = '\0'; | |
2167 | break; | |
2168 | } | |
2169 | } | |
1da177e4 LT |
2170 | if (!*this_char) |
2171 | continue; | |
2172 | if ((value = strchr(this_char,'=')) != NULL) { | |
2173 | *value++ = 0; | |
2174 | } else { | |
2175 | printk(KERN_ERR | |
2176 | "tmpfs: No value for mount option '%s'\n", | |
2177 | this_char); | |
2178 | return 1; | |
2179 | } | |
2180 | ||
2181 | if (!strcmp(this_char,"size")) { | |
2182 | unsigned long long size; | |
2183 | size = memparse(value,&rest); | |
2184 | if (*rest == '%') { | |
2185 | size <<= PAGE_SHIFT; | |
2186 | size *= totalram_pages; | |
2187 | do_div(size, 100); | |
2188 | rest++; | |
2189 | } | |
2190 | if (*rest) | |
2191 | goto bad_val; | |
680d794b | 2192 | sbinfo->max_blocks = |
2193 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2194 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2195 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2196 | if (*rest) |
2197 | goto bad_val; | |
2198 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2199 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2200 | if (*rest) |
2201 | goto bad_val; | |
2202 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2203 | if (remount) |
1da177e4 | 2204 | continue; |
680d794b | 2205 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2206 | if (*rest) |
2207 | goto bad_val; | |
2208 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2209 | if (remount) |
1da177e4 | 2210 | continue; |
680d794b | 2211 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2212 | if (*rest) |
2213 | goto bad_val; | |
2214 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2215 | if (remount) |
1da177e4 | 2216 | continue; |
680d794b | 2217 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2218 | if (*rest) |
2219 | goto bad_val; | |
7339ff83 | 2220 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2221 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2222 | goto bad_val; |
1da177e4 LT |
2223 | } else { |
2224 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2225 | this_char); | |
2226 | return 1; | |
2227 | } | |
2228 | } | |
2229 | return 0; | |
2230 | ||
2231 | bad_val: | |
2232 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2233 | value, this_char); | |
2234 | return 1; | |
2235 | ||
2236 | } | |
2237 | ||
2238 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2239 | { | |
2240 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2241 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2242 | unsigned long blocks; |
2243 | unsigned long inodes; | |
2244 | int error = -EINVAL; | |
2245 | ||
680d794b | 2246 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2247 | return error; |
1da177e4 | 2248 | |
0edd73b3 HD |
2249 | spin_lock(&sbinfo->stat_lock); |
2250 | blocks = sbinfo->max_blocks - sbinfo->free_blocks; | |
2251 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
680d794b | 2252 | if (config.max_blocks < blocks) |
0edd73b3 | 2253 | goto out; |
680d794b | 2254 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2255 | goto out; |
2256 | /* | |
2257 | * Those tests also disallow limited->unlimited while any are in | |
2258 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2259 | * but we must separately disallow unlimited->limited, because | |
2260 | * in that case we have no record of how much is already in use. | |
2261 | */ | |
680d794b | 2262 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2263 | goto out; |
680d794b | 2264 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2265 | goto out; |
2266 | ||
2267 | error = 0; | |
680d794b | 2268 | sbinfo->max_blocks = config.max_blocks; |
2269 | sbinfo->free_blocks = config.max_blocks - blocks; | |
2270 | sbinfo->max_inodes = config.max_inodes; | |
2271 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2272 | |
2273 | mpol_put(sbinfo->mpol); | |
2274 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2275 | out: |
2276 | spin_unlock(&sbinfo->stat_lock); | |
2277 | return error; | |
1da177e4 | 2278 | } |
680d794b | 2279 | |
2280 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
2281 | { | |
2282 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
2283 | ||
2284 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2285 | seq_printf(seq, ",size=%luk", | |
2286 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2287 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2288 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2289 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
2290 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
2291 | if (sbinfo->uid != 0) | |
2292 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2293 | if (sbinfo->gid != 0) | |
2294 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 2295 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b | 2296 | return 0; |
2297 | } | |
2298 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2299 | |
2300 | static void shmem_put_super(struct super_block *sb) | |
2301 | { | |
2302 | kfree(sb->s_fs_info); | |
2303 | sb->s_fs_info = NULL; | |
2304 | } | |
2305 | ||
2b2af54a | 2306 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2307 | { |
2308 | struct inode *inode; | |
2309 | struct dentry *root; | |
0edd73b3 | 2310 | struct shmem_sb_info *sbinfo; |
680d794b | 2311 | int err = -ENOMEM; |
2312 | ||
2313 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2314 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b | 2315 | L1_CACHE_BYTES), GFP_KERNEL); |
2316 | if (!sbinfo) | |
2317 | return -ENOMEM; | |
2318 | ||
680d794b | 2319 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2320 | sbinfo->uid = current_fsuid(); |
2321 | sbinfo->gid = current_fsgid(); | |
680d794b | 2322 | sb->s_fs_info = sbinfo; |
1da177e4 | 2323 | |
0edd73b3 | 2324 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2325 | /* |
2326 | * Per default we only allow half of the physical ram per | |
2327 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2328 | * but the internal instance is left unlimited. | |
2329 | */ | |
2330 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b | 2331 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2332 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2333 | if (shmem_parse_options(data, sbinfo, false)) { | |
2334 | err = -EINVAL; | |
2335 | goto failed; | |
2336 | } | |
1da177e4 | 2337 | } |
91828a40 | 2338 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2339 | #else |
2340 | sb->s_flags |= MS_NOUSER; | |
2341 | #endif | |
2342 | ||
0edd73b3 | 2343 | spin_lock_init(&sbinfo->stat_lock); |
680d794b | 2344 | sbinfo->free_blocks = sbinfo->max_blocks; |
2345 | sbinfo->free_inodes = sbinfo->max_inodes; | |
0edd73b3 | 2346 | |
1da177e4 LT |
2347 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2348 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2349 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2350 | sb->s_magic = TMPFS_MAGIC; | |
2351 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2352 | sb->s_time_gran = 1; |
39f0247d AG |
2353 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2354 | sb->s_xattr = shmem_xattr_handlers; | |
2355 | sb->s_flags |= MS_POSIXACL; | |
2356 | #endif | |
0edd73b3 | 2357 | |
454abafe | 2358 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2359 | if (!inode) |
2360 | goto failed; | |
680d794b | 2361 | inode->i_uid = sbinfo->uid; |
2362 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2363 | root = d_alloc_root(inode); |
2364 | if (!root) | |
2365 | goto failed_iput; | |
2366 | sb->s_root = root; | |
2367 | return 0; | |
2368 | ||
2369 | failed_iput: | |
2370 | iput(inode); | |
2371 | failed: | |
2372 | shmem_put_super(sb); | |
2373 | return err; | |
2374 | } | |
2375 | ||
fcc234f8 | 2376 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2377 | |
2378 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2379 | { | |
2380 | struct shmem_inode_info *p; | |
e94b1766 | 2381 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2382 | if (!p) |
2383 | return NULL; | |
2384 | return &p->vfs_inode; | |
2385 | } | |
2386 | ||
2387 | static void shmem_destroy_inode(struct inode *inode) | |
2388 | { | |
2389 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2390 | /* only struct inode is valid if it's an inline symlink */ | |
2391 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2392 | } | |
2393 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2394 | } | |
2395 | ||
51cc5068 | 2396 | static void init_once(void *foo) |
1da177e4 LT |
2397 | { |
2398 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2399 | ||
a35afb83 | 2400 | inode_init_once(&p->vfs_inode); |
1da177e4 LT |
2401 | } |
2402 | ||
2403 | static int init_inodecache(void) | |
2404 | { | |
2405 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2406 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2407 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2408 | return 0; |
2409 | } | |
2410 | ||
2411 | static void destroy_inodecache(void) | |
2412 | { | |
1a1d92c1 | 2413 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2414 | } |
2415 | ||
f5e54d6e | 2416 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2417 | .writepage = shmem_writepage, |
76719325 | 2418 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2419 | #ifdef CONFIG_TMPFS |
ae976416 | 2420 | .readpage = shmem_readpage, |
800d15a5 NP |
2421 | .write_begin = shmem_write_begin, |
2422 | .write_end = shmem_write_end, | |
1da177e4 | 2423 | #endif |
304dbdb7 | 2424 | .migratepage = migrate_page, |
aa261f54 | 2425 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2426 | }; |
2427 | ||
15ad7cdc | 2428 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2429 | .mmap = shmem_mmap, |
2430 | #ifdef CONFIG_TMPFS | |
2431 | .llseek = generic_file_llseek, | |
bcd78e49 | 2432 | .read = do_sync_read, |
5402b976 | 2433 | .write = do_sync_write, |
bcd78e49 | 2434 | .aio_read = shmem_file_aio_read, |
5402b976 | 2435 | .aio_write = generic_file_aio_write, |
1da177e4 | 2436 | .fsync = simple_sync_file, |
ae976416 HD |
2437 | .splice_read = generic_file_splice_read, |
2438 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2439 | #endif |
2440 | }; | |
2441 | ||
92e1d5be | 2442 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 LT |
2443 | .truncate = shmem_truncate, |
2444 | .setattr = shmem_notify_change, | |
f6b3ec23 | 2445 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2446 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2447 | .setxattr = generic_setxattr, | |
2448 | .getxattr = generic_getxattr, | |
2449 | .listxattr = generic_listxattr, | |
2450 | .removexattr = generic_removexattr, | |
1c7c474c | 2451 | .check_acl = generic_check_acl, |
39f0247d AG |
2452 | #endif |
2453 | ||
1da177e4 LT |
2454 | }; |
2455 | ||
92e1d5be | 2456 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2457 | #ifdef CONFIG_TMPFS |
2458 | .create = shmem_create, | |
2459 | .lookup = simple_lookup, | |
2460 | .link = shmem_link, | |
2461 | .unlink = shmem_unlink, | |
2462 | .symlink = shmem_symlink, | |
2463 | .mkdir = shmem_mkdir, | |
2464 | .rmdir = shmem_rmdir, | |
2465 | .mknod = shmem_mknod, | |
2466 | .rename = shmem_rename, | |
1da177e4 | 2467 | #endif |
39f0247d AG |
2468 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2469 | .setattr = shmem_notify_change, | |
2470 | .setxattr = generic_setxattr, | |
2471 | .getxattr = generic_getxattr, | |
2472 | .listxattr = generic_listxattr, | |
2473 | .removexattr = generic_removexattr, | |
1c7c474c | 2474 | .check_acl = generic_check_acl, |
39f0247d AG |
2475 | #endif |
2476 | }; | |
2477 | ||
92e1d5be | 2478 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2479 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2480 | .setattr = shmem_notify_change, | |
2481 | .setxattr = generic_setxattr, | |
2482 | .getxattr = generic_getxattr, | |
2483 | .listxattr = generic_listxattr, | |
2484 | .removexattr = generic_removexattr, | |
1c7c474c | 2485 | .check_acl = generic_check_acl, |
39f0247d | 2486 | #endif |
1da177e4 LT |
2487 | }; |
2488 | ||
759b9775 | 2489 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2490 | .alloc_inode = shmem_alloc_inode, |
2491 | .destroy_inode = shmem_destroy_inode, | |
2492 | #ifdef CONFIG_TMPFS | |
2493 | .statfs = shmem_statfs, | |
2494 | .remount_fs = shmem_remount_fs, | |
680d794b | 2495 | .show_options = shmem_show_options, |
1da177e4 LT |
2496 | #endif |
2497 | .delete_inode = shmem_delete_inode, | |
2498 | .drop_inode = generic_delete_inode, | |
2499 | .put_super = shmem_put_super, | |
2500 | }; | |
2501 | ||
f0f37e2f | 2502 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2503 | .fault = shmem_fault, |
1da177e4 LT |
2504 | #ifdef CONFIG_NUMA |
2505 | .set_policy = shmem_set_policy, | |
2506 | .get_policy = shmem_get_policy, | |
2507 | #endif | |
2508 | }; | |
2509 | ||
2510 | ||
454e2398 DH |
2511 | static int shmem_get_sb(struct file_system_type *fs_type, |
2512 | int flags, const char *dev_name, void *data, struct vfsmount *mnt) | |
1da177e4 | 2513 | { |
454e2398 | 2514 | return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt); |
1da177e4 LT |
2515 | } |
2516 | ||
2517 | static struct file_system_type tmpfs_fs_type = { | |
2518 | .owner = THIS_MODULE, | |
2519 | .name = "tmpfs", | |
2520 | .get_sb = shmem_get_sb, | |
2521 | .kill_sb = kill_litter_super, | |
2522 | }; | |
1da177e4 | 2523 | |
2b2af54a | 2524 | int __init init_tmpfs(void) |
1da177e4 LT |
2525 | { |
2526 | int error; | |
2527 | ||
e0bf68dd PZ |
2528 | error = bdi_init(&shmem_backing_dev_info); |
2529 | if (error) | |
2530 | goto out4; | |
2531 | ||
1da177e4 LT |
2532 | error = init_inodecache(); |
2533 | if (error) | |
2534 | goto out3; | |
2535 | ||
2536 | error = register_filesystem(&tmpfs_fs_type); | |
2537 | if (error) { | |
2538 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2539 | goto out2; | |
2540 | } | |
95dc112a | 2541 | |
1f5ce9e9 | 2542 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2543 | tmpfs_fs_type.name, NULL); |
2544 | if (IS_ERR(shm_mnt)) { | |
2545 | error = PTR_ERR(shm_mnt); | |
2546 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2547 | goto out1; | |
2548 | } | |
2549 | return 0; | |
2550 | ||
2551 | out1: | |
2552 | unregister_filesystem(&tmpfs_fs_type); | |
2553 | out2: | |
2554 | destroy_inodecache(); | |
2555 | out3: | |
e0bf68dd PZ |
2556 | bdi_destroy(&shmem_backing_dev_info); |
2557 | out4: | |
1da177e4 LT |
2558 | shm_mnt = ERR_PTR(error); |
2559 | return error; | |
2560 | } | |
853ac43a | 2561 | |
87946a72 DN |
2562 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2563 | /** | |
2564 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2565 | * @inode: the inode to be searched | |
2566 | * @pgoff: the offset to be searched | |
2567 | * @pagep: the pointer for the found page to be stored | |
2568 | * @ent: the pointer for the found swap entry to be stored | |
2569 | * | |
2570 | * If a page is found, refcount of it is incremented. Callers should handle | |
2571 | * these refcount. | |
2572 | */ | |
2573 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2574 | struct page **pagep, swp_entry_t *ent) | |
2575 | { | |
2576 | swp_entry_t entry = { .val = 0 }, *ptr; | |
2577 | struct page *page = NULL; | |
2578 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2579 | ||
2580 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2581 | goto out; | |
2582 | ||
2583 | spin_lock(&info->lock); | |
2584 | ptr = shmem_swp_entry(info, pgoff, NULL); | |
2585 | #ifdef CONFIG_SWAP | |
2586 | if (ptr && ptr->val) { | |
2587 | entry.val = ptr->val; | |
2588 | page = find_get_page(&swapper_space, entry.val); | |
2589 | } else | |
2590 | #endif | |
2591 | page = find_get_page(inode->i_mapping, pgoff); | |
2592 | if (ptr) | |
2593 | shmem_swp_unmap(ptr); | |
2594 | spin_unlock(&info->lock); | |
2595 | out: | |
2596 | *pagep = page; | |
2597 | *ent = entry; | |
2598 | } | |
2599 | #endif | |
2600 | ||
853ac43a MM |
2601 | #else /* !CONFIG_SHMEM */ |
2602 | ||
2603 | /* | |
2604 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2605 | * | |
2606 | * This is intended for small system where the benefits of the full | |
2607 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2608 | * their complexity. On systems without swap this code should be | |
2609 | * effectively equivalent, but much lighter weight. | |
2610 | */ | |
2611 | ||
2612 | #include <linux/ramfs.h> | |
2613 | ||
2614 | static struct file_system_type tmpfs_fs_type = { | |
2615 | .name = "tmpfs", | |
2616 | .get_sb = ramfs_get_sb, | |
2617 | .kill_sb = kill_litter_super, | |
2618 | }; | |
2619 | ||
2b2af54a | 2620 | int __init init_tmpfs(void) |
853ac43a MM |
2621 | { |
2622 | BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); | |
2623 | ||
2624 | shm_mnt = kern_mount(&tmpfs_fs_type); | |
2625 | BUG_ON(IS_ERR(shm_mnt)); | |
2626 | ||
2627 | return 0; | |
2628 | } | |
2629 | ||
2630 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
2631 | { | |
2632 | return 0; | |
2633 | } | |
2634 | ||
3f96b79a HD |
2635 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2636 | { | |
2637 | return 0; | |
2638 | } | |
2639 | ||
87946a72 DN |
2640 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2641 | /** | |
2642 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2643 | * @inode: the inode to be searched | |
2644 | * @pgoff: the offset to be searched | |
2645 | * @pagep: the pointer for the found page to be stored | |
2646 | * @ent: the pointer for the found swap entry to be stored | |
2647 | * | |
2648 | * If a page is found, refcount of it is incremented. Callers should handle | |
2649 | * these refcount. | |
2650 | */ | |
2651 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2652 | struct page **pagep, swp_entry_t *ent) | |
2653 | { | |
2654 | struct page *page = NULL; | |
2655 | ||
2656 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2657 | goto out; | |
2658 | page = find_get_page(inode->i_mapping, pgoff); | |
2659 | out: | |
2660 | *pagep = page; | |
2661 | *ent = (swp_entry_t){ .val = 0 }; | |
2662 | } | |
2663 | #endif | |
2664 | ||
0b0a0806 HD |
2665 | #define shmem_vm_ops generic_file_vm_ops |
2666 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2667 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2668 | #define shmem_acct_size(flags, size) 0 |
2669 | #define shmem_unacct_size(flags, size) do {} while (0) | |
caefba17 | 2670 | #define SHMEM_MAX_BYTES MAX_LFS_FILESIZE |
853ac43a MM |
2671 | |
2672 | #endif /* CONFIG_SHMEM */ | |
2673 | ||
2674 | /* common code */ | |
1da177e4 | 2675 | |
46711810 | 2676 | /** |
1da177e4 | 2677 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2678 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2679 | * @size: size to be set for the file | |
0b0a0806 | 2680 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2681 | */ |
168f5ac6 | 2682 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2683 | { |
2684 | int error; | |
2685 | struct file *file; | |
2686 | struct inode *inode; | |
2c48b9c4 AV |
2687 | struct path path; |
2688 | struct dentry *root; | |
1da177e4 LT |
2689 | struct qstr this; |
2690 | ||
2691 | if (IS_ERR(shm_mnt)) | |
2692 | return (void *)shm_mnt; | |
2693 | ||
2694 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2695 | return ERR_PTR(-EINVAL); | |
2696 | ||
2697 | if (shmem_acct_size(flags, size)) | |
2698 | return ERR_PTR(-ENOMEM); | |
2699 | ||
2700 | error = -ENOMEM; | |
2701 | this.name = name; | |
2702 | this.len = strlen(name); | |
2703 | this.hash = 0; /* will go */ | |
2704 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2705 | path.dentry = d_alloc(root, &this); |
2706 | if (!path.dentry) | |
1da177e4 | 2707 | goto put_memory; |
2c48b9c4 | 2708 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2709 | |
1da177e4 | 2710 | error = -ENOSPC; |
454abafe | 2711 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2712 | if (!inode) |
4b42af81 | 2713 | goto put_dentry; |
1da177e4 | 2714 | |
2c48b9c4 | 2715 | d_instantiate(path.dentry, inode); |
1da177e4 LT |
2716 | inode->i_size = size; |
2717 | inode->i_nlink = 0; /* It is unlinked */ | |
853ac43a MM |
2718 | #ifndef CONFIG_MMU |
2719 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2720 | if (error) | |
4b42af81 | 2721 | goto put_dentry; |
853ac43a | 2722 | #endif |
4b42af81 AV |
2723 | |
2724 | error = -ENFILE; | |
2c48b9c4 | 2725 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2726 | &shmem_file_operations); |
2727 | if (!file) | |
2728 | goto put_dentry; | |
2729 | ||
1da177e4 LT |
2730 | return file; |
2731 | ||
1da177e4 | 2732 | put_dentry: |
2c48b9c4 | 2733 | path_put(&path); |
1da177e4 LT |
2734 | put_memory: |
2735 | shmem_unacct_size(flags, size); | |
2736 | return ERR_PTR(error); | |
2737 | } | |
395e0ddc | 2738 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2739 | |
46711810 | 2740 | /** |
1da177e4 | 2741 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2742 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2743 | */ | |
2744 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2745 | { | |
2746 | struct file *file; | |
2747 | loff_t size = vma->vm_end - vma->vm_start; | |
2748 | ||
2749 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2750 | if (IS_ERR(file)) | |
2751 | return PTR_ERR(file); | |
2752 | ||
2753 | if (vma->vm_file) | |
2754 | fput(vma->vm_file); | |
2755 | vma->vm_file = file; | |
2756 | vma->vm_ops = &shmem_vm_ops; | |
2757 | return 0; | |
2758 | } |