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> | |
7e496299 | 31 | #include <linux/percpu_counter.h> |
853ac43a MM |
32 | #include <linux/swap.h> |
33 | ||
34 | static struct vfsmount *shm_mnt; | |
35 | ||
36 | #ifdef CONFIG_SHMEM | |
1da177e4 LT |
37 | /* |
38 | * This virtual memory filesystem is heavily based on the ramfs. It | |
39 | * extends ramfs by the ability to use swap and honor resource limits | |
40 | * which makes it a completely usable filesystem. | |
41 | */ | |
42 | ||
39f0247d | 43 | #include <linux/xattr.h> |
a5694255 | 44 | #include <linux/exportfs.h> |
1c7c474c | 45 | #include <linux/posix_acl.h> |
39f0247d | 46 | #include <linux/generic_acl.h> |
1da177e4 | 47 | #include <linux/mman.h> |
1da177e4 LT |
48 | #include <linux/string.h> |
49 | #include <linux/slab.h> | |
50 | #include <linux/backing-dev.h> | |
51 | #include <linux/shmem_fs.h> | |
1da177e4 | 52 | #include <linux/writeback.h> |
1da177e4 LT |
53 | #include <linux/blkdev.h> |
54 | #include <linux/security.h> | |
55 | #include <linux/swapops.h> | |
56 | #include <linux/mempolicy.h> | |
57 | #include <linux/namei.h> | |
b00dc3ad | 58 | #include <linux/ctype.h> |
304dbdb7 | 59 | #include <linux/migrate.h> |
c1f60a5a | 60 | #include <linux/highmem.h> |
680d794b | 61 | #include <linux/seq_file.h> |
92562927 | 62 | #include <linux/magic.h> |
304dbdb7 | 63 | |
1da177e4 LT |
64 | #include <asm/uaccess.h> |
65 | #include <asm/div64.h> | |
66 | #include <asm/pgtable.h> | |
67 | ||
caefba17 HD |
68 | /* |
69 | * The maximum size of a shmem/tmpfs file is limited by the maximum size of | |
70 | * its triple-indirect swap vector - see illustration at shmem_swp_entry(). | |
71 | * | |
72 | * With 4kB page size, maximum file size is just over 2TB on a 32-bit kernel, | |
73 | * but one eighth of that on a 64-bit kernel. With 8kB page size, maximum | |
74 | * file size is just over 4TB on a 64-bit kernel, but 16TB on a 32-bit kernel, | |
75 | * MAX_LFS_FILESIZE being then more restrictive than swap vector layout. | |
76 | * | |
77 | * We use / and * instead of shifts in the definitions below, so that the swap | |
78 | * vector can be tested with small even values (e.g. 20) for ENTRIES_PER_PAGE. | |
79 | */ | |
1da177e4 | 80 | #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long)) |
61609d01 | 81 | #define ENTRIES_PER_PAGEPAGE ((unsigned long long)ENTRIES_PER_PAGE*ENTRIES_PER_PAGE) |
1da177e4 | 82 | |
caefba17 HD |
83 | #define SHMSWP_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1)) |
84 | #define SHMSWP_MAX_BYTES (SHMSWP_MAX_INDEX << PAGE_CACHE_SHIFT) | |
1da177e4 | 85 | |
caefba17 HD |
86 | #define SHMEM_MAX_BYTES min_t(unsigned long long, SHMSWP_MAX_BYTES, MAX_LFS_FILESIZE) |
87 | #define SHMEM_MAX_INDEX ((unsigned long)((SHMEM_MAX_BYTES+1) >> PAGE_CACHE_SHIFT)) | |
88 | ||
89 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) | |
1da177e4 LT |
90 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
91 | ||
92 | /* info->flags needs VM_flags to handle pagein/truncate races efficiently */ | |
93 | #define SHMEM_PAGEIN VM_READ | |
94 | #define SHMEM_TRUNCATE VM_WRITE | |
95 | ||
96 | /* Definition to limit shmem_truncate's steps between cond_rescheds */ | |
97 | #define LATENCY_LIMIT 64 | |
98 | ||
99 | /* Pretend that each entry is of this size in directory's i_size */ | |
100 | #define BOGO_DIRENT_SIZE 20 | |
101 | ||
1da177e4 LT |
102 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
103 | enum sgp_type { | |
1da177e4 LT |
104 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
105 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 106 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
107 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
108 | }; | |
109 | ||
b76db735 | 110 | #ifdef CONFIG_TMPFS |
680d794b | 111 | static unsigned long shmem_default_max_blocks(void) |
112 | { | |
113 | return totalram_pages / 2; | |
114 | } | |
115 | ||
116 | static unsigned long shmem_default_max_inodes(void) | |
117 | { | |
118 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
119 | } | |
b76db735 | 120 | #endif |
680d794b | 121 | |
1da177e4 LT |
122 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
123 | struct page **pagep, enum sgp_type sgp, int *type); | |
124 | ||
6daa0e28 | 125 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
126 | { |
127 | /* | |
128 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
129 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
130 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 | 131 | * |
e12ba74d | 132 | * Mobility flags are masked out as swap vectors cannot move |
1da177e4 | 133 | */ |
e12ba74d | 134 | return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO, |
769848c0 | 135 | PAGE_CACHE_SHIFT-PAGE_SHIFT); |
1da177e4 LT |
136 | } |
137 | ||
138 | static inline void shmem_dir_free(struct page *page) | |
139 | { | |
140 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
141 | } | |
142 | ||
143 | static struct page **shmem_dir_map(struct page *page) | |
144 | { | |
145 | return (struct page **)kmap_atomic(page, KM_USER0); | |
146 | } | |
147 | ||
148 | static inline void shmem_dir_unmap(struct page **dir) | |
149 | { | |
150 | kunmap_atomic(dir, KM_USER0); | |
151 | } | |
152 | ||
153 | static swp_entry_t *shmem_swp_map(struct page *page) | |
154 | { | |
155 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
156 | } | |
157 | ||
158 | static inline void shmem_swp_balance_unmap(void) | |
159 | { | |
160 | /* | |
161 | * When passing a pointer to an i_direct entry, to code which | |
162 | * also handles indirect entries and so will shmem_swp_unmap, | |
163 | * we must arrange for the preempt count to remain in balance. | |
164 | * What kmap_atomic of a lowmem page does depends on config | |
165 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
166 | */ | |
167 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
168 | } | |
169 | ||
170 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
171 | { | |
172 | kunmap_atomic(entry, KM_USER1); | |
173 | } | |
174 | ||
175 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
176 | { | |
177 | return sb->s_fs_info; | |
178 | } | |
179 | ||
180 | /* | |
181 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
182 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
183 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
184 | * consistent with the pre-accounting of private mappings ... | |
185 | */ | |
186 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
187 | { | |
0b0a0806 HD |
188 | return (flags & VM_NORESERVE) ? |
189 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
190 | } |
191 | ||
192 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
193 | { | |
0b0a0806 | 194 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
195 | vm_unacct_memory(VM_ACCT(size)); |
196 | } | |
197 | ||
198 | /* | |
199 | * ... whereas tmpfs objects are accounted incrementally as | |
200 | * pages are allocated, in order to allow huge sparse files. | |
201 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
202 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
203 | */ | |
204 | static inline int shmem_acct_block(unsigned long flags) | |
205 | { | |
0b0a0806 HD |
206 | return (flags & VM_NORESERVE) ? |
207 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
208 | } |
209 | ||
210 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
211 | { | |
0b0a0806 | 212 | if (flags & VM_NORESERVE) |
1da177e4 LT |
213 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
214 | } | |
215 | ||
759b9775 | 216 | static const struct super_operations shmem_ops; |
f5e54d6e | 217 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 218 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
219 | static const struct inode_operations shmem_inode_operations; |
220 | static const struct inode_operations shmem_dir_inode_operations; | |
221 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 222 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 223 | |
6c231b7b | 224 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 225 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 226 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
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) { |
7e496299 TC |
236 | percpu_counter_add(&sbinfo->used_blocks, -pages); |
237 | spin_lock(&inode->i_lock); | |
1da177e4 | 238 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; |
7e496299 | 239 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
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 | /* | |
7e496299 | 419 | * Test used_blocks against 1 less max_blocks, since we have 1 data |
1da177e4 LT |
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) { |
fc5da22a HD |
424 | if (percpu_counter_compare(&sbinfo->used_blocks, |
425 | sbinfo->max_blocks - 1) >= 0) | |
1da177e4 | 426 | return ERR_PTR(-ENOSPC); |
7e496299 TC |
427 | percpu_counter_inc(&sbinfo->used_blocks); |
428 | spin_lock(&inode->i_lock); | |
1da177e4 | 429 | inode->i_blocks += BLOCKS_PER_PAGE; |
7e496299 | 430 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
431 | } |
432 | ||
433 | spin_unlock(&info->lock); | |
769848c0 | 434 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
1da177e4 LT |
435 | spin_lock(&info->lock); |
436 | ||
437 | if (!page) { | |
438 | shmem_free_blocks(inode, 1); | |
439 | return ERR_PTR(-ENOMEM); | |
440 | } | |
441 | if (sgp != SGP_WRITE && | |
442 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
443 | entry = ERR_PTR(-EINVAL); | |
444 | break; | |
445 | } | |
446 | if (info->next_index <= index) | |
447 | info->next_index = index + 1; | |
448 | } | |
449 | if (page) { | |
450 | /* another task gave its page, or truncated the file */ | |
451 | shmem_free_blocks(inode, 1); | |
452 | shmem_dir_free(page); | |
453 | } | |
454 | if (info->next_index <= index && !IS_ERR(entry)) | |
455 | info->next_index = index + 1; | |
456 | return entry; | |
457 | } | |
458 | ||
46711810 | 459 | /** |
1da177e4 | 460 | * shmem_free_swp - free some swap entries in a directory |
1ae70006 HD |
461 | * @dir: pointer to the directory |
462 | * @edir: pointer after last entry of the directory | |
463 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 464 | */ |
1ae70006 HD |
465 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
466 | spinlock_t *punch_lock) | |
1da177e4 | 467 | { |
1ae70006 | 468 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
469 | swp_entry_t *ptr; |
470 | int freed = 0; | |
471 | ||
472 | for (ptr = dir; ptr < edir; ptr++) { | |
473 | if (ptr->val) { | |
1ae70006 HD |
474 | if (unlikely(punch_lock)) { |
475 | punch_unlock = punch_lock; | |
476 | punch_lock = NULL; | |
477 | spin_lock(punch_unlock); | |
478 | if (!ptr->val) | |
479 | continue; | |
480 | } | |
1da177e4 LT |
481 | free_swap_and_cache(*ptr); |
482 | *ptr = (swp_entry_t){0}; | |
483 | freed++; | |
484 | } | |
485 | } | |
1ae70006 HD |
486 | if (punch_unlock) |
487 | spin_unlock(punch_unlock); | |
1da177e4 LT |
488 | return freed; |
489 | } | |
490 | ||
1ae70006 HD |
491 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
492 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
493 | { |
494 | swp_entry_t *ptr; | |
495 | int freed = 0; | |
496 | ||
497 | ptr = shmem_swp_map(subdir); | |
498 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
499 | int size = limit - offset; | |
500 | if (size > LATENCY_LIMIT) | |
501 | size = LATENCY_LIMIT; | |
1ae70006 HD |
502 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
503 | punch_lock); | |
1da177e4 LT |
504 | if (need_resched()) { |
505 | shmem_swp_unmap(ptr); | |
506 | if (*dir) { | |
507 | shmem_dir_unmap(*dir); | |
508 | *dir = NULL; | |
509 | } | |
510 | cond_resched(); | |
511 | ptr = shmem_swp_map(subdir); | |
512 | } | |
513 | } | |
514 | shmem_swp_unmap(ptr); | |
515 | return freed; | |
516 | } | |
517 | ||
518 | static void shmem_free_pages(struct list_head *next) | |
519 | { | |
520 | struct page *page; | |
521 | int freed = 0; | |
522 | ||
523 | do { | |
524 | page = container_of(next, struct page, lru); | |
525 | next = next->next; | |
526 | shmem_dir_free(page); | |
527 | freed++; | |
528 | if (freed >= LATENCY_LIMIT) { | |
529 | cond_resched(); | |
530 | freed = 0; | |
531 | } | |
532 | } while (next); | |
533 | } | |
534 | ||
f6b3ec23 | 535 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
536 | { |
537 | struct shmem_inode_info *info = SHMEM_I(inode); | |
538 | unsigned long idx; | |
539 | unsigned long size; | |
540 | unsigned long limit; | |
541 | unsigned long stage; | |
542 | unsigned long diroff; | |
543 | struct page **dir; | |
544 | struct page *topdir; | |
545 | struct page *middir; | |
546 | struct page *subdir; | |
547 | swp_entry_t *ptr; | |
548 | LIST_HEAD(pages_to_free); | |
549 | long nr_pages_to_free = 0; | |
550 | long nr_swaps_freed = 0; | |
551 | int offset; | |
552 | int freed; | |
a2646d1e | 553 | int punch_hole; |
1ae70006 HD |
554 | spinlock_t *needs_lock; |
555 | spinlock_t *punch_lock; | |
a2646d1e | 556 | unsigned long upper_limit; |
1da177e4 LT |
557 | |
558 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 559 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
560 | if (idx >= info->next_index) |
561 | return; | |
562 | ||
563 | spin_lock(&info->lock); | |
564 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
565 | if (likely(end == (loff_t) -1)) { |
566 | limit = info->next_index; | |
a2646d1e | 567 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 568 | info->next_index = idx; |
1ae70006 | 569 | needs_lock = NULL; |
a2646d1e | 570 | punch_hole = 0; |
f6b3ec23 | 571 | } else { |
a2646d1e HD |
572 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
573 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
574 | PAGE_CACHE_SHIFT; | |
575 | upper_limit = SHMEM_MAX_INDEX; | |
576 | } else { | |
577 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
578 | upper_limit = limit; | |
579 | } | |
1ae70006 | 580 | needs_lock = &info->lock; |
f6b3ec23 BP |
581 | punch_hole = 1; |
582 | } | |
583 | ||
1da177e4 | 584 | topdir = info->i_indirect; |
f6b3ec23 | 585 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
586 | info->i_indirect = NULL; |
587 | nr_pages_to_free++; | |
588 | list_add(&topdir->lru, &pages_to_free); | |
589 | } | |
590 | spin_unlock(&info->lock); | |
591 | ||
592 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
593 | ptr = info->i_direct; | |
594 | size = limit; | |
595 | if (size > SHMEM_NR_DIRECT) | |
596 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 597 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 598 | } |
92a3d03a BP |
599 | |
600 | /* | |
601 | * If there are no indirect blocks or we are punching a hole | |
602 | * below indirect blocks, nothing to be done. | |
603 | */ | |
a2646d1e | 604 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
605 | goto done2; |
606 | ||
1ae70006 HD |
607 | /* |
608 | * The truncation case has already dropped info->lock, and we're safe | |
609 | * because i_size and next_index have already been lowered, preventing | |
610 | * access beyond. But in the punch_hole case, we still need to take | |
611 | * the lock when updating the swap directory, because there might be | |
612 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
613 | * shmem_writepage. However, whenever we find we can remove a whole | |
614 | * directory page (not at the misaligned start or end of the range), | |
615 | * we first NULLify its pointer in the level above, and then have no | |
616 | * need to take the lock when updating its contents: needs_lock and | |
617 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
618 | */ | |
619 | ||
a2646d1e | 620 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
621 | limit -= SHMEM_NR_DIRECT; |
622 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
623 | offset = idx % ENTRIES_PER_PAGE; | |
624 | idx -= offset; | |
625 | ||
626 | dir = shmem_dir_map(topdir); | |
627 | stage = ENTRIES_PER_PAGEPAGE/2; | |
628 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
629 | middir = topdir; | |
630 | diroff = idx/ENTRIES_PER_PAGE; | |
631 | } else { | |
632 | dir += ENTRIES_PER_PAGE/2; | |
633 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
634 | while (stage <= idx) | |
635 | stage += ENTRIES_PER_PAGEPAGE; | |
636 | middir = *dir; | |
637 | if (*dir) { | |
638 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
639 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 640 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
641 | if (needs_lock) { |
642 | spin_lock(needs_lock); | |
643 | *dir = NULL; | |
644 | spin_unlock(needs_lock); | |
645 | needs_lock = NULL; | |
646 | } else | |
647 | *dir = NULL; | |
1da177e4 LT |
648 | nr_pages_to_free++; |
649 | list_add(&middir->lru, &pages_to_free); | |
650 | } | |
651 | shmem_dir_unmap(dir); | |
652 | dir = shmem_dir_map(middir); | |
653 | } else { | |
654 | diroff = 0; | |
655 | offset = 0; | |
656 | idx = stage; | |
657 | } | |
658 | } | |
659 | ||
660 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
661 | if (unlikely(idx == stage)) { | |
662 | shmem_dir_unmap(dir); | |
663 | dir = shmem_dir_map(topdir) + | |
664 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
665 | while (!*dir) { | |
666 | dir++; | |
667 | idx += ENTRIES_PER_PAGEPAGE; | |
668 | if (idx >= limit) | |
669 | goto done1; | |
670 | } | |
671 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
672 | middir = *dir; | |
1ae70006 HD |
673 | if (punch_hole) |
674 | needs_lock = &info->lock; | |
a2646d1e | 675 | if (upper_limit >= stage) { |
1ae70006 HD |
676 | if (needs_lock) { |
677 | spin_lock(needs_lock); | |
678 | *dir = NULL; | |
679 | spin_unlock(needs_lock); | |
680 | needs_lock = NULL; | |
681 | } else | |
682 | *dir = NULL; | |
a2646d1e HD |
683 | nr_pages_to_free++; |
684 | list_add(&middir->lru, &pages_to_free); | |
685 | } | |
1da177e4 LT |
686 | shmem_dir_unmap(dir); |
687 | cond_resched(); | |
688 | dir = shmem_dir_map(middir); | |
689 | diroff = 0; | |
690 | } | |
1ae70006 | 691 | punch_lock = needs_lock; |
1da177e4 | 692 | subdir = dir[diroff]; |
1ae70006 HD |
693 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
694 | if (needs_lock) { | |
695 | spin_lock(needs_lock); | |
696 | dir[diroff] = NULL; | |
697 | spin_unlock(needs_lock); | |
698 | punch_lock = NULL; | |
699 | } else | |
700 | dir[diroff] = NULL; | |
701 | nr_pages_to_free++; | |
702 | list_add(&subdir->lru, &pages_to_free); | |
703 | } | |
704 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
705 | size = limit - idx; |
706 | if (size > ENTRIES_PER_PAGE) | |
707 | size = ENTRIES_PER_PAGE; | |
708 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 709 | offset, size, &dir, punch_lock); |
1da177e4 LT |
710 | if (!dir) |
711 | dir = shmem_dir_map(middir); | |
712 | nr_swaps_freed += freed; | |
1ae70006 | 713 | if (offset || punch_lock) { |
1da177e4 | 714 | spin_lock(&info->lock); |
1ae70006 HD |
715 | set_page_private(subdir, |
716 | page_private(subdir) - freed); | |
1da177e4 | 717 | spin_unlock(&info->lock); |
1ae70006 HD |
718 | } else |
719 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 720 | } |
1ae70006 | 721 | offset = 0; |
1da177e4 LT |
722 | } |
723 | done1: | |
724 | shmem_dir_unmap(dir); | |
725 | done2: | |
726 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
727 | /* | |
728 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
3889e6e7 | 729 | * may have swizzled a page in from swap since |
730 | * truncate_pagecache or generic_delete_inode did it, before we | |
731 | * lowered next_index. Also, though shmem_getpage checks | |
732 | * i_size before adding to cache, no recheck after: so fix the | |
733 | * 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 | ||
763 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) | |
764 | { | |
765 | struct inode *inode = dentry->d_inode; | |
af5a30d8 | 766 | loff_t newsize = attr->ia_size; |
1da177e4 LT |
767 | int error; |
768 | ||
db78b877 CH |
769 | error = inode_change_ok(inode, attr); |
770 | if (error) | |
771 | return error; | |
772 | ||
af5a30d8 NP |
773 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE) |
774 | && newsize != inode->i_size) { | |
3889e6e7 | 775 | struct page *page = NULL; |
776 | ||
777 | if (newsize < inode->i_size) { | |
1da177e4 LT |
778 | /* |
779 | * If truncating down to a partial page, then | |
780 | * if that page is already allocated, hold it | |
781 | * in memory until the truncation is over, so | |
ae0e47f0 | 782 | * truncate_partial_page cannot miss it were |
1da177e4 LT |
783 | * it assigned to swap. |
784 | */ | |
3889e6e7 | 785 | if (newsize & (PAGE_CACHE_SIZE-1)) { |
1da177e4 | 786 | (void) shmem_getpage(inode, |
3889e6e7 | 787 | newsize >> PAGE_CACHE_SHIFT, |
1da177e4 | 788 | &page, SGP_READ, NULL); |
d3602444 HD |
789 | if (page) |
790 | unlock_page(page); | |
1da177e4 LT |
791 | } |
792 | /* | |
793 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
794 | * detect if any pages might have been added to cache | |
795 | * after truncate_inode_pages. But we needn't bother | |
796 | * if it's being fully truncated to zero-length: the | |
797 | * nrpages check is efficient enough in that case. | |
798 | */ | |
3889e6e7 | 799 | if (newsize) { |
1da177e4 LT |
800 | struct shmem_inode_info *info = SHMEM_I(inode); |
801 | spin_lock(&info->lock); | |
802 | info->flags &= ~SHMEM_PAGEIN; | |
803 | spin_unlock(&info->lock); | |
804 | } | |
805 | } | |
3889e6e7 | 806 | |
2c27c65e CH |
807 | /* XXX(truncate): truncate_setsize should be called last */ |
808 | truncate_setsize(inode, newsize); | |
3889e6e7 | 809 | if (page) |
810 | page_cache_release(page); | |
3889e6e7 | 811 | shmem_truncate_range(inode, newsize, (loff_t)-1); |
1da177e4 LT |
812 | } |
813 | ||
db78b877 | 814 | setattr_copy(inode, attr); |
39f0247d | 815 | #ifdef CONFIG_TMPFS_POSIX_ACL |
db78b877 | 816 | if (attr->ia_valid & ATTR_MODE) |
1c7c474c | 817 | error = generic_acl_chmod(inode); |
39f0247d | 818 | #endif |
1da177e4 LT |
819 | return error; |
820 | } | |
821 | ||
1f895f75 | 822 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 823 | { |
1da177e4 LT |
824 | struct shmem_inode_info *info = SHMEM_I(inode); |
825 | ||
3889e6e7 | 826 | if (inode->i_mapping->a_ops == &shmem_aops) { |
fef26658 | 827 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
828 | shmem_unacct_size(info->flags, inode->i_size); |
829 | inode->i_size = 0; | |
3889e6e7 | 830 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 831 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 832 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 833 | list_del_init(&info->swaplist); |
cb5f7b9a | 834 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
835 | } |
836 | } | |
0edd73b3 | 837 | BUG_ON(inode->i_blocks); |
5b04c689 | 838 | shmem_free_inode(inode->i_sb); |
1f895f75 | 839 | end_writeback(inode); |
1da177e4 LT |
840 | } |
841 | ||
842 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
843 | { | |
844 | swp_entry_t *ptr; | |
845 | ||
846 | for (ptr = dir; ptr < edir; ptr++) { | |
847 | if (ptr->val == entry.val) | |
848 | return ptr - dir; | |
849 | } | |
850 | return -1; | |
851 | } | |
852 | ||
853 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
854 | { | |
778dd893 | 855 | struct address_space *mapping; |
1da177e4 LT |
856 | unsigned long idx; |
857 | unsigned long size; | |
858 | unsigned long limit; | |
859 | unsigned long stage; | |
860 | struct page **dir; | |
861 | struct page *subdir; | |
862 | swp_entry_t *ptr; | |
863 | int offset; | |
d9fe526a | 864 | int error; |
1da177e4 LT |
865 | |
866 | idx = 0; | |
867 | ptr = info->i_direct; | |
868 | spin_lock(&info->lock); | |
1b1b32f2 HD |
869 | if (!info->swapped) { |
870 | list_del_init(&info->swaplist); | |
871 | goto lost2; | |
872 | } | |
1da177e4 LT |
873 | limit = info->next_index; |
874 | size = limit; | |
875 | if (size > SHMEM_NR_DIRECT) | |
876 | size = SHMEM_NR_DIRECT; | |
877 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
778dd893 HD |
878 | if (offset >= 0) { |
879 | shmem_swp_balance_unmap(); | |
1da177e4 | 880 | goto found; |
778dd893 | 881 | } |
1da177e4 LT |
882 | if (!info->i_indirect) |
883 | goto lost2; | |
884 | ||
885 | dir = shmem_dir_map(info->i_indirect); | |
886 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
887 | ||
888 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
889 | if (unlikely(idx == stage)) { | |
890 | shmem_dir_unmap(dir-1); | |
cb5f7b9a HD |
891 | if (cond_resched_lock(&info->lock)) { |
892 | /* check it has not been truncated */ | |
893 | if (limit > info->next_index) { | |
894 | limit = info->next_index; | |
895 | if (idx >= limit) | |
896 | goto lost2; | |
897 | } | |
898 | } | |
1da177e4 LT |
899 | dir = shmem_dir_map(info->i_indirect) + |
900 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
901 | while (!*dir) { | |
902 | dir++; | |
903 | idx += ENTRIES_PER_PAGEPAGE; | |
904 | if (idx >= limit) | |
905 | goto lost1; | |
906 | } | |
907 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
908 | subdir = *dir; | |
909 | shmem_dir_unmap(dir); | |
910 | dir = shmem_dir_map(subdir); | |
911 | } | |
912 | subdir = *dir; | |
4c21e2f2 | 913 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
914 | ptr = shmem_swp_map(subdir); |
915 | size = limit - idx; | |
916 | if (size > ENTRIES_PER_PAGE) | |
917 | size = ENTRIES_PER_PAGE; | |
918 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
919 | if (offset >= 0) { | |
920 | shmem_dir_unmap(dir); | |
921 | goto found; | |
922 | } | |
778dd893 | 923 | shmem_swp_unmap(ptr); |
1da177e4 LT |
924 | } |
925 | } | |
926 | lost1: | |
927 | shmem_dir_unmap(dir-1); | |
928 | lost2: | |
929 | spin_unlock(&info->lock); | |
930 | return 0; | |
931 | found: | |
932 | idx += offset; | |
778dd893 | 933 | ptr += offset; |
2e0e26c7 | 934 | |
1b1b32f2 HD |
935 | /* |
936 | * Move _head_ to start search for next from here. | |
1f895f75 | 937 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 HD |
938 | * mutex, and there's an instant in list_move_tail when info->swaplist |
939 | * would appear empty, if it were the only one on shmem_swaplist. We | |
940 | * could avoid doing it if inode NULL; or use this minor optimization. | |
941 | */ | |
942 | if (shmem_swaplist.next != &info->swaplist) | |
943 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 944 | |
d13d1443 | 945 | /* |
778dd893 HD |
946 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
947 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
948 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 949 | */ |
778dd893 HD |
950 | mapping = info->vfs_inode.i_mapping; |
951 | error = add_to_page_cache_locked(page, mapping, idx, GFP_NOWAIT); | |
952 | /* which does mem_cgroup_uncharge_cache_page on error */ | |
69029cd5 | 953 | |
d9fe526a | 954 | if (error == -EEXIST) { |
778dd893 | 955 | struct page *filepage = find_get_page(mapping, idx); |
2e0e26c7 | 956 | error = 1; |
d9fe526a HD |
957 | if (filepage) { |
958 | /* | |
959 | * There might be a more uptodate page coming down | |
960 | * from a stacked writepage: forget our swappage if so. | |
961 | */ | |
962 | if (PageUptodate(filepage)) | |
963 | error = 0; | |
964 | page_cache_release(filepage); | |
965 | } | |
966 | } | |
967 | if (!error) { | |
73b1262f HD |
968 | delete_from_swap_cache(page); |
969 | set_page_dirty(page); | |
1da177e4 | 970 | info->flags |= SHMEM_PAGEIN; |
2e0e26c7 HD |
971 | shmem_swp_set(info, ptr, 0); |
972 | swap_free(entry); | |
973 | error = 1; /* not an error, but entry was found */ | |
1da177e4 | 974 | } |
778dd893 | 975 | shmem_swp_unmap(ptr); |
1da177e4 | 976 | spin_unlock(&info->lock); |
2e0e26c7 | 977 | return error; |
1da177e4 LT |
978 | } |
979 | ||
980 | /* | |
981 | * shmem_unuse() search for an eventually swapped out shmem page. | |
982 | */ | |
983 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
984 | { | |
985 | struct list_head *p, *next; | |
986 | struct shmem_inode_info *info; | |
987 | int found = 0; | |
778dd893 HD |
988 | int error; |
989 | ||
990 | /* | |
991 | * Charge page using GFP_KERNEL while we can wait, before taking | |
992 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
993 | * Charged back to the user (not to caller) when swap account is used. | |
994 | * add_to_page_cache() will be called with GFP_NOWAIT. | |
995 | */ | |
996 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
997 | if (error) | |
998 | goto out; | |
999 | /* | |
1000 | * Try to preload while we can wait, to not make a habit of | |
1001 | * draining atomic reserves; but don't latch on to this cpu, | |
1002 | * it's okay if sometimes we get rescheduled after this. | |
1003 | */ | |
1004 | error = radix_tree_preload(GFP_KERNEL); | |
1005 | if (error) | |
1006 | goto uncharge; | |
1007 | radix_tree_preload_end(); | |
1da177e4 | 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 | 1014 | if (found) |
778dd893 | 1015 | break; |
1da177e4 | 1016 | } |
cb5f7b9a | 1017 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 HD |
1018 | |
1019 | uncharge: | |
1020 | if (!found) | |
1021 | mem_cgroup_uncharge_cache_page(page); | |
1022 | if (found < 0) | |
1023 | error = found; | |
1024 | out: | |
aaa46865 HD |
1025 | unlock_page(page); |
1026 | page_cache_release(page); | |
778dd893 | 1027 | return error; |
1da177e4 LT |
1028 | } |
1029 | ||
1030 | /* | |
1031 | * Move the page from the page cache to the swap cache. | |
1032 | */ | |
1033 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
1034 | { | |
1035 | struct shmem_inode_info *info; | |
1036 | swp_entry_t *entry, swap; | |
1037 | struct address_space *mapping; | |
1038 | unsigned long index; | |
1039 | struct inode *inode; | |
1040 | ||
1041 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
1042 | mapping = page->mapping; |
1043 | index = page->index; | |
1044 | inode = mapping->host; | |
1045 | info = SHMEM_I(inode); | |
1046 | if (info->flags & VM_LOCKED) | |
1047 | goto redirty; | |
d9fe526a | 1048 | if (!total_swap_pages) |
1da177e4 LT |
1049 | goto redirty; |
1050 | ||
d9fe526a HD |
1051 | /* |
1052 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
1053 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
1054 | * may use the ->writepage of its underlying filesystem, in which case | |
1055 | * tmpfs should write out to swap only in response to memory pressure, | |
5b0830cb JA |
1056 | * and not for the writeback threads or sync. However, in those cases, |
1057 | * we do still want to check if there's a redundant swappage to be | |
1058 | * discarded. | |
d9fe526a HD |
1059 | */ |
1060 | if (wbc->for_reclaim) | |
1061 | swap = get_swap_page(); | |
1062 | else | |
1063 | swap.val = 0; | |
1064 | ||
b1dea800 HD |
1065 | /* |
1066 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
1067 | * if it's not already there. Do it now because we cannot take | |
1068 | * mutex while holding spinlock, and must do so before the page | |
1069 | * is moved to swap cache, when its pagelock no longer protects | |
1070 | * the inode from eviction. But don't unlock the mutex until | |
1071 | * we've taken the spinlock, because shmem_unuse_inode() will | |
1072 | * prune a !swapped inode from the swaplist under both locks. | |
1073 | */ | |
05bf86b4 | 1074 | if (swap.val) { |
b1dea800 | 1075 | mutex_lock(&shmem_swaplist_mutex); |
05bf86b4 HD |
1076 | if (list_empty(&info->swaplist)) |
1077 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 HD |
1078 | } |
1079 | ||
1da177e4 | 1080 | spin_lock(&info->lock); |
05bf86b4 | 1081 | if (swap.val) |
b1dea800 HD |
1082 | mutex_unlock(&shmem_swaplist_mutex); |
1083 | ||
1da177e4 LT |
1084 | if (index >= info->next_index) { |
1085 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
1086 | goto unlock; | |
1087 | } | |
1088 | entry = shmem_swp_entry(info, index, NULL); | |
d9fe526a HD |
1089 | if (entry->val) { |
1090 | /* | |
1091 | * The more uptodate page coming down from a stacked | |
1092 | * writepage should replace our old swappage. | |
1093 | */ | |
1094 | free_swap_and_cache(*entry); | |
1095 | shmem_swp_set(info, entry, 0); | |
1096 | } | |
1097 | shmem_recalc_inode(inode); | |
1da177e4 | 1098 | |
d9fe526a | 1099 | if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
4c73b1bc | 1100 | delete_from_page_cache(page); |
1da177e4 LT |
1101 | shmem_swp_set(info, entry, swap.val); |
1102 | shmem_swp_unmap(entry); | |
1103 | spin_unlock(&info->lock); | |
aaa46865 | 1104 | swap_shmem_alloc(swap); |
d9fe526a | 1105 | BUG_ON(page_mapped(page)); |
9fab5619 | 1106 | swap_writepage(page, wbc); |
1da177e4 LT |
1107 | return 0; |
1108 | } | |
1109 | ||
1110 | shmem_swp_unmap(entry); | |
1111 | unlock: | |
1112 | spin_unlock(&info->lock); | |
2ca4532a DN |
1113 | /* |
1114 | * add_to_swap_cache() doesn't return -EEXIST, so we can safely | |
1115 | * clear SWAP_HAS_CACHE flag. | |
1116 | */ | |
cb4b86ba | 1117 | swapcache_free(swap, NULL); |
1da177e4 LT |
1118 | redirty: |
1119 | set_page_dirty(page); | |
d9fe526a HD |
1120 | if (wbc->for_reclaim) |
1121 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1122 | unlock_page(page); | |
1123 | return 0; | |
1da177e4 LT |
1124 | } |
1125 | ||
1126 | #ifdef CONFIG_NUMA | |
680d794b | 1127 | #ifdef CONFIG_TMPFS |
71fe804b | 1128 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 1129 | { |
095f1fc4 | 1130 | char buffer[64]; |
680d794b | 1131 | |
71fe804b | 1132 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 1133 | return; /* show nothing */ |
680d794b | 1134 | |
71fe804b | 1135 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
1136 | |
1137 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 1138 | } |
71fe804b LS |
1139 | |
1140 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1141 | { | |
1142 | struct mempolicy *mpol = NULL; | |
1143 | if (sbinfo->mpol) { | |
1144 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
1145 | mpol = sbinfo->mpol; | |
1146 | mpol_get(mpol); | |
1147 | spin_unlock(&sbinfo->stat_lock); | |
1148 | } | |
1149 | return mpol; | |
1150 | } | |
680d794b | 1151 | #endif /* CONFIG_TMPFS */ |
1152 | ||
02098fea HD |
1153 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1154 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1155 | { |
52cd3b07 | 1156 | struct mempolicy mpol, *spol; |
1da177e4 | 1157 | struct vm_area_struct pvma; |
c4cc6d07 | 1158 | struct page *page; |
1da177e4 | 1159 | |
52cd3b07 LS |
1160 | spol = mpol_cond_copy(&mpol, |
1161 | mpol_shared_policy_lookup(&info->policy, idx)); | |
1162 | ||
1da177e4 | 1163 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 1164 | pvma.vm_start = 0; |
1da177e4 | 1165 | pvma.vm_pgoff = idx; |
c4cc6d07 | 1166 | pvma.vm_ops = NULL; |
52cd3b07 | 1167 | pvma.vm_policy = spol; |
02098fea | 1168 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1169 | return page; |
1170 | } | |
1171 | ||
02098fea HD |
1172 | static struct page *shmem_alloc_page(gfp_t gfp, |
1173 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1174 | { |
1175 | struct vm_area_struct pvma; | |
1da177e4 | 1176 | |
c4cc6d07 HD |
1177 | /* Create a pseudo vma that just contains the policy */ |
1178 | pvma.vm_start = 0; | |
1da177e4 | 1179 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1180 | pvma.vm_ops = NULL; |
1181 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
52cd3b07 LS |
1182 | |
1183 | /* | |
1184 | * alloc_page_vma() will drop the shared policy reference | |
1185 | */ | |
1186 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 1187 | } |
680d794b | 1188 | #else /* !CONFIG_NUMA */ |
1189 | #ifdef CONFIG_TMPFS | |
71fe804b | 1190 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p) |
680d794b | 1191 | { |
1192 | } | |
1193 | #endif /* CONFIG_TMPFS */ | |
1194 | ||
02098fea HD |
1195 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1196 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1197 | { |
02098fea | 1198 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1199 | } |
1200 | ||
02098fea HD |
1201 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1202 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1203 | { |
e84e2e13 | 1204 | return alloc_page(gfp); |
1da177e4 | 1205 | } |
680d794b | 1206 | #endif /* CONFIG_NUMA */ |
1da177e4 | 1207 | |
71fe804b LS |
1208 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
1209 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1210 | { | |
1211 | return NULL; | |
1212 | } | |
1213 | #endif | |
1214 | ||
1da177e4 LT |
1215 | /* |
1216 | * shmem_getpage - either get the page from swap or allocate a new one | |
1217 | * | |
1218 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1219 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1220 | * entry since a page cannot live in both the swap and page cache | |
1221 | */ | |
1222 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1223 | struct page **pagep, enum sgp_type sgp, int *type) | |
1224 | { | |
1225 | struct address_space *mapping = inode->i_mapping; | |
1226 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1227 | struct shmem_sb_info *sbinfo; | |
1228 | struct page *filepage = *pagep; | |
1229 | struct page *swappage; | |
ff36b801 | 1230 | struct page *prealloc_page = NULL; |
1da177e4 LT |
1231 | swp_entry_t *entry; |
1232 | swp_entry_t swap; | |
02098fea | 1233 | gfp_t gfp; |
1da177e4 LT |
1234 | int error; |
1235 | ||
1236 | if (idx >= SHMEM_MAX_INDEX) | |
1237 | return -EFBIG; | |
54cb8821 NP |
1238 | |
1239 | if (type) | |
83c54070 | 1240 | *type = 0; |
54cb8821 | 1241 | |
1da177e4 LT |
1242 | /* |
1243 | * Normally, filepage is NULL on entry, and either found | |
1244 | * uptodate immediately, or allocated and zeroed, or read | |
1245 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1246 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1247 | * filepage, which may be found not uptodate by other callers |
1248 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1249 | */ |
1250 | repeat: | |
1251 | if (!filepage) | |
1252 | filepage = find_lock_page(mapping, idx); | |
1253 | if (filepage && PageUptodate(filepage)) | |
1254 | goto done; | |
02098fea | 1255 | gfp = mapping_gfp_mask(mapping); |
b409f9fc HD |
1256 | if (!filepage) { |
1257 | /* | |
1258 | * Try to preload while we can wait, to not make a habit of | |
1259 | * draining atomic reserves; but don't latch on to this cpu. | |
1260 | */ | |
1261 | error = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
1262 | if (error) | |
1263 | goto failed; | |
1264 | radix_tree_preload_end(); | |
ff36b801 SL |
1265 | if (sgp != SGP_READ && !prealloc_page) { |
1266 | /* We don't care if this fails */ | |
1267 | prealloc_page = shmem_alloc_page(gfp, info, idx); | |
1268 | if (prealloc_page) { | |
1269 | if (mem_cgroup_cache_charge(prealloc_page, | |
1270 | current->mm, GFP_KERNEL)) { | |
1271 | page_cache_release(prealloc_page); | |
1272 | prealloc_page = NULL; | |
1273 | } | |
1274 | } | |
1275 | } | |
b409f9fc | 1276 | } |
ff36b801 | 1277 | error = 0; |
1da177e4 LT |
1278 | |
1279 | spin_lock(&info->lock); | |
1280 | shmem_recalc_inode(inode); | |
1281 | entry = shmem_swp_alloc(info, idx, sgp); | |
1282 | if (IS_ERR(entry)) { | |
1283 | spin_unlock(&info->lock); | |
1284 | error = PTR_ERR(entry); | |
1285 | goto failed; | |
1286 | } | |
1287 | swap = *entry; | |
1288 | ||
1289 | if (swap.val) { | |
1290 | /* Look it up and read it in.. */ | |
1291 | swappage = lookup_swap_cache(swap); | |
1292 | if (!swappage) { | |
1293 | shmem_swp_unmap(entry); | |
1da177e4 | 1294 | /* here we actually do the io */ |
83c54070 | 1295 | if (type && !(*type & VM_FAULT_MAJOR)) { |
f8891e5e | 1296 | __count_vm_event(PGMAJFAULT); |
83c54070 | 1297 | *type |= VM_FAULT_MAJOR; |
1da177e4 | 1298 | } |
f8891e5e | 1299 | spin_unlock(&info->lock); |
02098fea | 1300 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1301 | if (!swappage) { |
1302 | spin_lock(&info->lock); | |
1303 | entry = shmem_swp_alloc(info, idx, sgp); | |
1304 | if (IS_ERR(entry)) | |
1305 | error = PTR_ERR(entry); | |
1306 | else { | |
1307 | if (entry->val == swap.val) | |
1308 | error = -ENOMEM; | |
1309 | shmem_swp_unmap(entry); | |
1310 | } | |
1311 | spin_unlock(&info->lock); | |
1312 | if (error) | |
1313 | goto failed; | |
1314 | goto repeat; | |
1315 | } | |
1316 | wait_on_page_locked(swappage); | |
1317 | page_cache_release(swappage); | |
1318 | goto repeat; | |
1319 | } | |
1320 | ||
1321 | /* We have to do this with page locked to prevent races */ | |
529ae9aa | 1322 | if (!trylock_page(swappage)) { |
1da177e4 LT |
1323 | shmem_swp_unmap(entry); |
1324 | spin_unlock(&info->lock); | |
1325 | wait_on_page_locked(swappage); | |
1326 | page_cache_release(swappage); | |
1327 | goto repeat; | |
1328 | } | |
1329 | if (PageWriteback(swappage)) { | |
1330 | shmem_swp_unmap(entry); | |
1331 | spin_unlock(&info->lock); | |
1332 | wait_on_page_writeback(swappage); | |
1333 | unlock_page(swappage); | |
1334 | page_cache_release(swappage); | |
1335 | goto repeat; | |
1336 | } | |
1337 | if (!PageUptodate(swappage)) { | |
1338 | shmem_swp_unmap(entry); | |
1339 | spin_unlock(&info->lock); | |
1340 | unlock_page(swappage); | |
1341 | page_cache_release(swappage); | |
1342 | error = -EIO; | |
1343 | goto failed; | |
1344 | } | |
1345 | ||
1346 | if (filepage) { | |
1347 | shmem_swp_set(info, entry, 0); | |
1348 | shmem_swp_unmap(entry); | |
1349 | delete_from_swap_cache(swappage); | |
1350 | spin_unlock(&info->lock); | |
1351 | copy_highpage(filepage, swappage); | |
1352 | unlock_page(swappage); | |
1353 | page_cache_release(swappage); | |
1354 | flush_dcache_page(filepage); | |
1355 | SetPageUptodate(filepage); | |
1356 | set_page_dirty(filepage); | |
1357 | swap_free(swap); | |
e286781d NP |
1358 | } else if (!(error = add_to_page_cache_locked(swappage, mapping, |
1359 | idx, GFP_NOWAIT))) { | |
1da177e4 LT |
1360 | info->flags |= SHMEM_PAGEIN; |
1361 | shmem_swp_set(info, entry, 0); | |
1362 | shmem_swp_unmap(entry); | |
73b1262f | 1363 | delete_from_swap_cache(swappage); |
1da177e4 LT |
1364 | spin_unlock(&info->lock); |
1365 | filepage = swappage; | |
73b1262f | 1366 | set_page_dirty(filepage); |
1da177e4 LT |
1367 | swap_free(swap); |
1368 | } else { | |
1369 | shmem_swp_unmap(entry); | |
1370 | spin_unlock(&info->lock); | |
82369553 | 1371 | if (error == -ENOMEM) { |
ae3abae6 DN |
1372 | /* |
1373 | * reclaim from proper memory cgroup and | |
1374 | * call memcg's OOM if needed. | |
1375 | */ | |
1376 | error = mem_cgroup_shmem_charge_fallback( | |
1377 | swappage, | |
b5a84319 | 1378 | current->mm, |
c9b0ed51 | 1379 | gfp); |
b5a84319 KH |
1380 | if (error) { |
1381 | unlock_page(swappage); | |
1382 | page_cache_release(swappage); | |
82369553 | 1383 | goto failed; |
b5a84319 | 1384 | } |
82369553 | 1385 | } |
b5a84319 KH |
1386 | unlock_page(swappage); |
1387 | page_cache_release(swappage); | |
1da177e4 LT |
1388 | goto repeat; |
1389 | } | |
1390 | } else if (sgp == SGP_READ && !filepage) { | |
1391 | shmem_swp_unmap(entry); | |
1392 | filepage = find_get_page(mapping, idx); | |
1393 | if (filepage && | |
529ae9aa | 1394 | (!PageUptodate(filepage) || !trylock_page(filepage))) { |
1da177e4 LT |
1395 | spin_unlock(&info->lock); |
1396 | wait_on_page_locked(filepage); | |
1397 | page_cache_release(filepage); | |
1398 | filepage = NULL; | |
1399 | goto repeat; | |
1400 | } | |
1401 | spin_unlock(&info->lock); | |
1402 | } else { | |
1403 | shmem_swp_unmap(entry); | |
1404 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1405 | if (sbinfo->max_blocks) { |
fc5da22a HD |
1406 | if (percpu_counter_compare(&sbinfo->used_blocks, |
1407 | sbinfo->max_blocks) >= 0 || | |
59a16ead HD |
1408 | shmem_acct_block(info->flags)) |
1409 | goto nospace; | |
7e496299 TC |
1410 | percpu_counter_inc(&sbinfo->used_blocks); |
1411 | spin_lock(&inode->i_lock); | |
1da177e4 | 1412 | inode->i_blocks += BLOCKS_PER_PAGE; |
7e496299 | 1413 | spin_unlock(&inode->i_lock); |
59a16ead HD |
1414 | } else if (shmem_acct_block(info->flags)) |
1415 | goto nospace; | |
1da177e4 LT |
1416 | |
1417 | if (!filepage) { | |
69029cd5 KH |
1418 | int ret; |
1419 | ||
ff36b801 SL |
1420 | if (!prealloc_page) { |
1421 | spin_unlock(&info->lock); | |
1422 | filepage = shmem_alloc_page(gfp, info, idx); | |
1423 | if (!filepage) { | |
1424 | shmem_unacct_blocks(info->flags, 1); | |
1425 | shmem_free_blocks(inode, 1); | |
1426 | error = -ENOMEM; | |
1427 | goto failed; | |
1428 | } | |
1429 | SetPageSwapBacked(filepage); | |
1da177e4 | 1430 | |
ff36b801 SL |
1431 | /* |
1432 | * Precharge page while we can wait, compensate | |
1433 | * after | |
1434 | */ | |
1435 | error = mem_cgroup_cache_charge(filepage, | |
1436 | current->mm, GFP_KERNEL); | |
1437 | if (error) { | |
1438 | page_cache_release(filepage); | |
1439 | shmem_unacct_blocks(info->flags, 1); | |
1440 | shmem_free_blocks(inode, 1); | |
1441 | filepage = NULL; | |
1442 | goto failed; | |
1443 | } | |
1444 | ||
1445 | spin_lock(&info->lock); | |
1446 | } else { | |
1447 | filepage = prealloc_page; | |
1448 | prealloc_page = NULL; | |
1449 | SetPageSwapBacked(filepage); | |
82369553 HD |
1450 | } |
1451 | ||
1da177e4 LT |
1452 | entry = shmem_swp_alloc(info, idx, sgp); |
1453 | if (IS_ERR(entry)) | |
1454 | error = PTR_ERR(entry); | |
1455 | else { | |
1456 | swap = *entry; | |
1457 | shmem_swp_unmap(entry); | |
1458 | } | |
69029cd5 KH |
1459 | ret = error || swap.val; |
1460 | if (ret) | |
1461 | mem_cgroup_uncharge_cache_page(filepage); | |
1462 | else | |
1463 | ret = add_to_page_cache_lru(filepage, mapping, | |
1464 | idx, GFP_NOWAIT); | |
1465 | /* | |
1466 | * At add_to_page_cache_lru() failure, uncharge will | |
1467 | * be done automatically. | |
1468 | */ | |
1469 | if (ret) { | |
1da177e4 LT |
1470 | spin_unlock(&info->lock); |
1471 | page_cache_release(filepage); | |
1472 | shmem_unacct_blocks(info->flags, 1); | |
1473 | shmem_free_blocks(inode, 1); | |
1474 | filepage = NULL; | |
1475 | if (error) | |
1476 | goto failed; | |
1477 | goto repeat; | |
1478 | } | |
1479 | info->flags |= SHMEM_PAGEIN; | |
1480 | } | |
1481 | ||
1482 | info->alloced++; | |
1483 | spin_unlock(&info->lock); | |
e84e2e13 | 1484 | clear_highpage(filepage); |
1da177e4 LT |
1485 | flush_dcache_page(filepage); |
1486 | SetPageUptodate(filepage); | |
a0ee5ec5 HD |
1487 | if (sgp == SGP_DIRTY) |
1488 | set_page_dirty(filepage); | |
1da177e4 LT |
1489 | } |
1490 | done: | |
d3602444 | 1491 | *pagep = filepage; |
ff36b801 SL |
1492 | error = 0; |
1493 | goto out; | |
1da177e4 | 1494 | |
59a16ead HD |
1495 | nospace: |
1496 | /* | |
1497 | * Perhaps the page was brought in from swap between find_lock_page | |
1498 | * and taking info->lock? We allow for that at add_to_page_cache_lru, | |
1499 | * but must also avoid reporting a spurious ENOSPC while working on a | |
1500 | * full tmpfs. (When filepage has been passed in to shmem_getpage, it | |
1501 | * is already in page cache, which prevents this race from occurring.) | |
1502 | */ | |
1503 | if (!filepage) { | |
1504 | struct page *page = find_get_page(mapping, idx); | |
1505 | if (page) { | |
1506 | spin_unlock(&info->lock); | |
1507 | page_cache_release(page); | |
1508 | goto repeat; | |
1509 | } | |
1510 | } | |
1511 | spin_unlock(&info->lock); | |
1512 | error = -ENOSPC; | |
1da177e4 LT |
1513 | failed: |
1514 | if (*pagep != filepage) { | |
1515 | unlock_page(filepage); | |
1516 | page_cache_release(filepage); | |
1517 | } | |
ff36b801 SL |
1518 | out: |
1519 | if (prealloc_page) { | |
1520 | mem_cgroup_uncharge_cache_page(prealloc_page); | |
1521 | page_cache_release(prealloc_page); | |
1522 | } | |
1da177e4 LT |
1523 | return error; |
1524 | } | |
1525 | ||
d0217ac0 | 1526 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1527 | { |
d3ac7f89 | 1528 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1529 | int error; |
d0217ac0 | 1530 | int ret; |
1da177e4 | 1531 | |
d0217ac0 NP |
1532 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1533 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1534 | |
27d54b39 | 1535 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1536 | if (error) |
1537 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1da177e4 | 1538 | |
83c54070 | 1539 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1540 | } |
1541 | ||
1da177e4 | 1542 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1543 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1544 | { |
d3ac7f89 | 1545 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1546 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1547 | } | |
1548 | ||
d8dc74f2 AB |
1549 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1550 | unsigned long addr) | |
1da177e4 | 1551 | { |
d3ac7f89 | 1552 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1553 | unsigned long idx; |
1554 | ||
1555 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1556 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1557 | } | |
1558 | #endif | |
1559 | ||
1560 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1561 | { | |
d3ac7f89 | 1562 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1563 | struct shmem_inode_info *info = SHMEM_I(inode); |
1564 | int retval = -ENOMEM; | |
1565 | ||
1566 | spin_lock(&info->lock); | |
1567 | if (lock && !(info->flags & VM_LOCKED)) { | |
1568 | if (!user_shm_lock(inode->i_size, user)) | |
1569 | goto out_nomem; | |
1570 | info->flags |= VM_LOCKED; | |
89e004ea | 1571 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1572 | } |
1573 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1574 | user_shm_unlock(inode->i_size, user); | |
1575 | info->flags &= ~VM_LOCKED; | |
89e004ea LS |
1576 | mapping_clear_unevictable(file->f_mapping); |
1577 | scan_mapping_unevictable_pages(file->f_mapping); | |
1da177e4 LT |
1578 | } |
1579 | retval = 0; | |
89e004ea | 1580 | |
1da177e4 LT |
1581 | out_nomem: |
1582 | spin_unlock(&info->lock); | |
1583 | return retval; | |
1584 | } | |
1585 | ||
9b83a6a8 | 1586 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1587 | { |
1588 | file_accessed(file); | |
1589 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1590 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1591 | return 0; |
1592 | } | |
1593 | ||
454abafe DM |
1594 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
1595 | int mode, dev_t dev, unsigned long flags) | |
1da177e4 LT |
1596 | { |
1597 | struct inode *inode; | |
1598 | struct shmem_inode_info *info; | |
1599 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1600 | ||
5b04c689 PE |
1601 | if (shmem_reserve_inode(sb)) |
1602 | return NULL; | |
1da177e4 LT |
1603 | |
1604 | inode = new_inode(sb); | |
1605 | if (inode) { | |
85fe4025 | 1606 | inode->i_ino = get_next_ino(); |
454abafe | 1607 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1608 | inode->i_blocks = 0; |
1da177e4 LT |
1609 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1610 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1611 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1612 | info = SHMEM_I(inode); |
1613 | memset(info, 0, (char *)inode - (char *)info); | |
1614 | spin_lock_init(&info->lock); | |
0b0a0806 | 1615 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1616 | INIT_LIST_HEAD(&info->swaplist); |
72c04902 | 1617 | cache_no_acl(inode); |
1da177e4 LT |
1618 | |
1619 | switch (mode & S_IFMT) { | |
1620 | default: | |
39f0247d | 1621 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1622 | init_special_inode(inode, mode, dev); |
1623 | break; | |
1624 | case S_IFREG: | |
14fcc23f | 1625 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1626 | inode->i_op = &shmem_inode_operations; |
1627 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1628 | mpol_shared_policy_init(&info->policy, |
1629 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1630 | break; |
1631 | case S_IFDIR: | |
d8c76e6f | 1632 | inc_nlink(inode); |
1da177e4 LT |
1633 | /* Some things misbehave if size == 0 on a directory */ |
1634 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1635 | inode->i_op = &shmem_dir_inode_operations; | |
1636 | inode->i_fop = &simple_dir_operations; | |
1637 | break; | |
1638 | case S_IFLNK: | |
1639 | /* | |
1640 | * Must not load anything in the rbtree, | |
1641 | * mpol_free_shared_policy will not be called. | |
1642 | */ | |
71fe804b | 1643 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1644 | break; |
1645 | } | |
5b04c689 PE |
1646 | } else |
1647 | shmem_free_inode(sb); | |
1da177e4 LT |
1648 | return inode; |
1649 | } | |
1650 | ||
1651 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1652 | static const struct inode_operations shmem_symlink_inode_operations; |
1653 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1654 | |
1655 | /* | |
800d15a5 | 1656 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1657 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1658 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1659 | */ |
ae976416 HD |
1660 | static int shmem_readpage(struct file *file, struct page *page) |
1661 | { | |
1662 | struct inode *inode = page->mapping->host; | |
1663 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1664 | unlock_page(page); | |
1665 | return error; | |
1666 | } | |
1667 | ||
1da177e4 | 1668 | static int |
800d15a5 NP |
1669 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1670 | loff_t pos, unsigned len, unsigned flags, | |
1671 | struct page **pagep, void **fsdata) | |
1da177e4 | 1672 | { |
800d15a5 NP |
1673 | struct inode *inode = mapping->host; |
1674 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1675 | *pagep = NULL; | |
1676 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1677 | } | |
1678 | ||
1679 | static int | |
1680 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1681 | loff_t pos, unsigned len, unsigned copied, | |
1682 | struct page *page, void *fsdata) | |
1683 | { | |
1684 | struct inode *inode = mapping->host; | |
1685 | ||
d3602444 HD |
1686 | if (pos + copied > inode->i_size) |
1687 | i_size_write(inode, pos + copied); | |
1688 | ||
800d15a5 | 1689 | set_page_dirty(page); |
6746aff7 | 1690 | unlock_page(page); |
800d15a5 NP |
1691 | page_cache_release(page); |
1692 | ||
800d15a5 | 1693 | return copied; |
1da177e4 LT |
1694 | } |
1695 | ||
1da177e4 LT |
1696 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1697 | { | |
d3ac7f89 | 1698 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1699 | struct address_space *mapping = inode->i_mapping; |
1700 | unsigned long index, offset; | |
a0ee5ec5 HD |
1701 | enum sgp_type sgp = SGP_READ; |
1702 | ||
1703 | /* | |
1704 | * Might this read be for a stacking filesystem? Then when reading | |
1705 | * holes of a sparse file, we actually need to allocate those pages, | |
1706 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1707 | */ | |
1708 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1709 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1710 | |
1711 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1712 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1713 | ||
1714 | for (;;) { | |
1715 | struct page *page = NULL; | |
1716 | unsigned long end_index, nr, ret; | |
1717 | loff_t i_size = i_size_read(inode); | |
1718 | ||
1719 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1720 | if (index > end_index) | |
1721 | break; | |
1722 | if (index == end_index) { | |
1723 | nr = i_size & ~PAGE_CACHE_MASK; | |
1724 | if (nr <= offset) | |
1725 | break; | |
1726 | } | |
1727 | ||
a0ee5ec5 | 1728 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1729 | if (desc->error) { |
1730 | if (desc->error == -EINVAL) | |
1731 | desc->error = 0; | |
1732 | break; | |
1733 | } | |
d3602444 HD |
1734 | if (page) |
1735 | unlock_page(page); | |
1da177e4 LT |
1736 | |
1737 | /* | |
1738 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1739 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1740 | */ |
1741 | nr = PAGE_CACHE_SIZE; | |
1742 | i_size = i_size_read(inode); | |
1743 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1744 | if (index == end_index) { | |
1745 | nr = i_size & ~PAGE_CACHE_MASK; | |
1746 | if (nr <= offset) { | |
1747 | if (page) | |
1748 | page_cache_release(page); | |
1749 | break; | |
1750 | } | |
1751 | } | |
1752 | nr -= offset; | |
1753 | ||
1754 | if (page) { | |
1755 | /* | |
1756 | * If users can be writing to this page using arbitrary | |
1757 | * virtual addresses, take care about potential aliasing | |
1758 | * before reading the page on the kernel side. | |
1759 | */ | |
1760 | if (mapping_writably_mapped(mapping)) | |
1761 | flush_dcache_page(page); | |
1762 | /* | |
1763 | * Mark the page accessed if we read the beginning. | |
1764 | */ | |
1765 | if (!offset) | |
1766 | mark_page_accessed(page); | |
b5810039 | 1767 | } else { |
1da177e4 | 1768 | page = ZERO_PAGE(0); |
b5810039 NP |
1769 | page_cache_get(page); |
1770 | } | |
1da177e4 LT |
1771 | |
1772 | /* | |
1773 | * Ok, we have the page, and it's up-to-date, so | |
1774 | * now we can copy it to user space... | |
1775 | * | |
1776 | * The actor routine returns how many bytes were actually used.. | |
1777 | * NOTE! This may not be the same as how much of a user buffer | |
1778 | * we filled up (we may be padding etc), so we can only update | |
1779 | * "pos" here (the actor routine has to update the user buffer | |
1780 | * pointers and the remaining count). | |
1781 | */ | |
1782 | ret = actor(desc, page, offset, nr); | |
1783 | offset += ret; | |
1784 | index += offset >> PAGE_CACHE_SHIFT; | |
1785 | offset &= ~PAGE_CACHE_MASK; | |
1786 | ||
1787 | page_cache_release(page); | |
1788 | if (ret != nr || !desc->count) | |
1789 | break; | |
1790 | ||
1791 | cond_resched(); | |
1792 | } | |
1793 | ||
1794 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1795 | file_accessed(filp); | |
1796 | } | |
1797 | ||
bcd78e49 HD |
1798 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1799 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1800 | { | |
1801 | struct file *filp = iocb->ki_filp; | |
1802 | ssize_t retval; | |
1803 | unsigned long seg; | |
1804 | size_t count; | |
1805 | loff_t *ppos = &iocb->ki_pos; | |
1806 | ||
1807 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1808 | if (retval) | |
1809 | return retval; | |
1810 | ||
1811 | for (seg = 0; seg < nr_segs; seg++) { | |
1812 | read_descriptor_t desc; | |
1813 | ||
1814 | desc.written = 0; | |
1815 | desc.arg.buf = iov[seg].iov_base; | |
1816 | desc.count = iov[seg].iov_len; | |
1817 | if (desc.count == 0) | |
1818 | continue; | |
1819 | desc.error = 0; | |
1820 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1821 | retval += desc.written; | |
1822 | if (desc.error) { | |
1823 | retval = retval ?: desc.error; | |
1824 | break; | |
1825 | } | |
1826 | if (desc.count > 0) | |
1827 | break; | |
1828 | } | |
1829 | return retval; | |
1da177e4 LT |
1830 | } |
1831 | ||
726c3342 | 1832 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1833 | { |
726c3342 | 1834 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1835 | |
1836 | buf->f_type = TMPFS_MAGIC; | |
1837 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1838 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1839 | if (sbinfo->max_blocks) { |
1da177e4 | 1840 | buf->f_blocks = sbinfo->max_blocks; |
7e496299 TC |
1841 | buf->f_bavail = buf->f_bfree = |
1842 | sbinfo->max_blocks - percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1843 | } |
1844 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1845 | buf->f_files = sbinfo->max_inodes; |
1846 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1847 | } |
1848 | /* else leave those fields 0 like simple_statfs */ | |
1849 | return 0; | |
1850 | } | |
1851 | ||
1852 | /* | |
1853 | * File creation. Allocate an inode, and we're done.. | |
1854 | */ | |
1855 | static int | |
1856 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1857 | { | |
0b0a0806 | 1858 | struct inode *inode; |
1da177e4 LT |
1859 | int error = -ENOSPC; |
1860 | ||
454abafe | 1861 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1862 | if (inode) { |
2a7dba39 EP |
1863 | error = security_inode_init_security(inode, dir, |
1864 | &dentry->d_name, NULL, | |
1865 | NULL, NULL); | |
570bc1c2 SS |
1866 | if (error) { |
1867 | if (error != -EOPNOTSUPP) { | |
1868 | iput(inode); | |
1869 | return error; | |
1870 | } | |
39f0247d | 1871 | } |
1c7c474c CH |
1872 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1873 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1874 | if (error) { |
1875 | iput(inode); | |
1876 | return error; | |
570bc1c2 | 1877 | } |
718deb6b AV |
1878 | #else |
1879 | error = 0; | |
1c7c474c | 1880 | #endif |
1da177e4 LT |
1881 | dir->i_size += BOGO_DIRENT_SIZE; |
1882 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1883 | d_instantiate(dentry, inode); | |
1884 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1885 | } |
1886 | return error; | |
1887 | } | |
1888 | ||
1889 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1890 | { | |
1891 | int error; | |
1892 | ||
1893 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1894 | return error; | |
d8c76e6f | 1895 | inc_nlink(dir); |
1da177e4 LT |
1896 | return 0; |
1897 | } | |
1898 | ||
1899 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1900 | struct nameidata *nd) | |
1901 | { | |
1902 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1903 | } | |
1904 | ||
1905 | /* | |
1906 | * Link a file.. | |
1907 | */ | |
1908 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1909 | { | |
1910 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1911 | int ret; |
1da177e4 LT |
1912 | |
1913 | /* | |
1914 | * No ordinary (disk based) filesystem counts links as inodes; | |
1915 | * but each new link needs a new dentry, pinning lowmem, and | |
1916 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1917 | */ | |
5b04c689 PE |
1918 | ret = shmem_reserve_inode(inode->i_sb); |
1919 | if (ret) | |
1920 | goto out; | |
1da177e4 LT |
1921 | |
1922 | dir->i_size += BOGO_DIRENT_SIZE; | |
1923 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1924 | inc_nlink(inode); |
7de9c6ee | 1925 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1926 | dget(dentry); /* Extra pinning count for the created dentry */ |
1927 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1928 | out: |
1929 | return ret; | |
1da177e4 LT |
1930 | } |
1931 | ||
1932 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1933 | { | |
1934 | struct inode *inode = dentry->d_inode; | |
1935 | ||
5b04c689 PE |
1936 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1937 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1938 | |
1939 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1940 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1941 | drop_nlink(inode); |
1da177e4 LT |
1942 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1943 | return 0; | |
1944 | } | |
1945 | ||
1946 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1947 | { | |
1948 | if (!simple_empty(dentry)) | |
1949 | return -ENOTEMPTY; | |
1950 | ||
9a53c3a7 DH |
1951 | drop_nlink(dentry->d_inode); |
1952 | drop_nlink(dir); | |
1da177e4 LT |
1953 | return shmem_unlink(dir, dentry); |
1954 | } | |
1955 | ||
1956 | /* | |
1957 | * The VFS layer already does all the dentry stuff for rename, | |
1958 | * we just have to decrement the usage count for the target if | |
1959 | * it exists so that the VFS layer correctly free's it when it | |
1960 | * gets overwritten. | |
1961 | */ | |
1962 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1963 | { | |
1964 | struct inode *inode = old_dentry->d_inode; | |
1965 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1966 | ||
1967 | if (!simple_empty(new_dentry)) | |
1968 | return -ENOTEMPTY; | |
1969 | ||
1970 | if (new_dentry->d_inode) { | |
1971 | (void) shmem_unlink(new_dir, new_dentry); | |
1972 | if (they_are_dirs) | |
9a53c3a7 | 1973 | drop_nlink(old_dir); |
1da177e4 | 1974 | } else if (they_are_dirs) { |
9a53c3a7 | 1975 | drop_nlink(old_dir); |
d8c76e6f | 1976 | inc_nlink(new_dir); |
1da177e4 LT |
1977 | } |
1978 | ||
1979 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1980 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1981 | old_dir->i_ctime = old_dir->i_mtime = | |
1982 | new_dir->i_ctime = new_dir->i_mtime = | |
1983 | inode->i_ctime = CURRENT_TIME; | |
1984 | return 0; | |
1985 | } | |
1986 | ||
1987 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1988 | { | |
1989 | int error; | |
1990 | int len; | |
1991 | struct inode *inode; | |
1992 | struct page *page = NULL; | |
1993 | char *kaddr; | |
1994 | struct shmem_inode_info *info; | |
1995 | ||
1996 | len = strlen(symname) + 1; | |
1997 | if (len > PAGE_CACHE_SIZE) | |
1998 | return -ENAMETOOLONG; | |
1999 | ||
454abafe | 2000 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
2001 | if (!inode) |
2002 | return -ENOSPC; | |
2003 | ||
2a7dba39 EP |
2004 | error = security_inode_init_security(inode, dir, &dentry->d_name, NULL, |
2005 | NULL, NULL); | |
570bc1c2 SS |
2006 | if (error) { |
2007 | if (error != -EOPNOTSUPP) { | |
2008 | iput(inode); | |
2009 | return error; | |
2010 | } | |
2011 | error = 0; | |
2012 | } | |
2013 | ||
1da177e4 LT |
2014 | info = SHMEM_I(inode); |
2015 | inode->i_size = len-1; | |
2016 | if (len <= (char *)inode - (char *)info) { | |
2017 | /* do it inline */ | |
2018 | memcpy(info, symname, len); | |
2019 | inode->i_op = &shmem_symlink_inline_operations; | |
2020 | } else { | |
2021 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
2022 | if (error) { | |
2023 | iput(inode); | |
2024 | return error; | |
2025 | } | |
14fcc23f | 2026 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
2027 | inode->i_op = &shmem_symlink_inode_operations; |
2028 | kaddr = kmap_atomic(page, KM_USER0); | |
2029 | memcpy(kaddr, symname, len); | |
2030 | kunmap_atomic(kaddr, KM_USER0); | |
2031 | set_page_dirty(page); | |
6746aff7 | 2032 | unlock_page(page); |
1da177e4 LT |
2033 | page_cache_release(page); |
2034 | } | |
1da177e4 LT |
2035 | dir->i_size += BOGO_DIRENT_SIZE; |
2036 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
2037 | d_instantiate(dentry, inode); | |
2038 | dget(dentry); | |
2039 | return 0; | |
2040 | } | |
2041 | ||
cc314eef | 2042 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
2043 | { |
2044 | nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode)); | |
cc314eef | 2045 | return NULL; |
1da177e4 LT |
2046 | } |
2047 | ||
cc314eef | 2048 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
2049 | { |
2050 | struct page *page = NULL; | |
2051 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
2052 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
2053 | if (page) |
2054 | unlock_page(page); | |
cc314eef | 2055 | return page; |
1da177e4 LT |
2056 | } |
2057 | ||
cc314eef | 2058 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
2059 | { |
2060 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 2061 | struct page *page = cookie; |
1da177e4 LT |
2062 | kunmap(page); |
2063 | mark_page_accessed(page); | |
2064 | page_cache_release(page); | |
1da177e4 LT |
2065 | } |
2066 | } | |
2067 | ||
92e1d5be | 2068 | static const struct inode_operations shmem_symlink_inline_operations = { |
1da177e4 LT |
2069 | .readlink = generic_readlink, |
2070 | .follow_link = shmem_follow_link_inline, | |
1da177e4 LT |
2071 | }; |
2072 | ||
92e1d5be | 2073 | static const struct inode_operations shmem_symlink_inode_operations = { |
1da177e4 LT |
2074 | .readlink = generic_readlink, |
2075 | .follow_link = shmem_follow_link, | |
2076 | .put_link = shmem_put_link, | |
1da177e4 LT |
2077 | }; |
2078 | ||
39f0247d | 2079 | #ifdef CONFIG_TMPFS_POSIX_ACL |
46711810 | 2080 | /* |
39f0247d AG |
2081 | * Superblocks without xattr inode operations will get security.* xattr |
2082 | * support from the VFS "for free". As soon as we have any other xattrs | |
2083 | * like ACLs, we also need to implement the security.* handlers at | |
2084 | * filesystem level, though. | |
2085 | */ | |
2086 | ||
431547b3 | 2087 | static size_t shmem_xattr_security_list(struct dentry *dentry, char *list, |
39f0247d | 2088 | size_t list_len, const char *name, |
431547b3 | 2089 | size_t name_len, int handler_flags) |
39f0247d | 2090 | { |
431547b3 | 2091 | return security_inode_listsecurity(dentry->d_inode, list, list_len); |
39f0247d AG |
2092 | } |
2093 | ||
431547b3 CH |
2094 | static int shmem_xattr_security_get(struct dentry *dentry, const char *name, |
2095 | void *buffer, size_t size, int handler_flags) | |
39f0247d AG |
2096 | { |
2097 | if (strcmp(name, "") == 0) | |
2098 | return -EINVAL; | |
431547b3 | 2099 | return xattr_getsecurity(dentry->d_inode, name, buffer, size); |
39f0247d AG |
2100 | } |
2101 | ||
431547b3 CH |
2102 | static int shmem_xattr_security_set(struct dentry *dentry, const char *name, |
2103 | const void *value, size_t size, int flags, int handler_flags) | |
39f0247d AG |
2104 | { |
2105 | if (strcmp(name, "") == 0) | |
2106 | return -EINVAL; | |
431547b3 CH |
2107 | return security_inode_setsecurity(dentry->d_inode, name, value, |
2108 | size, flags); | |
39f0247d AG |
2109 | } |
2110 | ||
bb435453 | 2111 | static const struct xattr_handler shmem_xattr_security_handler = { |
39f0247d AG |
2112 | .prefix = XATTR_SECURITY_PREFIX, |
2113 | .list = shmem_xattr_security_list, | |
2114 | .get = shmem_xattr_security_get, | |
2115 | .set = shmem_xattr_security_set, | |
2116 | }; | |
2117 | ||
bb435453 | 2118 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
1c7c474c CH |
2119 | &generic_acl_access_handler, |
2120 | &generic_acl_default_handler, | |
39f0247d AG |
2121 | &shmem_xattr_security_handler, |
2122 | NULL | |
2123 | }; | |
2124 | #endif | |
2125 | ||
91828a40 DG |
2126 | static struct dentry *shmem_get_parent(struct dentry *child) |
2127 | { | |
2128 | return ERR_PTR(-ESTALE); | |
2129 | } | |
2130 | ||
2131 | static int shmem_match(struct inode *ino, void *vfh) | |
2132 | { | |
2133 | __u32 *fh = vfh; | |
2134 | __u64 inum = fh[2]; | |
2135 | inum = (inum << 32) | fh[1]; | |
2136 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2137 | } | |
2138 | ||
480b116c CH |
2139 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2140 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2141 | { |
91828a40 | 2142 | struct inode *inode; |
480b116c CH |
2143 | struct dentry *dentry = NULL; |
2144 | u64 inum = fid->raw[2]; | |
2145 | inum = (inum << 32) | fid->raw[1]; | |
2146 | ||
2147 | if (fh_len < 3) | |
2148 | return NULL; | |
91828a40 | 2149 | |
480b116c CH |
2150 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2151 | shmem_match, fid->raw); | |
91828a40 | 2152 | if (inode) { |
480b116c | 2153 | dentry = d_find_alias(inode); |
91828a40 DG |
2154 | iput(inode); |
2155 | } | |
2156 | ||
480b116c | 2157 | return dentry; |
91828a40 DG |
2158 | } |
2159 | ||
2160 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2161 | int connectable) | |
2162 | { | |
2163 | struct inode *inode = dentry->d_inode; | |
2164 | ||
5fe0c237 AK |
2165 | if (*len < 3) { |
2166 | *len = 3; | |
91828a40 | 2167 | return 255; |
5fe0c237 | 2168 | } |
91828a40 | 2169 | |
1d3382cb | 2170 | if (inode_unhashed(inode)) { |
91828a40 DG |
2171 | /* Unfortunately insert_inode_hash is not idempotent, |
2172 | * so as we hash inodes here rather than at creation | |
2173 | * time, we need a lock to ensure we only try | |
2174 | * to do it once | |
2175 | */ | |
2176 | static DEFINE_SPINLOCK(lock); | |
2177 | spin_lock(&lock); | |
1d3382cb | 2178 | if (inode_unhashed(inode)) |
91828a40 DG |
2179 | __insert_inode_hash(inode, |
2180 | inode->i_ino + inode->i_generation); | |
2181 | spin_unlock(&lock); | |
2182 | } | |
2183 | ||
2184 | fh[0] = inode->i_generation; | |
2185 | fh[1] = inode->i_ino; | |
2186 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2187 | ||
2188 | *len = 3; | |
2189 | return 1; | |
2190 | } | |
2191 | ||
39655164 | 2192 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2193 | .get_parent = shmem_get_parent, |
91828a40 | 2194 | .encode_fh = shmem_encode_fh, |
480b116c | 2195 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2196 | }; |
2197 | ||
680d794b | 2198 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2199 | bool remount) | |
1da177e4 LT |
2200 | { |
2201 | char *this_char, *value, *rest; | |
2202 | ||
b00dc3ad HD |
2203 | while (options != NULL) { |
2204 | this_char = options; | |
2205 | for (;;) { | |
2206 | /* | |
2207 | * NUL-terminate this option: unfortunately, | |
2208 | * mount options form a comma-separated list, | |
2209 | * but mpol's nodelist may also contain commas. | |
2210 | */ | |
2211 | options = strchr(options, ','); | |
2212 | if (options == NULL) | |
2213 | break; | |
2214 | options++; | |
2215 | if (!isdigit(*options)) { | |
2216 | options[-1] = '\0'; | |
2217 | break; | |
2218 | } | |
2219 | } | |
1da177e4 LT |
2220 | if (!*this_char) |
2221 | continue; | |
2222 | if ((value = strchr(this_char,'=')) != NULL) { | |
2223 | *value++ = 0; | |
2224 | } else { | |
2225 | printk(KERN_ERR | |
2226 | "tmpfs: No value for mount option '%s'\n", | |
2227 | this_char); | |
2228 | return 1; | |
2229 | } | |
2230 | ||
2231 | if (!strcmp(this_char,"size")) { | |
2232 | unsigned long long size; | |
2233 | size = memparse(value,&rest); | |
2234 | if (*rest == '%') { | |
2235 | size <<= PAGE_SHIFT; | |
2236 | size *= totalram_pages; | |
2237 | do_div(size, 100); | |
2238 | rest++; | |
2239 | } | |
2240 | if (*rest) | |
2241 | goto bad_val; | |
680d794b | 2242 | sbinfo->max_blocks = |
2243 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2244 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2245 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2246 | if (*rest) |
2247 | goto bad_val; | |
2248 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2249 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2250 | if (*rest) |
2251 | goto bad_val; | |
2252 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2253 | if (remount) |
1da177e4 | 2254 | continue; |
680d794b | 2255 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2256 | if (*rest) |
2257 | goto bad_val; | |
2258 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2259 | if (remount) |
1da177e4 | 2260 | continue; |
680d794b | 2261 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2262 | if (*rest) |
2263 | goto bad_val; | |
2264 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2265 | if (remount) |
1da177e4 | 2266 | continue; |
680d794b | 2267 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2268 | if (*rest) |
2269 | goto bad_val; | |
7339ff83 | 2270 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2271 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2272 | goto bad_val; |
1da177e4 LT |
2273 | } else { |
2274 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2275 | this_char); | |
2276 | return 1; | |
2277 | } | |
2278 | } | |
2279 | return 0; | |
2280 | ||
2281 | bad_val: | |
2282 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2283 | value, this_char); | |
2284 | return 1; | |
2285 | ||
2286 | } | |
2287 | ||
2288 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2289 | { | |
2290 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2291 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2292 | unsigned long inodes; |
2293 | int error = -EINVAL; | |
2294 | ||
680d794b | 2295 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2296 | return error; |
1da177e4 | 2297 | |
0edd73b3 | 2298 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2299 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2300 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2301 | goto out; |
680d794b | 2302 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2303 | goto out; |
2304 | /* | |
2305 | * Those tests also disallow limited->unlimited while any are in | |
2306 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2307 | * but we must separately disallow unlimited->limited, because | |
2308 | * in that case we have no record of how much is already in use. | |
2309 | */ | |
680d794b | 2310 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2311 | goto out; |
680d794b | 2312 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2313 | goto out; |
2314 | ||
2315 | error = 0; | |
680d794b | 2316 | sbinfo->max_blocks = config.max_blocks; |
680d794b | 2317 | sbinfo->max_inodes = config.max_inodes; |
2318 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2319 | |
2320 | mpol_put(sbinfo->mpol); | |
2321 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2322 | out: |
2323 | spin_unlock(&sbinfo->stat_lock); | |
2324 | return error; | |
1da177e4 | 2325 | } |
680d794b | 2326 | |
2327 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
2328 | { | |
2329 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
2330 | ||
2331 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2332 | seq_printf(seq, ",size=%luk", | |
2333 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2334 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2335 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2336 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
2337 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
2338 | if (sbinfo->uid != 0) | |
2339 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2340 | if (sbinfo->gid != 0) | |
2341 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 2342 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b | 2343 | return 0; |
2344 | } | |
2345 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2346 | |
2347 | static void shmem_put_super(struct super_block *sb) | |
2348 | { | |
602586a8 HD |
2349 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2350 | ||
2351 | percpu_counter_destroy(&sbinfo->used_blocks); | |
2352 | kfree(sbinfo); | |
1da177e4 LT |
2353 | sb->s_fs_info = NULL; |
2354 | } | |
2355 | ||
2b2af54a | 2356 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2357 | { |
2358 | struct inode *inode; | |
2359 | struct dentry *root; | |
0edd73b3 | 2360 | struct shmem_sb_info *sbinfo; |
680d794b | 2361 | int err = -ENOMEM; |
2362 | ||
2363 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2364 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b | 2365 | L1_CACHE_BYTES), GFP_KERNEL); |
2366 | if (!sbinfo) | |
2367 | return -ENOMEM; | |
2368 | ||
680d794b | 2369 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2370 | sbinfo->uid = current_fsuid(); |
2371 | sbinfo->gid = current_fsgid(); | |
680d794b | 2372 | sb->s_fs_info = sbinfo; |
1da177e4 | 2373 | |
0edd73b3 | 2374 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2375 | /* |
2376 | * Per default we only allow half of the physical ram per | |
2377 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2378 | * but the internal instance is left unlimited. | |
2379 | */ | |
2380 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b | 2381 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2382 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2383 | if (shmem_parse_options(data, sbinfo, false)) { | |
2384 | err = -EINVAL; | |
2385 | goto failed; | |
2386 | } | |
1da177e4 | 2387 | } |
91828a40 | 2388 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2389 | #else |
2390 | sb->s_flags |= MS_NOUSER; | |
2391 | #endif | |
2392 | ||
0edd73b3 | 2393 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2394 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2395 | goto failed; | |
680d794b | 2396 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2397 | |
1da177e4 LT |
2398 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2399 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2400 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2401 | sb->s_magic = TMPFS_MAGIC; | |
2402 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2403 | sb->s_time_gran = 1; |
39f0247d AG |
2404 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2405 | sb->s_xattr = shmem_xattr_handlers; | |
2406 | sb->s_flags |= MS_POSIXACL; | |
2407 | #endif | |
0edd73b3 | 2408 | |
454abafe | 2409 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2410 | if (!inode) |
2411 | goto failed; | |
680d794b | 2412 | inode->i_uid = sbinfo->uid; |
2413 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2414 | root = d_alloc_root(inode); |
2415 | if (!root) | |
2416 | goto failed_iput; | |
2417 | sb->s_root = root; | |
2418 | return 0; | |
2419 | ||
2420 | failed_iput: | |
2421 | iput(inode); | |
2422 | failed: | |
2423 | shmem_put_super(sb); | |
2424 | return err; | |
2425 | } | |
2426 | ||
fcc234f8 | 2427 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2428 | |
2429 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2430 | { | |
2431 | struct shmem_inode_info *p; | |
e94b1766 | 2432 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2433 | if (!p) |
2434 | return NULL; | |
2435 | return &p->vfs_inode; | |
2436 | } | |
2437 | ||
fa0d7e3d NP |
2438 | static void shmem_i_callback(struct rcu_head *head) |
2439 | { | |
2440 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
2441 | INIT_LIST_HEAD(&inode->i_dentry); | |
2442 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2443 | } | |
2444 | ||
1da177e4 LT |
2445 | static void shmem_destroy_inode(struct inode *inode) |
2446 | { | |
2447 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2448 | /* only struct inode is valid if it's an inline symlink */ | |
2449 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2450 | } | |
fa0d7e3d | 2451 | call_rcu(&inode->i_rcu, shmem_i_callback); |
1da177e4 LT |
2452 | } |
2453 | ||
51cc5068 | 2454 | static void init_once(void *foo) |
1da177e4 LT |
2455 | { |
2456 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2457 | ||
a35afb83 | 2458 | inode_init_once(&p->vfs_inode); |
1da177e4 LT |
2459 | } |
2460 | ||
2461 | static int init_inodecache(void) | |
2462 | { | |
2463 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2464 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2465 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2466 | return 0; |
2467 | } | |
2468 | ||
2469 | static void destroy_inodecache(void) | |
2470 | { | |
1a1d92c1 | 2471 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2472 | } |
2473 | ||
f5e54d6e | 2474 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2475 | .writepage = shmem_writepage, |
76719325 | 2476 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2477 | #ifdef CONFIG_TMPFS |
ae976416 | 2478 | .readpage = shmem_readpage, |
800d15a5 NP |
2479 | .write_begin = shmem_write_begin, |
2480 | .write_end = shmem_write_end, | |
1da177e4 | 2481 | #endif |
304dbdb7 | 2482 | .migratepage = migrate_page, |
aa261f54 | 2483 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2484 | }; |
2485 | ||
15ad7cdc | 2486 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2487 | .mmap = shmem_mmap, |
2488 | #ifdef CONFIG_TMPFS | |
2489 | .llseek = generic_file_llseek, | |
bcd78e49 | 2490 | .read = do_sync_read, |
5402b976 | 2491 | .write = do_sync_write, |
bcd78e49 | 2492 | .aio_read = shmem_file_aio_read, |
5402b976 | 2493 | .aio_write = generic_file_aio_write, |
1b061d92 | 2494 | .fsync = noop_fsync, |
ae976416 HD |
2495 | .splice_read = generic_file_splice_read, |
2496 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2497 | #endif |
2498 | }; | |
2499 | ||
92e1d5be | 2500 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 | 2501 | .setattr = shmem_notify_change, |
f6b3ec23 | 2502 | .truncate_range = shmem_truncate_range, |
39f0247d AG |
2503 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2504 | .setxattr = generic_setxattr, | |
2505 | .getxattr = generic_getxattr, | |
2506 | .listxattr = generic_listxattr, | |
2507 | .removexattr = generic_removexattr, | |
1c7c474c | 2508 | .check_acl = generic_check_acl, |
39f0247d AG |
2509 | #endif |
2510 | ||
1da177e4 LT |
2511 | }; |
2512 | ||
92e1d5be | 2513 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2514 | #ifdef CONFIG_TMPFS |
2515 | .create = shmem_create, | |
2516 | .lookup = simple_lookup, | |
2517 | .link = shmem_link, | |
2518 | .unlink = shmem_unlink, | |
2519 | .symlink = shmem_symlink, | |
2520 | .mkdir = shmem_mkdir, | |
2521 | .rmdir = shmem_rmdir, | |
2522 | .mknod = shmem_mknod, | |
2523 | .rename = shmem_rename, | |
1da177e4 | 2524 | #endif |
39f0247d AG |
2525 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2526 | .setattr = shmem_notify_change, | |
2527 | .setxattr = generic_setxattr, | |
2528 | .getxattr = generic_getxattr, | |
2529 | .listxattr = generic_listxattr, | |
2530 | .removexattr = generic_removexattr, | |
1c7c474c | 2531 | .check_acl = generic_check_acl, |
39f0247d AG |
2532 | #endif |
2533 | }; | |
2534 | ||
92e1d5be | 2535 | static const struct inode_operations shmem_special_inode_operations = { |
39f0247d AG |
2536 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2537 | .setattr = shmem_notify_change, | |
2538 | .setxattr = generic_setxattr, | |
2539 | .getxattr = generic_getxattr, | |
2540 | .listxattr = generic_listxattr, | |
2541 | .removexattr = generic_removexattr, | |
1c7c474c | 2542 | .check_acl = generic_check_acl, |
39f0247d | 2543 | #endif |
1da177e4 LT |
2544 | }; |
2545 | ||
759b9775 | 2546 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2547 | .alloc_inode = shmem_alloc_inode, |
2548 | .destroy_inode = shmem_destroy_inode, | |
2549 | #ifdef CONFIG_TMPFS | |
2550 | .statfs = shmem_statfs, | |
2551 | .remount_fs = shmem_remount_fs, | |
680d794b | 2552 | .show_options = shmem_show_options, |
1da177e4 | 2553 | #endif |
1f895f75 | 2554 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2555 | .drop_inode = generic_delete_inode, |
2556 | .put_super = shmem_put_super, | |
2557 | }; | |
2558 | ||
f0f37e2f | 2559 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2560 | .fault = shmem_fault, |
1da177e4 LT |
2561 | #ifdef CONFIG_NUMA |
2562 | .set_policy = shmem_set_policy, | |
2563 | .get_policy = shmem_get_policy, | |
2564 | #endif | |
2565 | }; | |
2566 | ||
2567 | ||
3c26ff6e AV |
2568 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2569 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2570 | { |
3c26ff6e | 2571 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2572 | } |
2573 | ||
2574 | static struct file_system_type tmpfs_fs_type = { | |
2575 | .owner = THIS_MODULE, | |
2576 | .name = "tmpfs", | |
3c26ff6e | 2577 | .mount = shmem_mount, |
1da177e4 LT |
2578 | .kill_sb = kill_litter_super, |
2579 | }; | |
1da177e4 | 2580 | |
2b2af54a | 2581 | int __init init_tmpfs(void) |
1da177e4 LT |
2582 | { |
2583 | int error; | |
2584 | ||
e0bf68dd PZ |
2585 | error = bdi_init(&shmem_backing_dev_info); |
2586 | if (error) | |
2587 | goto out4; | |
2588 | ||
1da177e4 LT |
2589 | error = init_inodecache(); |
2590 | if (error) | |
2591 | goto out3; | |
2592 | ||
2593 | error = register_filesystem(&tmpfs_fs_type); | |
2594 | if (error) { | |
2595 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2596 | goto out2; | |
2597 | } | |
95dc112a | 2598 | |
1f5ce9e9 | 2599 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2600 | tmpfs_fs_type.name, NULL); |
2601 | if (IS_ERR(shm_mnt)) { | |
2602 | error = PTR_ERR(shm_mnt); | |
2603 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2604 | goto out1; | |
2605 | } | |
2606 | return 0; | |
2607 | ||
2608 | out1: | |
2609 | unregister_filesystem(&tmpfs_fs_type); | |
2610 | out2: | |
2611 | destroy_inodecache(); | |
2612 | out3: | |
e0bf68dd PZ |
2613 | bdi_destroy(&shmem_backing_dev_info); |
2614 | out4: | |
1da177e4 LT |
2615 | shm_mnt = ERR_PTR(error); |
2616 | return error; | |
2617 | } | |
853ac43a | 2618 | |
87946a72 DN |
2619 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2620 | /** | |
2621 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2622 | * @inode: the inode to be searched | |
2623 | * @pgoff: the offset to be searched | |
2624 | * @pagep: the pointer for the found page to be stored | |
2625 | * @ent: the pointer for the found swap entry to be stored | |
2626 | * | |
2627 | * If a page is found, refcount of it is incremented. Callers should handle | |
2628 | * these refcount. | |
2629 | */ | |
2630 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2631 | struct page **pagep, swp_entry_t *ent) | |
2632 | { | |
2633 | swp_entry_t entry = { .val = 0 }, *ptr; | |
2634 | struct page *page = NULL; | |
2635 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2636 | ||
2637 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2638 | goto out; | |
2639 | ||
2640 | spin_lock(&info->lock); | |
2641 | ptr = shmem_swp_entry(info, pgoff, NULL); | |
2642 | #ifdef CONFIG_SWAP | |
2643 | if (ptr && ptr->val) { | |
2644 | entry.val = ptr->val; | |
2645 | page = find_get_page(&swapper_space, entry.val); | |
2646 | } else | |
2647 | #endif | |
2648 | page = find_get_page(inode->i_mapping, pgoff); | |
2649 | if (ptr) | |
2650 | shmem_swp_unmap(ptr); | |
2651 | spin_unlock(&info->lock); | |
2652 | out: | |
2653 | *pagep = page; | |
2654 | *ent = entry; | |
2655 | } | |
2656 | #endif | |
2657 | ||
853ac43a MM |
2658 | #else /* !CONFIG_SHMEM */ |
2659 | ||
2660 | /* | |
2661 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2662 | * | |
2663 | * This is intended for small system where the benefits of the full | |
2664 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2665 | * their complexity. On systems without swap this code should be | |
2666 | * effectively equivalent, but much lighter weight. | |
2667 | */ | |
2668 | ||
2669 | #include <linux/ramfs.h> | |
2670 | ||
2671 | static struct file_system_type tmpfs_fs_type = { | |
2672 | .name = "tmpfs", | |
3c26ff6e | 2673 | .mount = ramfs_mount, |
853ac43a MM |
2674 | .kill_sb = kill_litter_super, |
2675 | }; | |
2676 | ||
2b2af54a | 2677 | int __init init_tmpfs(void) |
853ac43a MM |
2678 | { |
2679 | BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); | |
2680 | ||
2681 | shm_mnt = kern_mount(&tmpfs_fs_type); | |
2682 | BUG_ON(IS_ERR(shm_mnt)); | |
2683 | ||
2684 | return 0; | |
2685 | } | |
2686 | ||
2687 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
2688 | { | |
2689 | return 0; | |
2690 | } | |
2691 | ||
3f96b79a HD |
2692 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2693 | { | |
2694 | return 0; | |
2695 | } | |
2696 | ||
87946a72 DN |
2697 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2698 | /** | |
2699 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2700 | * @inode: the inode to be searched | |
2701 | * @pgoff: the offset to be searched | |
2702 | * @pagep: the pointer for the found page to be stored | |
2703 | * @ent: the pointer for the found swap entry to be stored | |
2704 | * | |
2705 | * If a page is found, refcount of it is incremented. Callers should handle | |
2706 | * these refcount. | |
2707 | */ | |
2708 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2709 | struct page **pagep, swp_entry_t *ent) | |
2710 | { | |
2711 | struct page *page = NULL; | |
2712 | ||
2713 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2714 | goto out; | |
2715 | page = find_get_page(inode->i_mapping, pgoff); | |
2716 | out: | |
2717 | *pagep = page; | |
2718 | *ent = (swp_entry_t){ .val = 0 }; | |
2719 | } | |
2720 | #endif | |
2721 | ||
0b0a0806 HD |
2722 | #define shmem_vm_ops generic_file_vm_ops |
2723 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2724 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2725 | #define shmem_acct_size(flags, size) 0 |
2726 | #define shmem_unacct_size(flags, size) do {} while (0) | |
caefba17 | 2727 | #define SHMEM_MAX_BYTES MAX_LFS_FILESIZE |
853ac43a MM |
2728 | |
2729 | #endif /* CONFIG_SHMEM */ | |
2730 | ||
2731 | /* common code */ | |
1da177e4 | 2732 | |
46711810 | 2733 | /** |
1da177e4 | 2734 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2735 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2736 | * @size: size to be set for the file | |
0b0a0806 | 2737 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2738 | */ |
168f5ac6 | 2739 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2740 | { |
2741 | int error; | |
2742 | struct file *file; | |
2743 | struct inode *inode; | |
2c48b9c4 AV |
2744 | struct path path; |
2745 | struct dentry *root; | |
1da177e4 LT |
2746 | struct qstr this; |
2747 | ||
2748 | if (IS_ERR(shm_mnt)) | |
2749 | return (void *)shm_mnt; | |
2750 | ||
2751 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2752 | return ERR_PTR(-EINVAL); | |
2753 | ||
2754 | if (shmem_acct_size(flags, size)) | |
2755 | return ERR_PTR(-ENOMEM); | |
2756 | ||
2757 | error = -ENOMEM; | |
2758 | this.name = name; | |
2759 | this.len = strlen(name); | |
2760 | this.hash = 0; /* will go */ | |
2761 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2762 | path.dentry = d_alloc(root, &this); |
2763 | if (!path.dentry) | |
1da177e4 | 2764 | goto put_memory; |
2c48b9c4 | 2765 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2766 | |
1da177e4 | 2767 | error = -ENOSPC; |
454abafe | 2768 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2769 | if (!inode) |
4b42af81 | 2770 | goto put_dentry; |
1da177e4 | 2771 | |
2c48b9c4 | 2772 | d_instantiate(path.dentry, inode); |
1da177e4 LT |
2773 | inode->i_size = size; |
2774 | inode->i_nlink = 0; /* It is unlinked */ | |
853ac43a MM |
2775 | #ifndef CONFIG_MMU |
2776 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2777 | if (error) | |
4b42af81 | 2778 | goto put_dentry; |
853ac43a | 2779 | #endif |
4b42af81 AV |
2780 | |
2781 | error = -ENFILE; | |
2c48b9c4 | 2782 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2783 | &shmem_file_operations); |
2784 | if (!file) | |
2785 | goto put_dentry; | |
2786 | ||
1da177e4 LT |
2787 | return file; |
2788 | ||
1da177e4 | 2789 | put_dentry: |
2c48b9c4 | 2790 | path_put(&path); |
1da177e4 LT |
2791 | put_memory: |
2792 | shmem_unacct_size(flags, size); | |
2793 | return ERR_PTR(error); | |
2794 | } | |
395e0ddc | 2795 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2796 | |
46711810 | 2797 | /** |
1da177e4 | 2798 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2799 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2800 | */ | |
2801 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2802 | { | |
2803 | struct file *file; | |
2804 | loff_t size = vma->vm_end - vma->vm_start; | |
2805 | ||
2806 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2807 | if (IS_ERR(file)) | |
2808 | return PTR_ERR(file); | |
2809 | ||
2810 | if (vma->vm_file) | |
2811 | fput(vma->vm_file); | |
2812 | vma->vm_file = file; | |
2813 | vma->vm_ops = &shmem_vm_ops; | |
bee4c36a | 2814 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
2815 | return 0; |
2816 | } |