Commit | Line | Data |
---|---|---|
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 | ||
b09e0fa4 EP |
102 | struct shmem_xattr { |
103 | struct list_head list; /* anchored by shmem_inode_info->xattr_list */ | |
104 | char *name; /* xattr name */ | |
105 | size_t size; | |
106 | char value[0]; | |
107 | }; | |
108 | ||
1da177e4 LT |
109 | /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */ |
110 | enum sgp_type { | |
1da177e4 LT |
111 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
112 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 113 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
114 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
115 | }; | |
116 | ||
b76db735 | 117 | #ifdef CONFIG_TMPFS |
680d794b | 118 | static unsigned long shmem_default_max_blocks(void) |
119 | { | |
120 | return totalram_pages / 2; | |
121 | } | |
122 | ||
123 | static unsigned long shmem_default_max_inodes(void) | |
124 | { | |
125 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
126 | } | |
b76db735 | 127 | #endif |
680d794b | 128 | |
1da177e4 LT |
129 | static int shmem_getpage(struct inode *inode, unsigned long idx, |
130 | struct page **pagep, enum sgp_type sgp, int *type); | |
131 | ||
6daa0e28 | 132 | static inline struct page *shmem_dir_alloc(gfp_t gfp_mask) |
1da177e4 LT |
133 | { |
134 | /* | |
135 | * The above definition of ENTRIES_PER_PAGE, and the use of | |
136 | * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE: | |
137 | * might be reconsidered if it ever diverges from PAGE_SIZE. | |
769848c0 | 138 | * |
e12ba74d | 139 | * Mobility flags are masked out as swap vectors cannot move |
1da177e4 | 140 | */ |
e12ba74d | 141 | return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO, |
769848c0 | 142 | PAGE_CACHE_SHIFT-PAGE_SHIFT); |
1da177e4 LT |
143 | } |
144 | ||
145 | static inline void shmem_dir_free(struct page *page) | |
146 | { | |
147 | __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT); | |
148 | } | |
149 | ||
150 | static struct page **shmem_dir_map(struct page *page) | |
151 | { | |
152 | return (struct page **)kmap_atomic(page, KM_USER0); | |
153 | } | |
154 | ||
155 | static inline void shmem_dir_unmap(struct page **dir) | |
156 | { | |
157 | kunmap_atomic(dir, KM_USER0); | |
158 | } | |
159 | ||
160 | static swp_entry_t *shmem_swp_map(struct page *page) | |
161 | { | |
162 | return (swp_entry_t *)kmap_atomic(page, KM_USER1); | |
163 | } | |
164 | ||
165 | static inline void shmem_swp_balance_unmap(void) | |
166 | { | |
167 | /* | |
168 | * When passing a pointer to an i_direct entry, to code which | |
169 | * also handles indirect entries and so will shmem_swp_unmap, | |
170 | * we must arrange for the preempt count to remain in balance. | |
171 | * What kmap_atomic of a lowmem page does depends on config | |
172 | * and architecture, so pretend to kmap_atomic some lowmem page. | |
173 | */ | |
174 | (void) kmap_atomic(ZERO_PAGE(0), KM_USER1); | |
175 | } | |
176 | ||
177 | static inline void shmem_swp_unmap(swp_entry_t *entry) | |
178 | { | |
179 | kunmap_atomic(entry, KM_USER1); | |
180 | } | |
181 | ||
182 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) | |
183 | { | |
184 | return sb->s_fs_info; | |
185 | } | |
186 | ||
187 | /* | |
188 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
189 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
190 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
191 | * consistent with the pre-accounting of private mappings ... | |
192 | */ | |
193 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
194 | { | |
0b0a0806 HD |
195 | return (flags & VM_NORESERVE) ? |
196 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
197 | } |
198 | ||
199 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
200 | { | |
0b0a0806 | 201 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
202 | vm_unacct_memory(VM_ACCT(size)); |
203 | } | |
204 | ||
205 | /* | |
206 | * ... whereas tmpfs objects are accounted incrementally as | |
207 | * pages are allocated, in order to allow huge sparse files. | |
208 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
209 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
210 | */ | |
211 | static inline int shmem_acct_block(unsigned long flags) | |
212 | { | |
0b0a0806 HD |
213 | return (flags & VM_NORESERVE) ? |
214 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
215 | } |
216 | ||
217 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
218 | { | |
0b0a0806 | 219 | if (flags & VM_NORESERVE) |
1da177e4 LT |
220 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
221 | } | |
222 | ||
759b9775 | 223 | static const struct super_operations shmem_ops; |
f5e54d6e | 224 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 225 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
226 | static const struct inode_operations shmem_inode_operations; |
227 | static const struct inode_operations shmem_dir_inode_operations; | |
228 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 229 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 230 | |
6c231b7b | 231 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 232 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 233 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
234 | }; |
235 | ||
236 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 237 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 LT |
238 | |
239 | static void shmem_free_blocks(struct inode *inode, long pages) | |
240 | { | |
241 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 242 | if (sbinfo->max_blocks) { |
7e496299 TC |
243 | percpu_counter_add(&sbinfo->used_blocks, -pages); |
244 | spin_lock(&inode->i_lock); | |
1da177e4 | 245 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; |
7e496299 | 246 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
247 | } |
248 | } | |
249 | ||
5b04c689 PE |
250 | static int shmem_reserve_inode(struct super_block *sb) |
251 | { | |
252 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
253 | if (sbinfo->max_inodes) { | |
254 | spin_lock(&sbinfo->stat_lock); | |
255 | if (!sbinfo->free_inodes) { | |
256 | spin_unlock(&sbinfo->stat_lock); | |
257 | return -ENOSPC; | |
258 | } | |
259 | sbinfo->free_inodes--; | |
260 | spin_unlock(&sbinfo->stat_lock); | |
261 | } | |
262 | return 0; | |
263 | } | |
264 | ||
265 | static void shmem_free_inode(struct super_block *sb) | |
266 | { | |
267 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
268 | if (sbinfo->max_inodes) { | |
269 | spin_lock(&sbinfo->stat_lock); | |
270 | sbinfo->free_inodes++; | |
271 | spin_unlock(&sbinfo->stat_lock); | |
272 | } | |
273 | } | |
274 | ||
46711810 | 275 | /** |
1da177e4 | 276 | * shmem_recalc_inode - recalculate the size of an inode |
1da177e4 LT |
277 | * @inode: inode to recalc |
278 | * | |
279 | * We have to calculate the free blocks since the mm can drop | |
280 | * undirtied hole pages behind our back. | |
281 | * | |
282 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
283 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
284 | * | |
285 | * It has to be called with the spinlock held. | |
286 | */ | |
287 | static void shmem_recalc_inode(struct inode *inode) | |
288 | { | |
289 | struct shmem_inode_info *info = SHMEM_I(inode); | |
290 | long freed; | |
291 | ||
292 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
293 | if (freed > 0) { | |
294 | info->alloced -= freed; | |
295 | shmem_unacct_blocks(info->flags, freed); | |
296 | shmem_free_blocks(inode, freed); | |
297 | } | |
298 | } | |
299 | ||
46711810 | 300 | /** |
1da177e4 | 301 | * shmem_swp_entry - find the swap vector position in the info structure |
1da177e4 LT |
302 | * @info: info structure for the inode |
303 | * @index: index of the page to find | |
304 | * @page: optional page to add to the structure. Has to be preset to | |
305 | * all zeros | |
306 | * | |
307 | * If there is no space allocated yet it will return NULL when | |
308 | * page is NULL, else it will use the page for the needed block, | |
309 | * setting it to NULL on return to indicate that it has been used. | |
310 | * | |
311 | * The swap vector is organized the following way: | |
312 | * | |
313 | * There are SHMEM_NR_DIRECT entries directly stored in the | |
314 | * shmem_inode_info structure. So small files do not need an addional | |
315 | * allocation. | |
316 | * | |
317 | * For pages with index > SHMEM_NR_DIRECT there is the pointer | |
318 | * i_indirect which points to a page which holds in the first half | |
319 | * doubly indirect blocks, in the second half triple indirect blocks: | |
320 | * | |
321 | * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the | |
322 | * following layout (for SHMEM_NR_DIRECT == 16): | |
323 | * | |
324 | * i_indirect -> dir --> 16-19 | |
325 | * | +-> 20-23 | |
326 | * | | |
327 | * +-->dir2 --> 24-27 | |
328 | * | +-> 28-31 | |
329 | * | +-> 32-35 | |
330 | * | +-> 36-39 | |
331 | * | | |
332 | * +-->dir3 --> 40-43 | |
333 | * +-> 44-47 | |
334 | * +-> 48-51 | |
335 | * +-> 52-55 | |
336 | */ | |
337 | static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page) | |
338 | { | |
339 | unsigned long offset; | |
340 | struct page **dir; | |
341 | struct page *subdir; | |
342 | ||
343 | if (index < SHMEM_NR_DIRECT) { | |
344 | shmem_swp_balance_unmap(); | |
345 | return info->i_direct+index; | |
346 | } | |
347 | if (!info->i_indirect) { | |
348 | if (page) { | |
349 | info->i_indirect = *page; | |
350 | *page = NULL; | |
351 | } | |
352 | return NULL; /* need another page */ | |
353 | } | |
354 | ||
355 | index -= SHMEM_NR_DIRECT; | |
356 | offset = index % ENTRIES_PER_PAGE; | |
357 | index /= ENTRIES_PER_PAGE; | |
358 | dir = shmem_dir_map(info->i_indirect); | |
359 | ||
360 | if (index >= ENTRIES_PER_PAGE/2) { | |
361 | index -= ENTRIES_PER_PAGE/2; | |
362 | dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE; | |
363 | index %= ENTRIES_PER_PAGE; | |
364 | subdir = *dir; | |
365 | if (!subdir) { | |
366 | if (page) { | |
367 | *dir = *page; | |
368 | *page = NULL; | |
369 | } | |
370 | shmem_dir_unmap(dir); | |
371 | return NULL; /* need another page */ | |
372 | } | |
373 | shmem_dir_unmap(dir); | |
374 | dir = shmem_dir_map(subdir); | |
375 | } | |
376 | ||
377 | dir += index; | |
378 | subdir = *dir; | |
379 | if (!subdir) { | |
380 | if (!page || !(subdir = *page)) { | |
381 | shmem_dir_unmap(dir); | |
382 | return NULL; /* need a page */ | |
383 | } | |
384 | *dir = subdir; | |
385 | *page = NULL; | |
386 | } | |
387 | shmem_dir_unmap(dir); | |
388 | return shmem_swp_map(subdir) + offset; | |
389 | } | |
390 | ||
391 | static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value) | |
392 | { | |
393 | long incdec = value? 1: -1; | |
394 | ||
395 | entry->val = value; | |
396 | info->swapped += incdec; | |
4c21e2f2 HD |
397 | if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) { |
398 | struct page *page = kmap_atomic_to_page(entry); | |
399 | set_page_private(page, page_private(page) + incdec); | |
400 | } | |
1da177e4 LT |
401 | } |
402 | ||
46711810 | 403 | /** |
1da177e4 | 404 | * shmem_swp_alloc - get the position of the swap entry for the page. |
1da177e4 LT |
405 | * @info: info structure for the inode |
406 | * @index: index of the page to find | |
407 | * @sgp: check and recheck i_size? skip allocation? | |
46711810 RD |
408 | * |
409 | * If the entry does not exist, allocate it. | |
1da177e4 LT |
410 | */ |
411 | static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp) | |
412 | { | |
413 | struct inode *inode = &info->vfs_inode; | |
414 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
415 | struct page *page = NULL; | |
416 | swp_entry_t *entry; | |
417 | ||
418 | if (sgp != SGP_WRITE && | |
419 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
420 | return ERR_PTR(-EINVAL); | |
421 | ||
422 | while (!(entry = shmem_swp_entry(info, index, &page))) { | |
423 | if (sgp == SGP_READ) | |
424 | return shmem_swp_map(ZERO_PAGE(0)); | |
425 | /* | |
7e496299 | 426 | * Test used_blocks against 1 less max_blocks, since we have 1 data |
1da177e4 LT |
427 | * page (and perhaps indirect index pages) yet to allocate: |
428 | * a waste to allocate index if we cannot allocate data. | |
429 | */ | |
0edd73b3 | 430 | if (sbinfo->max_blocks) { |
fc5da22a HD |
431 | if (percpu_counter_compare(&sbinfo->used_blocks, |
432 | sbinfo->max_blocks - 1) >= 0) | |
1da177e4 | 433 | return ERR_PTR(-ENOSPC); |
7e496299 TC |
434 | percpu_counter_inc(&sbinfo->used_blocks); |
435 | spin_lock(&inode->i_lock); | |
1da177e4 | 436 | inode->i_blocks += BLOCKS_PER_PAGE; |
7e496299 | 437 | spin_unlock(&inode->i_lock); |
1da177e4 LT |
438 | } |
439 | ||
440 | spin_unlock(&info->lock); | |
769848c0 | 441 | page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping)); |
1da177e4 LT |
442 | spin_lock(&info->lock); |
443 | ||
444 | if (!page) { | |
445 | shmem_free_blocks(inode, 1); | |
446 | return ERR_PTR(-ENOMEM); | |
447 | } | |
448 | if (sgp != SGP_WRITE && | |
449 | ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) { | |
450 | entry = ERR_PTR(-EINVAL); | |
451 | break; | |
452 | } | |
453 | if (info->next_index <= index) | |
454 | info->next_index = index + 1; | |
455 | } | |
456 | if (page) { | |
457 | /* another task gave its page, or truncated the file */ | |
458 | shmem_free_blocks(inode, 1); | |
459 | shmem_dir_free(page); | |
460 | } | |
461 | if (info->next_index <= index && !IS_ERR(entry)) | |
462 | info->next_index = index + 1; | |
463 | return entry; | |
464 | } | |
465 | ||
46711810 | 466 | /** |
1da177e4 | 467 | * shmem_free_swp - free some swap entries in a directory |
1ae70006 HD |
468 | * @dir: pointer to the directory |
469 | * @edir: pointer after last entry of the directory | |
470 | * @punch_lock: pointer to spinlock when needed for the holepunch case | |
1da177e4 | 471 | */ |
1ae70006 HD |
472 | static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir, |
473 | spinlock_t *punch_lock) | |
1da177e4 | 474 | { |
1ae70006 | 475 | spinlock_t *punch_unlock = NULL; |
1da177e4 LT |
476 | swp_entry_t *ptr; |
477 | int freed = 0; | |
478 | ||
479 | for (ptr = dir; ptr < edir; ptr++) { | |
480 | if (ptr->val) { | |
1ae70006 HD |
481 | if (unlikely(punch_lock)) { |
482 | punch_unlock = punch_lock; | |
483 | punch_lock = NULL; | |
484 | spin_lock(punch_unlock); | |
485 | if (!ptr->val) | |
486 | continue; | |
487 | } | |
1da177e4 LT |
488 | free_swap_and_cache(*ptr); |
489 | *ptr = (swp_entry_t){0}; | |
490 | freed++; | |
491 | } | |
492 | } | |
1ae70006 HD |
493 | if (punch_unlock) |
494 | spin_unlock(punch_unlock); | |
1da177e4 LT |
495 | return freed; |
496 | } | |
497 | ||
1ae70006 HD |
498 | static int shmem_map_and_free_swp(struct page *subdir, int offset, |
499 | int limit, struct page ***dir, spinlock_t *punch_lock) | |
1da177e4 LT |
500 | { |
501 | swp_entry_t *ptr; | |
502 | int freed = 0; | |
503 | ||
504 | ptr = shmem_swp_map(subdir); | |
505 | for (; offset < limit; offset += LATENCY_LIMIT) { | |
506 | int size = limit - offset; | |
507 | if (size > LATENCY_LIMIT) | |
508 | size = LATENCY_LIMIT; | |
1ae70006 HD |
509 | freed += shmem_free_swp(ptr+offset, ptr+offset+size, |
510 | punch_lock); | |
1da177e4 LT |
511 | if (need_resched()) { |
512 | shmem_swp_unmap(ptr); | |
513 | if (*dir) { | |
514 | shmem_dir_unmap(*dir); | |
515 | *dir = NULL; | |
516 | } | |
517 | cond_resched(); | |
518 | ptr = shmem_swp_map(subdir); | |
519 | } | |
520 | } | |
521 | shmem_swp_unmap(ptr); | |
522 | return freed; | |
523 | } | |
524 | ||
525 | static void shmem_free_pages(struct list_head *next) | |
526 | { | |
527 | struct page *page; | |
528 | int freed = 0; | |
529 | ||
530 | do { | |
531 | page = container_of(next, struct page, lru); | |
532 | next = next->next; | |
533 | shmem_dir_free(page); | |
534 | freed++; | |
535 | if (freed >= LATENCY_LIMIT) { | |
536 | cond_resched(); | |
537 | freed = 0; | |
538 | } | |
539 | } while (next); | |
540 | } | |
541 | ||
f6b3ec23 | 542 | static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
1da177e4 LT |
543 | { |
544 | struct shmem_inode_info *info = SHMEM_I(inode); | |
545 | unsigned long idx; | |
546 | unsigned long size; | |
547 | unsigned long limit; | |
548 | unsigned long stage; | |
549 | unsigned long diroff; | |
550 | struct page **dir; | |
551 | struct page *topdir; | |
552 | struct page *middir; | |
553 | struct page *subdir; | |
554 | swp_entry_t *ptr; | |
555 | LIST_HEAD(pages_to_free); | |
556 | long nr_pages_to_free = 0; | |
557 | long nr_swaps_freed = 0; | |
558 | int offset; | |
559 | int freed; | |
a2646d1e | 560 | int punch_hole; |
1ae70006 HD |
561 | spinlock_t *needs_lock; |
562 | spinlock_t *punch_lock; | |
a2646d1e | 563 | unsigned long upper_limit; |
1da177e4 LT |
564 | |
565 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
f6b3ec23 | 566 | idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
1da177e4 LT |
567 | if (idx >= info->next_index) |
568 | return; | |
569 | ||
570 | spin_lock(&info->lock); | |
571 | info->flags |= SHMEM_TRUNCATE; | |
f6b3ec23 BP |
572 | if (likely(end == (loff_t) -1)) { |
573 | limit = info->next_index; | |
a2646d1e | 574 | upper_limit = SHMEM_MAX_INDEX; |
f6b3ec23 | 575 | info->next_index = idx; |
1ae70006 | 576 | needs_lock = NULL; |
a2646d1e | 577 | punch_hole = 0; |
f6b3ec23 | 578 | } else { |
a2646d1e HD |
579 | if (end + 1 >= inode->i_size) { /* we may free a little more */ |
580 | limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >> | |
581 | PAGE_CACHE_SHIFT; | |
582 | upper_limit = SHMEM_MAX_INDEX; | |
583 | } else { | |
584 | limit = (end + 1) >> PAGE_CACHE_SHIFT; | |
585 | upper_limit = limit; | |
586 | } | |
1ae70006 | 587 | needs_lock = &info->lock; |
f6b3ec23 BP |
588 | punch_hole = 1; |
589 | } | |
590 | ||
1da177e4 | 591 | topdir = info->i_indirect; |
f6b3ec23 | 592 | if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) { |
1da177e4 LT |
593 | info->i_indirect = NULL; |
594 | nr_pages_to_free++; | |
595 | list_add(&topdir->lru, &pages_to_free); | |
596 | } | |
597 | spin_unlock(&info->lock); | |
598 | ||
599 | if (info->swapped && idx < SHMEM_NR_DIRECT) { | |
600 | ptr = info->i_direct; | |
601 | size = limit; | |
602 | if (size > SHMEM_NR_DIRECT) | |
603 | size = SHMEM_NR_DIRECT; | |
1ae70006 | 604 | nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock); |
1da177e4 | 605 | } |
92a3d03a BP |
606 | |
607 | /* | |
608 | * If there are no indirect blocks or we are punching a hole | |
609 | * below indirect blocks, nothing to be done. | |
610 | */ | |
a2646d1e | 611 | if (!topdir || limit <= SHMEM_NR_DIRECT) |
1da177e4 LT |
612 | goto done2; |
613 | ||
1ae70006 HD |
614 | /* |
615 | * The truncation case has already dropped info->lock, and we're safe | |
616 | * because i_size and next_index have already been lowered, preventing | |
617 | * access beyond. But in the punch_hole case, we still need to take | |
618 | * the lock when updating the swap directory, because there might be | |
619 | * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or | |
620 | * shmem_writepage. However, whenever we find we can remove a whole | |
621 | * directory page (not at the misaligned start or end of the range), | |
622 | * we first NULLify its pointer in the level above, and then have no | |
623 | * need to take the lock when updating its contents: needs_lock and | |
624 | * punch_lock (either pointing to info->lock or NULL) manage this. | |
625 | */ | |
626 | ||
a2646d1e | 627 | upper_limit -= SHMEM_NR_DIRECT; |
1da177e4 LT |
628 | limit -= SHMEM_NR_DIRECT; |
629 | idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0; | |
630 | offset = idx % ENTRIES_PER_PAGE; | |
631 | idx -= offset; | |
632 | ||
633 | dir = shmem_dir_map(topdir); | |
634 | stage = ENTRIES_PER_PAGEPAGE/2; | |
635 | if (idx < ENTRIES_PER_PAGEPAGE/2) { | |
636 | middir = topdir; | |
637 | diroff = idx/ENTRIES_PER_PAGE; | |
638 | } else { | |
639 | dir += ENTRIES_PER_PAGE/2; | |
640 | dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE; | |
641 | while (stage <= idx) | |
642 | stage += ENTRIES_PER_PAGEPAGE; | |
643 | middir = *dir; | |
644 | if (*dir) { | |
645 | diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) % | |
646 | ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE; | |
a2646d1e | 647 | if (!diroff && !offset && upper_limit >= stage) { |
1ae70006 HD |
648 | if (needs_lock) { |
649 | spin_lock(needs_lock); | |
650 | *dir = NULL; | |
651 | spin_unlock(needs_lock); | |
652 | needs_lock = NULL; | |
653 | } else | |
654 | *dir = NULL; | |
1da177e4 LT |
655 | nr_pages_to_free++; |
656 | list_add(&middir->lru, &pages_to_free); | |
657 | } | |
658 | shmem_dir_unmap(dir); | |
659 | dir = shmem_dir_map(middir); | |
660 | } else { | |
661 | diroff = 0; | |
662 | offset = 0; | |
663 | idx = stage; | |
664 | } | |
665 | } | |
666 | ||
667 | for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) { | |
668 | if (unlikely(idx == stage)) { | |
669 | shmem_dir_unmap(dir); | |
670 | dir = shmem_dir_map(topdir) + | |
671 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
672 | while (!*dir) { | |
673 | dir++; | |
674 | idx += ENTRIES_PER_PAGEPAGE; | |
675 | if (idx >= limit) | |
676 | goto done1; | |
677 | } | |
678 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
679 | middir = *dir; | |
1ae70006 HD |
680 | if (punch_hole) |
681 | needs_lock = &info->lock; | |
a2646d1e | 682 | if (upper_limit >= stage) { |
1ae70006 HD |
683 | if (needs_lock) { |
684 | spin_lock(needs_lock); | |
685 | *dir = NULL; | |
686 | spin_unlock(needs_lock); | |
687 | needs_lock = NULL; | |
688 | } else | |
689 | *dir = NULL; | |
a2646d1e HD |
690 | nr_pages_to_free++; |
691 | list_add(&middir->lru, &pages_to_free); | |
692 | } | |
1da177e4 LT |
693 | shmem_dir_unmap(dir); |
694 | cond_resched(); | |
695 | dir = shmem_dir_map(middir); | |
696 | diroff = 0; | |
697 | } | |
1ae70006 | 698 | punch_lock = needs_lock; |
1da177e4 | 699 | subdir = dir[diroff]; |
1ae70006 HD |
700 | if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) { |
701 | if (needs_lock) { | |
702 | spin_lock(needs_lock); | |
703 | dir[diroff] = NULL; | |
704 | spin_unlock(needs_lock); | |
705 | punch_lock = NULL; | |
706 | } else | |
707 | dir[diroff] = NULL; | |
708 | nr_pages_to_free++; | |
709 | list_add(&subdir->lru, &pages_to_free); | |
710 | } | |
711 | if (subdir && page_private(subdir) /* has swap entries */) { | |
1da177e4 LT |
712 | size = limit - idx; |
713 | if (size > ENTRIES_PER_PAGE) | |
714 | size = ENTRIES_PER_PAGE; | |
715 | freed = shmem_map_and_free_swp(subdir, | |
1ae70006 | 716 | offset, size, &dir, punch_lock); |
1da177e4 LT |
717 | if (!dir) |
718 | dir = shmem_dir_map(middir); | |
719 | nr_swaps_freed += freed; | |
1ae70006 | 720 | if (offset || punch_lock) { |
1da177e4 | 721 | spin_lock(&info->lock); |
1ae70006 HD |
722 | set_page_private(subdir, |
723 | page_private(subdir) - freed); | |
1da177e4 | 724 | spin_unlock(&info->lock); |
1ae70006 HD |
725 | } else |
726 | BUG_ON(page_private(subdir) != freed); | |
1da177e4 | 727 | } |
1ae70006 | 728 | offset = 0; |
1da177e4 LT |
729 | } |
730 | done1: | |
731 | shmem_dir_unmap(dir); | |
732 | done2: | |
733 | if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) { | |
734 | /* | |
735 | * Call truncate_inode_pages again: racing shmem_unuse_inode | |
3889e6e7 | 736 | * may have swizzled a page in from swap since |
737 | * truncate_pagecache or generic_delete_inode did it, before we | |
738 | * lowered next_index. Also, though shmem_getpage checks | |
739 | * i_size before adding to cache, no recheck after: so fix the | |
740 | * narrow window there too. | |
16a10019 HD |
741 | * |
742 | * Recalling truncate_inode_pages_range and unmap_mapping_range | |
743 | * every time for punch_hole (which never got a chance to clear | |
744 | * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive, | |
745 | * yet hardly ever necessary: try to optimize them out later. | |
1da177e4 | 746 | */ |
f6b3ec23 | 747 | truncate_inode_pages_range(inode->i_mapping, start, end); |
16a10019 HD |
748 | if (punch_hole) |
749 | unmap_mapping_range(inode->i_mapping, start, | |
750 | end - start, 1); | |
1da177e4 LT |
751 | } |
752 | ||
753 | spin_lock(&info->lock); | |
754 | info->flags &= ~SHMEM_TRUNCATE; | |
755 | info->swapped -= nr_swaps_freed; | |
756 | if (nr_pages_to_free) | |
757 | shmem_free_blocks(inode, nr_pages_to_free); | |
758 | shmem_recalc_inode(inode); | |
759 | spin_unlock(&info->lock); | |
760 | ||
761 | /* | |
762 | * Empty swap vector directory pages to be freed? | |
763 | */ | |
764 | if (!list_empty(&pages_to_free)) { | |
765 | pages_to_free.prev->next = NULL; | |
766 | shmem_free_pages(pages_to_free.next); | |
767 | } | |
768 | } | |
769 | ||
770 | static int shmem_notify_change(struct dentry *dentry, struct iattr *attr) | |
771 | { | |
772 | struct inode *inode = dentry->d_inode; | |
af5a30d8 | 773 | loff_t newsize = attr->ia_size; |
1da177e4 LT |
774 | int error; |
775 | ||
db78b877 CH |
776 | error = inode_change_ok(inode, attr); |
777 | if (error) | |
778 | return error; | |
779 | ||
af5a30d8 NP |
780 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE) |
781 | && newsize != inode->i_size) { | |
3889e6e7 | 782 | struct page *page = NULL; |
783 | ||
784 | if (newsize < inode->i_size) { | |
1da177e4 LT |
785 | /* |
786 | * If truncating down to a partial page, then | |
787 | * if that page is already allocated, hold it | |
788 | * in memory until the truncation is over, so | |
ae0e47f0 | 789 | * truncate_partial_page cannot miss it were |
1da177e4 LT |
790 | * it assigned to swap. |
791 | */ | |
3889e6e7 | 792 | if (newsize & (PAGE_CACHE_SIZE-1)) { |
1da177e4 | 793 | (void) shmem_getpage(inode, |
3889e6e7 | 794 | newsize >> PAGE_CACHE_SHIFT, |
1da177e4 | 795 | &page, SGP_READ, NULL); |
d3602444 HD |
796 | if (page) |
797 | unlock_page(page); | |
1da177e4 LT |
798 | } |
799 | /* | |
800 | * Reset SHMEM_PAGEIN flag so that shmem_truncate can | |
801 | * detect if any pages might have been added to cache | |
802 | * after truncate_inode_pages. But we needn't bother | |
803 | * if it's being fully truncated to zero-length: the | |
804 | * nrpages check is efficient enough in that case. | |
805 | */ | |
3889e6e7 | 806 | if (newsize) { |
1da177e4 LT |
807 | struct shmem_inode_info *info = SHMEM_I(inode); |
808 | spin_lock(&info->lock); | |
809 | info->flags &= ~SHMEM_PAGEIN; | |
810 | spin_unlock(&info->lock); | |
811 | } | |
812 | } | |
3889e6e7 | 813 | |
2c27c65e CH |
814 | /* XXX(truncate): truncate_setsize should be called last */ |
815 | truncate_setsize(inode, newsize); | |
3889e6e7 | 816 | if (page) |
817 | page_cache_release(page); | |
3889e6e7 | 818 | shmem_truncate_range(inode, newsize, (loff_t)-1); |
1da177e4 LT |
819 | } |
820 | ||
db78b877 | 821 | setattr_copy(inode, attr); |
39f0247d | 822 | #ifdef CONFIG_TMPFS_POSIX_ACL |
db78b877 | 823 | if (attr->ia_valid & ATTR_MODE) |
1c7c474c | 824 | error = generic_acl_chmod(inode); |
39f0247d | 825 | #endif |
1da177e4 LT |
826 | return error; |
827 | } | |
828 | ||
1f895f75 | 829 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 830 | { |
1da177e4 | 831 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 832 | struct shmem_xattr *xattr, *nxattr; |
1da177e4 | 833 | |
3889e6e7 | 834 | if (inode->i_mapping->a_ops == &shmem_aops) { |
fef26658 | 835 | truncate_inode_pages(inode->i_mapping, 0); |
1da177e4 LT |
836 | shmem_unacct_size(info->flags, inode->i_size); |
837 | inode->i_size = 0; | |
3889e6e7 | 838 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 839 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 840 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 841 | list_del_init(&info->swaplist); |
cb5f7b9a | 842 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
843 | } |
844 | } | |
b09e0fa4 EP |
845 | |
846 | list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { | |
847 | kfree(xattr->name); | |
848 | kfree(xattr); | |
849 | } | |
0edd73b3 | 850 | BUG_ON(inode->i_blocks); |
5b04c689 | 851 | shmem_free_inode(inode->i_sb); |
1f895f75 | 852 | end_writeback(inode); |
1da177e4 LT |
853 | } |
854 | ||
855 | static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir) | |
856 | { | |
857 | swp_entry_t *ptr; | |
858 | ||
859 | for (ptr = dir; ptr < edir; ptr++) { | |
860 | if (ptr->val == entry.val) | |
861 | return ptr - dir; | |
862 | } | |
863 | return -1; | |
864 | } | |
865 | ||
866 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) | |
867 | { | |
778dd893 | 868 | struct address_space *mapping; |
1da177e4 LT |
869 | unsigned long idx; |
870 | unsigned long size; | |
871 | unsigned long limit; | |
872 | unsigned long stage; | |
873 | struct page **dir; | |
874 | struct page *subdir; | |
875 | swp_entry_t *ptr; | |
876 | int offset; | |
d9fe526a | 877 | int error; |
1da177e4 LT |
878 | |
879 | idx = 0; | |
880 | ptr = info->i_direct; | |
881 | spin_lock(&info->lock); | |
1b1b32f2 HD |
882 | if (!info->swapped) { |
883 | list_del_init(&info->swaplist); | |
884 | goto lost2; | |
885 | } | |
1da177e4 LT |
886 | limit = info->next_index; |
887 | size = limit; | |
888 | if (size > SHMEM_NR_DIRECT) | |
889 | size = SHMEM_NR_DIRECT; | |
890 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
778dd893 HD |
891 | if (offset >= 0) { |
892 | shmem_swp_balance_unmap(); | |
1da177e4 | 893 | goto found; |
778dd893 | 894 | } |
1da177e4 LT |
895 | if (!info->i_indirect) |
896 | goto lost2; | |
897 | ||
898 | dir = shmem_dir_map(info->i_indirect); | |
899 | stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2; | |
900 | ||
901 | for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) { | |
902 | if (unlikely(idx == stage)) { | |
903 | shmem_dir_unmap(dir-1); | |
cb5f7b9a HD |
904 | if (cond_resched_lock(&info->lock)) { |
905 | /* check it has not been truncated */ | |
906 | if (limit > info->next_index) { | |
907 | limit = info->next_index; | |
908 | if (idx >= limit) | |
909 | goto lost2; | |
910 | } | |
911 | } | |
1da177e4 LT |
912 | dir = shmem_dir_map(info->i_indirect) + |
913 | ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE; | |
914 | while (!*dir) { | |
915 | dir++; | |
916 | idx += ENTRIES_PER_PAGEPAGE; | |
917 | if (idx >= limit) | |
918 | goto lost1; | |
919 | } | |
920 | stage = idx + ENTRIES_PER_PAGEPAGE; | |
921 | subdir = *dir; | |
922 | shmem_dir_unmap(dir); | |
923 | dir = shmem_dir_map(subdir); | |
924 | } | |
925 | subdir = *dir; | |
4c21e2f2 | 926 | if (subdir && page_private(subdir)) { |
1da177e4 LT |
927 | ptr = shmem_swp_map(subdir); |
928 | size = limit - idx; | |
929 | if (size > ENTRIES_PER_PAGE) | |
930 | size = ENTRIES_PER_PAGE; | |
931 | offset = shmem_find_swp(entry, ptr, ptr+size); | |
e6c9366b | 932 | shmem_swp_unmap(ptr); |
1da177e4 LT |
933 | if (offset >= 0) { |
934 | shmem_dir_unmap(dir); | |
e6c9366b | 935 | ptr = shmem_swp_map(subdir); |
1da177e4 LT |
936 | goto found; |
937 | } | |
1da177e4 LT |
938 | } |
939 | } | |
940 | lost1: | |
941 | shmem_dir_unmap(dir-1); | |
942 | lost2: | |
943 | spin_unlock(&info->lock); | |
944 | return 0; | |
945 | found: | |
946 | idx += offset; | |
778dd893 | 947 | ptr += offset; |
2e0e26c7 | 948 | |
1b1b32f2 HD |
949 | /* |
950 | * Move _head_ to start search for next from here. | |
1f895f75 | 951 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 HD |
952 | * mutex, and there's an instant in list_move_tail when info->swaplist |
953 | * would appear empty, if it were the only one on shmem_swaplist. We | |
954 | * could avoid doing it if inode NULL; or use this minor optimization. | |
955 | */ | |
956 | if (shmem_swaplist.next != &info->swaplist) | |
957 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 958 | |
d13d1443 | 959 | /* |
778dd893 HD |
960 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
961 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
962 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 963 | */ |
778dd893 HD |
964 | mapping = info->vfs_inode.i_mapping; |
965 | error = add_to_page_cache_locked(page, mapping, idx, GFP_NOWAIT); | |
966 | /* which does mem_cgroup_uncharge_cache_page on error */ | |
69029cd5 | 967 | |
d9fe526a | 968 | if (error == -EEXIST) { |
778dd893 | 969 | struct page *filepage = find_get_page(mapping, idx); |
2e0e26c7 | 970 | error = 1; |
d9fe526a HD |
971 | if (filepage) { |
972 | /* | |
973 | * There might be a more uptodate page coming down | |
974 | * from a stacked writepage: forget our swappage if so. | |
975 | */ | |
976 | if (PageUptodate(filepage)) | |
977 | error = 0; | |
978 | page_cache_release(filepage); | |
979 | } | |
980 | } | |
981 | if (!error) { | |
73b1262f HD |
982 | delete_from_swap_cache(page); |
983 | set_page_dirty(page); | |
1da177e4 | 984 | info->flags |= SHMEM_PAGEIN; |
2e0e26c7 HD |
985 | shmem_swp_set(info, ptr, 0); |
986 | swap_free(entry); | |
987 | error = 1; /* not an error, but entry was found */ | |
1da177e4 | 988 | } |
778dd893 | 989 | shmem_swp_unmap(ptr); |
1da177e4 | 990 | spin_unlock(&info->lock); |
2e0e26c7 | 991 | return error; |
1da177e4 LT |
992 | } |
993 | ||
994 | /* | |
995 | * shmem_unuse() search for an eventually swapped out shmem page. | |
996 | */ | |
997 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
998 | { | |
999 | struct list_head *p, *next; | |
1000 | struct shmem_inode_info *info; | |
1001 | int found = 0; | |
778dd893 HD |
1002 | int error; |
1003 | ||
1004 | /* | |
1005 | * Charge page using GFP_KERNEL while we can wait, before taking | |
1006 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
1007 | * Charged back to the user (not to caller) when swap account is used. | |
1008 | * add_to_page_cache() will be called with GFP_NOWAIT. | |
1009 | */ | |
1010 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
1011 | if (error) | |
1012 | goto out; | |
1013 | /* | |
1014 | * Try to preload while we can wait, to not make a habit of | |
1015 | * draining atomic reserves; but don't latch on to this cpu, | |
1016 | * it's okay if sometimes we get rescheduled after this. | |
1017 | */ | |
1018 | error = radix_tree_preload(GFP_KERNEL); | |
1019 | if (error) | |
1020 | goto uncharge; | |
1021 | radix_tree_preload_end(); | |
1da177e4 | 1022 | |
cb5f7b9a | 1023 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 LT |
1024 | list_for_each_safe(p, next, &shmem_swaplist) { |
1025 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
1b1b32f2 | 1026 | found = shmem_unuse_inode(info, entry, page); |
cb5f7b9a | 1027 | cond_resched(); |
2e0e26c7 | 1028 | if (found) |
778dd893 | 1029 | break; |
1da177e4 | 1030 | } |
cb5f7b9a | 1031 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 HD |
1032 | |
1033 | uncharge: | |
1034 | if (!found) | |
1035 | mem_cgroup_uncharge_cache_page(page); | |
1036 | if (found < 0) | |
1037 | error = found; | |
1038 | out: | |
aaa46865 HD |
1039 | unlock_page(page); |
1040 | page_cache_release(page); | |
778dd893 | 1041 | return error; |
1da177e4 LT |
1042 | } |
1043 | ||
1044 | /* | |
1045 | * Move the page from the page cache to the swap cache. | |
1046 | */ | |
1047 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
1048 | { | |
1049 | struct shmem_inode_info *info; | |
1050 | swp_entry_t *entry, swap; | |
1051 | struct address_space *mapping; | |
1052 | unsigned long index; | |
1053 | struct inode *inode; | |
1054 | ||
1055 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
1056 | mapping = page->mapping; |
1057 | index = page->index; | |
1058 | inode = mapping->host; | |
1059 | info = SHMEM_I(inode); | |
1060 | if (info->flags & VM_LOCKED) | |
1061 | goto redirty; | |
d9fe526a | 1062 | if (!total_swap_pages) |
1da177e4 LT |
1063 | goto redirty; |
1064 | ||
d9fe526a HD |
1065 | /* |
1066 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
1067 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
1068 | * may use the ->writepage of its underlying filesystem, in which case | |
1069 | * tmpfs should write out to swap only in response to memory pressure, | |
5b0830cb JA |
1070 | * and not for the writeback threads or sync. However, in those cases, |
1071 | * we do still want to check if there's a redundant swappage to be | |
1072 | * discarded. | |
d9fe526a HD |
1073 | */ |
1074 | if (wbc->for_reclaim) | |
1075 | swap = get_swap_page(); | |
1076 | else | |
1077 | swap.val = 0; | |
1078 | ||
b1dea800 HD |
1079 | /* |
1080 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
1081 | * if it's not already there. Do it now because we cannot take | |
1082 | * mutex while holding spinlock, and must do so before the page | |
1083 | * is moved to swap cache, when its pagelock no longer protects | |
1084 | * the inode from eviction. But don't unlock the mutex until | |
1085 | * we've taken the spinlock, because shmem_unuse_inode() will | |
1086 | * prune a !swapped inode from the swaplist under both locks. | |
1087 | */ | |
05bf86b4 | 1088 | if (swap.val) { |
b1dea800 | 1089 | mutex_lock(&shmem_swaplist_mutex); |
05bf86b4 HD |
1090 | if (list_empty(&info->swaplist)) |
1091 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 HD |
1092 | } |
1093 | ||
1da177e4 | 1094 | spin_lock(&info->lock); |
05bf86b4 | 1095 | if (swap.val) |
b1dea800 HD |
1096 | mutex_unlock(&shmem_swaplist_mutex); |
1097 | ||
1da177e4 LT |
1098 | if (index >= info->next_index) { |
1099 | BUG_ON(!(info->flags & SHMEM_TRUNCATE)); | |
1100 | goto unlock; | |
1101 | } | |
1102 | entry = shmem_swp_entry(info, index, NULL); | |
d9fe526a HD |
1103 | if (entry->val) { |
1104 | /* | |
1105 | * The more uptodate page coming down from a stacked | |
1106 | * writepage should replace our old swappage. | |
1107 | */ | |
1108 | free_swap_and_cache(*entry); | |
1109 | shmem_swp_set(info, entry, 0); | |
1110 | } | |
1111 | shmem_recalc_inode(inode); | |
1da177e4 | 1112 | |
d9fe526a | 1113 | if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
4c73b1bc | 1114 | delete_from_page_cache(page); |
1da177e4 LT |
1115 | shmem_swp_set(info, entry, swap.val); |
1116 | shmem_swp_unmap(entry); | |
aaa46865 | 1117 | swap_shmem_alloc(swap); |
826267cf | 1118 | spin_unlock(&info->lock); |
d9fe526a | 1119 | BUG_ON(page_mapped(page)); |
9fab5619 | 1120 | swap_writepage(page, wbc); |
1da177e4 LT |
1121 | return 0; |
1122 | } | |
1123 | ||
1124 | shmem_swp_unmap(entry); | |
1125 | unlock: | |
1126 | spin_unlock(&info->lock); | |
2ca4532a DN |
1127 | /* |
1128 | * add_to_swap_cache() doesn't return -EEXIST, so we can safely | |
1129 | * clear SWAP_HAS_CACHE flag. | |
1130 | */ | |
cb4b86ba | 1131 | swapcache_free(swap, NULL); |
1da177e4 LT |
1132 | redirty: |
1133 | set_page_dirty(page); | |
d9fe526a HD |
1134 | if (wbc->for_reclaim) |
1135 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1136 | unlock_page(page); | |
1137 | return 0; | |
1da177e4 LT |
1138 | } |
1139 | ||
1140 | #ifdef CONFIG_NUMA | |
680d794b | 1141 | #ifdef CONFIG_TMPFS |
71fe804b | 1142 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 1143 | { |
095f1fc4 | 1144 | char buffer[64]; |
680d794b | 1145 | |
71fe804b | 1146 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 1147 | return; /* show nothing */ |
680d794b | 1148 | |
71fe804b | 1149 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
1150 | |
1151 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 1152 | } |
71fe804b LS |
1153 | |
1154 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1155 | { | |
1156 | struct mempolicy *mpol = NULL; | |
1157 | if (sbinfo->mpol) { | |
1158 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
1159 | mpol = sbinfo->mpol; | |
1160 | mpol_get(mpol); | |
1161 | spin_unlock(&sbinfo->stat_lock); | |
1162 | } | |
1163 | return mpol; | |
1164 | } | |
680d794b | 1165 | #endif /* CONFIG_TMPFS */ |
1166 | ||
02098fea HD |
1167 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1168 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1169 | { |
52cd3b07 | 1170 | struct mempolicy mpol, *spol; |
1da177e4 | 1171 | struct vm_area_struct pvma; |
c4cc6d07 | 1172 | struct page *page; |
1da177e4 | 1173 | |
52cd3b07 LS |
1174 | spol = mpol_cond_copy(&mpol, |
1175 | mpol_shared_policy_lookup(&info->policy, idx)); | |
1176 | ||
1da177e4 | 1177 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 1178 | pvma.vm_start = 0; |
1da177e4 | 1179 | pvma.vm_pgoff = idx; |
c4cc6d07 | 1180 | pvma.vm_ops = NULL; |
52cd3b07 | 1181 | pvma.vm_policy = spol; |
02098fea | 1182 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
1183 | return page; |
1184 | } | |
1185 | ||
02098fea HD |
1186 | static struct page *shmem_alloc_page(gfp_t gfp, |
1187 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
1188 | { |
1189 | struct vm_area_struct pvma; | |
1da177e4 | 1190 | |
c4cc6d07 HD |
1191 | /* Create a pseudo vma that just contains the policy */ |
1192 | pvma.vm_start = 0; | |
1da177e4 | 1193 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
1194 | pvma.vm_ops = NULL; |
1195 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
52cd3b07 LS |
1196 | |
1197 | /* | |
1198 | * alloc_page_vma() will drop the shared policy reference | |
1199 | */ | |
1200 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 1201 | } |
680d794b | 1202 | #else /* !CONFIG_NUMA */ |
1203 | #ifdef CONFIG_TMPFS | |
71fe804b | 1204 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p) |
680d794b | 1205 | { |
1206 | } | |
1207 | #endif /* CONFIG_TMPFS */ | |
1208 | ||
02098fea HD |
1209 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
1210 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1211 | { |
02098fea | 1212 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
1213 | } |
1214 | ||
02098fea HD |
1215 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
1216 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 1217 | { |
e84e2e13 | 1218 | return alloc_page(gfp); |
1da177e4 | 1219 | } |
680d794b | 1220 | #endif /* CONFIG_NUMA */ |
1da177e4 | 1221 | |
71fe804b LS |
1222 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
1223 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1224 | { | |
1225 | return NULL; | |
1226 | } | |
1227 | #endif | |
1228 | ||
1da177e4 LT |
1229 | /* |
1230 | * shmem_getpage - either get the page from swap or allocate a new one | |
1231 | * | |
1232 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1233 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1234 | * entry since a page cannot live in both the swap and page cache | |
1235 | */ | |
1236 | static int shmem_getpage(struct inode *inode, unsigned long idx, | |
1237 | struct page **pagep, enum sgp_type sgp, int *type) | |
1238 | { | |
1239 | struct address_space *mapping = inode->i_mapping; | |
1240 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1241 | struct shmem_sb_info *sbinfo; | |
1242 | struct page *filepage = *pagep; | |
1243 | struct page *swappage; | |
ff36b801 | 1244 | struct page *prealloc_page = NULL; |
1da177e4 LT |
1245 | swp_entry_t *entry; |
1246 | swp_entry_t swap; | |
02098fea | 1247 | gfp_t gfp; |
1da177e4 LT |
1248 | int error; |
1249 | ||
1250 | if (idx >= SHMEM_MAX_INDEX) | |
1251 | return -EFBIG; | |
54cb8821 NP |
1252 | |
1253 | if (type) | |
83c54070 | 1254 | *type = 0; |
54cb8821 | 1255 | |
1da177e4 LT |
1256 | /* |
1257 | * Normally, filepage is NULL on entry, and either found | |
1258 | * uptodate immediately, or allocated and zeroed, or read | |
1259 | * in under swappage, which is then assigned to filepage. | |
5402b976 | 1260 | * But shmem_readpage (required for splice) passes in a locked |
ae976416 HD |
1261 | * filepage, which may be found not uptodate by other callers |
1262 | * too, and may need to be copied from the swappage read in. | |
1da177e4 LT |
1263 | */ |
1264 | repeat: | |
1265 | if (!filepage) | |
1266 | filepage = find_lock_page(mapping, idx); | |
1267 | if (filepage && PageUptodate(filepage)) | |
1268 | goto done; | |
02098fea | 1269 | gfp = mapping_gfp_mask(mapping); |
b409f9fc HD |
1270 | if (!filepage) { |
1271 | /* | |
1272 | * Try to preload while we can wait, to not make a habit of | |
1273 | * draining atomic reserves; but don't latch on to this cpu. | |
1274 | */ | |
1275 | error = radix_tree_preload(gfp & ~__GFP_HIGHMEM); | |
1276 | if (error) | |
1277 | goto failed; | |
1278 | radix_tree_preload_end(); | |
ff36b801 SL |
1279 | if (sgp != SGP_READ && !prealloc_page) { |
1280 | /* We don't care if this fails */ | |
1281 | prealloc_page = shmem_alloc_page(gfp, info, idx); | |
1282 | if (prealloc_page) { | |
1283 | if (mem_cgroup_cache_charge(prealloc_page, | |
1284 | current->mm, GFP_KERNEL)) { | |
1285 | page_cache_release(prealloc_page); | |
1286 | prealloc_page = NULL; | |
1287 | } | |
1288 | } | |
1289 | } | |
b409f9fc | 1290 | } |
ff36b801 | 1291 | error = 0; |
1da177e4 LT |
1292 | |
1293 | spin_lock(&info->lock); | |
1294 | shmem_recalc_inode(inode); | |
1295 | entry = shmem_swp_alloc(info, idx, sgp); | |
1296 | if (IS_ERR(entry)) { | |
1297 | spin_unlock(&info->lock); | |
1298 | error = PTR_ERR(entry); | |
1299 | goto failed; | |
1300 | } | |
1301 | swap = *entry; | |
1302 | ||
1303 | if (swap.val) { | |
1304 | /* Look it up and read it in.. */ | |
1305 | swappage = lookup_swap_cache(swap); | |
1306 | if (!swappage) { | |
1307 | shmem_swp_unmap(entry); | |
456f998e | 1308 | spin_unlock(&info->lock); |
1da177e4 | 1309 | /* here we actually do the io */ |
456f998e | 1310 | if (type) |
83c54070 | 1311 | *type |= VM_FAULT_MAJOR; |
02098fea | 1312 | swappage = shmem_swapin(swap, gfp, info, idx); |
1da177e4 LT |
1313 | if (!swappage) { |
1314 | spin_lock(&info->lock); | |
1315 | entry = shmem_swp_alloc(info, idx, sgp); | |
1316 | if (IS_ERR(entry)) | |
1317 | error = PTR_ERR(entry); | |
1318 | else { | |
1319 | if (entry->val == swap.val) | |
1320 | error = -ENOMEM; | |
1321 | shmem_swp_unmap(entry); | |
1322 | } | |
1323 | spin_unlock(&info->lock); | |
1324 | if (error) | |
1325 | goto failed; | |
1326 | goto repeat; | |
1327 | } | |
1328 | wait_on_page_locked(swappage); | |
1329 | page_cache_release(swappage); | |
1330 | goto repeat; | |
1331 | } | |
1332 | ||
1333 | /* We have to do this with page locked to prevent races */ | |
529ae9aa | 1334 | if (!trylock_page(swappage)) { |
1da177e4 LT |
1335 | shmem_swp_unmap(entry); |
1336 | spin_unlock(&info->lock); | |
1337 | wait_on_page_locked(swappage); | |
1338 | page_cache_release(swappage); | |
1339 | goto repeat; | |
1340 | } | |
1341 | if (PageWriteback(swappage)) { | |
1342 | shmem_swp_unmap(entry); | |
1343 | spin_unlock(&info->lock); | |
1344 | wait_on_page_writeback(swappage); | |
1345 | unlock_page(swappage); | |
1346 | page_cache_release(swappage); | |
1347 | goto repeat; | |
1348 | } | |
1349 | if (!PageUptodate(swappage)) { | |
1350 | shmem_swp_unmap(entry); | |
1351 | spin_unlock(&info->lock); | |
1352 | unlock_page(swappage); | |
1353 | page_cache_release(swappage); | |
1354 | error = -EIO; | |
1355 | goto failed; | |
1356 | } | |
1357 | ||
1358 | if (filepage) { | |
1359 | shmem_swp_set(info, entry, 0); | |
1360 | shmem_swp_unmap(entry); | |
1361 | delete_from_swap_cache(swappage); | |
1362 | spin_unlock(&info->lock); | |
1363 | copy_highpage(filepage, swappage); | |
1364 | unlock_page(swappage); | |
1365 | page_cache_release(swappage); | |
1366 | flush_dcache_page(filepage); | |
1367 | SetPageUptodate(filepage); | |
1368 | set_page_dirty(filepage); | |
1369 | swap_free(swap); | |
e286781d NP |
1370 | } else if (!(error = add_to_page_cache_locked(swappage, mapping, |
1371 | idx, GFP_NOWAIT))) { | |
1da177e4 LT |
1372 | info->flags |= SHMEM_PAGEIN; |
1373 | shmem_swp_set(info, entry, 0); | |
1374 | shmem_swp_unmap(entry); | |
73b1262f | 1375 | delete_from_swap_cache(swappage); |
1da177e4 LT |
1376 | spin_unlock(&info->lock); |
1377 | filepage = swappage; | |
73b1262f | 1378 | set_page_dirty(filepage); |
1da177e4 LT |
1379 | swap_free(swap); |
1380 | } else { | |
1381 | shmem_swp_unmap(entry); | |
1382 | spin_unlock(&info->lock); | |
82369553 | 1383 | if (error == -ENOMEM) { |
ae3abae6 DN |
1384 | /* |
1385 | * reclaim from proper memory cgroup and | |
1386 | * call memcg's OOM if needed. | |
1387 | */ | |
1388 | error = mem_cgroup_shmem_charge_fallback( | |
1389 | swappage, | |
b5a84319 | 1390 | current->mm, |
c9b0ed51 | 1391 | gfp); |
b5a84319 KH |
1392 | if (error) { |
1393 | unlock_page(swappage); | |
1394 | page_cache_release(swappage); | |
82369553 | 1395 | goto failed; |
b5a84319 | 1396 | } |
82369553 | 1397 | } |
b5a84319 KH |
1398 | unlock_page(swappage); |
1399 | page_cache_release(swappage); | |
1da177e4 LT |
1400 | goto repeat; |
1401 | } | |
1402 | } else if (sgp == SGP_READ && !filepage) { | |
1403 | shmem_swp_unmap(entry); | |
1404 | filepage = find_get_page(mapping, idx); | |
1405 | if (filepage && | |
529ae9aa | 1406 | (!PageUptodate(filepage) || !trylock_page(filepage))) { |
1da177e4 LT |
1407 | spin_unlock(&info->lock); |
1408 | wait_on_page_locked(filepage); | |
1409 | page_cache_release(filepage); | |
1410 | filepage = NULL; | |
1411 | goto repeat; | |
1412 | } | |
1413 | spin_unlock(&info->lock); | |
1414 | } else { | |
1415 | shmem_swp_unmap(entry); | |
1416 | sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 1417 | if (sbinfo->max_blocks) { |
fc5da22a HD |
1418 | if (percpu_counter_compare(&sbinfo->used_blocks, |
1419 | sbinfo->max_blocks) >= 0 || | |
59a16ead HD |
1420 | shmem_acct_block(info->flags)) |
1421 | goto nospace; | |
7e496299 TC |
1422 | percpu_counter_inc(&sbinfo->used_blocks); |
1423 | spin_lock(&inode->i_lock); | |
1da177e4 | 1424 | inode->i_blocks += BLOCKS_PER_PAGE; |
7e496299 | 1425 | spin_unlock(&inode->i_lock); |
59a16ead HD |
1426 | } else if (shmem_acct_block(info->flags)) |
1427 | goto nospace; | |
1da177e4 LT |
1428 | |
1429 | if (!filepage) { | |
69029cd5 KH |
1430 | int ret; |
1431 | ||
ff36b801 SL |
1432 | if (!prealloc_page) { |
1433 | spin_unlock(&info->lock); | |
1434 | filepage = shmem_alloc_page(gfp, info, idx); | |
1435 | if (!filepage) { | |
1436 | shmem_unacct_blocks(info->flags, 1); | |
1437 | shmem_free_blocks(inode, 1); | |
1438 | error = -ENOMEM; | |
1439 | goto failed; | |
1440 | } | |
1441 | SetPageSwapBacked(filepage); | |
1da177e4 | 1442 | |
ff36b801 SL |
1443 | /* |
1444 | * Precharge page while we can wait, compensate | |
1445 | * after | |
1446 | */ | |
1447 | error = mem_cgroup_cache_charge(filepage, | |
1448 | current->mm, GFP_KERNEL); | |
1449 | if (error) { | |
1450 | page_cache_release(filepage); | |
1451 | shmem_unacct_blocks(info->flags, 1); | |
1452 | shmem_free_blocks(inode, 1); | |
1453 | filepage = NULL; | |
1454 | goto failed; | |
1455 | } | |
1456 | ||
1457 | spin_lock(&info->lock); | |
1458 | } else { | |
1459 | filepage = prealloc_page; | |
1460 | prealloc_page = NULL; | |
1461 | SetPageSwapBacked(filepage); | |
82369553 HD |
1462 | } |
1463 | ||
1da177e4 LT |
1464 | entry = shmem_swp_alloc(info, idx, sgp); |
1465 | if (IS_ERR(entry)) | |
1466 | error = PTR_ERR(entry); | |
1467 | else { | |
1468 | swap = *entry; | |
1469 | shmem_swp_unmap(entry); | |
1470 | } | |
69029cd5 KH |
1471 | ret = error || swap.val; |
1472 | if (ret) | |
1473 | mem_cgroup_uncharge_cache_page(filepage); | |
1474 | else | |
1475 | ret = add_to_page_cache_lru(filepage, mapping, | |
1476 | idx, GFP_NOWAIT); | |
1477 | /* | |
1478 | * At add_to_page_cache_lru() failure, uncharge will | |
1479 | * be done automatically. | |
1480 | */ | |
1481 | if (ret) { | |
1da177e4 LT |
1482 | spin_unlock(&info->lock); |
1483 | page_cache_release(filepage); | |
1484 | shmem_unacct_blocks(info->flags, 1); | |
1485 | shmem_free_blocks(inode, 1); | |
1486 | filepage = NULL; | |
1487 | if (error) | |
1488 | goto failed; | |
1489 | goto repeat; | |
1490 | } | |
1491 | info->flags |= SHMEM_PAGEIN; | |
1492 | } | |
1493 | ||
1494 | info->alloced++; | |
1495 | spin_unlock(&info->lock); | |
e84e2e13 | 1496 | clear_highpage(filepage); |
1da177e4 LT |
1497 | flush_dcache_page(filepage); |
1498 | SetPageUptodate(filepage); | |
a0ee5ec5 HD |
1499 | if (sgp == SGP_DIRTY) |
1500 | set_page_dirty(filepage); | |
1da177e4 LT |
1501 | } |
1502 | done: | |
d3602444 | 1503 | *pagep = filepage; |
ff36b801 SL |
1504 | error = 0; |
1505 | goto out; | |
1da177e4 | 1506 | |
59a16ead HD |
1507 | nospace: |
1508 | /* | |
1509 | * Perhaps the page was brought in from swap between find_lock_page | |
1510 | * and taking info->lock? We allow for that at add_to_page_cache_lru, | |
1511 | * but must also avoid reporting a spurious ENOSPC while working on a | |
1512 | * full tmpfs. (When filepage has been passed in to shmem_getpage, it | |
1513 | * is already in page cache, which prevents this race from occurring.) | |
1514 | */ | |
1515 | if (!filepage) { | |
1516 | struct page *page = find_get_page(mapping, idx); | |
1517 | if (page) { | |
1518 | spin_unlock(&info->lock); | |
1519 | page_cache_release(page); | |
1520 | goto repeat; | |
1521 | } | |
1522 | } | |
1523 | spin_unlock(&info->lock); | |
1524 | error = -ENOSPC; | |
1da177e4 LT |
1525 | failed: |
1526 | if (*pagep != filepage) { | |
1527 | unlock_page(filepage); | |
1528 | page_cache_release(filepage); | |
1529 | } | |
ff36b801 SL |
1530 | out: |
1531 | if (prealloc_page) { | |
1532 | mem_cgroup_uncharge_cache_page(prealloc_page); | |
1533 | page_cache_release(prealloc_page); | |
1534 | } | |
1da177e4 LT |
1535 | return error; |
1536 | } | |
1537 | ||
d0217ac0 | 1538 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1539 | { |
d3ac7f89 | 1540 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 1541 | int error; |
d0217ac0 | 1542 | int ret; |
1da177e4 | 1543 | |
d0217ac0 NP |
1544 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
1545 | return VM_FAULT_SIGBUS; | |
d00806b1 | 1546 | |
27d54b39 | 1547 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
1548 | if (error) |
1549 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
456f998e YH |
1550 | if (ret & VM_FAULT_MAJOR) { |
1551 | count_vm_event(PGMAJFAULT); | |
1552 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
1553 | } | |
83c54070 | 1554 | return ret | VM_FAULT_LOCKED; |
1da177e4 LT |
1555 | } |
1556 | ||
1da177e4 | 1557 | #ifdef CONFIG_NUMA |
d8dc74f2 | 1558 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 1559 | { |
d3ac7f89 | 1560 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1561 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
1562 | } | |
1563 | ||
d8dc74f2 AB |
1564 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
1565 | unsigned long addr) | |
1da177e4 | 1566 | { |
d3ac7f89 | 1567 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
1568 | unsigned long idx; |
1569 | ||
1570 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
1571 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
1572 | } | |
1573 | #endif | |
1574 | ||
1575 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
1576 | { | |
d3ac7f89 | 1577 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
1578 | struct shmem_inode_info *info = SHMEM_I(inode); |
1579 | int retval = -ENOMEM; | |
1580 | ||
1581 | spin_lock(&info->lock); | |
1582 | if (lock && !(info->flags & VM_LOCKED)) { | |
1583 | if (!user_shm_lock(inode->i_size, user)) | |
1584 | goto out_nomem; | |
1585 | info->flags |= VM_LOCKED; | |
89e004ea | 1586 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
1587 | } |
1588 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
1589 | user_shm_unlock(inode->i_size, user); | |
1590 | info->flags &= ~VM_LOCKED; | |
89e004ea LS |
1591 | mapping_clear_unevictable(file->f_mapping); |
1592 | scan_mapping_unevictable_pages(file->f_mapping); | |
1da177e4 LT |
1593 | } |
1594 | retval = 0; | |
89e004ea | 1595 | |
1da177e4 LT |
1596 | out_nomem: |
1597 | spin_unlock(&info->lock); | |
1598 | return retval; | |
1599 | } | |
1600 | ||
9b83a6a8 | 1601 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
1602 | { |
1603 | file_accessed(file); | |
1604 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 1605 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
1606 | return 0; |
1607 | } | |
1608 | ||
454abafe DM |
1609 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
1610 | int mode, dev_t dev, unsigned long flags) | |
1da177e4 LT |
1611 | { |
1612 | struct inode *inode; | |
1613 | struct shmem_inode_info *info; | |
1614 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
1615 | ||
5b04c689 PE |
1616 | if (shmem_reserve_inode(sb)) |
1617 | return NULL; | |
1da177e4 LT |
1618 | |
1619 | inode = new_inode(sb); | |
1620 | if (inode) { | |
85fe4025 | 1621 | inode->i_ino = get_next_ino(); |
454abafe | 1622 | inode_init_owner(inode, dir, mode); |
1da177e4 | 1623 | inode->i_blocks = 0; |
1da177e4 LT |
1624 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
1625 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 1626 | inode->i_generation = get_seconds(); |
1da177e4 LT |
1627 | info = SHMEM_I(inode); |
1628 | memset(info, 0, (char *)inode - (char *)info); | |
1629 | spin_lock_init(&info->lock); | |
0b0a0806 | 1630 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 1631 | INIT_LIST_HEAD(&info->swaplist); |
b09e0fa4 | 1632 | INIT_LIST_HEAD(&info->xattr_list); |
72c04902 | 1633 | cache_no_acl(inode); |
1da177e4 LT |
1634 | |
1635 | switch (mode & S_IFMT) { | |
1636 | default: | |
39f0247d | 1637 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
1638 | init_special_inode(inode, mode, dev); |
1639 | break; | |
1640 | case S_IFREG: | |
14fcc23f | 1641 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1642 | inode->i_op = &shmem_inode_operations; |
1643 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
1644 | mpol_shared_policy_init(&info->policy, |
1645 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
1646 | break; |
1647 | case S_IFDIR: | |
d8c76e6f | 1648 | inc_nlink(inode); |
1da177e4 LT |
1649 | /* Some things misbehave if size == 0 on a directory */ |
1650 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
1651 | inode->i_op = &shmem_dir_inode_operations; | |
1652 | inode->i_fop = &simple_dir_operations; | |
1653 | break; | |
1654 | case S_IFLNK: | |
1655 | /* | |
1656 | * Must not load anything in the rbtree, | |
1657 | * mpol_free_shared_policy will not be called. | |
1658 | */ | |
71fe804b | 1659 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
1660 | break; |
1661 | } | |
5b04c689 PE |
1662 | } else |
1663 | shmem_free_inode(sb); | |
1da177e4 LT |
1664 | return inode; |
1665 | } | |
1666 | ||
1667 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
1668 | static const struct inode_operations shmem_symlink_inode_operations; |
1669 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 LT |
1670 | |
1671 | /* | |
800d15a5 | 1672 | * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin; |
ae976416 HD |
1673 | * but providing them allows a tmpfs file to be used for splice, sendfile, and |
1674 | * below the loop driver, in the generic fashion that many filesystems support. | |
1da177e4 | 1675 | */ |
ae976416 HD |
1676 | static int shmem_readpage(struct file *file, struct page *page) |
1677 | { | |
1678 | struct inode *inode = page->mapping->host; | |
1679 | int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL); | |
1680 | unlock_page(page); | |
1681 | return error; | |
1682 | } | |
1683 | ||
1da177e4 | 1684 | static int |
800d15a5 NP |
1685 | shmem_write_begin(struct file *file, struct address_space *mapping, |
1686 | loff_t pos, unsigned len, unsigned flags, | |
1687 | struct page **pagep, void **fsdata) | |
1da177e4 | 1688 | { |
800d15a5 NP |
1689 | struct inode *inode = mapping->host; |
1690 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
1691 | *pagep = NULL; | |
1692 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); | |
1693 | } | |
1694 | ||
1695 | static int | |
1696 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1697 | loff_t pos, unsigned len, unsigned copied, | |
1698 | struct page *page, void *fsdata) | |
1699 | { | |
1700 | struct inode *inode = mapping->host; | |
1701 | ||
d3602444 HD |
1702 | if (pos + copied > inode->i_size) |
1703 | i_size_write(inode, pos + copied); | |
1704 | ||
800d15a5 | 1705 | set_page_dirty(page); |
6746aff7 | 1706 | unlock_page(page); |
800d15a5 NP |
1707 | page_cache_release(page); |
1708 | ||
800d15a5 | 1709 | return copied; |
1da177e4 LT |
1710 | } |
1711 | ||
1da177e4 LT |
1712 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1713 | { | |
d3ac7f89 | 1714 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1715 | struct address_space *mapping = inode->i_mapping; |
1716 | unsigned long index, offset; | |
a0ee5ec5 HD |
1717 | enum sgp_type sgp = SGP_READ; |
1718 | ||
1719 | /* | |
1720 | * Might this read be for a stacking filesystem? Then when reading | |
1721 | * holes of a sparse file, we actually need to allocate those pages, | |
1722 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1723 | */ | |
1724 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1725 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1726 | |
1727 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1728 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1729 | ||
1730 | for (;;) { | |
1731 | struct page *page = NULL; | |
1732 | unsigned long end_index, nr, ret; | |
1733 | loff_t i_size = i_size_read(inode); | |
1734 | ||
1735 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1736 | if (index > end_index) | |
1737 | break; | |
1738 | if (index == end_index) { | |
1739 | nr = i_size & ~PAGE_CACHE_MASK; | |
1740 | if (nr <= offset) | |
1741 | break; | |
1742 | } | |
1743 | ||
a0ee5ec5 | 1744 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1745 | if (desc->error) { |
1746 | if (desc->error == -EINVAL) | |
1747 | desc->error = 0; | |
1748 | break; | |
1749 | } | |
d3602444 HD |
1750 | if (page) |
1751 | unlock_page(page); | |
1da177e4 LT |
1752 | |
1753 | /* | |
1754 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1755 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1756 | */ |
1757 | nr = PAGE_CACHE_SIZE; | |
1758 | i_size = i_size_read(inode); | |
1759 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1760 | if (index == end_index) { | |
1761 | nr = i_size & ~PAGE_CACHE_MASK; | |
1762 | if (nr <= offset) { | |
1763 | if (page) | |
1764 | page_cache_release(page); | |
1765 | break; | |
1766 | } | |
1767 | } | |
1768 | nr -= offset; | |
1769 | ||
1770 | if (page) { | |
1771 | /* | |
1772 | * If users can be writing to this page using arbitrary | |
1773 | * virtual addresses, take care about potential aliasing | |
1774 | * before reading the page on the kernel side. | |
1775 | */ | |
1776 | if (mapping_writably_mapped(mapping)) | |
1777 | flush_dcache_page(page); | |
1778 | /* | |
1779 | * Mark the page accessed if we read the beginning. | |
1780 | */ | |
1781 | if (!offset) | |
1782 | mark_page_accessed(page); | |
b5810039 | 1783 | } else { |
1da177e4 | 1784 | page = ZERO_PAGE(0); |
b5810039 NP |
1785 | page_cache_get(page); |
1786 | } | |
1da177e4 LT |
1787 | |
1788 | /* | |
1789 | * Ok, we have the page, and it's up-to-date, so | |
1790 | * now we can copy it to user space... | |
1791 | * | |
1792 | * The actor routine returns how many bytes were actually used.. | |
1793 | * NOTE! This may not be the same as how much of a user buffer | |
1794 | * we filled up (we may be padding etc), so we can only update | |
1795 | * "pos" here (the actor routine has to update the user buffer | |
1796 | * pointers and the remaining count). | |
1797 | */ | |
1798 | ret = actor(desc, page, offset, nr); | |
1799 | offset += ret; | |
1800 | index += offset >> PAGE_CACHE_SHIFT; | |
1801 | offset &= ~PAGE_CACHE_MASK; | |
1802 | ||
1803 | page_cache_release(page); | |
1804 | if (ret != nr || !desc->count) | |
1805 | break; | |
1806 | ||
1807 | cond_resched(); | |
1808 | } | |
1809 | ||
1810 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1811 | file_accessed(filp); | |
1812 | } | |
1813 | ||
bcd78e49 HD |
1814 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1815 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1816 | { | |
1817 | struct file *filp = iocb->ki_filp; | |
1818 | ssize_t retval; | |
1819 | unsigned long seg; | |
1820 | size_t count; | |
1821 | loff_t *ppos = &iocb->ki_pos; | |
1822 | ||
1823 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1824 | if (retval) | |
1825 | return retval; | |
1826 | ||
1827 | for (seg = 0; seg < nr_segs; seg++) { | |
1828 | read_descriptor_t desc; | |
1829 | ||
1830 | desc.written = 0; | |
1831 | desc.arg.buf = iov[seg].iov_base; | |
1832 | desc.count = iov[seg].iov_len; | |
1833 | if (desc.count == 0) | |
1834 | continue; | |
1835 | desc.error = 0; | |
1836 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1837 | retval += desc.written; | |
1838 | if (desc.error) { | |
1839 | retval = retval ?: desc.error; | |
1840 | break; | |
1841 | } | |
1842 | if (desc.count > 0) | |
1843 | break; | |
1844 | } | |
1845 | return retval; | |
1da177e4 LT |
1846 | } |
1847 | ||
726c3342 | 1848 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1849 | { |
726c3342 | 1850 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1851 | |
1852 | buf->f_type = TMPFS_MAGIC; | |
1853 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1854 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1855 | if (sbinfo->max_blocks) { |
1da177e4 | 1856 | buf->f_blocks = sbinfo->max_blocks; |
7e496299 TC |
1857 | buf->f_bavail = buf->f_bfree = |
1858 | sbinfo->max_blocks - percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1859 | } |
1860 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1861 | buf->f_files = sbinfo->max_inodes; |
1862 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1863 | } |
1864 | /* else leave those fields 0 like simple_statfs */ | |
1865 | return 0; | |
1866 | } | |
1867 | ||
1868 | /* | |
1869 | * File creation. Allocate an inode, and we're done.. | |
1870 | */ | |
1871 | static int | |
1872 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1873 | { | |
0b0a0806 | 1874 | struct inode *inode; |
1da177e4 LT |
1875 | int error = -ENOSPC; |
1876 | ||
454abafe | 1877 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1878 | if (inode) { |
2a7dba39 EP |
1879 | error = security_inode_init_security(inode, dir, |
1880 | &dentry->d_name, NULL, | |
1881 | NULL, NULL); | |
570bc1c2 SS |
1882 | if (error) { |
1883 | if (error != -EOPNOTSUPP) { | |
1884 | iput(inode); | |
1885 | return error; | |
1886 | } | |
39f0247d | 1887 | } |
1c7c474c CH |
1888 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1889 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1890 | if (error) { |
1891 | iput(inode); | |
1892 | return error; | |
570bc1c2 | 1893 | } |
718deb6b AV |
1894 | #else |
1895 | error = 0; | |
1c7c474c | 1896 | #endif |
1da177e4 LT |
1897 | dir->i_size += BOGO_DIRENT_SIZE; |
1898 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1899 | d_instantiate(dentry, inode); | |
1900 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1901 | } |
1902 | return error; | |
1903 | } | |
1904 | ||
1905 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1906 | { | |
1907 | int error; | |
1908 | ||
1909 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1910 | return error; | |
d8c76e6f | 1911 | inc_nlink(dir); |
1da177e4 LT |
1912 | return 0; |
1913 | } | |
1914 | ||
1915 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1916 | struct nameidata *nd) | |
1917 | { | |
1918 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1919 | } | |
1920 | ||
1921 | /* | |
1922 | * Link a file.. | |
1923 | */ | |
1924 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1925 | { | |
1926 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1927 | int ret; |
1da177e4 LT |
1928 | |
1929 | /* | |
1930 | * No ordinary (disk based) filesystem counts links as inodes; | |
1931 | * but each new link needs a new dentry, pinning lowmem, and | |
1932 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1933 | */ | |
5b04c689 PE |
1934 | ret = shmem_reserve_inode(inode->i_sb); |
1935 | if (ret) | |
1936 | goto out; | |
1da177e4 LT |
1937 | |
1938 | dir->i_size += BOGO_DIRENT_SIZE; | |
1939 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1940 | inc_nlink(inode); |
7de9c6ee | 1941 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1942 | dget(dentry); /* Extra pinning count for the created dentry */ |
1943 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1944 | out: |
1945 | return ret; | |
1da177e4 LT |
1946 | } |
1947 | ||
1948 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1949 | { | |
1950 | struct inode *inode = dentry->d_inode; | |
1951 | ||
5b04c689 PE |
1952 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1953 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1954 | |
1955 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1956 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1957 | drop_nlink(inode); |
1da177e4 LT |
1958 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1959 | return 0; | |
1960 | } | |
1961 | ||
1962 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1963 | { | |
1964 | if (!simple_empty(dentry)) | |
1965 | return -ENOTEMPTY; | |
1966 | ||
9a53c3a7 DH |
1967 | drop_nlink(dentry->d_inode); |
1968 | drop_nlink(dir); | |
1da177e4 LT |
1969 | return shmem_unlink(dir, dentry); |
1970 | } | |
1971 | ||
1972 | /* | |
1973 | * The VFS layer already does all the dentry stuff for rename, | |
1974 | * we just have to decrement the usage count for the target if | |
1975 | * it exists so that the VFS layer correctly free's it when it | |
1976 | * gets overwritten. | |
1977 | */ | |
1978 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1979 | { | |
1980 | struct inode *inode = old_dentry->d_inode; | |
1981 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1982 | ||
1983 | if (!simple_empty(new_dentry)) | |
1984 | return -ENOTEMPTY; | |
1985 | ||
1986 | if (new_dentry->d_inode) { | |
1987 | (void) shmem_unlink(new_dir, new_dentry); | |
1988 | if (they_are_dirs) | |
9a53c3a7 | 1989 | drop_nlink(old_dir); |
1da177e4 | 1990 | } else if (they_are_dirs) { |
9a53c3a7 | 1991 | drop_nlink(old_dir); |
d8c76e6f | 1992 | inc_nlink(new_dir); |
1da177e4 LT |
1993 | } |
1994 | ||
1995 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1996 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1997 | old_dir->i_ctime = old_dir->i_mtime = | |
1998 | new_dir->i_ctime = new_dir->i_mtime = | |
1999 | inode->i_ctime = CURRENT_TIME; | |
2000 | return 0; | |
2001 | } | |
2002 | ||
2003 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
2004 | { | |
2005 | int error; | |
2006 | int len; | |
2007 | struct inode *inode; | |
2008 | struct page *page = NULL; | |
2009 | char *kaddr; | |
2010 | struct shmem_inode_info *info; | |
2011 | ||
2012 | len = strlen(symname) + 1; | |
2013 | if (len > PAGE_CACHE_SIZE) | |
2014 | return -ENAMETOOLONG; | |
2015 | ||
454abafe | 2016 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
2017 | if (!inode) |
2018 | return -ENOSPC; | |
2019 | ||
2a7dba39 EP |
2020 | error = security_inode_init_security(inode, dir, &dentry->d_name, NULL, |
2021 | NULL, NULL); | |
570bc1c2 SS |
2022 | if (error) { |
2023 | if (error != -EOPNOTSUPP) { | |
2024 | iput(inode); | |
2025 | return error; | |
2026 | } | |
2027 | error = 0; | |
2028 | } | |
2029 | ||
1da177e4 LT |
2030 | info = SHMEM_I(inode); |
2031 | inode->i_size = len-1; | |
b09e0fa4 | 2032 | if (len <= SHMEM_SYMLINK_INLINE_LEN) { |
1da177e4 | 2033 | /* do it inline */ |
b09e0fa4 | 2034 | memcpy(info->inline_symlink, symname, len); |
1da177e4 LT |
2035 | inode->i_op = &shmem_symlink_inline_operations; |
2036 | } else { | |
2037 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
2038 | if (error) { | |
2039 | iput(inode); | |
2040 | return error; | |
2041 | } | |
14fcc23f | 2042 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
2043 | inode->i_op = &shmem_symlink_inode_operations; |
2044 | kaddr = kmap_atomic(page, KM_USER0); | |
2045 | memcpy(kaddr, symname, len); | |
2046 | kunmap_atomic(kaddr, KM_USER0); | |
2047 | set_page_dirty(page); | |
6746aff7 | 2048 | unlock_page(page); |
1da177e4 LT |
2049 | page_cache_release(page); |
2050 | } | |
1da177e4 LT |
2051 | dir->i_size += BOGO_DIRENT_SIZE; |
2052 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
2053 | d_instantiate(dentry, inode); | |
2054 | dget(dentry); | |
2055 | return 0; | |
2056 | } | |
2057 | ||
cc314eef | 2058 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 2059 | { |
b09e0fa4 | 2060 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink); |
cc314eef | 2061 | return NULL; |
1da177e4 LT |
2062 | } |
2063 | ||
cc314eef | 2064 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
2065 | { |
2066 | struct page *page = NULL; | |
2067 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
2068 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
2069 | if (page) |
2070 | unlock_page(page); | |
cc314eef | 2071 | return page; |
1da177e4 LT |
2072 | } |
2073 | ||
cc314eef | 2074 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
2075 | { |
2076 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 2077 | struct page *page = cookie; |
1da177e4 LT |
2078 | kunmap(page); |
2079 | mark_page_accessed(page); | |
2080 | page_cache_release(page); | |
1da177e4 LT |
2081 | } |
2082 | } | |
2083 | ||
b09e0fa4 | 2084 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 2085 | /* |
b09e0fa4 EP |
2086 | * Superblocks without xattr inode operations may get some security.* xattr |
2087 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
2088 | * like ACLs, we also need to implement the security.* handlers at |
2089 | * filesystem level, though. | |
2090 | */ | |
2091 | ||
b09e0fa4 EP |
2092 | static int shmem_xattr_get(struct dentry *dentry, const char *name, |
2093 | void *buffer, size_t size) | |
39f0247d | 2094 | { |
b09e0fa4 EP |
2095 | struct shmem_inode_info *info; |
2096 | struct shmem_xattr *xattr; | |
2097 | int ret = -ENODATA; | |
39f0247d | 2098 | |
b09e0fa4 EP |
2099 | info = SHMEM_I(dentry->d_inode); |
2100 | ||
2101 | spin_lock(&info->lock); | |
2102 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
2103 | if (strcmp(name, xattr->name)) | |
2104 | continue; | |
2105 | ||
2106 | ret = xattr->size; | |
2107 | if (buffer) { | |
2108 | if (size < xattr->size) | |
2109 | ret = -ERANGE; | |
2110 | else | |
2111 | memcpy(buffer, xattr->value, xattr->size); | |
2112 | } | |
2113 | break; | |
2114 | } | |
2115 | spin_unlock(&info->lock); | |
2116 | return ret; | |
39f0247d AG |
2117 | } |
2118 | ||
b09e0fa4 EP |
2119 | static int shmem_xattr_set(struct dentry *dentry, const char *name, |
2120 | const void *value, size_t size, int flags) | |
39f0247d | 2121 | { |
b09e0fa4 EP |
2122 | struct inode *inode = dentry->d_inode; |
2123 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2124 | struct shmem_xattr *xattr; | |
2125 | struct shmem_xattr *new_xattr = NULL; | |
2126 | size_t len; | |
2127 | int err = 0; | |
2128 | ||
2129 | /* value == NULL means remove */ | |
2130 | if (value) { | |
2131 | /* wrap around? */ | |
2132 | len = sizeof(*new_xattr) + size; | |
2133 | if (len <= sizeof(*new_xattr)) | |
2134 | return -ENOMEM; | |
2135 | ||
2136 | new_xattr = kmalloc(len, GFP_KERNEL); | |
2137 | if (!new_xattr) | |
2138 | return -ENOMEM; | |
2139 | ||
2140 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
2141 | if (!new_xattr->name) { | |
2142 | kfree(new_xattr); | |
2143 | return -ENOMEM; | |
2144 | } | |
2145 | ||
2146 | new_xattr->size = size; | |
2147 | memcpy(new_xattr->value, value, size); | |
2148 | } | |
2149 | ||
2150 | spin_lock(&info->lock); | |
2151 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
2152 | if (!strcmp(name, xattr->name)) { | |
2153 | if (flags & XATTR_CREATE) { | |
2154 | xattr = new_xattr; | |
2155 | err = -EEXIST; | |
2156 | } else if (new_xattr) { | |
2157 | list_replace(&xattr->list, &new_xattr->list); | |
2158 | } else { | |
2159 | list_del(&xattr->list); | |
2160 | } | |
2161 | goto out; | |
2162 | } | |
2163 | } | |
2164 | if (flags & XATTR_REPLACE) { | |
2165 | xattr = new_xattr; | |
2166 | err = -ENODATA; | |
2167 | } else { | |
2168 | list_add(&new_xattr->list, &info->xattr_list); | |
2169 | xattr = NULL; | |
2170 | } | |
2171 | out: | |
2172 | spin_unlock(&info->lock); | |
2173 | if (xattr) | |
2174 | kfree(xattr->name); | |
2175 | kfree(xattr); | |
2176 | return err; | |
39f0247d AG |
2177 | } |
2178 | ||
39f0247d | 2179 | |
bb435453 | 2180 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 2181 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1c7c474c CH |
2182 | &generic_acl_access_handler, |
2183 | &generic_acl_default_handler, | |
b09e0fa4 | 2184 | #endif |
39f0247d AG |
2185 | NULL |
2186 | }; | |
b09e0fa4 EP |
2187 | |
2188 | static int shmem_xattr_validate(const char *name) | |
2189 | { | |
2190 | struct { const char *prefix; size_t len; } arr[] = { | |
2191 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
2192 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
2193 | }; | |
2194 | int i; | |
2195 | ||
2196 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
2197 | size_t preflen = arr[i].len; | |
2198 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
2199 | if (!name[preflen]) | |
2200 | return -EINVAL; | |
2201 | return 0; | |
2202 | } | |
2203 | } | |
2204 | return -EOPNOTSUPP; | |
2205 | } | |
2206 | ||
2207 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
2208 | void *buffer, size_t size) | |
2209 | { | |
2210 | int err; | |
2211 | ||
2212 | /* | |
2213 | * If this is a request for a synthetic attribute in the system.* | |
2214 | * namespace use the generic infrastructure to resolve a handler | |
2215 | * for it via sb->s_xattr. | |
2216 | */ | |
2217 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2218 | return generic_getxattr(dentry, name, buffer, size); | |
2219 | ||
2220 | err = shmem_xattr_validate(name); | |
2221 | if (err) | |
2222 | return err; | |
2223 | ||
2224 | return shmem_xattr_get(dentry, name, buffer, size); | |
2225 | } | |
2226 | ||
2227 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
2228 | const void *value, size_t size, int flags) | |
2229 | { | |
2230 | int err; | |
2231 | ||
2232 | /* | |
2233 | * If this is a request for a synthetic attribute in the system.* | |
2234 | * namespace use the generic infrastructure to resolve a handler | |
2235 | * for it via sb->s_xattr. | |
2236 | */ | |
2237 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2238 | return generic_setxattr(dentry, name, value, size, flags); | |
2239 | ||
2240 | err = shmem_xattr_validate(name); | |
2241 | if (err) | |
2242 | return err; | |
2243 | ||
2244 | if (size == 0) | |
2245 | value = ""; /* empty EA, do not remove */ | |
2246 | ||
2247 | return shmem_xattr_set(dentry, name, value, size, flags); | |
2248 | ||
2249 | } | |
2250 | ||
2251 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
2252 | { | |
2253 | int err; | |
2254 | ||
2255 | /* | |
2256 | * If this is a request for a synthetic attribute in the system.* | |
2257 | * namespace use the generic infrastructure to resolve a handler | |
2258 | * for it via sb->s_xattr. | |
2259 | */ | |
2260 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
2261 | return generic_removexattr(dentry, name); | |
2262 | ||
2263 | err = shmem_xattr_validate(name); | |
2264 | if (err) | |
2265 | return err; | |
2266 | ||
2267 | return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE); | |
2268 | } | |
2269 | ||
2270 | static bool xattr_is_trusted(const char *name) | |
2271 | { | |
2272 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
2273 | } | |
2274 | ||
2275 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
2276 | { | |
2277 | bool trusted = capable(CAP_SYS_ADMIN); | |
2278 | struct shmem_xattr *xattr; | |
2279 | struct shmem_inode_info *info; | |
2280 | size_t used = 0; | |
2281 | ||
2282 | info = SHMEM_I(dentry->d_inode); | |
2283 | ||
2284 | spin_lock(&info->lock); | |
2285 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
2286 | size_t len; | |
2287 | ||
2288 | /* skip "trusted." attributes for unprivileged callers */ | |
2289 | if (!trusted && xattr_is_trusted(xattr->name)) | |
2290 | continue; | |
2291 | ||
2292 | len = strlen(xattr->name) + 1; | |
2293 | used += len; | |
2294 | if (buffer) { | |
2295 | if (size < used) { | |
2296 | used = -ERANGE; | |
2297 | break; | |
2298 | } | |
2299 | memcpy(buffer, xattr->name, len); | |
2300 | buffer += len; | |
2301 | } | |
2302 | } | |
2303 | spin_unlock(&info->lock); | |
2304 | ||
2305 | return used; | |
2306 | } | |
2307 | #endif /* CONFIG_TMPFS_XATTR */ | |
2308 | ||
2309 | static const struct inode_operations shmem_symlink_inline_operations = { | |
2310 | .readlink = generic_readlink, | |
2311 | .follow_link = shmem_follow_link_inline, | |
2312 | #ifdef CONFIG_TMPFS_XATTR | |
2313 | .setxattr = shmem_setxattr, | |
2314 | .getxattr = shmem_getxattr, | |
2315 | .listxattr = shmem_listxattr, | |
2316 | .removexattr = shmem_removexattr, | |
2317 | #endif | |
2318 | }; | |
2319 | ||
2320 | static const struct inode_operations shmem_symlink_inode_operations = { | |
2321 | .readlink = generic_readlink, | |
2322 | .follow_link = shmem_follow_link, | |
2323 | .put_link = shmem_put_link, | |
2324 | #ifdef CONFIG_TMPFS_XATTR | |
2325 | .setxattr = shmem_setxattr, | |
2326 | .getxattr = shmem_getxattr, | |
2327 | .listxattr = shmem_listxattr, | |
2328 | .removexattr = shmem_removexattr, | |
39f0247d | 2329 | #endif |
b09e0fa4 | 2330 | }; |
39f0247d | 2331 | |
91828a40 DG |
2332 | static struct dentry *shmem_get_parent(struct dentry *child) |
2333 | { | |
2334 | return ERR_PTR(-ESTALE); | |
2335 | } | |
2336 | ||
2337 | static int shmem_match(struct inode *ino, void *vfh) | |
2338 | { | |
2339 | __u32 *fh = vfh; | |
2340 | __u64 inum = fh[2]; | |
2341 | inum = (inum << 32) | fh[1]; | |
2342 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
2343 | } | |
2344 | ||
480b116c CH |
2345 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
2346 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 2347 | { |
91828a40 | 2348 | struct inode *inode; |
480b116c CH |
2349 | struct dentry *dentry = NULL; |
2350 | u64 inum = fid->raw[2]; | |
2351 | inum = (inum << 32) | fid->raw[1]; | |
2352 | ||
2353 | if (fh_len < 3) | |
2354 | return NULL; | |
91828a40 | 2355 | |
480b116c CH |
2356 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
2357 | shmem_match, fid->raw); | |
91828a40 | 2358 | if (inode) { |
480b116c | 2359 | dentry = d_find_alias(inode); |
91828a40 DG |
2360 | iput(inode); |
2361 | } | |
2362 | ||
480b116c | 2363 | return dentry; |
91828a40 DG |
2364 | } |
2365 | ||
2366 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
2367 | int connectable) | |
2368 | { | |
2369 | struct inode *inode = dentry->d_inode; | |
2370 | ||
5fe0c237 AK |
2371 | if (*len < 3) { |
2372 | *len = 3; | |
91828a40 | 2373 | return 255; |
5fe0c237 | 2374 | } |
91828a40 | 2375 | |
1d3382cb | 2376 | if (inode_unhashed(inode)) { |
91828a40 DG |
2377 | /* Unfortunately insert_inode_hash is not idempotent, |
2378 | * so as we hash inodes here rather than at creation | |
2379 | * time, we need a lock to ensure we only try | |
2380 | * to do it once | |
2381 | */ | |
2382 | static DEFINE_SPINLOCK(lock); | |
2383 | spin_lock(&lock); | |
1d3382cb | 2384 | if (inode_unhashed(inode)) |
91828a40 DG |
2385 | __insert_inode_hash(inode, |
2386 | inode->i_ino + inode->i_generation); | |
2387 | spin_unlock(&lock); | |
2388 | } | |
2389 | ||
2390 | fh[0] = inode->i_generation; | |
2391 | fh[1] = inode->i_ino; | |
2392 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
2393 | ||
2394 | *len = 3; | |
2395 | return 1; | |
2396 | } | |
2397 | ||
39655164 | 2398 | static const struct export_operations shmem_export_ops = { |
91828a40 | 2399 | .get_parent = shmem_get_parent, |
91828a40 | 2400 | .encode_fh = shmem_encode_fh, |
480b116c | 2401 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
2402 | }; |
2403 | ||
680d794b | 2404 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
2405 | bool remount) | |
1da177e4 LT |
2406 | { |
2407 | char *this_char, *value, *rest; | |
2408 | ||
b00dc3ad HD |
2409 | while (options != NULL) { |
2410 | this_char = options; | |
2411 | for (;;) { | |
2412 | /* | |
2413 | * NUL-terminate this option: unfortunately, | |
2414 | * mount options form a comma-separated list, | |
2415 | * but mpol's nodelist may also contain commas. | |
2416 | */ | |
2417 | options = strchr(options, ','); | |
2418 | if (options == NULL) | |
2419 | break; | |
2420 | options++; | |
2421 | if (!isdigit(*options)) { | |
2422 | options[-1] = '\0'; | |
2423 | break; | |
2424 | } | |
2425 | } | |
1da177e4 LT |
2426 | if (!*this_char) |
2427 | continue; | |
2428 | if ((value = strchr(this_char,'=')) != NULL) { | |
2429 | *value++ = 0; | |
2430 | } else { | |
2431 | printk(KERN_ERR | |
2432 | "tmpfs: No value for mount option '%s'\n", | |
2433 | this_char); | |
2434 | return 1; | |
2435 | } | |
2436 | ||
2437 | if (!strcmp(this_char,"size")) { | |
2438 | unsigned long long size; | |
2439 | size = memparse(value,&rest); | |
2440 | if (*rest == '%') { | |
2441 | size <<= PAGE_SHIFT; | |
2442 | size *= totalram_pages; | |
2443 | do_div(size, 100); | |
2444 | rest++; | |
2445 | } | |
2446 | if (*rest) | |
2447 | goto bad_val; | |
680d794b | 2448 | sbinfo->max_blocks = |
2449 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 2450 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 2451 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
2452 | if (*rest) |
2453 | goto bad_val; | |
2454 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 2455 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
2456 | if (*rest) |
2457 | goto bad_val; | |
2458 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 2459 | if (remount) |
1da177e4 | 2460 | continue; |
680d794b | 2461 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
2462 | if (*rest) |
2463 | goto bad_val; | |
2464 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 2465 | if (remount) |
1da177e4 | 2466 | continue; |
680d794b | 2467 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2468 | if (*rest) |
2469 | goto bad_val; | |
2470 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 2471 | if (remount) |
1da177e4 | 2472 | continue; |
680d794b | 2473 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
2474 | if (*rest) |
2475 | goto bad_val; | |
7339ff83 | 2476 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 2477 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 2478 | goto bad_val; |
1da177e4 LT |
2479 | } else { |
2480 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
2481 | this_char); | |
2482 | return 1; | |
2483 | } | |
2484 | } | |
2485 | return 0; | |
2486 | ||
2487 | bad_val: | |
2488 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
2489 | value, this_char); | |
2490 | return 1; | |
2491 | ||
2492 | } | |
2493 | ||
2494 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
2495 | { | |
2496 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 2497 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
2498 | unsigned long inodes; |
2499 | int error = -EINVAL; | |
2500 | ||
680d794b | 2501 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 2502 | return error; |
1da177e4 | 2503 | |
0edd73b3 | 2504 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 2505 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 2506 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 2507 | goto out; |
680d794b | 2508 | if (config.max_inodes < inodes) |
0edd73b3 HD |
2509 | goto out; |
2510 | /* | |
2511 | * Those tests also disallow limited->unlimited while any are in | |
2512 | * use, so i_blocks will always be zero when max_blocks is zero; | |
2513 | * but we must separately disallow unlimited->limited, because | |
2514 | * in that case we have no record of how much is already in use. | |
2515 | */ | |
680d794b | 2516 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 2517 | goto out; |
680d794b | 2518 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
2519 | goto out; |
2520 | ||
2521 | error = 0; | |
680d794b | 2522 | sbinfo->max_blocks = config.max_blocks; |
680d794b | 2523 | sbinfo->max_inodes = config.max_inodes; |
2524 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
2525 | |
2526 | mpol_put(sbinfo->mpol); | |
2527 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
2528 | out: |
2529 | spin_unlock(&sbinfo->stat_lock); | |
2530 | return error; | |
1da177e4 | 2531 | } |
680d794b | 2532 | |
2533 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
2534 | { | |
2535 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
2536 | ||
2537 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
2538 | seq_printf(seq, ",size=%luk", | |
2539 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
2540 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
2541 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
2542 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
2543 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
2544 | if (sbinfo->uid != 0) | |
2545 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
2546 | if (sbinfo->gid != 0) | |
2547 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 2548 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b | 2549 | return 0; |
2550 | } | |
2551 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
2552 | |
2553 | static void shmem_put_super(struct super_block *sb) | |
2554 | { | |
602586a8 HD |
2555 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
2556 | ||
2557 | percpu_counter_destroy(&sbinfo->used_blocks); | |
2558 | kfree(sbinfo); | |
1da177e4 LT |
2559 | sb->s_fs_info = NULL; |
2560 | } | |
2561 | ||
2b2af54a | 2562 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
2563 | { |
2564 | struct inode *inode; | |
2565 | struct dentry *root; | |
0edd73b3 | 2566 | struct shmem_sb_info *sbinfo; |
680d794b | 2567 | int err = -ENOMEM; |
2568 | ||
2569 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 2570 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b | 2571 | L1_CACHE_BYTES), GFP_KERNEL); |
2572 | if (!sbinfo) | |
2573 | return -ENOMEM; | |
2574 | ||
680d794b | 2575 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
2576 | sbinfo->uid = current_fsuid(); |
2577 | sbinfo->gid = current_fsgid(); | |
680d794b | 2578 | sb->s_fs_info = sbinfo; |
1da177e4 | 2579 | |
0edd73b3 | 2580 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
2581 | /* |
2582 | * Per default we only allow half of the physical ram per | |
2583 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2584 | * but the internal instance is left unlimited. | |
2585 | */ | |
2586 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b | 2587 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2588 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2589 | if (shmem_parse_options(data, sbinfo, false)) { | |
2590 | err = -EINVAL; | |
2591 | goto failed; | |
2592 | } | |
1da177e4 | 2593 | } |
91828a40 | 2594 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2595 | #else |
2596 | sb->s_flags |= MS_NOUSER; | |
2597 | #endif | |
2598 | ||
0edd73b3 | 2599 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2600 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2601 | goto failed; | |
680d794b | 2602 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2603 | |
1da177e4 LT |
2604 | sb->s_maxbytes = SHMEM_MAX_BYTES; |
2605 | sb->s_blocksize = PAGE_CACHE_SIZE; | |
2606 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2607 | sb->s_magic = TMPFS_MAGIC; | |
2608 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2609 | sb->s_time_gran = 1; |
b09e0fa4 | 2610 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2611 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2612 | #endif |
2613 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2614 | sb->s_flags |= MS_POSIXACL; |
2615 | #endif | |
0edd73b3 | 2616 | |
454abafe | 2617 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2618 | if (!inode) |
2619 | goto failed; | |
680d794b | 2620 | inode->i_uid = sbinfo->uid; |
2621 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2622 | root = d_alloc_root(inode); |
2623 | if (!root) | |
2624 | goto failed_iput; | |
2625 | sb->s_root = root; | |
2626 | return 0; | |
2627 | ||
2628 | failed_iput: | |
2629 | iput(inode); | |
2630 | failed: | |
2631 | shmem_put_super(sb); | |
2632 | return err; | |
2633 | } | |
2634 | ||
fcc234f8 | 2635 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2636 | |
2637 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2638 | { | |
2639 | struct shmem_inode_info *p; | |
e94b1766 | 2640 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2641 | if (!p) |
2642 | return NULL; | |
2643 | return &p->vfs_inode; | |
2644 | } | |
2645 | ||
fa0d7e3d NP |
2646 | static void shmem_i_callback(struct rcu_head *head) |
2647 | { | |
2648 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
2649 | INIT_LIST_HEAD(&inode->i_dentry); | |
2650 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2651 | } | |
2652 | ||
1da177e4 LT |
2653 | static void shmem_destroy_inode(struct inode *inode) |
2654 | { | |
2655 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2656 | /* only struct inode is valid if it's an inline symlink */ | |
2657 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2658 | } | |
fa0d7e3d | 2659 | call_rcu(&inode->i_rcu, shmem_i_callback); |
1da177e4 LT |
2660 | } |
2661 | ||
51cc5068 | 2662 | static void init_once(void *foo) |
1da177e4 LT |
2663 | { |
2664 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2665 | ||
a35afb83 | 2666 | inode_init_once(&p->vfs_inode); |
1da177e4 LT |
2667 | } |
2668 | ||
2669 | static int init_inodecache(void) | |
2670 | { | |
2671 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2672 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2673 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2674 | return 0; |
2675 | } | |
2676 | ||
2677 | static void destroy_inodecache(void) | |
2678 | { | |
1a1d92c1 | 2679 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2680 | } |
2681 | ||
f5e54d6e | 2682 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2683 | .writepage = shmem_writepage, |
76719325 | 2684 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2685 | #ifdef CONFIG_TMPFS |
ae976416 | 2686 | .readpage = shmem_readpage, |
800d15a5 NP |
2687 | .write_begin = shmem_write_begin, |
2688 | .write_end = shmem_write_end, | |
1da177e4 | 2689 | #endif |
304dbdb7 | 2690 | .migratepage = migrate_page, |
aa261f54 | 2691 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2692 | }; |
2693 | ||
15ad7cdc | 2694 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2695 | .mmap = shmem_mmap, |
2696 | #ifdef CONFIG_TMPFS | |
2697 | .llseek = generic_file_llseek, | |
bcd78e49 | 2698 | .read = do_sync_read, |
5402b976 | 2699 | .write = do_sync_write, |
bcd78e49 | 2700 | .aio_read = shmem_file_aio_read, |
5402b976 | 2701 | .aio_write = generic_file_aio_write, |
1b061d92 | 2702 | .fsync = noop_fsync, |
ae976416 HD |
2703 | .splice_read = generic_file_splice_read, |
2704 | .splice_write = generic_file_splice_write, | |
1da177e4 LT |
2705 | #endif |
2706 | }; | |
2707 | ||
92e1d5be | 2708 | static const struct inode_operations shmem_inode_operations = { |
1da177e4 | 2709 | .setattr = shmem_notify_change, |
f6b3ec23 | 2710 | .truncate_range = shmem_truncate_range, |
b09e0fa4 EP |
2711 | #ifdef CONFIG_TMPFS_XATTR |
2712 | .setxattr = shmem_setxattr, | |
2713 | .getxattr = shmem_getxattr, | |
2714 | .listxattr = shmem_listxattr, | |
2715 | .removexattr = shmem_removexattr, | |
2716 | #endif | |
39f0247d | 2717 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1c7c474c | 2718 | .check_acl = generic_check_acl, |
39f0247d AG |
2719 | #endif |
2720 | ||
1da177e4 LT |
2721 | }; |
2722 | ||
92e1d5be | 2723 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2724 | #ifdef CONFIG_TMPFS |
2725 | .create = shmem_create, | |
2726 | .lookup = simple_lookup, | |
2727 | .link = shmem_link, | |
2728 | .unlink = shmem_unlink, | |
2729 | .symlink = shmem_symlink, | |
2730 | .mkdir = shmem_mkdir, | |
2731 | .rmdir = shmem_rmdir, | |
2732 | .mknod = shmem_mknod, | |
2733 | .rename = shmem_rename, | |
1da177e4 | 2734 | #endif |
b09e0fa4 EP |
2735 | #ifdef CONFIG_TMPFS_XATTR |
2736 | .setxattr = shmem_setxattr, | |
2737 | .getxattr = shmem_getxattr, | |
2738 | .listxattr = shmem_listxattr, | |
2739 | .removexattr = shmem_removexattr, | |
2740 | #endif | |
39f0247d AG |
2741 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2742 | .setattr = shmem_notify_change, | |
1c7c474c | 2743 | .check_acl = generic_check_acl, |
39f0247d AG |
2744 | #endif |
2745 | }; | |
2746 | ||
92e1d5be | 2747 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2748 | #ifdef CONFIG_TMPFS_XATTR |
2749 | .setxattr = shmem_setxattr, | |
2750 | .getxattr = shmem_getxattr, | |
2751 | .listxattr = shmem_listxattr, | |
2752 | .removexattr = shmem_removexattr, | |
2753 | #endif | |
39f0247d AG |
2754 | #ifdef CONFIG_TMPFS_POSIX_ACL |
2755 | .setattr = shmem_notify_change, | |
1c7c474c | 2756 | .check_acl = generic_check_acl, |
39f0247d | 2757 | #endif |
1da177e4 LT |
2758 | }; |
2759 | ||
759b9775 | 2760 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2761 | .alloc_inode = shmem_alloc_inode, |
2762 | .destroy_inode = shmem_destroy_inode, | |
2763 | #ifdef CONFIG_TMPFS | |
2764 | .statfs = shmem_statfs, | |
2765 | .remount_fs = shmem_remount_fs, | |
680d794b | 2766 | .show_options = shmem_show_options, |
1da177e4 | 2767 | #endif |
1f895f75 | 2768 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2769 | .drop_inode = generic_delete_inode, |
2770 | .put_super = shmem_put_super, | |
2771 | }; | |
2772 | ||
f0f37e2f | 2773 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2774 | .fault = shmem_fault, |
1da177e4 LT |
2775 | #ifdef CONFIG_NUMA |
2776 | .set_policy = shmem_set_policy, | |
2777 | .get_policy = shmem_get_policy, | |
2778 | #endif | |
2779 | }; | |
2780 | ||
2781 | ||
3c26ff6e AV |
2782 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2783 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2784 | { |
3c26ff6e | 2785 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2786 | } |
2787 | ||
2788 | static struct file_system_type tmpfs_fs_type = { | |
2789 | .owner = THIS_MODULE, | |
2790 | .name = "tmpfs", | |
3c26ff6e | 2791 | .mount = shmem_mount, |
1da177e4 LT |
2792 | .kill_sb = kill_litter_super, |
2793 | }; | |
1da177e4 | 2794 | |
2b2af54a | 2795 | int __init init_tmpfs(void) |
1da177e4 LT |
2796 | { |
2797 | int error; | |
2798 | ||
e0bf68dd PZ |
2799 | error = bdi_init(&shmem_backing_dev_info); |
2800 | if (error) | |
2801 | goto out4; | |
2802 | ||
1da177e4 LT |
2803 | error = init_inodecache(); |
2804 | if (error) | |
2805 | goto out3; | |
2806 | ||
2807 | error = register_filesystem(&tmpfs_fs_type); | |
2808 | if (error) { | |
2809 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2810 | goto out2; | |
2811 | } | |
95dc112a | 2812 | |
1f5ce9e9 | 2813 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2814 | tmpfs_fs_type.name, NULL); |
2815 | if (IS_ERR(shm_mnt)) { | |
2816 | error = PTR_ERR(shm_mnt); | |
2817 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2818 | goto out1; | |
2819 | } | |
2820 | return 0; | |
2821 | ||
2822 | out1: | |
2823 | unregister_filesystem(&tmpfs_fs_type); | |
2824 | out2: | |
2825 | destroy_inodecache(); | |
2826 | out3: | |
e0bf68dd PZ |
2827 | bdi_destroy(&shmem_backing_dev_info); |
2828 | out4: | |
1da177e4 LT |
2829 | shm_mnt = ERR_PTR(error); |
2830 | return error; | |
2831 | } | |
853ac43a | 2832 | |
87946a72 DN |
2833 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2834 | /** | |
2835 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2836 | * @inode: the inode to be searched | |
2837 | * @pgoff: the offset to be searched | |
2838 | * @pagep: the pointer for the found page to be stored | |
2839 | * @ent: the pointer for the found swap entry to be stored | |
2840 | * | |
2841 | * If a page is found, refcount of it is incremented. Callers should handle | |
2842 | * these refcount. | |
2843 | */ | |
2844 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2845 | struct page **pagep, swp_entry_t *ent) | |
2846 | { | |
2847 | swp_entry_t entry = { .val = 0 }, *ptr; | |
2848 | struct page *page = NULL; | |
2849 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2850 | ||
2851 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2852 | goto out; | |
2853 | ||
2854 | spin_lock(&info->lock); | |
2855 | ptr = shmem_swp_entry(info, pgoff, NULL); | |
2856 | #ifdef CONFIG_SWAP | |
2857 | if (ptr && ptr->val) { | |
2858 | entry.val = ptr->val; | |
2859 | page = find_get_page(&swapper_space, entry.val); | |
2860 | } else | |
2861 | #endif | |
2862 | page = find_get_page(inode->i_mapping, pgoff); | |
2863 | if (ptr) | |
2864 | shmem_swp_unmap(ptr); | |
2865 | spin_unlock(&info->lock); | |
2866 | out: | |
2867 | *pagep = page; | |
2868 | *ent = entry; | |
2869 | } | |
2870 | #endif | |
2871 | ||
853ac43a MM |
2872 | #else /* !CONFIG_SHMEM */ |
2873 | ||
2874 | /* | |
2875 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2876 | * | |
2877 | * This is intended for small system where the benefits of the full | |
2878 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2879 | * their complexity. On systems without swap this code should be | |
2880 | * effectively equivalent, but much lighter weight. | |
2881 | */ | |
2882 | ||
2883 | #include <linux/ramfs.h> | |
2884 | ||
2885 | static struct file_system_type tmpfs_fs_type = { | |
2886 | .name = "tmpfs", | |
3c26ff6e | 2887 | .mount = ramfs_mount, |
853ac43a MM |
2888 | .kill_sb = kill_litter_super, |
2889 | }; | |
2890 | ||
2b2af54a | 2891 | int __init init_tmpfs(void) |
853ac43a MM |
2892 | { |
2893 | BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); | |
2894 | ||
2895 | shm_mnt = kern_mount(&tmpfs_fs_type); | |
2896 | BUG_ON(IS_ERR(shm_mnt)); | |
2897 | ||
2898 | return 0; | |
2899 | } | |
2900 | ||
2901 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
2902 | { | |
2903 | return 0; | |
2904 | } | |
2905 | ||
3f96b79a HD |
2906 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2907 | { | |
2908 | return 0; | |
2909 | } | |
2910 | ||
87946a72 DN |
2911 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2912 | /** | |
2913 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2914 | * @inode: the inode to be searched | |
2915 | * @pgoff: the offset to be searched | |
2916 | * @pagep: the pointer for the found page to be stored | |
2917 | * @ent: the pointer for the found swap entry to be stored | |
2918 | * | |
2919 | * If a page is found, refcount of it is incremented. Callers should handle | |
2920 | * these refcount. | |
2921 | */ | |
2922 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2923 | struct page **pagep, swp_entry_t *ent) | |
2924 | { | |
2925 | struct page *page = NULL; | |
2926 | ||
2927 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2928 | goto out; | |
2929 | page = find_get_page(inode->i_mapping, pgoff); | |
2930 | out: | |
2931 | *pagep = page; | |
2932 | *ent = (swp_entry_t){ .val = 0 }; | |
2933 | } | |
2934 | #endif | |
2935 | ||
0b0a0806 HD |
2936 | #define shmem_vm_ops generic_file_vm_ops |
2937 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2938 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2939 | #define shmem_acct_size(flags, size) 0 |
2940 | #define shmem_unacct_size(flags, size) do {} while (0) | |
caefba17 | 2941 | #define SHMEM_MAX_BYTES MAX_LFS_FILESIZE |
853ac43a MM |
2942 | |
2943 | #endif /* CONFIG_SHMEM */ | |
2944 | ||
2945 | /* common code */ | |
1da177e4 | 2946 | |
46711810 | 2947 | /** |
1da177e4 | 2948 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2949 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2950 | * @size: size to be set for the file | |
0b0a0806 | 2951 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2952 | */ |
168f5ac6 | 2953 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2954 | { |
2955 | int error; | |
2956 | struct file *file; | |
2957 | struct inode *inode; | |
2c48b9c4 AV |
2958 | struct path path; |
2959 | struct dentry *root; | |
1da177e4 LT |
2960 | struct qstr this; |
2961 | ||
2962 | if (IS_ERR(shm_mnt)) | |
2963 | return (void *)shm_mnt; | |
2964 | ||
2965 | if (size < 0 || size > SHMEM_MAX_BYTES) | |
2966 | return ERR_PTR(-EINVAL); | |
2967 | ||
2968 | if (shmem_acct_size(flags, size)) | |
2969 | return ERR_PTR(-ENOMEM); | |
2970 | ||
2971 | error = -ENOMEM; | |
2972 | this.name = name; | |
2973 | this.len = strlen(name); | |
2974 | this.hash = 0; /* will go */ | |
2975 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2976 | path.dentry = d_alloc(root, &this); |
2977 | if (!path.dentry) | |
1da177e4 | 2978 | goto put_memory; |
2c48b9c4 | 2979 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2980 | |
1da177e4 | 2981 | error = -ENOSPC; |
454abafe | 2982 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2983 | if (!inode) |
4b42af81 | 2984 | goto put_dentry; |
1da177e4 | 2985 | |
2c48b9c4 | 2986 | d_instantiate(path.dentry, inode); |
1da177e4 LT |
2987 | inode->i_size = size; |
2988 | inode->i_nlink = 0; /* It is unlinked */ | |
853ac43a MM |
2989 | #ifndef CONFIG_MMU |
2990 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2991 | if (error) | |
4b42af81 | 2992 | goto put_dentry; |
853ac43a | 2993 | #endif |
4b42af81 AV |
2994 | |
2995 | error = -ENFILE; | |
2c48b9c4 | 2996 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2997 | &shmem_file_operations); |
2998 | if (!file) | |
2999 | goto put_dentry; | |
3000 | ||
1da177e4 LT |
3001 | return file; |
3002 | ||
1da177e4 | 3003 | put_dentry: |
2c48b9c4 | 3004 | path_put(&path); |
1da177e4 LT |
3005 | put_memory: |
3006 | shmem_unacct_size(flags, size); | |
3007 | return ERR_PTR(error); | |
3008 | } | |
395e0ddc | 3009 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 3010 | |
46711810 | 3011 | /** |
1da177e4 | 3012 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
3013 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
3014 | */ | |
3015 | int shmem_zero_setup(struct vm_area_struct *vma) | |
3016 | { | |
3017 | struct file *file; | |
3018 | loff_t size = vma->vm_end - vma->vm_start; | |
3019 | ||
3020 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
3021 | if (IS_ERR(file)) | |
3022 | return PTR_ERR(file); | |
3023 | ||
3024 | if (vma->vm_file) | |
3025 | fput(vma->vm_file); | |
3026 | vma->vm_file = file; | |
3027 | vma->vm_ops = &shmem_vm_ops; | |
bee4c36a | 3028 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
3029 | return 0; |
3030 | } |