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 | 53 | #include <linux/blkdev.h> |
708e3508 | 54 | #include <linux/splice.h> |
1da177e4 LT |
55 | #include <linux/security.h> |
56 | #include <linux/swapops.h> | |
57 | #include <linux/mempolicy.h> | |
58 | #include <linux/namei.h> | |
b00dc3ad | 59 | #include <linux/ctype.h> |
304dbdb7 | 60 | #include <linux/migrate.h> |
c1f60a5a | 61 | #include <linux/highmem.h> |
680d794b | 62 | #include <linux/seq_file.h> |
92562927 | 63 | #include <linux/magic.h> |
304dbdb7 | 64 | |
1da177e4 LT |
65 | #include <asm/uaccess.h> |
66 | #include <asm/div64.h> | |
67 | #include <asm/pgtable.h> | |
68 | ||
caefba17 | 69 | #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512) |
1da177e4 LT |
70 | #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT) |
71 | ||
1da177e4 LT |
72 | /* Pretend that each entry is of this size in directory's i_size */ |
73 | #define BOGO_DIRENT_SIZE 20 | |
74 | ||
b09e0fa4 EP |
75 | struct shmem_xattr { |
76 | struct list_head list; /* anchored by shmem_inode_info->xattr_list */ | |
77 | char *name; /* xattr name */ | |
78 | size_t size; | |
79 | char value[0]; | |
80 | }; | |
81 | ||
285b2c4f | 82 | /* Flag allocation requirements to shmem_getpage */ |
1da177e4 | 83 | enum sgp_type { |
1da177e4 LT |
84 | SGP_READ, /* don't exceed i_size, don't allocate page */ |
85 | SGP_CACHE, /* don't exceed i_size, may allocate page */ | |
a0ee5ec5 | 86 | SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */ |
1da177e4 LT |
87 | SGP_WRITE, /* may exceed i_size, may allocate page */ |
88 | }; | |
89 | ||
b76db735 | 90 | #ifdef CONFIG_TMPFS |
680d794b | 91 | static unsigned long shmem_default_max_blocks(void) |
92 | { | |
93 | return totalram_pages / 2; | |
94 | } | |
95 | ||
96 | static unsigned long shmem_default_max_inodes(void) | |
97 | { | |
98 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
99 | } | |
b76db735 | 100 | #endif |
680d794b | 101 | |
68da9f05 HD |
102 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
103 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type); | |
104 | ||
105 | static inline int shmem_getpage(struct inode *inode, pgoff_t index, | |
106 | struct page **pagep, enum sgp_type sgp, int *fault_type) | |
107 | { | |
108 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
109 | mapping_gfp_mask(inode->i_mapping), fault_type); | |
110 | } | |
1da177e4 | 111 | |
1da177e4 LT |
112 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
113 | { | |
114 | return sb->s_fs_info; | |
115 | } | |
116 | ||
117 | /* | |
118 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
119 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
120 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
121 | * consistent with the pre-accounting of private mappings ... | |
122 | */ | |
123 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
124 | { | |
0b0a0806 HD |
125 | return (flags & VM_NORESERVE) ? |
126 | 0 : security_vm_enough_memory_kern(VM_ACCT(size)); | |
1da177e4 LT |
127 | } |
128 | ||
129 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
130 | { | |
0b0a0806 | 131 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
132 | vm_unacct_memory(VM_ACCT(size)); |
133 | } | |
134 | ||
135 | /* | |
136 | * ... whereas tmpfs objects are accounted incrementally as | |
137 | * pages are allocated, in order to allow huge sparse files. | |
138 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, | |
139 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
140 | */ | |
141 | static inline int shmem_acct_block(unsigned long flags) | |
142 | { | |
0b0a0806 HD |
143 | return (flags & VM_NORESERVE) ? |
144 | security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE)) : 0; | |
1da177e4 LT |
145 | } |
146 | ||
147 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
148 | { | |
0b0a0806 | 149 | if (flags & VM_NORESERVE) |
1da177e4 LT |
150 | vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE)); |
151 | } | |
152 | ||
759b9775 | 153 | static const struct super_operations shmem_ops; |
f5e54d6e | 154 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 155 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
156 | static const struct inode_operations shmem_inode_operations; |
157 | static const struct inode_operations shmem_dir_inode_operations; | |
158 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 159 | static const struct vm_operations_struct shmem_vm_ops; |
1da177e4 | 160 | |
6c231b7b | 161 | static struct backing_dev_info shmem_backing_dev_info __read_mostly = { |
1da177e4 | 162 | .ra_pages = 0, /* No readahead */ |
4f98a2fe | 163 | .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED, |
1da177e4 LT |
164 | }; |
165 | ||
166 | static LIST_HEAD(shmem_swaplist); | |
cb5f7b9a | 167 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 LT |
168 | |
169 | static void shmem_free_blocks(struct inode *inode, long pages) | |
170 | { | |
171 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
0edd73b3 | 172 | if (sbinfo->max_blocks) { |
7e496299 | 173 | percpu_counter_add(&sbinfo->used_blocks, -pages); |
1da177e4 | 174 | inode->i_blocks -= pages*BLOCKS_PER_PAGE; |
1da177e4 LT |
175 | } |
176 | } | |
177 | ||
5b04c689 PE |
178 | static int shmem_reserve_inode(struct super_block *sb) |
179 | { | |
180 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
181 | if (sbinfo->max_inodes) { | |
182 | spin_lock(&sbinfo->stat_lock); | |
183 | if (!sbinfo->free_inodes) { | |
184 | spin_unlock(&sbinfo->stat_lock); | |
185 | return -ENOSPC; | |
186 | } | |
187 | sbinfo->free_inodes--; | |
188 | spin_unlock(&sbinfo->stat_lock); | |
189 | } | |
190 | return 0; | |
191 | } | |
192 | ||
193 | static void shmem_free_inode(struct super_block *sb) | |
194 | { | |
195 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
196 | if (sbinfo->max_inodes) { | |
197 | spin_lock(&sbinfo->stat_lock); | |
198 | sbinfo->free_inodes++; | |
199 | spin_unlock(&sbinfo->stat_lock); | |
200 | } | |
201 | } | |
202 | ||
46711810 | 203 | /** |
1da177e4 | 204 | * shmem_recalc_inode - recalculate the size of an inode |
1da177e4 LT |
205 | * @inode: inode to recalc |
206 | * | |
207 | * We have to calculate the free blocks since the mm can drop | |
208 | * undirtied hole pages behind our back. | |
209 | * | |
210 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
211 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
212 | * | |
213 | * It has to be called with the spinlock held. | |
214 | */ | |
215 | static void shmem_recalc_inode(struct inode *inode) | |
216 | { | |
217 | struct shmem_inode_info *info = SHMEM_I(inode); | |
218 | long freed; | |
219 | ||
220 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
221 | if (freed > 0) { | |
222 | info->alloced -= freed; | |
223 | shmem_unacct_blocks(info->flags, freed); | |
224 | shmem_free_blocks(inode, freed); | |
225 | } | |
226 | } | |
227 | ||
285b2c4f HD |
228 | static void shmem_put_swap(struct shmem_inode_info *info, pgoff_t index, |
229 | swp_entry_t swap) | |
1da177e4 | 230 | { |
285b2c4f HD |
231 | if (index < SHMEM_NR_DIRECT) |
232 | info->i_direct[index] = swap; | |
1da177e4 LT |
233 | } |
234 | ||
285b2c4f | 235 | static swp_entry_t shmem_get_swap(struct shmem_inode_info *info, pgoff_t index) |
1da177e4 | 236 | { |
285b2c4f HD |
237 | return (index < SHMEM_NR_DIRECT) ? |
238 | info->i_direct[index] : (swp_entry_t){0}; | |
1da177e4 LT |
239 | } |
240 | ||
285b2c4f | 241 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
1da177e4 | 242 | { |
285b2c4f | 243 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 244 | struct shmem_inode_info *info = SHMEM_I(inode); |
285b2c4f HD |
245 | pgoff_t start = (lstart + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; |
246 | pgoff_t end = (lend >> PAGE_CACHE_SHIFT); | |
247 | pgoff_t index; | |
248 | swp_entry_t swap; | |
1da177e4 | 249 | |
285b2c4f | 250 | truncate_inode_pages_range(mapping, lstart, lend); |
94c1e62d | 251 | |
285b2c4f HD |
252 | if (end > SHMEM_NR_DIRECT) |
253 | end = SHMEM_NR_DIRECT; | |
1da177e4 LT |
254 | |
255 | spin_lock(&info->lock); | |
285b2c4f HD |
256 | for (index = start; index < end; index++) { |
257 | swap = shmem_get_swap(info, index); | |
258 | if (swap.val) { | |
259 | free_swap_and_cache(swap); | |
260 | shmem_put_swap(info, index, (swp_entry_t){0}); | |
261 | info->swapped--; | |
1da177e4 LT |
262 | } |
263 | } | |
264 | ||
285b2c4f HD |
265 | if (mapping->nrpages) { |
266 | spin_unlock(&info->lock); | |
1da177e4 | 267 | /* |
285b2c4f | 268 | * A page may have meanwhile sneaked in from swap. |
1da177e4 | 269 | */ |
285b2c4f HD |
270 | truncate_inode_pages_range(mapping, lstart, lend); |
271 | spin_lock(&info->lock); | |
1da177e4 LT |
272 | } |
273 | ||
1da177e4 LT |
274 | shmem_recalc_inode(inode); |
275 | spin_unlock(&info->lock); | |
276 | ||
285b2c4f | 277 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; |
1da177e4 | 278 | } |
94c1e62d | 279 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 280 | |
94c1e62d | 281 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 LT |
282 | { |
283 | struct inode *inode = dentry->d_inode; | |
1da177e4 LT |
284 | int error; |
285 | ||
db78b877 CH |
286 | error = inode_change_ok(inode, attr); |
287 | if (error) | |
288 | return error; | |
289 | ||
94c1e62d HD |
290 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
291 | loff_t oldsize = inode->i_size; | |
292 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 293 | struct page *page = NULL; |
294 | ||
94c1e62d | 295 | if (newsize < oldsize) { |
1da177e4 LT |
296 | /* |
297 | * If truncating down to a partial page, then | |
298 | * if that page is already allocated, hold it | |
299 | * in memory until the truncation is over, so | |
ae0e47f0 | 300 | * truncate_partial_page cannot miss it were |
1da177e4 LT |
301 | * it assigned to swap. |
302 | */ | |
3889e6e7 | 303 | if (newsize & (PAGE_CACHE_SIZE-1)) { |
1da177e4 | 304 | (void) shmem_getpage(inode, |
3889e6e7 | 305 | newsize >> PAGE_CACHE_SHIFT, |
1da177e4 | 306 | &page, SGP_READ, NULL); |
d3602444 HD |
307 | if (page) |
308 | unlock_page(page); | |
1da177e4 | 309 | } |
1da177e4 | 310 | } |
94c1e62d HD |
311 | if (newsize != oldsize) { |
312 | i_size_write(inode, newsize); | |
313 | inode->i_ctime = inode->i_mtime = CURRENT_TIME; | |
314 | } | |
315 | if (newsize < oldsize) { | |
316 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
317 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
318 | shmem_truncate_range(inode, newsize, (loff_t)-1); | |
319 | /* unmap again to remove racily COWed private pages */ | |
320 | unmap_mapping_range(inode->i_mapping, holebegin, 0, 1); | |
321 | } | |
3889e6e7 | 322 | if (page) |
323 | page_cache_release(page); | |
1da177e4 LT |
324 | } |
325 | ||
db78b877 | 326 | setattr_copy(inode, attr); |
39f0247d | 327 | #ifdef CONFIG_TMPFS_POSIX_ACL |
db78b877 | 328 | if (attr->ia_valid & ATTR_MODE) |
1c7c474c | 329 | error = generic_acl_chmod(inode); |
39f0247d | 330 | #endif |
1da177e4 LT |
331 | return error; |
332 | } | |
333 | ||
1f895f75 | 334 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 335 | { |
1da177e4 | 336 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 337 | struct shmem_xattr *xattr, *nxattr; |
1da177e4 | 338 | |
3889e6e7 | 339 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
340 | shmem_unacct_size(info->flags, inode->i_size); |
341 | inode->i_size = 0; | |
3889e6e7 | 342 | shmem_truncate_range(inode, 0, (loff_t)-1); |
1da177e4 | 343 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 344 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 345 | list_del_init(&info->swaplist); |
cb5f7b9a | 346 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 LT |
347 | } |
348 | } | |
b09e0fa4 EP |
349 | |
350 | list_for_each_entry_safe(xattr, nxattr, &info->xattr_list, list) { | |
351 | kfree(xattr->name); | |
352 | kfree(xattr); | |
353 | } | |
0edd73b3 | 354 | BUG_ON(inode->i_blocks); |
5b04c689 | 355 | shmem_free_inode(inode->i_sb); |
1f895f75 | 356 | end_writeback(inode); |
1da177e4 LT |
357 | } |
358 | ||
1da177e4 LT |
359 | static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page) |
360 | { | |
285b2c4f | 361 | struct address_space *mapping = info->vfs_inode.i_mapping; |
1da177e4 | 362 | unsigned long idx; |
d9fe526a | 363 | int error; |
1da177e4 | 364 | |
285b2c4f HD |
365 | for (idx = 0; idx < SHMEM_NR_DIRECT; idx++) |
366 | if (shmem_get_swap(info, idx).val == entry.val) | |
367 | goto found; | |
1da177e4 LT |
368 | return 0; |
369 | found: | |
285b2c4f HD |
370 | spin_lock(&info->lock); |
371 | if (shmem_get_swap(info, idx).val != entry.val) { | |
372 | spin_unlock(&info->lock); | |
373 | return 0; | |
374 | } | |
2e0e26c7 | 375 | |
1b1b32f2 HD |
376 | /* |
377 | * Move _head_ to start search for next from here. | |
1f895f75 | 378 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 | 379 | * mutex, and there's an instant in list_move_tail when info->swaplist |
285b2c4f | 380 | * would appear empty, if it were the only one on shmem_swaplist. |
1b1b32f2 HD |
381 | */ |
382 | if (shmem_swaplist.next != &info->swaplist) | |
383 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 384 | |
d13d1443 | 385 | /* |
778dd893 HD |
386 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
387 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
388 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 389 | */ |
778dd893 HD |
390 | error = add_to_page_cache_locked(page, mapping, idx, GFP_NOWAIT); |
391 | /* which does mem_cgroup_uncharge_cache_page on error */ | |
69029cd5 | 392 | |
48f170fb | 393 | if (error != -ENOMEM) { |
73b1262f HD |
394 | delete_from_swap_cache(page); |
395 | set_page_dirty(page); | |
285b2c4f HD |
396 | shmem_put_swap(info, idx, (swp_entry_t){0}); |
397 | info->swapped--; | |
2e0e26c7 HD |
398 | swap_free(entry); |
399 | error = 1; /* not an error, but entry was found */ | |
1da177e4 | 400 | } |
1da177e4 | 401 | spin_unlock(&info->lock); |
2e0e26c7 | 402 | return error; |
1da177e4 LT |
403 | } |
404 | ||
405 | /* | |
406 | * shmem_unuse() search for an eventually swapped out shmem page. | |
407 | */ | |
408 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
409 | { | |
410 | struct list_head *p, *next; | |
411 | struct shmem_inode_info *info; | |
412 | int found = 0; | |
778dd893 HD |
413 | int error; |
414 | ||
415 | /* | |
416 | * Charge page using GFP_KERNEL while we can wait, before taking | |
417 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
418 | * Charged back to the user (not to caller) when swap account is used. | |
419 | * add_to_page_cache() will be called with GFP_NOWAIT. | |
420 | */ | |
421 | error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL); | |
422 | if (error) | |
423 | goto out; | |
424 | /* | |
425 | * Try to preload while we can wait, to not make a habit of | |
426 | * draining atomic reserves; but don't latch on to this cpu, | |
427 | * it's okay if sometimes we get rescheduled after this. | |
428 | */ | |
429 | error = radix_tree_preload(GFP_KERNEL); | |
430 | if (error) | |
431 | goto uncharge; | |
432 | radix_tree_preload_end(); | |
1da177e4 | 433 | |
cb5f7b9a | 434 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 LT |
435 | list_for_each_safe(p, next, &shmem_swaplist) { |
436 | info = list_entry(p, struct shmem_inode_info, swaplist); | |
285b2c4f HD |
437 | if (!info->swapped) { |
438 | spin_lock(&info->lock); | |
439 | if (!info->swapped) | |
440 | list_del_init(&info->swaplist); | |
441 | spin_unlock(&info->lock); | |
442 | } | |
443 | if (info->swapped) | |
444 | found = shmem_unuse_inode(info, entry, page); | |
cb5f7b9a | 445 | cond_resched(); |
2e0e26c7 | 446 | if (found) |
778dd893 | 447 | break; |
1da177e4 | 448 | } |
cb5f7b9a | 449 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 HD |
450 | |
451 | uncharge: | |
452 | if (!found) | |
453 | mem_cgroup_uncharge_cache_page(page); | |
454 | if (found < 0) | |
455 | error = found; | |
456 | out: | |
aaa46865 HD |
457 | unlock_page(page); |
458 | page_cache_release(page); | |
778dd893 | 459 | return error; |
1da177e4 LT |
460 | } |
461 | ||
462 | /* | |
463 | * Move the page from the page cache to the swap cache. | |
464 | */ | |
465 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
466 | { | |
467 | struct shmem_inode_info *info; | |
285b2c4f | 468 | swp_entry_t swap, oswap; |
1da177e4 LT |
469 | struct address_space *mapping; |
470 | unsigned long index; | |
471 | struct inode *inode; | |
472 | ||
473 | BUG_ON(!PageLocked(page)); | |
1da177e4 LT |
474 | mapping = page->mapping; |
475 | index = page->index; | |
476 | inode = mapping->host; | |
477 | info = SHMEM_I(inode); | |
478 | if (info->flags & VM_LOCKED) | |
479 | goto redirty; | |
d9fe526a | 480 | if (!total_swap_pages) |
1da177e4 LT |
481 | goto redirty; |
482 | ||
d9fe526a HD |
483 | /* |
484 | * shmem_backing_dev_info's capabilities prevent regular writeback or | |
485 | * sync from ever calling shmem_writepage; but a stacking filesystem | |
48f170fb | 486 | * might use ->writepage of its underlying filesystem, in which case |
d9fe526a | 487 | * tmpfs should write out to swap only in response to memory pressure, |
48f170fb | 488 | * and not for the writeback threads or sync. |
d9fe526a | 489 | */ |
48f170fb HD |
490 | if (!wbc->for_reclaim) { |
491 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
492 | goto redirty; | |
493 | } | |
285b2c4f HD |
494 | |
495 | /* | |
496 | * Just for this patch, we have a toy implementation, | |
497 | * which can swap out only the first SHMEM_NR_DIRECT pages: | |
498 | * for simple demonstration of where we need to think about swap. | |
499 | */ | |
500 | if (index >= SHMEM_NR_DIRECT) | |
501 | goto redirty; | |
502 | ||
48f170fb HD |
503 | swap = get_swap_page(); |
504 | if (!swap.val) | |
505 | goto redirty; | |
d9fe526a | 506 | |
b1dea800 HD |
507 | /* |
508 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
509 | * if it's not already there. Do it now because we cannot take | |
510 | * mutex while holding spinlock, and must do so before the page | |
511 | * is moved to swap cache, when its pagelock no longer protects | |
512 | * the inode from eviction. But don't unlock the mutex until | |
513 | * we've taken the spinlock, because shmem_unuse_inode() will | |
514 | * prune a !swapped inode from the swaplist under both locks. | |
515 | */ | |
48f170fb HD |
516 | mutex_lock(&shmem_swaplist_mutex); |
517 | if (list_empty(&info->swaplist)) | |
518 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 519 | |
1da177e4 | 520 | spin_lock(&info->lock); |
48f170fb | 521 | mutex_unlock(&shmem_swaplist_mutex); |
b1dea800 | 522 | |
285b2c4f HD |
523 | oswap = shmem_get_swap(info, index); |
524 | if (oswap.val) { | |
48f170fb | 525 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ |
285b2c4f HD |
526 | free_swap_and_cache(oswap); |
527 | shmem_put_swap(info, index, (swp_entry_t){0}); | |
528 | info->swapped--; | |
d9fe526a HD |
529 | } |
530 | shmem_recalc_inode(inode); | |
1da177e4 | 531 | |
48f170fb | 532 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
4c73b1bc | 533 | delete_from_page_cache(page); |
285b2c4f HD |
534 | shmem_put_swap(info, index, swap); |
535 | info->swapped++; | |
aaa46865 | 536 | swap_shmem_alloc(swap); |
826267cf | 537 | spin_unlock(&info->lock); |
d9fe526a | 538 | BUG_ON(page_mapped(page)); |
9fab5619 | 539 | swap_writepage(page, wbc); |
1da177e4 LT |
540 | return 0; |
541 | } | |
542 | ||
1da177e4 | 543 | spin_unlock(&info->lock); |
cb4b86ba | 544 | swapcache_free(swap, NULL); |
1da177e4 LT |
545 | redirty: |
546 | set_page_dirty(page); | |
d9fe526a HD |
547 | if (wbc->for_reclaim) |
548 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
549 | unlock_page(page); | |
550 | return 0; | |
1da177e4 LT |
551 | } |
552 | ||
553 | #ifdef CONFIG_NUMA | |
680d794b | 554 | #ifdef CONFIG_TMPFS |
71fe804b | 555 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 556 | { |
095f1fc4 | 557 | char buffer[64]; |
680d794b | 558 | |
71fe804b | 559 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 560 | return; /* show nothing */ |
680d794b | 561 | |
71fe804b | 562 | mpol_to_str(buffer, sizeof(buffer), mpol, 1); |
095f1fc4 LS |
563 | |
564 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 565 | } |
71fe804b LS |
566 | |
567 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
568 | { | |
569 | struct mempolicy *mpol = NULL; | |
570 | if (sbinfo->mpol) { | |
571 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
572 | mpol = sbinfo->mpol; | |
573 | mpol_get(mpol); | |
574 | spin_unlock(&sbinfo->stat_lock); | |
575 | } | |
576 | return mpol; | |
577 | } | |
680d794b | 578 | #endif /* CONFIG_TMPFS */ |
579 | ||
02098fea HD |
580 | static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
581 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 582 | { |
52cd3b07 | 583 | struct mempolicy mpol, *spol; |
1da177e4 | 584 | struct vm_area_struct pvma; |
c4cc6d07 | 585 | struct page *page; |
1da177e4 | 586 | |
52cd3b07 LS |
587 | spol = mpol_cond_copy(&mpol, |
588 | mpol_shared_policy_lookup(&info->policy, idx)); | |
589 | ||
1da177e4 | 590 | /* Create a pseudo vma that just contains the policy */ |
c4cc6d07 | 591 | pvma.vm_start = 0; |
1da177e4 | 592 | pvma.vm_pgoff = idx; |
c4cc6d07 | 593 | pvma.vm_ops = NULL; |
52cd3b07 | 594 | pvma.vm_policy = spol; |
02098fea | 595 | page = swapin_readahead(entry, gfp, &pvma, 0); |
1da177e4 LT |
596 | return page; |
597 | } | |
598 | ||
02098fea HD |
599 | static struct page *shmem_alloc_page(gfp_t gfp, |
600 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 LT |
601 | { |
602 | struct vm_area_struct pvma; | |
1da177e4 | 603 | |
c4cc6d07 HD |
604 | /* Create a pseudo vma that just contains the policy */ |
605 | pvma.vm_start = 0; | |
1da177e4 | 606 | pvma.vm_pgoff = idx; |
c4cc6d07 HD |
607 | pvma.vm_ops = NULL; |
608 | pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx); | |
52cd3b07 LS |
609 | |
610 | /* | |
611 | * alloc_page_vma() will drop the shared policy reference | |
612 | */ | |
613 | return alloc_page_vma(gfp, &pvma, 0); | |
1da177e4 | 614 | } |
680d794b | 615 | #else /* !CONFIG_NUMA */ |
616 | #ifdef CONFIG_TMPFS | |
71fe804b | 617 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p) |
680d794b | 618 | { |
619 | } | |
620 | #endif /* CONFIG_TMPFS */ | |
621 | ||
02098fea HD |
622 | static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp, |
623 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 624 | { |
02098fea | 625 | return swapin_readahead(entry, gfp, NULL, 0); |
1da177e4 LT |
626 | } |
627 | ||
02098fea HD |
628 | static inline struct page *shmem_alloc_page(gfp_t gfp, |
629 | struct shmem_inode_info *info, unsigned long idx) | |
1da177e4 | 630 | { |
e84e2e13 | 631 | return alloc_page(gfp); |
1da177e4 | 632 | } |
680d794b | 633 | #endif /* CONFIG_NUMA */ |
1da177e4 | 634 | |
71fe804b LS |
635 | #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS) |
636 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
637 | { | |
638 | return NULL; | |
639 | } | |
640 | #endif | |
641 | ||
1da177e4 | 642 | /* |
68da9f05 | 643 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
644 | * |
645 | * If we allocate a new one we do not mark it dirty. That's up to the | |
646 | * vm. If we swap it in we mark it dirty since we also free the swap | |
647 | * entry since a page cannot live in both the swap and page cache | |
648 | */ | |
68da9f05 HD |
649 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t idx, |
650 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, int *fault_type) | |
1da177e4 LT |
651 | { |
652 | struct address_space *mapping = inode->i_mapping; | |
653 | struct shmem_inode_info *info = SHMEM_I(inode); | |
654 | struct shmem_sb_info *sbinfo; | |
27ab7006 | 655 | struct page *page; |
ff36b801 | 656 | struct page *prealloc_page = NULL; |
1da177e4 LT |
657 | swp_entry_t swap; |
658 | int error; | |
659 | ||
285b2c4f | 660 | if (idx > (MAX_LFS_FILESIZE >> PAGE_CACHE_SHIFT)) |
1da177e4 | 661 | return -EFBIG; |
1da177e4 | 662 | repeat: |
27ab7006 HD |
663 | page = find_lock_page(mapping, idx); |
664 | if (page) { | |
b409f9fc | 665 | /* |
27ab7006 HD |
666 | * Once we can get the page lock, it must be uptodate: |
667 | * if there were an error in reading back from swap, | |
668 | * the page would not be inserted into the filecache. | |
b409f9fc | 669 | */ |
27ab7006 HD |
670 | BUG_ON(!PageUptodate(page)); |
671 | goto done; | |
672 | } | |
673 | ||
674 | /* | |
675 | * Try to preload while we can wait, to not make a habit of | |
676 | * draining atomic reserves; but don't latch on to this cpu. | |
677 | */ | |
678 | error = radix_tree_preload(gfp & GFP_RECLAIM_MASK); | |
679 | if (error) | |
680 | goto out; | |
681 | radix_tree_preload_end(); | |
682 | ||
683 | if (sgp != SGP_READ && !prealloc_page) { | |
684 | prealloc_page = shmem_alloc_page(gfp, info, idx); | |
685 | if (prealloc_page) { | |
686 | SetPageSwapBacked(prealloc_page); | |
687 | if (mem_cgroup_cache_charge(prealloc_page, | |
688 | current->mm, GFP_KERNEL)) { | |
689 | page_cache_release(prealloc_page); | |
690 | prealloc_page = NULL; | |
ff36b801 SL |
691 | } |
692 | } | |
b409f9fc | 693 | } |
1da177e4 LT |
694 | |
695 | spin_lock(&info->lock); | |
696 | shmem_recalc_inode(inode); | |
285b2c4f | 697 | swap = shmem_get_swap(info, idx); |
1da177e4 LT |
698 | if (swap.val) { |
699 | /* Look it up and read it in.. */ | |
27ab7006 HD |
700 | page = lookup_swap_cache(swap); |
701 | if (!page) { | |
456f998e | 702 | spin_unlock(&info->lock); |
1da177e4 | 703 | /* here we actually do the io */ |
68da9f05 HD |
704 | if (fault_type) |
705 | *fault_type |= VM_FAULT_MAJOR; | |
27ab7006 HD |
706 | page = shmem_swapin(swap, gfp, info, idx); |
707 | if (!page) { | |
285b2c4f HD |
708 | swp_entry_t nswap = shmem_get_swap(info, idx); |
709 | if (nswap.val == swap.val) { | |
710 | error = -ENOMEM; | |
27ab7006 | 711 | goto out; |
285b2c4f | 712 | } |
1da177e4 LT |
713 | goto repeat; |
714 | } | |
27ab7006 HD |
715 | wait_on_page_locked(page); |
716 | page_cache_release(page); | |
1da177e4 LT |
717 | goto repeat; |
718 | } | |
719 | ||
720 | /* We have to do this with page locked to prevent races */ | |
27ab7006 | 721 | if (!trylock_page(page)) { |
1da177e4 | 722 | spin_unlock(&info->lock); |
27ab7006 HD |
723 | wait_on_page_locked(page); |
724 | page_cache_release(page); | |
1da177e4 LT |
725 | goto repeat; |
726 | } | |
27ab7006 | 727 | if (PageWriteback(page)) { |
1da177e4 | 728 | spin_unlock(&info->lock); |
27ab7006 HD |
729 | wait_on_page_writeback(page); |
730 | unlock_page(page); | |
731 | page_cache_release(page); | |
1da177e4 LT |
732 | goto repeat; |
733 | } | |
27ab7006 | 734 | if (!PageUptodate(page)) { |
1da177e4 | 735 | spin_unlock(&info->lock); |
27ab7006 HD |
736 | unlock_page(page); |
737 | page_cache_release(page); | |
1da177e4 | 738 | error = -EIO; |
27ab7006 | 739 | goto out; |
1da177e4 LT |
740 | } |
741 | ||
27ab7006 HD |
742 | error = add_to_page_cache_locked(page, mapping, |
743 | idx, GFP_NOWAIT); | |
744 | if (error) { | |
1da177e4 | 745 | spin_unlock(&info->lock); |
82369553 | 746 | if (error == -ENOMEM) { |
ae3abae6 DN |
747 | /* |
748 | * reclaim from proper memory cgroup and | |
749 | * call memcg's OOM if needed. | |
750 | */ | |
751 | error = mem_cgroup_shmem_charge_fallback( | |
27ab7006 | 752 | page, current->mm, gfp); |
b5a84319 | 753 | if (error) { |
27ab7006 HD |
754 | unlock_page(page); |
755 | page_cache_release(page); | |
756 | goto out; | |
b5a84319 | 757 | } |
82369553 | 758 | } |
27ab7006 HD |
759 | unlock_page(page); |
760 | page_cache_release(page); | |
1da177e4 LT |
761 | goto repeat; |
762 | } | |
27ab7006 | 763 | |
27ab7006 | 764 | delete_from_swap_cache(page); |
285b2c4f HD |
765 | shmem_put_swap(info, idx, (swp_entry_t){0}); |
766 | info->swapped--; | |
27ab7006 HD |
767 | spin_unlock(&info->lock); |
768 | set_page_dirty(page); | |
769 | swap_free(swap); | |
770 | ||
771 | } else if (sgp == SGP_READ) { | |
27ab7006 HD |
772 | page = find_get_page(mapping, idx); |
773 | if (page && !trylock_page(page)) { | |
1da177e4 | 774 | spin_unlock(&info->lock); |
27ab7006 HD |
775 | wait_on_page_locked(page); |
776 | page_cache_release(page); | |
1da177e4 LT |
777 | goto repeat; |
778 | } | |
779 | spin_unlock(&info->lock); | |
e83c32e8 HD |
780 | |
781 | } else if (prealloc_page) { | |
1da177e4 | 782 | sbinfo = SHMEM_SB(inode->i_sb); |
0edd73b3 | 783 | if (sbinfo->max_blocks) { |
fc5da22a HD |
784 | if (percpu_counter_compare(&sbinfo->used_blocks, |
785 | sbinfo->max_blocks) >= 0 || | |
59a16ead HD |
786 | shmem_acct_block(info->flags)) |
787 | goto nospace; | |
7e496299 | 788 | percpu_counter_inc(&sbinfo->used_blocks); |
1da177e4 | 789 | inode->i_blocks += BLOCKS_PER_PAGE; |
59a16ead HD |
790 | } else if (shmem_acct_block(info->flags)) |
791 | goto nospace; | |
1da177e4 | 792 | |
27ab7006 HD |
793 | page = prealloc_page; |
794 | prealloc_page = NULL; | |
1da177e4 | 795 | |
285b2c4f HD |
796 | swap = shmem_get_swap(info, idx); |
797 | if (swap.val) | |
27ab7006 HD |
798 | mem_cgroup_uncharge_cache_page(page); |
799 | else | |
285b2c4f | 800 | error = add_to_page_cache_lru(page, mapping, |
69029cd5 | 801 | idx, GFP_NOWAIT); |
27ab7006 HD |
802 | /* |
803 | * At add_to_page_cache_lru() failure, | |
804 | * uncharge will be done automatically. | |
805 | */ | |
285b2c4f | 806 | if (swap.val || error) { |
27ab7006 HD |
807 | shmem_unacct_blocks(info->flags, 1); |
808 | shmem_free_blocks(inode, 1); | |
809 | spin_unlock(&info->lock); | |
810 | page_cache_release(page); | |
27ab7006 | 811 | goto repeat; |
1da177e4 LT |
812 | } |
813 | ||
814 | info->alloced++; | |
815 | spin_unlock(&info->lock); | |
27ab7006 HD |
816 | clear_highpage(page); |
817 | flush_dcache_page(page); | |
818 | SetPageUptodate(page); | |
a0ee5ec5 | 819 | if (sgp == SGP_DIRTY) |
27ab7006 HD |
820 | set_page_dirty(page); |
821 | ||
e83c32e8 HD |
822 | } else { |
823 | spin_unlock(&info->lock); | |
824 | error = -ENOMEM; | |
825 | goto out; | |
1da177e4 LT |
826 | } |
827 | done: | |
27ab7006 | 828 | *pagep = page; |
ff36b801 | 829 | error = 0; |
e83c32e8 HD |
830 | out: |
831 | if (prealloc_page) { | |
832 | mem_cgroup_uncharge_cache_page(prealloc_page); | |
833 | page_cache_release(prealloc_page); | |
834 | } | |
835 | return error; | |
1da177e4 | 836 | |
59a16ead HD |
837 | nospace: |
838 | /* | |
839 | * Perhaps the page was brought in from swap between find_lock_page | |
840 | * and taking info->lock? We allow for that at add_to_page_cache_lru, | |
841 | * but must also avoid reporting a spurious ENOSPC while working on a | |
9276aad6 | 842 | * full tmpfs. |
59a16ead | 843 | */ |
27ab7006 | 844 | page = find_get_page(mapping, idx); |
59a16ead | 845 | spin_unlock(&info->lock); |
27ab7006 HD |
846 | if (page) { |
847 | page_cache_release(page); | |
848 | goto repeat; | |
ff36b801 | 849 | } |
27ab7006 | 850 | error = -ENOSPC; |
e83c32e8 | 851 | goto out; |
1da177e4 LT |
852 | } |
853 | ||
d0217ac0 | 854 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 855 | { |
d3ac7f89 | 856 | struct inode *inode = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 | 857 | int error; |
68da9f05 | 858 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 859 | |
d0217ac0 NP |
860 | if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) |
861 | return VM_FAULT_SIGBUS; | |
d00806b1 | 862 | |
27d54b39 | 863 | error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret); |
d0217ac0 NP |
864 | if (error) |
865 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 866 | |
456f998e YH |
867 | if (ret & VM_FAULT_MAJOR) { |
868 | count_vm_event(PGMAJFAULT); | |
869 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); | |
870 | } | |
68da9f05 | 871 | return ret; |
1da177e4 LT |
872 | } |
873 | ||
1da177e4 | 874 | #ifdef CONFIG_NUMA |
d8dc74f2 | 875 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
1da177e4 | 876 | { |
d3ac7f89 | 877 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
878 | return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new); |
879 | } | |
880 | ||
d8dc74f2 AB |
881 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
882 | unsigned long addr) | |
1da177e4 | 883 | { |
d3ac7f89 | 884 | struct inode *i = vma->vm_file->f_path.dentry->d_inode; |
1da177e4 LT |
885 | unsigned long idx; |
886 | ||
887 | idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
888 | return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx); | |
889 | } | |
890 | #endif | |
891 | ||
892 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
893 | { | |
d3ac7f89 | 894 | struct inode *inode = file->f_path.dentry->d_inode; |
1da177e4 LT |
895 | struct shmem_inode_info *info = SHMEM_I(inode); |
896 | int retval = -ENOMEM; | |
897 | ||
898 | spin_lock(&info->lock); | |
899 | if (lock && !(info->flags & VM_LOCKED)) { | |
900 | if (!user_shm_lock(inode->i_size, user)) | |
901 | goto out_nomem; | |
902 | info->flags |= VM_LOCKED; | |
89e004ea | 903 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
904 | } |
905 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
906 | user_shm_unlock(inode->i_size, user); | |
907 | info->flags &= ~VM_LOCKED; | |
89e004ea LS |
908 | mapping_clear_unevictable(file->f_mapping); |
909 | scan_mapping_unevictable_pages(file->f_mapping); | |
1da177e4 LT |
910 | } |
911 | retval = 0; | |
89e004ea | 912 | |
1da177e4 LT |
913 | out_nomem: |
914 | spin_unlock(&info->lock); | |
915 | return retval; | |
916 | } | |
917 | ||
9b83a6a8 | 918 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
919 | { |
920 | file_accessed(file); | |
921 | vma->vm_ops = &shmem_vm_ops; | |
d0217ac0 | 922 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
923 | return 0; |
924 | } | |
925 | ||
454abafe DM |
926 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
927 | int mode, dev_t dev, unsigned long flags) | |
1da177e4 LT |
928 | { |
929 | struct inode *inode; | |
930 | struct shmem_inode_info *info; | |
931 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
932 | ||
5b04c689 PE |
933 | if (shmem_reserve_inode(sb)) |
934 | return NULL; | |
1da177e4 LT |
935 | |
936 | inode = new_inode(sb); | |
937 | if (inode) { | |
85fe4025 | 938 | inode->i_ino = get_next_ino(); |
454abafe | 939 | inode_init_owner(inode, dir, mode); |
1da177e4 | 940 | inode->i_blocks = 0; |
1da177e4 LT |
941 | inode->i_mapping->backing_dev_info = &shmem_backing_dev_info; |
942 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; | |
91828a40 | 943 | inode->i_generation = get_seconds(); |
1da177e4 LT |
944 | info = SHMEM_I(inode); |
945 | memset(info, 0, (char *)inode - (char *)info); | |
946 | spin_lock_init(&info->lock); | |
0b0a0806 | 947 | info->flags = flags & VM_NORESERVE; |
1da177e4 | 948 | INIT_LIST_HEAD(&info->swaplist); |
b09e0fa4 | 949 | INIT_LIST_HEAD(&info->xattr_list); |
72c04902 | 950 | cache_no_acl(inode); |
1da177e4 LT |
951 | |
952 | switch (mode & S_IFMT) { | |
953 | default: | |
39f0247d | 954 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
955 | init_special_inode(inode, mode, dev); |
956 | break; | |
957 | case S_IFREG: | |
14fcc23f | 958 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
959 | inode->i_op = &shmem_inode_operations; |
960 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
961 | mpol_shared_policy_init(&info->policy, |
962 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
963 | break; |
964 | case S_IFDIR: | |
d8c76e6f | 965 | inc_nlink(inode); |
1da177e4 LT |
966 | /* Some things misbehave if size == 0 on a directory */ |
967 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
968 | inode->i_op = &shmem_dir_inode_operations; | |
969 | inode->i_fop = &simple_dir_operations; | |
970 | break; | |
971 | case S_IFLNK: | |
972 | /* | |
973 | * Must not load anything in the rbtree, | |
974 | * mpol_free_shared_policy will not be called. | |
975 | */ | |
71fe804b | 976 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
977 | break; |
978 | } | |
5b04c689 PE |
979 | } else |
980 | shmem_free_inode(sb); | |
1da177e4 LT |
981 | return inode; |
982 | } | |
983 | ||
984 | #ifdef CONFIG_TMPFS | |
92e1d5be AV |
985 | static const struct inode_operations shmem_symlink_inode_operations; |
986 | static const struct inode_operations shmem_symlink_inline_operations; | |
1da177e4 | 987 | |
1da177e4 | 988 | static int |
800d15a5 NP |
989 | shmem_write_begin(struct file *file, struct address_space *mapping, |
990 | loff_t pos, unsigned len, unsigned flags, | |
991 | struct page **pagep, void **fsdata) | |
1da177e4 | 992 | { |
800d15a5 NP |
993 | struct inode *inode = mapping->host; |
994 | pgoff_t index = pos >> PAGE_CACHE_SHIFT; | |
800d15a5 NP |
995 | return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL); |
996 | } | |
997 | ||
998 | static int | |
999 | shmem_write_end(struct file *file, struct address_space *mapping, | |
1000 | loff_t pos, unsigned len, unsigned copied, | |
1001 | struct page *page, void *fsdata) | |
1002 | { | |
1003 | struct inode *inode = mapping->host; | |
1004 | ||
d3602444 HD |
1005 | if (pos + copied > inode->i_size) |
1006 | i_size_write(inode, pos + copied); | |
1007 | ||
800d15a5 | 1008 | set_page_dirty(page); |
6746aff7 | 1009 | unlock_page(page); |
800d15a5 NP |
1010 | page_cache_release(page); |
1011 | ||
800d15a5 | 1012 | return copied; |
1da177e4 LT |
1013 | } |
1014 | ||
1da177e4 LT |
1015 | static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor) |
1016 | { | |
d3ac7f89 | 1017 | struct inode *inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
1018 | struct address_space *mapping = inode->i_mapping; |
1019 | unsigned long index, offset; | |
a0ee5ec5 HD |
1020 | enum sgp_type sgp = SGP_READ; |
1021 | ||
1022 | /* | |
1023 | * Might this read be for a stacking filesystem? Then when reading | |
1024 | * holes of a sparse file, we actually need to allocate those pages, | |
1025 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
1026 | */ | |
1027 | if (segment_eq(get_fs(), KERNEL_DS)) | |
1028 | sgp = SGP_DIRTY; | |
1da177e4 LT |
1029 | |
1030 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1031 | offset = *ppos & ~PAGE_CACHE_MASK; | |
1032 | ||
1033 | for (;;) { | |
1034 | struct page *page = NULL; | |
1035 | unsigned long end_index, nr, ret; | |
1036 | loff_t i_size = i_size_read(inode); | |
1037 | ||
1038 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1039 | if (index > end_index) | |
1040 | break; | |
1041 | if (index == end_index) { | |
1042 | nr = i_size & ~PAGE_CACHE_MASK; | |
1043 | if (nr <= offset) | |
1044 | break; | |
1045 | } | |
1046 | ||
a0ee5ec5 | 1047 | desc->error = shmem_getpage(inode, index, &page, sgp, NULL); |
1da177e4 LT |
1048 | if (desc->error) { |
1049 | if (desc->error == -EINVAL) | |
1050 | desc->error = 0; | |
1051 | break; | |
1052 | } | |
d3602444 HD |
1053 | if (page) |
1054 | unlock_page(page); | |
1da177e4 LT |
1055 | |
1056 | /* | |
1057 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 1058 | * are called without i_mutex protection against truncate |
1da177e4 LT |
1059 | */ |
1060 | nr = PAGE_CACHE_SIZE; | |
1061 | i_size = i_size_read(inode); | |
1062 | end_index = i_size >> PAGE_CACHE_SHIFT; | |
1063 | if (index == end_index) { | |
1064 | nr = i_size & ~PAGE_CACHE_MASK; | |
1065 | if (nr <= offset) { | |
1066 | if (page) | |
1067 | page_cache_release(page); | |
1068 | break; | |
1069 | } | |
1070 | } | |
1071 | nr -= offset; | |
1072 | ||
1073 | if (page) { | |
1074 | /* | |
1075 | * If users can be writing to this page using arbitrary | |
1076 | * virtual addresses, take care about potential aliasing | |
1077 | * before reading the page on the kernel side. | |
1078 | */ | |
1079 | if (mapping_writably_mapped(mapping)) | |
1080 | flush_dcache_page(page); | |
1081 | /* | |
1082 | * Mark the page accessed if we read the beginning. | |
1083 | */ | |
1084 | if (!offset) | |
1085 | mark_page_accessed(page); | |
b5810039 | 1086 | } else { |
1da177e4 | 1087 | page = ZERO_PAGE(0); |
b5810039 NP |
1088 | page_cache_get(page); |
1089 | } | |
1da177e4 LT |
1090 | |
1091 | /* | |
1092 | * Ok, we have the page, and it's up-to-date, so | |
1093 | * now we can copy it to user space... | |
1094 | * | |
1095 | * The actor routine returns how many bytes were actually used.. | |
1096 | * NOTE! This may not be the same as how much of a user buffer | |
1097 | * we filled up (we may be padding etc), so we can only update | |
1098 | * "pos" here (the actor routine has to update the user buffer | |
1099 | * pointers and the remaining count). | |
1100 | */ | |
1101 | ret = actor(desc, page, offset, nr); | |
1102 | offset += ret; | |
1103 | index += offset >> PAGE_CACHE_SHIFT; | |
1104 | offset &= ~PAGE_CACHE_MASK; | |
1105 | ||
1106 | page_cache_release(page); | |
1107 | if (ret != nr || !desc->count) | |
1108 | break; | |
1109 | ||
1110 | cond_resched(); | |
1111 | } | |
1112 | ||
1113 | *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; | |
1114 | file_accessed(filp); | |
1115 | } | |
1116 | ||
bcd78e49 HD |
1117 | static ssize_t shmem_file_aio_read(struct kiocb *iocb, |
1118 | const struct iovec *iov, unsigned long nr_segs, loff_t pos) | |
1119 | { | |
1120 | struct file *filp = iocb->ki_filp; | |
1121 | ssize_t retval; | |
1122 | unsigned long seg; | |
1123 | size_t count; | |
1124 | loff_t *ppos = &iocb->ki_pos; | |
1125 | ||
1126 | retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE); | |
1127 | if (retval) | |
1128 | return retval; | |
1129 | ||
1130 | for (seg = 0; seg < nr_segs; seg++) { | |
1131 | read_descriptor_t desc; | |
1132 | ||
1133 | desc.written = 0; | |
1134 | desc.arg.buf = iov[seg].iov_base; | |
1135 | desc.count = iov[seg].iov_len; | |
1136 | if (desc.count == 0) | |
1137 | continue; | |
1138 | desc.error = 0; | |
1139 | do_shmem_file_read(filp, ppos, &desc, file_read_actor); | |
1140 | retval += desc.written; | |
1141 | if (desc.error) { | |
1142 | retval = retval ?: desc.error; | |
1143 | break; | |
1144 | } | |
1145 | if (desc.count > 0) | |
1146 | break; | |
1147 | } | |
1148 | return retval; | |
1da177e4 LT |
1149 | } |
1150 | ||
708e3508 HD |
1151 | static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos, |
1152 | struct pipe_inode_info *pipe, size_t len, | |
1153 | unsigned int flags) | |
1154 | { | |
1155 | struct address_space *mapping = in->f_mapping; | |
71f0e07a | 1156 | struct inode *inode = mapping->host; |
708e3508 HD |
1157 | unsigned int loff, nr_pages, req_pages; |
1158 | struct page *pages[PIPE_DEF_BUFFERS]; | |
1159 | struct partial_page partial[PIPE_DEF_BUFFERS]; | |
1160 | struct page *page; | |
1161 | pgoff_t index, end_index; | |
1162 | loff_t isize, left; | |
1163 | int error, page_nr; | |
1164 | struct splice_pipe_desc spd = { | |
1165 | .pages = pages, | |
1166 | .partial = partial, | |
1167 | .flags = flags, | |
1168 | .ops = &page_cache_pipe_buf_ops, | |
1169 | .spd_release = spd_release_page, | |
1170 | }; | |
1171 | ||
71f0e07a | 1172 | isize = i_size_read(inode); |
708e3508 HD |
1173 | if (unlikely(*ppos >= isize)) |
1174 | return 0; | |
1175 | ||
1176 | left = isize - *ppos; | |
1177 | if (unlikely(left < len)) | |
1178 | len = left; | |
1179 | ||
1180 | if (splice_grow_spd(pipe, &spd)) | |
1181 | return -ENOMEM; | |
1182 | ||
1183 | index = *ppos >> PAGE_CACHE_SHIFT; | |
1184 | loff = *ppos & ~PAGE_CACHE_MASK; | |
1185 | req_pages = (len + loff + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; | |
1186 | nr_pages = min(req_pages, pipe->buffers); | |
1187 | ||
708e3508 HD |
1188 | spd.nr_pages = find_get_pages_contig(mapping, index, |
1189 | nr_pages, spd.pages); | |
1190 | index += spd.nr_pages; | |
708e3508 | 1191 | error = 0; |
708e3508 | 1192 | |
71f0e07a | 1193 | while (spd.nr_pages < nr_pages) { |
71f0e07a HD |
1194 | error = shmem_getpage(inode, index, &page, SGP_CACHE, NULL); |
1195 | if (error) | |
1196 | break; | |
1197 | unlock_page(page); | |
708e3508 HD |
1198 | spd.pages[spd.nr_pages++] = page; |
1199 | index++; | |
1200 | } | |
1201 | ||
708e3508 HD |
1202 | index = *ppos >> PAGE_CACHE_SHIFT; |
1203 | nr_pages = spd.nr_pages; | |
1204 | spd.nr_pages = 0; | |
71f0e07a | 1205 | |
708e3508 HD |
1206 | for (page_nr = 0; page_nr < nr_pages; page_nr++) { |
1207 | unsigned int this_len; | |
1208 | ||
1209 | if (!len) | |
1210 | break; | |
1211 | ||
708e3508 HD |
1212 | this_len = min_t(unsigned long, len, PAGE_CACHE_SIZE - loff); |
1213 | page = spd.pages[page_nr]; | |
1214 | ||
71f0e07a | 1215 | if (!PageUptodate(page) || page->mapping != mapping) { |
71f0e07a HD |
1216 | error = shmem_getpage(inode, index, &page, |
1217 | SGP_CACHE, NULL); | |
1218 | if (error) | |
708e3508 | 1219 | break; |
71f0e07a HD |
1220 | unlock_page(page); |
1221 | page_cache_release(spd.pages[page_nr]); | |
1222 | spd.pages[page_nr] = page; | |
708e3508 | 1223 | } |
71f0e07a HD |
1224 | |
1225 | isize = i_size_read(inode); | |
708e3508 HD |
1226 | end_index = (isize - 1) >> PAGE_CACHE_SHIFT; |
1227 | if (unlikely(!isize || index > end_index)) | |
1228 | break; | |
1229 | ||
708e3508 HD |
1230 | if (end_index == index) { |
1231 | unsigned int plen; | |
1232 | ||
708e3508 HD |
1233 | plen = ((isize - 1) & ~PAGE_CACHE_MASK) + 1; |
1234 | if (plen <= loff) | |
1235 | break; | |
1236 | ||
708e3508 HD |
1237 | this_len = min(this_len, plen - loff); |
1238 | len = this_len; | |
1239 | } | |
1240 | ||
1241 | spd.partial[page_nr].offset = loff; | |
1242 | spd.partial[page_nr].len = this_len; | |
1243 | len -= this_len; | |
1244 | loff = 0; | |
1245 | spd.nr_pages++; | |
1246 | index++; | |
1247 | } | |
1248 | ||
708e3508 HD |
1249 | while (page_nr < nr_pages) |
1250 | page_cache_release(spd.pages[page_nr++]); | |
708e3508 HD |
1251 | |
1252 | if (spd.nr_pages) | |
1253 | error = splice_to_pipe(pipe, &spd); | |
1254 | ||
1255 | splice_shrink_spd(pipe, &spd); | |
1256 | ||
1257 | if (error > 0) { | |
1258 | *ppos += error; | |
1259 | file_accessed(in); | |
1260 | } | |
1261 | return error; | |
1262 | } | |
1263 | ||
726c3342 | 1264 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 1265 | { |
726c3342 | 1266 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
1267 | |
1268 | buf->f_type = TMPFS_MAGIC; | |
1269 | buf->f_bsize = PAGE_CACHE_SIZE; | |
1270 | buf->f_namelen = NAME_MAX; | |
0edd73b3 | 1271 | if (sbinfo->max_blocks) { |
1da177e4 | 1272 | buf->f_blocks = sbinfo->max_blocks; |
7e496299 TC |
1273 | buf->f_bavail = buf->f_bfree = |
1274 | sbinfo->max_blocks - percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
1275 | } |
1276 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
1277 | buf->f_files = sbinfo->max_inodes; |
1278 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
1279 | } |
1280 | /* else leave those fields 0 like simple_statfs */ | |
1281 | return 0; | |
1282 | } | |
1283 | ||
1284 | /* | |
1285 | * File creation. Allocate an inode, and we're done.. | |
1286 | */ | |
1287 | static int | |
1288 | shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev) | |
1289 | { | |
0b0a0806 | 1290 | struct inode *inode; |
1da177e4 LT |
1291 | int error = -ENOSPC; |
1292 | ||
454abafe | 1293 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 1294 | if (inode) { |
2a7dba39 EP |
1295 | error = security_inode_init_security(inode, dir, |
1296 | &dentry->d_name, NULL, | |
1297 | NULL, NULL); | |
570bc1c2 SS |
1298 | if (error) { |
1299 | if (error != -EOPNOTSUPP) { | |
1300 | iput(inode); | |
1301 | return error; | |
1302 | } | |
39f0247d | 1303 | } |
1c7c474c CH |
1304 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1305 | error = generic_acl_init(inode, dir); | |
39f0247d AG |
1306 | if (error) { |
1307 | iput(inode); | |
1308 | return error; | |
570bc1c2 | 1309 | } |
718deb6b AV |
1310 | #else |
1311 | error = 0; | |
1c7c474c | 1312 | #endif |
1da177e4 LT |
1313 | dir->i_size += BOGO_DIRENT_SIZE; |
1314 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1315 | d_instantiate(dentry, inode); | |
1316 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
1317 | } |
1318 | return error; | |
1319 | } | |
1320 | ||
1321 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
1322 | { | |
1323 | int error; | |
1324 | ||
1325 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
1326 | return error; | |
d8c76e6f | 1327 | inc_nlink(dir); |
1da177e4 LT |
1328 | return 0; |
1329 | } | |
1330 | ||
1331 | static int shmem_create(struct inode *dir, struct dentry *dentry, int mode, | |
1332 | struct nameidata *nd) | |
1333 | { | |
1334 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
1335 | } | |
1336 | ||
1337 | /* | |
1338 | * Link a file.. | |
1339 | */ | |
1340 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
1341 | { | |
1342 | struct inode *inode = old_dentry->d_inode; | |
5b04c689 | 1343 | int ret; |
1da177e4 LT |
1344 | |
1345 | /* | |
1346 | * No ordinary (disk based) filesystem counts links as inodes; | |
1347 | * but each new link needs a new dentry, pinning lowmem, and | |
1348 | * tmpfs dentries cannot be pruned until they are unlinked. | |
1349 | */ | |
5b04c689 PE |
1350 | ret = shmem_reserve_inode(inode->i_sb); |
1351 | if (ret) | |
1352 | goto out; | |
1da177e4 LT |
1353 | |
1354 | dir->i_size += BOGO_DIRENT_SIZE; | |
1355 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
d8c76e6f | 1356 | inc_nlink(inode); |
7de9c6ee | 1357 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
1358 | dget(dentry); /* Extra pinning count for the created dentry */ |
1359 | d_instantiate(dentry, inode); | |
5b04c689 PE |
1360 | out: |
1361 | return ret; | |
1da177e4 LT |
1362 | } |
1363 | ||
1364 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
1365 | { | |
1366 | struct inode *inode = dentry->d_inode; | |
1367 | ||
5b04c689 PE |
1368 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
1369 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
1370 | |
1371 | dir->i_size -= BOGO_DIRENT_SIZE; | |
1372 | inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
9a53c3a7 | 1373 | drop_nlink(inode); |
1da177e4 LT |
1374 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
1375 | return 0; | |
1376 | } | |
1377 | ||
1378 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
1379 | { | |
1380 | if (!simple_empty(dentry)) | |
1381 | return -ENOTEMPTY; | |
1382 | ||
9a53c3a7 DH |
1383 | drop_nlink(dentry->d_inode); |
1384 | drop_nlink(dir); | |
1da177e4 LT |
1385 | return shmem_unlink(dir, dentry); |
1386 | } | |
1387 | ||
1388 | /* | |
1389 | * The VFS layer already does all the dentry stuff for rename, | |
1390 | * we just have to decrement the usage count for the target if | |
1391 | * it exists so that the VFS layer correctly free's it when it | |
1392 | * gets overwritten. | |
1393 | */ | |
1394 | static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
1395 | { | |
1396 | struct inode *inode = old_dentry->d_inode; | |
1397 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
1398 | ||
1399 | if (!simple_empty(new_dentry)) | |
1400 | return -ENOTEMPTY; | |
1401 | ||
1402 | if (new_dentry->d_inode) { | |
1403 | (void) shmem_unlink(new_dir, new_dentry); | |
1404 | if (they_are_dirs) | |
9a53c3a7 | 1405 | drop_nlink(old_dir); |
1da177e4 | 1406 | } else if (they_are_dirs) { |
9a53c3a7 | 1407 | drop_nlink(old_dir); |
d8c76e6f | 1408 | inc_nlink(new_dir); |
1da177e4 LT |
1409 | } |
1410 | ||
1411 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
1412 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
1413 | old_dir->i_ctime = old_dir->i_mtime = | |
1414 | new_dir->i_ctime = new_dir->i_mtime = | |
1415 | inode->i_ctime = CURRENT_TIME; | |
1416 | return 0; | |
1417 | } | |
1418 | ||
1419 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
1420 | { | |
1421 | int error; | |
1422 | int len; | |
1423 | struct inode *inode; | |
9276aad6 | 1424 | struct page *page; |
1da177e4 LT |
1425 | char *kaddr; |
1426 | struct shmem_inode_info *info; | |
1427 | ||
1428 | len = strlen(symname) + 1; | |
1429 | if (len > PAGE_CACHE_SIZE) | |
1430 | return -ENAMETOOLONG; | |
1431 | ||
454abafe | 1432 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
1433 | if (!inode) |
1434 | return -ENOSPC; | |
1435 | ||
2a7dba39 EP |
1436 | error = security_inode_init_security(inode, dir, &dentry->d_name, NULL, |
1437 | NULL, NULL); | |
570bc1c2 SS |
1438 | if (error) { |
1439 | if (error != -EOPNOTSUPP) { | |
1440 | iput(inode); | |
1441 | return error; | |
1442 | } | |
1443 | error = 0; | |
1444 | } | |
1445 | ||
1da177e4 LT |
1446 | info = SHMEM_I(inode); |
1447 | inode->i_size = len-1; | |
b09e0fa4 | 1448 | if (len <= SHMEM_SYMLINK_INLINE_LEN) { |
1da177e4 | 1449 | /* do it inline */ |
b09e0fa4 | 1450 | memcpy(info->inline_symlink, symname, len); |
1da177e4 LT |
1451 | inode->i_op = &shmem_symlink_inline_operations; |
1452 | } else { | |
1453 | error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); | |
1454 | if (error) { | |
1455 | iput(inode); | |
1456 | return error; | |
1457 | } | |
14fcc23f | 1458 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
1459 | inode->i_op = &shmem_symlink_inode_operations; |
1460 | kaddr = kmap_atomic(page, KM_USER0); | |
1461 | memcpy(kaddr, symname, len); | |
1462 | kunmap_atomic(kaddr, KM_USER0); | |
1463 | set_page_dirty(page); | |
6746aff7 | 1464 | unlock_page(page); |
1da177e4 LT |
1465 | page_cache_release(page); |
1466 | } | |
1da177e4 LT |
1467 | dir->i_size += BOGO_DIRENT_SIZE; |
1468 | dir->i_ctime = dir->i_mtime = CURRENT_TIME; | |
1469 | d_instantiate(dentry, inode); | |
1470 | dget(dentry); | |
1471 | return 0; | |
1472 | } | |
1473 | ||
cc314eef | 1474 | static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd) |
1da177e4 | 1475 | { |
b09e0fa4 | 1476 | nd_set_link(nd, SHMEM_I(dentry->d_inode)->inline_symlink); |
cc314eef | 1477 | return NULL; |
1da177e4 LT |
1478 | } |
1479 | ||
cc314eef | 1480 | static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd) |
1da177e4 LT |
1481 | { |
1482 | struct page *page = NULL; | |
1483 | int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL); | |
1484 | nd_set_link(nd, res ? ERR_PTR(res) : kmap(page)); | |
d3602444 HD |
1485 | if (page) |
1486 | unlock_page(page); | |
cc314eef | 1487 | return page; |
1da177e4 LT |
1488 | } |
1489 | ||
cc314eef | 1490 | static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
1da177e4 LT |
1491 | { |
1492 | if (!IS_ERR(nd_get_link(nd))) { | |
cc314eef | 1493 | struct page *page = cookie; |
1da177e4 LT |
1494 | kunmap(page); |
1495 | mark_page_accessed(page); | |
1496 | page_cache_release(page); | |
1da177e4 LT |
1497 | } |
1498 | } | |
1499 | ||
b09e0fa4 | 1500 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 1501 | /* |
b09e0fa4 EP |
1502 | * Superblocks without xattr inode operations may get some security.* xattr |
1503 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
1504 | * like ACLs, we also need to implement the security.* handlers at |
1505 | * filesystem level, though. | |
1506 | */ | |
1507 | ||
b09e0fa4 EP |
1508 | static int shmem_xattr_get(struct dentry *dentry, const char *name, |
1509 | void *buffer, size_t size) | |
39f0247d | 1510 | { |
b09e0fa4 EP |
1511 | struct shmem_inode_info *info; |
1512 | struct shmem_xattr *xattr; | |
1513 | int ret = -ENODATA; | |
39f0247d | 1514 | |
b09e0fa4 EP |
1515 | info = SHMEM_I(dentry->d_inode); |
1516 | ||
1517 | spin_lock(&info->lock); | |
1518 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1519 | if (strcmp(name, xattr->name)) | |
1520 | continue; | |
1521 | ||
1522 | ret = xattr->size; | |
1523 | if (buffer) { | |
1524 | if (size < xattr->size) | |
1525 | ret = -ERANGE; | |
1526 | else | |
1527 | memcpy(buffer, xattr->value, xattr->size); | |
1528 | } | |
1529 | break; | |
1530 | } | |
1531 | spin_unlock(&info->lock); | |
1532 | return ret; | |
39f0247d AG |
1533 | } |
1534 | ||
b09e0fa4 EP |
1535 | static int shmem_xattr_set(struct dentry *dentry, const char *name, |
1536 | const void *value, size_t size, int flags) | |
39f0247d | 1537 | { |
b09e0fa4 EP |
1538 | struct inode *inode = dentry->d_inode; |
1539 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1540 | struct shmem_xattr *xattr; | |
1541 | struct shmem_xattr *new_xattr = NULL; | |
1542 | size_t len; | |
1543 | int err = 0; | |
1544 | ||
1545 | /* value == NULL means remove */ | |
1546 | if (value) { | |
1547 | /* wrap around? */ | |
1548 | len = sizeof(*new_xattr) + size; | |
1549 | if (len <= sizeof(*new_xattr)) | |
1550 | return -ENOMEM; | |
1551 | ||
1552 | new_xattr = kmalloc(len, GFP_KERNEL); | |
1553 | if (!new_xattr) | |
1554 | return -ENOMEM; | |
1555 | ||
1556 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
1557 | if (!new_xattr->name) { | |
1558 | kfree(new_xattr); | |
1559 | return -ENOMEM; | |
1560 | } | |
1561 | ||
1562 | new_xattr->size = size; | |
1563 | memcpy(new_xattr->value, value, size); | |
1564 | } | |
1565 | ||
1566 | spin_lock(&info->lock); | |
1567 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1568 | if (!strcmp(name, xattr->name)) { | |
1569 | if (flags & XATTR_CREATE) { | |
1570 | xattr = new_xattr; | |
1571 | err = -EEXIST; | |
1572 | } else if (new_xattr) { | |
1573 | list_replace(&xattr->list, &new_xattr->list); | |
1574 | } else { | |
1575 | list_del(&xattr->list); | |
1576 | } | |
1577 | goto out; | |
1578 | } | |
1579 | } | |
1580 | if (flags & XATTR_REPLACE) { | |
1581 | xattr = new_xattr; | |
1582 | err = -ENODATA; | |
1583 | } else { | |
1584 | list_add(&new_xattr->list, &info->xattr_list); | |
1585 | xattr = NULL; | |
1586 | } | |
1587 | out: | |
1588 | spin_unlock(&info->lock); | |
1589 | if (xattr) | |
1590 | kfree(xattr->name); | |
1591 | kfree(xattr); | |
1592 | return err; | |
39f0247d AG |
1593 | } |
1594 | ||
39f0247d | 1595 | |
bb435453 | 1596 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
b09e0fa4 | 1597 | #ifdef CONFIG_TMPFS_POSIX_ACL |
1c7c474c CH |
1598 | &generic_acl_access_handler, |
1599 | &generic_acl_default_handler, | |
b09e0fa4 | 1600 | #endif |
39f0247d AG |
1601 | NULL |
1602 | }; | |
b09e0fa4 EP |
1603 | |
1604 | static int shmem_xattr_validate(const char *name) | |
1605 | { | |
1606 | struct { const char *prefix; size_t len; } arr[] = { | |
1607 | { XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN }, | |
1608 | { XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN } | |
1609 | }; | |
1610 | int i; | |
1611 | ||
1612 | for (i = 0; i < ARRAY_SIZE(arr); i++) { | |
1613 | size_t preflen = arr[i].len; | |
1614 | if (strncmp(name, arr[i].prefix, preflen) == 0) { | |
1615 | if (!name[preflen]) | |
1616 | return -EINVAL; | |
1617 | return 0; | |
1618 | } | |
1619 | } | |
1620 | return -EOPNOTSUPP; | |
1621 | } | |
1622 | ||
1623 | static ssize_t shmem_getxattr(struct dentry *dentry, const char *name, | |
1624 | void *buffer, size_t size) | |
1625 | { | |
1626 | int err; | |
1627 | ||
1628 | /* | |
1629 | * If this is a request for a synthetic attribute in the system.* | |
1630 | * namespace use the generic infrastructure to resolve a handler | |
1631 | * for it via sb->s_xattr. | |
1632 | */ | |
1633 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1634 | return generic_getxattr(dentry, name, buffer, size); | |
1635 | ||
1636 | err = shmem_xattr_validate(name); | |
1637 | if (err) | |
1638 | return err; | |
1639 | ||
1640 | return shmem_xattr_get(dentry, name, buffer, size); | |
1641 | } | |
1642 | ||
1643 | static int shmem_setxattr(struct dentry *dentry, const char *name, | |
1644 | const void *value, size_t size, int flags) | |
1645 | { | |
1646 | int err; | |
1647 | ||
1648 | /* | |
1649 | * If this is a request for a synthetic attribute in the system.* | |
1650 | * namespace use the generic infrastructure to resolve a handler | |
1651 | * for it via sb->s_xattr. | |
1652 | */ | |
1653 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1654 | return generic_setxattr(dentry, name, value, size, flags); | |
1655 | ||
1656 | err = shmem_xattr_validate(name); | |
1657 | if (err) | |
1658 | return err; | |
1659 | ||
1660 | if (size == 0) | |
1661 | value = ""; /* empty EA, do not remove */ | |
1662 | ||
1663 | return shmem_xattr_set(dentry, name, value, size, flags); | |
1664 | ||
1665 | } | |
1666 | ||
1667 | static int shmem_removexattr(struct dentry *dentry, const char *name) | |
1668 | { | |
1669 | int err; | |
1670 | ||
1671 | /* | |
1672 | * If this is a request for a synthetic attribute in the system.* | |
1673 | * namespace use the generic infrastructure to resolve a handler | |
1674 | * for it via sb->s_xattr. | |
1675 | */ | |
1676 | if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
1677 | return generic_removexattr(dentry, name); | |
1678 | ||
1679 | err = shmem_xattr_validate(name); | |
1680 | if (err) | |
1681 | return err; | |
1682 | ||
1683 | return shmem_xattr_set(dentry, name, NULL, 0, XATTR_REPLACE); | |
1684 | } | |
1685 | ||
1686 | static bool xattr_is_trusted(const char *name) | |
1687 | { | |
1688 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
1689 | } | |
1690 | ||
1691 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
1692 | { | |
1693 | bool trusted = capable(CAP_SYS_ADMIN); | |
1694 | struct shmem_xattr *xattr; | |
1695 | struct shmem_inode_info *info; | |
1696 | size_t used = 0; | |
1697 | ||
1698 | info = SHMEM_I(dentry->d_inode); | |
1699 | ||
1700 | spin_lock(&info->lock); | |
1701 | list_for_each_entry(xattr, &info->xattr_list, list) { | |
1702 | size_t len; | |
1703 | ||
1704 | /* skip "trusted." attributes for unprivileged callers */ | |
1705 | if (!trusted && xattr_is_trusted(xattr->name)) | |
1706 | continue; | |
1707 | ||
1708 | len = strlen(xattr->name) + 1; | |
1709 | used += len; | |
1710 | if (buffer) { | |
1711 | if (size < used) { | |
1712 | used = -ERANGE; | |
1713 | break; | |
1714 | } | |
1715 | memcpy(buffer, xattr->name, len); | |
1716 | buffer += len; | |
1717 | } | |
1718 | } | |
1719 | spin_unlock(&info->lock); | |
1720 | ||
1721 | return used; | |
1722 | } | |
1723 | #endif /* CONFIG_TMPFS_XATTR */ | |
1724 | ||
1725 | static const struct inode_operations shmem_symlink_inline_operations = { | |
1726 | .readlink = generic_readlink, | |
1727 | .follow_link = shmem_follow_link_inline, | |
1728 | #ifdef CONFIG_TMPFS_XATTR | |
1729 | .setxattr = shmem_setxattr, | |
1730 | .getxattr = shmem_getxattr, | |
1731 | .listxattr = shmem_listxattr, | |
1732 | .removexattr = shmem_removexattr, | |
1733 | #endif | |
1734 | }; | |
1735 | ||
1736 | static const struct inode_operations shmem_symlink_inode_operations = { | |
1737 | .readlink = generic_readlink, | |
1738 | .follow_link = shmem_follow_link, | |
1739 | .put_link = shmem_put_link, | |
1740 | #ifdef CONFIG_TMPFS_XATTR | |
1741 | .setxattr = shmem_setxattr, | |
1742 | .getxattr = shmem_getxattr, | |
1743 | .listxattr = shmem_listxattr, | |
1744 | .removexattr = shmem_removexattr, | |
39f0247d | 1745 | #endif |
b09e0fa4 | 1746 | }; |
39f0247d | 1747 | |
91828a40 DG |
1748 | static struct dentry *shmem_get_parent(struct dentry *child) |
1749 | { | |
1750 | return ERR_PTR(-ESTALE); | |
1751 | } | |
1752 | ||
1753 | static int shmem_match(struct inode *ino, void *vfh) | |
1754 | { | |
1755 | __u32 *fh = vfh; | |
1756 | __u64 inum = fh[2]; | |
1757 | inum = (inum << 32) | fh[1]; | |
1758 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
1759 | } | |
1760 | ||
480b116c CH |
1761 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
1762 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 1763 | { |
91828a40 | 1764 | struct inode *inode; |
480b116c CH |
1765 | struct dentry *dentry = NULL; |
1766 | u64 inum = fid->raw[2]; | |
1767 | inum = (inum << 32) | fid->raw[1]; | |
1768 | ||
1769 | if (fh_len < 3) | |
1770 | return NULL; | |
91828a40 | 1771 | |
480b116c CH |
1772 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
1773 | shmem_match, fid->raw); | |
91828a40 | 1774 | if (inode) { |
480b116c | 1775 | dentry = d_find_alias(inode); |
91828a40 DG |
1776 | iput(inode); |
1777 | } | |
1778 | ||
480b116c | 1779 | return dentry; |
91828a40 DG |
1780 | } |
1781 | ||
1782 | static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len, | |
1783 | int connectable) | |
1784 | { | |
1785 | struct inode *inode = dentry->d_inode; | |
1786 | ||
5fe0c237 AK |
1787 | if (*len < 3) { |
1788 | *len = 3; | |
91828a40 | 1789 | return 255; |
5fe0c237 | 1790 | } |
91828a40 | 1791 | |
1d3382cb | 1792 | if (inode_unhashed(inode)) { |
91828a40 DG |
1793 | /* Unfortunately insert_inode_hash is not idempotent, |
1794 | * so as we hash inodes here rather than at creation | |
1795 | * time, we need a lock to ensure we only try | |
1796 | * to do it once | |
1797 | */ | |
1798 | static DEFINE_SPINLOCK(lock); | |
1799 | spin_lock(&lock); | |
1d3382cb | 1800 | if (inode_unhashed(inode)) |
91828a40 DG |
1801 | __insert_inode_hash(inode, |
1802 | inode->i_ino + inode->i_generation); | |
1803 | spin_unlock(&lock); | |
1804 | } | |
1805 | ||
1806 | fh[0] = inode->i_generation; | |
1807 | fh[1] = inode->i_ino; | |
1808 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
1809 | ||
1810 | *len = 3; | |
1811 | return 1; | |
1812 | } | |
1813 | ||
39655164 | 1814 | static const struct export_operations shmem_export_ops = { |
91828a40 | 1815 | .get_parent = shmem_get_parent, |
91828a40 | 1816 | .encode_fh = shmem_encode_fh, |
480b116c | 1817 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
1818 | }; |
1819 | ||
680d794b | 1820 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
1821 | bool remount) | |
1da177e4 LT |
1822 | { |
1823 | char *this_char, *value, *rest; | |
1824 | ||
b00dc3ad HD |
1825 | while (options != NULL) { |
1826 | this_char = options; | |
1827 | for (;;) { | |
1828 | /* | |
1829 | * NUL-terminate this option: unfortunately, | |
1830 | * mount options form a comma-separated list, | |
1831 | * but mpol's nodelist may also contain commas. | |
1832 | */ | |
1833 | options = strchr(options, ','); | |
1834 | if (options == NULL) | |
1835 | break; | |
1836 | options++; | |
1837 | if (!isdigit(*options)) { | |
1838 | options[-1] = '\0'; | |
1839 | break; | |
1840 | } | |
1841 | } | |
1da177e4 LT |
1842 | if (!*this_char) |
1843 | continue; | |
1844 | if ((value = strchr(this_char,'=')) != NULL) { | |
1845 | *value++ = 0; | |
1846 | } else { | |
1847 | printk(KERN_ERR | |
1848 | "tmpfs: No value for mount option '%s'\n", | |
1849 | this_char); | |
1850 | return 1; | |
1851 | } | |
1852 | ||
1853 | if (!strcmp(this_char,"size")) { | |
1854 | unsigned long long size; | |
1855 | size = memparse(value,&rest); | |
1856 | if (*rest == '%') { | |
1857 | size <<= PAGE_SHIFT; | |
1858 | size *= totalram_pages; | |
1859 | do_div(size, 100); | |
1860 | rest++; | |
1861 | } | |
1862 | if (*rest) | |
1863 | goto bad_val; | |
680d794b | 1864 | sbinfo->max_blocks = |
1865 | DIV_ROUND_UP(size, PAGE_CACHE_SIZE); | |
1da177e4 | 1866 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 1867 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
1868 | if (*rest) |
1869 | goto bad_val; | |
1870 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 1871 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
1872 | if (*rest) |
1873 | goto bad_val; | |
1874 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 1875 | if (remount) |
1da177e4 | 1876 | continue; |
680d794b | 1877 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
1878 | if (*rest) |
1879 | goto bad_val; | |
1880 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 1881 | if (remount) |
1da177e4 | 1882 | continue; |
680d794b | 1883 | sbinfo->uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
1884 | if (*rest) |
1885 | goto bad_val; | |
1886 | } else if (!strcmp(this_char,"gid")) { | |
680d794b | 1887 | if (remount) |
1da177e4 | 1888 | continue; |
680d794b | 1889 | sbinfo->gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
1890 | if (*rest) |
1891 | goto bad_val; | |
7339ff83 | 1892 | } else if (!strcmp(this_char,"mpol")) { |
71fe804b | 1893 | if (mpol_parse_str(value, &sbinfo->mpol, 1)) |
7339ff83 | 1894 | goto bad_val; |
1da177e4 LT |
1895 | } else { |
1896 | printk(KERN_ERR "tmpfs: Bad mount option %s\n", | |
1897 | this_char); | |
1898 | return 1; | |
1899 | } | |
1900 | } | |
1901 | return 0; | |
1902 | ||
1903 | bad_val: | |
1904 | printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n", | |
1905 | value, this_char); | |
1906 | return 1; | |
1907 | ||
1908 | } | |
1909 | ||
1910 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
1911 | { | |
1912 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 1913 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
1914 | unsigned long inodes; |
1915 | int error = -EINVAL; | |
1916 | ||
680d794b | 1917 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 1918 | return error; |
1da177e4 | 1919 | |
0edd73b3 | 1920 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 1921 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 1922 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 1923 | goto out; |
680d794b | 1924 | if (config.max_inodes < inodes) |
0edd73b3 HD |
1925 | goto out; |
1926 | /* | |
1927 | * Those tests also disallow limited->unlimited while any are in | |
1928 | * use, so i_blocks will always be zero when max_blocks is zero; | |
1929 | * but we must separately disallow unlimited->limited, because | |
1930 | * in that case we have no record of how much is already in use. | |
1931 | */ | |
680d794b | 1932 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 1933 | goto out; |
680d794b | 1934 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
1935 | goto out; |
1936 | ||
1937 | error = 0; | |
680d794b | 1938 | sbinfo->max_blocks = config.max_blocks; |
680d794b | 1939 | sbinfo->max_inodes = config.max_inodes; |
1940 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b LS |
1941 | |
1942 | mpol_put(sbinfo->mpol); | |
1943 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
0edd73b3 HD |
1944 | out: |
1945 | spin_unlock(&sbinfo->stat_lock); | |
1946 | return error; | |
1da177e4 | 1947 | } |
680d794b | 1948 | |
1949 | static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs) | |
1950 | { | |
1951 | struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb); | |
1952 | ||
1953 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
1954 | seq_printf(seq, ",size=%luk", | |
1955 | sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10)); | |
1956 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
1957 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
1958 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
1959 | seq_printf(seq, ",mode=%03o", sbinfo->mode); | |
1960 | if (sbinfo->uid != 0) | |
1961 | seq_printf(seq, ",uid=%u", sbinfo->uid); | |
1962 | if (sbinfo->gid != 0) | |
1963 | seq_printf(seq, ",gid=%u", sbinfo->gid); | |
71fe804b | 1964 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b | 1965 | return 0; |
1966 | } | |
1967 | #endif /* CONFIG_TMPFS */ | |
1da177e4 LT |
1968 | |
1969 | static void shmem_put_super(struct super_block *sb) | |
1970 | { | |
602586a8 HD |
1971 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
1972 | ||
1973 | percpu_counter_destroy(&sbinfo->used_blocks); | |
1974 | kfree(sbinfo); | |
1da177e4 LT |
1975 | sb->s_fs_info = NULL; |
1976 | } | |
1977 | ||
2b2af54a | 1978 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
1979 | { |
1980 | struct inode *inode; | |
1981 | struct dentry *root; | |
0edd73b3 | 1982 | struct shmem_sb_info *sbinfo; |
680d794b | 1983 | int err = -ENOMEM; |
1984 | ||
1985 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 1986 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b | 1987 | L1_CACHE_BYTES), GFP_KERNEL); |
1988 | if (!sbinfo) | |
1989 | return -ENOMEM; | |
1990 | ||
680d794b | 1991 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
1992 | sbinfo->uid = current_fsuid(); |
1993 | sbinfo->gid = current_fsgid(); | |
680d794b | 1994 | sb->s_fs_info = sbinfo; |
1da177e4 | 1995 | |
0edd73b3 | 1996 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
1997 | /* |
1998 | * Per default we only allow half of the physical ram per | |
1999 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
2000 | * but the internal instance is left unlimited. | |
2001 | */ | |
2002 | if (!(sb->s_flags & MS_NOUSER)) { | |
680d794b | 2003 | sbinfo->max_blocks = shmem_default_max_blocks(); |
2004 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
2005 | if (shmem_parse_options(data, sbinfo, false)) { | |
2006 | err = -EINVAL; | |
2007 | goto failed; | |
2008 | } | |
1da177e4 | 2009 | } |
91828a40 | 2010 | sb->s_export_op = &shmem_export_ops; |
1da177e4 LT |
2011 | #else |
2012 | sb->s_flags |= MS_NOUSER; | |
2013 | #endif | |
2014 | ||
0edd73b3 | 2015 | spin_lock_init(&sbinfo->stat_lock); |
602586a8 HD |
2016 | if (percpu_counter_init(&sbinfo->used_blocks, 0)) |
2017 | goto failed; | |
680d794b | 2018 | sbinfo->free_inodes = sbinfo->max_inodes; |
0edd73b3 | 2019 | |
285b2c4f | 2020 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
1da177e4 LT |
2021 | sb->s_blocksize = PAGE_CACHE_SIZE; |
2022 | sb->s_blocksize_bits = PAGE_CACHE_SHIFT; | |
2023 | sb->s_magic = TMPFS_MAGIC; | |
2024 | sb->s_op = &shmem_ops; | |
cfd95a9c | 2025 | sb->s_time_gran = 1; |
b09e0fa4 | 2026 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 2027 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
2028 | #endif |
2029 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
2030 | sb->s_flags |= MS_POSIXACL; |
2031 | #endif | |
0edd73b3 | 2032 | |
454abafe | 2033 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
2034 | if (!inode) |
2035 | goto failed; | |
680d794b | 2036 | inode->i_uid = sbinfo->uid; |
2037 | inode->i_gid = sbinfo->gid; | |
1da177e4 LT |
2038 | root = d_alloc_root(inode); |
2039 | if (!root) | |
2040 | goto failed_iput; | |
2041 | sb->s_root = root; | |
2042 | return 0; | |
2043 | ||
2044 | failed_iput: | |
2045 | iput(inode); | |
2046 | failed: | |
2047 | shmem_put_super(sb); | |
2048 | return err; | |
2049 | } | |
2050 | ||
fcc234f8 | 2051 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
2052 | |
2053 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
2054 | { | |
2055 | struct shmem_inode_info *p; | |
e94b1766 | 2056 | p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); |
1da177e4 LT |
2057 | if (!p) |
2058 | return NULL; | |
2059 | return &p->vfs_inode; | |
2060 | } | |
2061 | ||
fa0d7e3d NP |
2062 | static void shmem_i_callback(struct rcu_head *head) |
2063 | { | |
2064 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
2065 | INIT_LIST_HEAD(&inode->i_dentry); | |
2066 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
2067 | } | |
2068 | ||
1da177e4 LT |
2069 | static void shmem_destroy_inode(struct inode *inode) |
2070 | { | |
2071 | if ((inode->i_mode & S_IFMT) == S_IFREG) { | |
2072 | /* only struct inode is valid if it's an inline symlink */ | |
2073 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
2074 | } | |
fa0d7e3d | 2075 | call_rcu(&inode->i_rcu, shmem_i_callback); |
1da177e4 LT |
2076 | } |
2077 | ||
51cc5068 | 2078 | static void init_once(void *foo) |
1da177e4 LT |
2079 | { |
2080 | struct shmem_inode_info *p = (struct shmem_inode_info *) foo; | |
2081 | ||
a35afb83 | 2082 | inode_init_once(&p->vfs_inode); |
1da177e4 LT |
2083 | } |
2084 | ||
2085 | static int init_inodecache(void) | |
2086 | { | |
2087 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
2088 | sizeof(struct shmem_inode_info), | |
040b5c6f | 2089 | 0, SLAB_PANIC, init_once); |
1da177e4 LT |
2090 | return 0; |
2091 | } | |
2092 | ||
2093 | static void destroy_inodecache(void) | |
2094 | { | |
1a1d92c1 | 2095 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
2096 | } |
2097 | ||
f5e54d6e | 2098 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 2099 | .writepage = shmem_writepage, |
76719325 | 2100 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 2101 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
2102 | .write_begin = shmem_write_begin, |
2103 | .write_end = shmem_write_end, | |
1da177e4 | 2104 | #endif |
304dbdb7 | 2105 | .migratepage = migrate_page, |
aa261f54 | 2106 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
2107 | }; |
2108 | ||
15ad7cdc | 2109 | static const struct file_operations shmem_file_operations = { |
1da177e4 LT |
2110 | .mmap = shmem_mmap, |
2111 | #ifdef CONFIG_TMPFS | |
2112 | .llseek = generic_file_llseek, | |
bcd78e49 | 2113 | .read = do_sync_read, |
5402b976 | 2114 | .write = do_sync_write, |
bcd78e49 | 2115 | .aio_read = shmem_file_aio_read, |
5402b976 | 2116 | .aio_write = generic_file_aio_write, |
1b061d92 | 2117 | .fsync = noop_fsync, |
708e3508 | 2118 | .splice_read = shmem_file_splice_read, |
ae976416 | 2119 | .splice_write = generic_file_splice_write, |
1da177e4 LT |
2120 | #endif |
2121 | }; | |
2122 | ||
92e1d5be | 2123 | static const struct inode_operations shmem_inode_operations = { |
94c1e62d | 2124 | .setattr = shmem_setattr, |
f6b3ec23 | 2125 | .truncate_range = shmem_truncate_range, |
b09e0fa4 EP |
2126 | #ifdef CONFIG_TMPFS_XATTR |
2127 | .setxattr = shmem_setxattr, | |
2128 | .getxattr = shmem_getxattr, | |
2129 | .listxattr = shmem_listxattr, | |
2130 | .removexattr = shmem_removexattr, | |
2131 | #endif | |
1da177e4 LT |
2132 | }; |
2133 | ||
92e1d5be | 2134 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
2135 | #ifdef CONFIG_TMPFS |
2136 | .create = shmem_create, | |
2137 | .lookup = simple_lookup, | |
2138 | .link = shmem_link, | |
2139 | .unlink = shmem_unlink, | |
2140 | .symlink = shmem_symlink, | |
2141 | .mkdir = shmem_mkdir, | |
2142 | .rmdir = shmem_rmdir, | |
2143 | .mknod = shmem_mknod, | |
2144 | .rename = shmem_rename, | |
1da177e4 | 2145 | #endif |
b09e0fa4 EP |
2146 | #ifdef CONFIG_TMPFS_XATTR |
2147 | .setxattr = shmem_setxattr, | |
2148 | .getxattr = shmem_getxattr, | |
2149 | .listxattr = shmem_listxattr, | |
2150 | .removexattr = shmem_removexattr, | |
2151 | #endif | |
39f0247d | 2152 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2153 | .setattr = shmem_setattr, |
39f0247d AG |
2154 | #endif |
2155 | }; | |
2156 | ||
92e1d5be | 2157 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 EP |
2158 | #ifdef CONFIG_TMPFS_XATTR |
2159 | .setxattr = shmem_setxattr, | |
2160 | .getxattr = shmem_getxattr, | |
2161 | .listxattr = shmem_listxattr, | |
2162 | .removexattr = shmem_removexattr, | |
2163 | #endif | |
39f0247d | 2164 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 2165 | .setattr = shmem_setattr, |
39f0247d | 2166 | #endif |
1da177e4 LT |
2167 | }; |
2168 | ||
759b9775 | 2169 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
2170 | .alloc_inode = shmem_alloc_inode, |
2171 | .destroy_inode = shmem_destroy_inode, | |
2172 | #ifdef CONFIG_TMPFS | |
2173 | .statfs = shmem_statfs, | |
2174 | .remount_fs = shmem_remount_fs, | |
680d794b | 2175 | .show_options = shmem_show_options, |
1da177e4 | 2176 | #endif |
1f895f75 | 2177 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
2178 | .drop_inode = generic_delete_inode, |
2179 | .put_super = shmem_put_super, | |
2180 | }; | |
2181 | ||
f0f37e2f | 2182 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 2183 | .fault = shmem_fault, |
1da177e4 LT |
2184 | #ifdef CONFIG_NUMA |
2185 | .set_policy = shmem_set_policy, | |
2186 | .get_policy = shmem_get_policy, | |
2187 | #endif | |
2188 | }; | |
2189 | ||
2190 | ||
3c26ff6e AV |
2191 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
2192 | int flags, const char *dev_name, void *data) | |
1da177e4 | 2193 | { |
3c26ff6e | 2194 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
2195 | } |
2196 | ||
2197 | static struct file_system_type tmpfs_fs_type = { | |
2198 | .owner = THIS_MODULE, | |
2199 | .name = "tmpfs", | |
3c26ff6e | 2200 | .mount = shmem_mount, |
1da177e4 LT |
2201 | .kill_sb = kill_litter_super, |
2202 | }; | |
1da177e4 | 2203 | |
2b2af54a | 2204 | int __init init_tmpfs(void) |
1da177e4 LT |
2205 | { |
2206 | int error; | |
2207 | ||
e0bf68dd PZ |
2208 | error = bdi_init(&shmem_backing_dev_info); |
2209 | if (error) | |
2210 | goto out4; | |
2211 | ||
1da177e4 LT |
2212 | error = init_inodecache(); |
2213 | if (error) | |
2214 | goto out3; | |
2215 | ||
2216 | error = register_filesystem(&tmpfs_fs_type); | |
2217 | if (error) { | |
2218 | printk(KERN_ERR "Could not register tmpfs\n"); | |
2219 | goto out2; | |
2220 | } | |
95dc112a | 2221 | |
1f5ce9e9 | 2222 | shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER, |
1da177e4 LT |
2223 | tmpfs_fs_type.name, NULL); |
2224 | if (IS_ERR(shm_mnt)) { | |
2225 | error = PTR_ERR(shm_mnt); | |
2226 | printk(KERN_ERR "Could not kern_mount tmpfs\n"); | |
2227 | goto out1; | |
2228 | } | |
2229 | return 0; | |
2230 | ||
2231 | out1: | |
2232 | unregister_filesystem(&tmpfs_fs_type); | |
2233 | out2: | |
2234 | destroy_inodecache(); | |
2235 | out3: | |
e0bf68dd PZ |
2236 | bdi_destroy(&shmem_backing_dev_info); |
2237 | out4: | |
1da177e4 LT |
2238 | shm_mnt = ERR_PTR(error); |
2239 | return error; | |
2240 | } | |
853ac43a | 2241 | |
87946a72 DN |
2242 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2243 | /** | |
2244 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2245 | * @inode: the inode to be searched | |
2246 | * @pgoff: the offset to be searched | |
2247 | * @pagep: the pointer for the found page to be stored | |
2248 | * @ent: the pointer for the found swap entry to be stored | |
2249 | * | |
2250 | * If a page is found, refcount of it is incremented. Callers should handle | |
2251 | * these refcount. | |
2252 | */ | |
2253 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2254 | struct page **pagep, swp_entry_t *ent) | |
2255 | { | |
285b2c4f | 2256 | swp_entry_t entry = { .val = 0 }; |
87946a72 DN |
2257 | struct page *page = NULL; |
2258 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2259 | ||
2260 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2261 | goto out; | |
2262 | ||
2263 | spin_lock(&info->lock); | |
87946a72 | 2264 | #ifdef CONFIG_SWAP |
285b2c4f HD |
2265 | entry = shmem_get_swap(info, pgoff); |
2266 | if (entry.val) | |
87946a72 | 2267 | page = find_get_page(&swapper_space, entry.val); |
285b2c4f | 2268 | else |
87946a72 DN |
2269 | #endif |
2270 | page = find_get_page(inode->i_mapping, pgoff); | |
87946a72 DN |
2271 | spin_unlock(&info->lock); |
2272 | out: | |
2273 | *pagep = page; | |
2274 | *ent = entry; | |
2275 | } | |
2276 | #endif | |
2277 | ||
853ac43a MM |
2278 | #else /* !CONFIG_SHMEM */ |
2279 | ||
2280 | /* | |
2281 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
2282 | * | |
2283 | * This is intended for small system where the benefits of the full | |
2284 | * shmem code (swap-backed and resource-limited) are outweighed by | |
2285 | * their complexity. On systems without swap this code should be | |
2286 | * effectively equivalent, but much lighter weight. | |
2287 | */ | |
2288 | ||
2289 | #include <linux/ramfs.h> | |
2290 | ||
2291 | static struct file_system_type tmpfs_fs_type = { | |
2292 | .name = "tmpfs", | |
3c26ff6e | 2293 | .mount = ramfs_mount, |
853ac43a MM |
2294 | .kill_sb = kill_litter_super, |
2295 | }; | |
2296 | ||
2b2af54a | 2297 | int __init init_tmpfs(void) |
853ac43a MM |
2298 | { |
2299 | BUG_ON(register_filesystem(&tmpfs_fs_type) != 0); | |
2300 | ||
2301 | shm_mnt = kern_mount(&tmpfs_fs_type); | |
2302 | BUG_ON(IS_ERR(shm_mnt)); | |
2303 | ||
2304 | return 0; | |
2305 | } | |
2306 | ||
2307 | int shmem_unuse(swp_entry_t entry, struct page *page) | |
2308 | { | |
2309 | return 0; | |
2310 | } | |
2311 | ||
3f96b79a HD |
2312 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
2313 | { | |
2314 | return 0; | |
2315 | } | |
2316 | ||
94c1e62d HD |
2317 | void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end) |
2318 | { | |
2319 | truncate_inode_pages_range(inode->i_mapping, start, end); | |
2320 | } | |
2321 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
2322 | ||
87946a72 DN |
2323 | #ifdef CONFIG_CGROUP_MEM_RES_CTLR |
2324 | /** | |
2325 | * mem_cgroup_get_shmem_target - find a page or entry assigned to the shmem file | |
2326 | * @inode: the inode to be searched | |
2327 | * @pgoff: the offset to be searched | |
2328 | * @pagep: the pointer for the found page to be stored | |
2329 | * @ent: the pointer for the found swap entry to be stored | |
2330 | * | |
2331 | * If a page is found, refcount of it is incremented. Callers should handle | |
2332 | * these refcount. | |
2333 | */ | |
2334 | void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff, | |
2335 | struct page **pagep, swp_entry_t *ent) | |
2336 | { | |
2337 | struct page *page = NULL; | |
2338 | ||
2339 | if ((pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode)) | |
2340 | goto out; | |
2341 | page = find_get_page(inode->i_mapping, pgoff); | |
2342 | out: | |
2343 | *pagep = page; | |
2344 | *ent = (swp_entry_t){ .val = 0 }; | |
2345 | } | |
2346 | #endif | |
2347 | ||
0b0a0806 HD |
2348 | #define shmem_vm_ops generic_file_vm_ops |
2349 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 2350 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
2351 | #define shmem_acct_size(flags, size) 0 |
2352 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
2353 | |
2354 | #endif /* CONFIG_SHMEM */ | |
2355 | ||
2356 | /* common code */ | |
1da177e4 | 2357 | |
46711810 | 2358 | /** |
1da177e4 | 2359 | * shmem_file_setup - get an unlinked file living in tmpfs |
1da177e4 LT |
2360 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
2361 | * @size: size to be set for the file | |
0b0a0806 | 2362 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size |
1da177e4 | 2363 | */ |
168f5ac6 | 2364 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) |
1da177e4 LT |
2365 | { |
2366 | int error; | |
2367 | struct file *file; | |
2368 | struct inode *inode; | |
2c48b9c4 AV |
2369 | struct path path; |
2370 | struct dentry *root; | |
1da177e4 LT |
2371 | struct qstr this; |
2372 | ||
2373 | if (IS_ERR(shm_mnt)) | |
2374 | return (void *)shm_mnt; | |
2375 | ||
285b2c4f | 2376 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
2377 | return ERR_PTR(-EINVAL); |
2378 | ||
2379 | if (shmem_acct_size(flags, size)) | |
2380 | return ERR_PTR(-ENOMEM); | |
2381 | ||
2382 | error = -ENOMEM; | |
2383 | this.name = name; | |
2384 | this.len = strlen(name); | |
2385 | this.hash = 0; /* will go */ | |
2386 | root = shm_mnt->mnt_root; | |
2c48b9c4 AV |
2387 | path.dentry = d_alloc(root, &this); |
2388 | if (!path.dentry) | |
1da177e4 | 2389 | goto put_memory; |
2c48b9c4 | 2390 | path.mnt = mntget(shm_mnt); |
1da177e4 | 2391 | |
1da177e4 | 2392 | error = -ENOSPC; |
454abafe | 2393 | inode = shmem_get_inode(root->d_sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 2394 | if (!inode) |
4b42af81 | 2395 | goto put_dentry; |
1da177e4 | 2396 | |
2c48b9c4 | 2397 | d_instantiate(path.dentry, inode); |
1da177e4 LT |
2398 | inode->i_size = size; |
2399 | inode->i_nlink = 0; /* It is unlinked */ | |
853ac43a MM |
2400 | #ifndef CONFIG_MMU |
2401 | error = ramfs_nommu_expand_for_mapping(inode, size); | |
2402 | if (error) | |
4b42af81 | 2403 | goto put_dentry; |
853ac43a | 2404 | #endif |
4b42af81 AV |
2405 | |
2406 | error = -ENFILE; | |
2c48b9c4 | 2407 | file = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 AV |
2408 | &shmem_file_operations); |
2409 | if (!file) | |
2410 | goto put_dentry; | |
2411 | ||
1da177e4 LT |
2412 | return file; |
2413 | ||
1da177e4 | 2414 | put_dentry: |
2c48b9c4 | 2415 | path_put(&path); |
1da177e4 LT |
2416 | put_memory: |
2417 | shmem_unacct_size(flags, size); | |
2418 | return ERR_PTR(error); | |
2419 | } | |
395e0ddc | 2420 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 2421 | |
46711810 | 2422 | /** |
1da177e4 | 2423 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
2424 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
2425 | */ | |
2426 | int shmem_zero_setup(struct vm_area_struct *vma) | |
2427 | { | |
2428 | struct file *file; | |
2429 | loff_t size = vma->vm_end - vma->vm_start; | |
2430 | ||
2431 | file = shmem_file_setup("dev/zero", size, vma->vm_flags); | |
2432 | if (IS_ERR(file)) | |
2433 | return PTR_ERR(file); | |
2434 | ||
2435 | if (vma->vm_file) | |
2436 | fput(vma->vm_file); | |
2437 | vma->vm_file = file; | |
2438 | vma->vm_ops = &shmem_vm_ops; | |
bee4c36a | 2439 | vma->vm_flags |= VM_CAN_NONLINEAR; |
1da177e4 LT |
2440 | return 0; |
2441 | } | |
d9d90e5e HD |
2442 | |
2443 | /** | |
2444 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
2445 | * @mapping: the page's address_space | |
2446 | * @index: the page index | |
2447 | * @gfp: the page allocator flags to use if allocating | |
2448 | * | |
2449 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
2450 | * with any new page allocations done using the specified allocation flags. | |
2451 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
2452 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
2453 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
2454 | * | |
68da9f05 HD |
2455 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
2456 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
2457 | */ |
2458 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
2459 | pgoff_t index, gfp_t gfp) | |
2460 | { | |
68da9f05 HD |
2461 | #ifdef CONFIG_SHMEM |
2462 | struct inode *inode = mapping->host; | |
9276aad6 | 2463 | struct page *page; |
68da9f05 HD |
2464 | int error; |
2465 | ||
2466 | BUG_ON(mapping->a_ops != &shmem_aops); | |
2467 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, gfp, NULL); | |
2468 | if (error) | |
2469 | page = ERR_PTR(error); | |
2470 | else | |
2471 | unlock_page(page); | |
2472 | return page; | |
2473 | #else | |
2474 | /* | |
2475 | * The tiny !SHMEM case uses ramfs without swap | |
2476 | */ | |
d9d90e5e | 2477 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 2478 | #endif |
d9d90e5e HD |
2479 | } |
2480 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |