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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Resizable virtual memory filesystem for Linux. | |
3 | * | |
4 | * Copyright (C) 2000 Linus Torvalds. | |
5 | * 2000 Transmeta Corp. | |
6 | * 2000-2001 Christoph Rohland | |
7 | * 2000-2001 SAP AG | |
8 | * 2002 Red Hat Inc. | |
6922c0c7 HD |
9 | * Copyright (C) 2002-2011 Hugh Dickins. |
10 | * Copyright (C) 2011 Google Inc. | |
0edd73b3 | 11 | * Copyright (C) 2002-2005 VERITAS Software Corporation. |
1da177e4 LT |
12 | * Copyright (C) 2004 Andi Kleen, SuSE Labs |
13 | * | |
14 | * Extended attribute support for tmpfs: | |
15 | * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net> | |
16 | * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
17 | * | |
853ac43a MM |
18 | * tiny-shmem: |
19 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
20 | * | |
1da177e4 LT |
21 | * This file is released under the GPL. |
22 | */ | |
23 | ||
853ac43a MM |
24 | #include <linux/fs.h> |
25 | #include <linux/init.h> | |
26 | #include <linux/vfs.h> | |
27 | #include <linux/mount.h> | |
250297ed | 28 | #include <linux/ramfs.h> |
caefba17 | 29 | #include <linux/pagemap.h> |
853ac43a MM |
30 | #include <linux/file.h> |
31 | #include <linux/mm.h> | |
b95f1b31 | 32 | #include <linux/export.h> |
853ac43a | 33 | #include <linux/swap.h> |
e2e40f2c | 34 | #include <linux/uio.h> |
f3f0e1d2 | 35 | #include <linux/khugepaged.h> |
853ac43a MM |
36 | |
37 | static struct vfsmount *shm_mnt; | |
38 | ||
39 | #ifdef CONFIG_SHMEM | |
1da177e4 LT |
40 | /* |
41 | * This virtual memory filesystem is heavily based on the ramfs. It | |
42 | * extends ramfs by the ability to use swap and honor resource limits | |
43 | * which makes it a completely usable filesystem. | |
44 | */ | |
45 | ||
39f0247d | 46 | #include <linux/xattr.h> |
a5694255 | 47 | #include <linux/exportfs.h> |
1c7c474c | 48 | #include <linux/posix_acl.h> |
feda821e | 49 | #include <linux/posix_acl_xattr.h> |
1da177e4 | 50 | #include <linux/mman.h> |
1da177e4 LT |
51 | #include <linux/string.h> |
52 | #include <linux/slab.h> | |
53 | #include <linux/backing-dev.h> | |
54 | #include <linux/shmem_fs.h> | |
1da177e4 | 55 | #include <linux/writeback.h> |
1da177e4 | 56 | #include <linux/blkdev.h> |
bda97eab | 57 | #include <linux/pagevec.h> |
41ffe5d5 | 58 | #include <linux/percpu_counter.h> |
83e4fa9c | 59 | #include <linux/falloc.h> |
708e3508 | 60 | #include <linux/splice.h> |
1da177e4 LT |
61 | #include <linux/security.h> |
62 | #include <linux/swapops.h> | |
63 | #include <linux/mempolicy.h> | |
64 | #include <linux/namei.h> | |
b00dc3ad | 65 | #include <linux/ctype.h> |
304dbdb7 | 66 | #include <linux/migrate.h> |
c1f60a5a | 67 | #include <linux/highmem.h> |
680d794b | 68 | #include <linux/seq_file.h> |
92562927 | 69 | #include <linux/magic.h> |
9183df25 | 70 | #include <linux/syscalls.h> |
40e041a2 | 71 | #include <linux/fcntl.h> |
9183df25 | 72 | #include <uapi/linux/memfd.h> |
304dbdb7 | 73 | |
1da177e4 | 74 | #include <asm/uaccess.h> |
1da177e4 LT |
75 | #include <asm/pgtable.h> |
76 | ||
dd56b046 MG |
77 | #include "internal.h" |
78 | ||
09cbfeaf KS |
79 | #define BLOCKS_PER_PAGE (PAGE_SIZE/512) |
80 | #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT) | |
1da177e4 | 81 | |
1da177e4 LT |
82 | /* Pretend that each entry is of this size in directory's i_size */ |
83 | #define BOGO_DIRENT_SIZE 20 | |
84 | ||
69f07ec9 HD |
85 | /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ |
86 | #define SHORT_SYMLINK_LEN 128 | |
87 | ||
1aac1400 | 88 | /* |
f00cdc6d HD |
89 | * shmem_fallocate communicates with shmem_fault or shmem_writepage via |
90 | * inode->i_private (with i_mutex making sure that it has only one user at | |
91 | * a time): we would prefer not to enlarge the shmem inode just for that. | |
1aac1400 HD |
92 | */ |
93 | struct shmem_falloc { | |
8e205f77 | 94 | wait_queue_head_t *waitq; /* faults into hole wait for punch to end */ |
1aac1400 HD |
95 | pgoff_t start; /* start of range currently being fallocated */ |
96 | pgoff_t next; /* the next page offset to be fallocated */ | |
97 | pgoff_t nr_falloced; /* how many new pages have been fallocated */ | |
98 | pgoff_t nr_unswapped; /* how often writepage refused to swap out */ | |
99 | }; | |
100 | ||
b76db735 | 101 | #ifdef CONFIG_TMPFS |
680d794b AM |
102 | static unsigned long shmem_default_max_blocks(void) |
103 | { | |
104 | return totalram_pages / 2; | |
105 | } | |
106 | ||
107 | static unsigned long shmem_default_max_inodes(void) | |
108 | { | |
109 | return min(totalram_pages - totalhigh_pages, totalram_pages / 2); | |
110 | } | |
b76db735 | 111 | #endif |
680d794b | 112 | |
bde05d1c HD |
113 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp); |
114 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
115 | struct shmem_inode_info *info, pgoff_t index); | |
68da9f05 | 116 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
9e18eb29 ALC |
117 | struct page **pagep, enum sgp_type sgp, |
118 | gfp_t gfp, struct mm_struct *fault_mm, int *fault_type); | |
68da9f05 | 119 | |
f3f0e1d2 | 120 | int shmem_getpage(struct inode *inode, pgoff_t index, |
9e18eb29 | 121 | struct page **pagep, enum sgp_type sgp) |
68da9f05 HD |
122 | { |
123 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
9e18eb29 | 124 | mapping_gfp_mask(inode->i_mapping), NULL, NULL); |
68da9f05 | 125 | } |
1da177e4 | 126 | |
1da177e4 LT |
127 | static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb) |
128 | { | |
129 | return sb->s_fs_info; | |
130 | } | |
131 | ||
132 | /* | |
133 | * shmem_file_setup pre-accounts the whole fixed size of a VM object, | |
134 | * for shared memory and for shared anonymous (/dev/zero) mappings | |
135 | * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1), | |
136 | * consistent with the pre-accounting of private mappings ... | |
137 | */ | |
138 | static inline int shmem_acct_size(unsigned long flags, loff_t size) | |
139 | { | |
0b0a0806 | 140 | return (flags & VM_NORESERVE) ? |
191c5424 | 141 | 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size)); |
1da177e4 LT |
142 | } |
143 | ||
144 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
145 | { | |
0b0a0806 | 146 | if (!(flags & VM_NORESERVE)) |
1da177e4 LT |
147 | vm_unacct_memory(VM_ACCT(size)); |
148 | } | |
149 | ||
77142517 KK |
150 | static inline int shmem_reacct_size(unsigned long flags, |
151 | loff_t oldsize, loff_t newsize) | |
152 | { | |
153 | if (!(flags & VM_NORESERVE)) { | |
154 | if (VM_ACCT(newsize) > VM_ACCT(oldsize)) | |
155 | return security_vm_enough_memory_mm(current->mm, | |
156 | VM_ACCT(newsize) - VM_ACCT(oldsize)); | |
157 | else if (VM_ACCT(newsize) < VM_ACCT(oldsize)) | |
158 | vm_unacct_memory(VM_ACCT(oldsize) - VM_ACCT(newsize)); | |
159 | } | |
160 | return 0; | |
161 | } | |
162 | ||
1da177e4 LT |
163 | /* |
164 | * ... whereas tmpfs objects are accounted incrementally as | |
75edd345 | 165 | * pages are allocated, in order to allow large sparse files. |
1da177e4 LT |
166 | * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM, |
167 | * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM. | |
168 | */ | |
800d8c63 | 169 | static inline int shmem_acct_block(unsigned long flags, long pages) |
1da177e4 | 170 | { |
800d8c63 KS |
171 | if (!(flags & VM_NORESERVE)) |
172 | return 0; | |
173 | ||
174 | return security_vm_enough_memory_mm(current->mm, | |
175 | pages * VM_ACCT(PAGE_SIZE)); | |
1da177e4 LT |
176 | } |
177 | ||
178 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
179 | { | |
0b0a0806 | 180 | if (flags & VM_NORESERVE) |
09cbfeaf | 181 | vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE)); |
1da177e4 LT |
182 | } |
183 | ||
759b9775 | 184 | static const struct super_operations shmem_ops; |
f5e54d6e | 185 | static const struct address_space_operations shmem_aops; |
15ad7cdc | 186 | static const struct file_operations shmem_file_operations; |
92e1d5be AV |
187 | static const struct inode_operations shmem_inode_operations; |
188 | static const struct inode_operations shmem_dir_inode_operations; | |
189 | static const struct inode_operations shmem_special_inode_operations; | |
f0f37e2f | 190 | static const struct vm_operations_struct shmem_vm_ops; |
779750d2 | 191 | static struct file_system_type shmem_fs_type; |
1da177e4 | 192 | |
1da177e4 | 193 | static LIST_HEAD(shmem_swaplist); |
cb5f7b9a | 194 | static DEFINE_MUTEX(shmem_swaplist_mutex); |
1da177e4 | 195 | |
5b04c689 PE |
196 | static int shmem_reserve_inode(struct super_block *sb) |
197 | { | |
198 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
199 | if (sbinfo->max_inodes) { | |
200 | spin_lock(&sbinfo->stat_lock); | |
201 | if (!sbinfo->free_inodes) { | |
202 | spin_unlock(&sbinfo->stat_lock); | |
203 | return -ENOSPC; | |
204 | } | |
205 | sbinfo->free_inodes--; | |
206 | spin_unlock(&sbinfo->stat_lock); | |
207 | } | |
208 | return 0; | |
209 | } | |
210 | ||
211 | static void shmem_free_inode(struct super_block *sb) | |
212 | { | |
213 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
214 | if (sbinfo->max_inodes) { | |
215 | spin_lock(&sbinfo->stat_lock); | |
216 | sbinfo->free_inodes++; | |
217 | spin_unlock(&sbinfo->stat_lock); | |
218 | } | |
219 | } | |
220 | ||
46711810 | 221 | /** |
41ffe5d5 | 222 | * shmem_recalc_inode - recalculate the block usage of an inode |
1da177e4 LT |
223 | * @inode: inode to recalc |
224 | * | |
225 | * We have to calculate the free blocks since the mm can drop | |
226 | * undirtied hole pages behind our back. | |
227 | * | |
228 | * But normally info->alloced == inode->i_mapping->nrpages + info->swapped | |
229 | * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped) | |
230 | * | |
231 | * It has to be called with the spinlock held. | |
232 | */ | |
233 | static void shmem_recalc_inode(struct inode *inode) | |
234 | { | |
235 | struct shmem_inode_info *info = SHMEM_I(inode); | |
236 | long freed; | |
237 | ||
238 | freed = info->alloced - info->swapped - inode->i_mapping->nrpages; | |
239 | if (freed > 0) { | |
54af6042 HD |
240 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
241 | if (sbinfo->max_blocks) | |
242 | percpu_counter_add(&sbinfo->used_blocks, -freed); | |
1da177e4 | 243 | info->alloced -= freed; |
54af6042 | 244 | inode->i_blocks -= freed * BLOCKS_PER_PAGE; |
1da177e4 | 245 | shmem_unacct_blocks(info->flags, freed); |
1da177e4 LT |
246 | } |
247 | } | |
248 | ||
800d8c63 KS |
249 | bool shmem_charge(struct inode *inode, long pages) |
250 | { | |
251 | struct shmem_inode_info *info = SHMEM_I(inode); | |
252 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
4595ef88 | 253 | unsigned long flags; |
800d8c63 KS |
254 | |
255 | if (shmem_acct_block(info->flags, pages)) | |
256 | return false; | |
4595ef88 | 257 | spin_lock_irqsave(&info->lock, flags); |
800d8c63 KS |
258 | info->alloced += pages; |
259 | inode->i_blocks += pages * BLOCKS_PER_PAGE; | |
260 | shmem_recalc_inode(inode); | |
4595ef88 | 261 | spin_unlock_irqrestore(&info->lock, flags); |
800d8c63 KS |
262 | inode->i_mapping->nrpages += pages; |
263 | ||
264 | if (!sbinfo->max_blocks) | |
265 | return true; | |
266 | if (percpu_counter_compare(&sbinfo->used_blocks, | |
267 | sbinfo->max_blocks - pages) > 0) { | |
268 | inode->i_mapping->nrpages -= pages; | |
4595ef88 | 269 | spin_lock_irqsave(&info->lock, flags); |
800d8c63 KS |
270 | info->alloced -= pages; |
271 | shmem_recalc_inode(inode); | |
4595ef88 | 272 | spin_unlock_irqrestore(&info->lock, flags); |
71664665 | 273 | shmem_unacct_blocks(info->flags, pages); |
800d8c63 KS |
274 | return false; |
275 | } | |
276 | percpu_counter_add(&sbinfo->used_blocks, pages); | |
277 | return true; | |
278 | } | |
279 | ||
280 | void shmem_uncharge(struct inode *inode, long pages) | |
281 | { | |
282 | struct shmem_inode_info *info = SHMEM_I(inode); | |
283 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
4595ef88 | 284 | unsigned long flags; |
800d8c63 | 285 | |
4595ef88 | 286 | spin_lock_irqsave(&info->lock, flags); |
800d8c63 KS |
287 | info->alloced -= pages; |
288 | inode->i_blocks -= pages * BLOCKS_PER_PAGE; | |
289 | shmem_recalc_inode(inode); | |
4595ef88 | 290 | spin_unlock_irqrestore(&info->lock, flags); |
800d8c63 KS |
291 | |
292 | if (sbinfo->max_blocks) | |
293 | percpu_counter_sub(&sbinfo->used_blocks, pages); | |
71664665 | 294 | shmem_unacct_blocks(info->flags, pages); |
800d8c63 KS |
295 | } |
296 | ||
7a5d0fbb HD |
297 | /* |
298 | * Replace item expected in radix tree by a new item, while holding tree lock. | |
299 | */ | |
300 | static int shmem_radix_tree_replace(struct address_space *mapping, | |
301 | pgoff_t index, void *expected, void *replacement) | |
302 | { | |
303 | void **pslot; | |
6dbaf22c | 304 | void *item; |
7a5d0fbb HD |
305 | |
306 | VM_BUG_ON(!expected); | |
6dbaf22c | 307 | VM_BUG_ON(!replacement); |
7a5d0fbb | 308 | pslot = radix_tree_lookup_slot(&mapping->page_tree, index); |
6dbaf22c JW |
309 | if (!pslot) |
310 | return -ENOENT; | |
311 | item = radix_tree_deref_slot_protected(pslot, &mapping->tree_lock); | |
7a5d0fbb HD |
312 | if (item != expected) |
313 | return -ENOENT; | |
6dbaf22c | 314 | radix_tree_replace_slot(pslot, replacement); |
7a5d0fbb HD |
315 | return 0; |
316 | } | |
317 | ||
d1899228 HD |
318 | /* |
319 | * Sometimes, before we decide whether to proceed or to fail, we must check | |
320 | * that an entry was not already brought back from swap by a racing thread. | |
321 | * | |
322 | * Checking page is not enough: by the time a SwapCache page is locked, it | |
323 | * might be reused, and again be SwapCache, using the same swap as before. | |
324 | */ | |
325 | static bool shmem_confirm_swap(struct address_space *mapping, | |
326 | pgoff_t index, swp_entry_t swap) | |
327 | { | |
328 | void *item; | |
329 | ||
330 | rcu_read_lock(); | |
331 | item = radix_tree_lookup(&mapping->page_tree, index); | |
332 | rcu_read_unlock(); | |
333 | return item == swp_to_radix_entry(swap); | |
334 | } | |
335 | ||
5a6e75f8 KS |
336 | /* |
337 | * Definitions for "huge tmpfs": tmpfs mounted with the huge= option | |
338 | * | |
339 | * SHMEM_HUGE_NEVER: | |
340 | * disables huge pages for the mount; | |
341 | * SHMEM_HUGE_ALWAYS: | |
342 | * enables huge pages for the mount; | |
343 | * SHMEM_HUGE_WITHIN_SIZE: | |
344 | * only allocate huge pages if the page will be fully within i_size, | |
345 | * also respect fadvise()/madvise() hints; | |
346 | * SHMEM_HUGE_ADVISE: | |
347 | * only allocate huge pages if requested with fadvise()/madvise(); | |
348 | */ | |
349 | ||
350 | #define SHMEM_HUGE_NEVER 0 | |
351 | #define SHMEM_HUGE_ALWAYS 1 | |
352 | #define SHMEM_HUGE_WITHIN_SIZE 2 | |
353 | #define SHMEM_HUGE_ADVISE 3 | |
354 | ||
355 | /* | |
356 | * Special values. | |
357 | * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled: | |
358 | * | |
359 | * SHMEM_HUGE_DENY: | |
360 | * disables huge on shm_mnt and all mounts, for emergency use; | |
361 | * SHMEM_HUGE_FORCE: | |
362 | * enables huge on shm_mnt and all mounts, w/o needing option, for testing; | |
363 | * | |
364 | */ | |
365 | #define SHMEM_HUGE_DENY (-1) | |
366 | #define SHMEM_HUGE_FORCE (-2) | |
367 | ||
e496cf3d | 368 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
5a6e75f8 KS |
369 | /* ifdef here to avoid bloating shmem.o when not necessary */ |
370 | ||
371 | int shmem_huge __read_mostly; | |
372 | ||
373 | static int shmem_parse_huge(const char *str) | |
374 | { | |
375 | if (!strcmp(str, "never")) | |
376 | return SHMEM_HUGE_NEVER; | |
377 | if (!strcmp(str, "always")) | |
378 | return SHMEM_HUGE_ALWAYS; | |
379 | if (!strcmp(str, "within_size")) | |
380 | return SHMEM_HUGE_WITHIN_SIZE; | |
381 | if (!strcmp(str, "advise")) | |
382 | return SHMEM_HUGE_ADVISE; | |
383 | if (!strcmp(str, "deny")) | |
384 | return SHMEM_HUGE_DENY; | |
385 | if (!strcmp(str, "force")) | |
386 | return SHMEM_HUGE_FORCE; | |
387 | return -EINVAL; | |
388 | } | |
389 | ||
390 | static const char *shmem_format_huge(int huge) | |
391 | { | |
392 | switch (huge) { | |
393 | case SHMEM_HUGE_NEVER: | |
394 | return "never"; | |
395 | case SHMEM_HUGE_ALWAYS: | |
396 | return "always"; | |
397 | case SHMEM_HUGE_WITHIN_SIZE: | |
398 | return "within_size"; | |
399 | case SHMEM_HUGE_ADVISE: | |
400 | return "advise"; | |
401 | case SHMEM_HUGE_DENY: | |
402 | return "deny"; | |
403 | case SHMEM_HUGE_FORCE: | |
404 | return "force"; | |
405 | default: | |
406 | VM_BUG_ON(1); | |
407 | return "bad_val"; | |
408 | } | |
409 | } | |
410 | ||
779750d2 KS |
411 | static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, |
412 | struct shrink_control *sc, unsigned long nr_to_split) | |
413 | { | |
414 | LIST_HEAD(list), *pos, *next; | |
415 | struct inode *inode; | |
416 | struct shmem_inode_info *info; | |
417 | struct page *page; | |
418 | unsigned long batch = sc ? sc->nr_to_scan : 128; | |
419 | int removed = 0, split = 0; | |
420 | ||
421 | if (list_empty(&sbinfo->shrinklist)) | |
422 | return SHRINK_STOP; | |
423 | ||
424 | spin_lock(&sbinfo->shrinklist_lock); | |
425 | list_for_each_safe(pos, next, &sbinfo->shrinklist) { | |
426 | info = list_entry(pos, struct shmem_inode_info, shrinklist); | |
427 | ||
428 | /* pin the inode */ | |
429 | inode = igrab(&info->vfs_inode); | |
430 | ||
431 | /* inode is about to be evicted */ | |
432 | if (!inode) { | |
433 | list_del_init(&info->shrinklist); | |
434 | removed++; | |
435 | goto next; | |
436 | } | |
437 | ||
438 | /* Check if there's anything to gain */ | |
439 | if (round_up(inode->i_size, PAGE_SIZE) == | |
440 | round_up(inode->i_size, HPAGE_PMD_SIZE)) { | |
441 | list_del_init(&info->shrinklist); | |
442 | removed++; | |
443 | iput(inode); | |
444 | goto next; | |
445 | } | |
446 | ||
447 | list_move(&info->shrinklist, &list); | |
448 | next: | |
449 | if (!--batch) | |
450 | break; | |
451 | } | |
452 | spin_unlock(&sbinfo->shrinklist_lock); | |
453 | ||
454 | list_for_each_safe(pos, next, &list) { | |
455 | int ret; | |
456 | ||
457 | info = list_entry(pos, struct shmem_inode_info, shrinklist); | |
458 | inode = &info->vfs_inode; | |
459 | ||
460 | if (nr_to_split && split >= nr_to_split) { | |
461 | iput(inode); | |
462 | continue; | |
463 | } | |
464 | ||
465 | page = find_lock_page(inode->i_mapping, | |
466 | (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT); | |
467 | if (!page) | |
468 | goto drop; | |
469 | ||
470 | if (!PageTransHuge(page)) { | |
471 | unlock_page(page); | |
472 | put_page(page); | |
473 | goto drop; | |
474 | } | |
475 | ||
476 | ret = split_huge_page(page); | |
477 | unlock_page(page); | |
478 | put_page(page); | |
479 | ||
480 | if (ret) { | |
481 | /* split failed: leave it on the list */ | |
482 | iput(inode); | |
483 | continue; | |
484 | } | |
485 | ||
486 | split++; | |
487 | drop: | |
488 | list_del_init(&info->shrinklist); | |
489 | removed++; | |
490 | iput(inode); | |
491 | } | |
492 | ||
493 | spin_lock(&sbinfo->shrinklist_lock); | |
494 | list_splice_tail(&list, &sbinfo->shrinklist); | |
495 | sbinfo->shrinklist_len -= removed; | |
496 | spin_unlock(&sbinfo->shrinklist_lock); | |
497 | ||
498 | return split; | |
499 | } | |
500 | ||
501 | static long shmem_unused_huge_scan(struct super_block *sb, | |
502 | struct shrink_control *sc) | |
503 | { | |
504 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
505 | ||
506 | if (!READ_ONCE(sbinfo->shrinklist_len)) | |
507 | return SHRINK_STOP; | |
508 | ||
509 | return shmem_unused_huge_shrink(sbinfo, sc, 0); | |
510 | } | |
511 | ||
512 | static long shmem_unused_huge_count(struct super_block *sb, | |
513 | struct shrink_control *sc) | |
514 | { | |
515 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
516 | return READ_ONCE(sbinfo->shrinklist_len); | |
517 | } | |
e496cf3d | 518 | #else /* !CONFIG_TRANSPARENT_HUGE_PAGECACHE */ |
5a6e75f8 KS |
519 | |
520 | #define shmem_huge SHMEM_HUGE_DENY | |
521 | ||
779750d2 KS |
522 | static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, |
523 | struct shrink_control *sc, unsigned long nr_to_split) | |
524 | { | |
525 | return 0; | |
526 | } | |
e496cf3d | 527 | #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */ |
5a6e75f8 | 528 | |
46f65ec1 HD |
529 | /* |
530 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
531 | */ | |
532 | static int shmem_add_to_page_cache(struct page *page, | |
533 | struct address_space *mapping, | |
fed400a1 | 534 | pgoff_t index, void *expected) |
46f65ec1 | 535 | { |
800d8c63 | 536 | int error, nr = hpage_nr_pages(page); |
46f65ec1 | 537 | |
800d8c63 KS |
538 | VM_BUG_ON_PAGE(PageTail(page), page); |
539 | VM_BUG_ON_PAGE(index != round_down(index, nr), page); | |
309381fe SL |
540 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
541 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); | |
800d8c63 | 542 | VM_BUG_ON(expected && PageTransHuge(page)); |
46f65ec1 | 543 | |
800d8c63 | 544 | page_ref_add(page, nr); |
b065b432 HD |
545 | page->mapping = mapping; |
546 | page->index = index; | |
547 | ||
548 | spin_lock_irq(&mapping->tree_lock); | |
800d8c63 KS |
549 | if (PageTransHuge(page)) { |
550 | void __rcu **results; | |
551 | pgoff_t idx; | |
552 | int i; | |
553 | ||
554 | error = 0; | |
555 | if (radix_tree_gang_lookup_slot(&mapping->page_tree, | |
556 | &results, &idx, index, 1) && | |
557 | idx < index + HPAGE_PMD_NR) { | |
558 | error = -EEXIST; | |
559 | } | |
560 | ||
561 | if (!error) { | |
562 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
563 | error = radix_tree_insert(&mapping->page_tree, | |
564 | index + i, page + i); | |
565 | VM_BUG_ON(error); | |
566 | } | |
567 | count_vm_event(THP_FILE_ALLOC); | |
568 | } | |
569 | } else if (!expected) { | |
b065b432 | 570 | error = radix_tree_insert(&mapping->page_tree, index, page); |
800d8c63 | 571 | } else { |
b065b432 HD |
572 | error = shmem_radix_tree_replace(mapping, index, expected, |
573 | page); | |
800d8c63 KS |
574 | } |
575 | ||
46f65ec1 | 576 | if (!error) { |
800d8c63 KS |
577 | mapping->nrpages += nr; |
578 | if (PageTransHuge(page)) | |
11fb9989 MG |
579 | __inc_node_page_state(page, NR_SHMEM_THPS); |
580 | __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr); | |
581 | __mod_node_page_state(page_pgdat(page), NR_SHMEM, nr); | |
b065b432 HD |
582 | spin_unlock_irq(&mapping->tree_lock); |
583 | } else { | |
584 | page->mapping = NULL; | |
585 | spin_unlock_irq(&mapping->tree_lock); | |
800d8c63 | 586 | page_ref_sub(page, nr); |
46f65ec1 | 587 | } |
46f65ec1 HD |
588 | return error; |
589 | } | |
590 | ||
6922c0c7 HD |
591 | /* |
592 | * Like delete_from_page_cache, but substitutes swap for page. | |
593 | */ | |
594 | static void shmem_delete_from_page_cache(struct page *page, void *radswap) | |
595 | { | |
596 | struct address_space *mapping = page->mapping; | |
597 | int error; | |
598 | ||
800d8c63 KS |
599 | VM_BUG_ON_PAGE(PageCompound(page), page); |
600 | ||
6922c0c7 HD |
601 | spin_lock_irq(&mapping->tree_lock); |
602 | error = shmem_radix_tree_replace(mapping, page->index, page, radswap); | |
603 | page->mapping = NULL; | |
604 | mapping->nrpages--; | |
11fb9989 MG |
605 | __dec_node_page_state(page, NR_FILE_PAGES); |
606 | __dec_node_page_state(page, NR_SHMEM); | |
6922c0c7 | 607 | spin_unlock_irq(&mapping->tree_lock); |
09cbfeaf | 608 | put_page(page); |
6922c0c7 HD |
609 | BUG_ON(error); |
610 | } | |
611 | ||
7a5d0fbb HD |
612 | /* |
613 | * Remove swap entry from radix tree, free the swap and its page cache. | |
614 | */ | |
615 | static int shmem_free_swap(struct address_space *mapping, | |
616 | pgoff_t index, void *radswap) | |
617 | { | |
6dbaf22c | 618 | void *old; |
7a5d0fbb HD |
619 | |
620 | spin_lock_irq(&mapping->tree_lock); | |
6dbaf22c | 621 | old = radix_tree_delete_item(&mapping->page_tree, index, radswap); |
7a5d0fbb | 622 | spin_unlock_irq(&mapping->tree_lock); |
6dbaf22c JW |
623 | if (old != radswap) |
624 | return -ENOENT; | |
625 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
626 | return 0; | |
7a5d0fbb HD |
627 | } |
628 | ||
6a15a370 VB |
629 | /* |
630 | * Determine (in bytes) how many of the shmem object's pages mapped by the | |
48131e03 | 631 | * given offsets are swapped out. |
6a15a370 VB |
632 | * |
633 | * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, | |
634 | * as long as the inode doesn't go away and racy results are not a problem. | |
635 | */ | |
48131e03 VB |
636 | unsigned long shmem_partial_swap_usage(struct address_space *mapping, |
637 | pgoff_t start, pgoff_t end) | |
6a15a370 | 638 | { |
6a15a370 VB |
639 | struct radix_tree_iter iter; |
640 | void **slot; | |
641 | struct page *page; | |
48131e03 | 642 | unsigned long swapped = 0; |
6a15a370 VB |
643 | |
644 | rcu_read_lock(); | |
645 | ||
6a15a370 VB |
646 | radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { |
647 | if (iter.index >= end) | |
648 | break; | |
649 | ||
650 | page = radix_tree_deref_slot(slot); | |
651 | ||
2cf938aa MW |
652 | if (radix_tree_deref_retry(page)) { |
653 | slot = radix_tree_iter_retry(&iter); | |
654 | continue; | |
655 | } | |
6a15a370 VB |
656 | |
657 | if (radix_tree_exceptional_entry(page)) | |
658 | swapped++; | |
659 | ||
660 | if (need_resched()) { | |
661 | cond_resched_rcu(); | |
7165092f | 662 | slot = radix_tree_iter_next(&iter); |
6a15a370 VB |
663 | } |
664 | } | |
665 | ||
666 | rcu_read_unlock(); | |
667 | ||
668 | return swapped << PAGE_SHIFT; | |
669 | } | |
670 | ||
48131e03 VB |
671 | /* |
672 | * Determine (in bytes) how many of the shmem object's pages mapped by the | |
673 | * given vma is swapped out. | |
674 | * | |
675 | * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, | |
676 | * as long as the inode doesn't go away and racy results are not a problem. | |
677 | */ | |
678 | unsigned long shmem_swap_usage(struct vm_area_struct *vma) | |
679 | { | |
680 | struct inode *inode = file_inode(vma->vm_file); | |
681 | struct shmem_inode_info *info = SHMEM_I(inode); | |
682 | struct address_space *mapping = inode->i_mapping; | |
683 | unsigned long swapped; | |
684 | ||
685 | /* Be careful as we don't hold info->lock */ | |
686 | swapped = READ_ONCE(info->swapped); | |
687 | ||
688 | /* | |
689 | * The easier cases are when the shmem object has nothing in swap, or | |
690 | * the vma maps it whole. Then we can simply use the stats that we | |
691 | * already track. | |
692 | */ | |
693 | if (!swapped) | |
694 | return 0; | |
695 | ||
696 | if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size) | |
697 | return swapped << PAGE_SHIFT; | |
698 | ||
699 | /* Here comes the more involved part */ | |
700 | return shmem_partial_swap_usage(mapping, | |
701 | linear_page_index(vma, vma->vm_start), | |
702 | linear_page_index(vma, vma->vm_end)); | |
703 | } | |
704 | ||
24513264 HD |
705 | /* |
706 | * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. | |
707 | */ | |
708 | void shmem_unlock_mapping(struct address_space *mapping) | |
709 | { | |
710 | struct pagevec pvec; | |
711 | pgoff_t indices[PAGEVEC_SIZE]; | |
712 | pgoff_t index = 0; | |
713 | ||
714 | pagevec_init(&pvec, 0); | |
715 | /* | |
716 | * Minor point, but we might as well stop if someone else SHM_LOCKs it. | |
717 | */ | |
718 | while (!mapping_unevictable(mapping)) { | |
719 | /* | |
720 | * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it | |
721 | * has finished, if it hits a row of PAGEVEC_SIZE swap entries. | |
722 | */ | |
0cd6144a JW |
723 | pvec.nr = find_get_entries(mapping, index, |
724 | PAGEVEC_SIZE, pvec.pages, indices); | |
24513264 HD |
725 | if (!pvec.nr) |
726 | break; | |
727 | index = indices[pvec.nr - 1] + 1; | |
0cd6144a | 728 | pagevec_remove_exceptionals(&pvec); |
24513264 HD |
729 | check_move_unevictable_pages(pvec.pages, pvec.nr); |
730 | pagevec_release(&pvec); | |
731 | cond_resched(); | |
732 | } | |
7a5d0fbb HD |
733 | } |
734 | ||
735 | /* | |
736 | * Remove range of pages and swap entries from radix tree, and free them. | |
1635f6a7 | 737 | * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate. |
7a5d0fbb | 738 | */ |
1635f6a7 HD |
739 | static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, |
740 | bool unfalloc) | |
1da177e4 | 741 | { |
285b2c4f | 742 | struct address_space *mapping = inode->i_mapping; |
1da177e4 | 743 | struct shmem_inode_info *info = SHMEM_I(inode); |
09cbfeaf KS |
744 | pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; |
745 | pgoff_t end = (lend + 1) >> PAGE_SHIFT; | |
746 | unsigned int partial_start = lstart & (PAGE_SIZE - 1); | |
747 | unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1); | |
bda97eab | 748 | struct pagevec pvec; |
7a5d0fbb HD |
749 | pgoff_t indices[PAGEVEC_SIZE]; |
750 | long nr_swaps_freed = 0; | |
285b2c4f | 751 | pgoff_t index; |
bda97eab HD |
752 | int i; |
753 | ||
83e4fa9c HD |
754 | if (lend == -1) |
755 | end = -1; /* unsigned, so actually very big */ | |
bda97eab HD |
756 | |
757 | pagevec_init(&pvec, 0); | |
758 | index = start; | |
83e4fa9c | 759 | while (index < end) { |
0cd6144a JW |
760 | pvec.nr = find_get_entries(mapping, index, |
761 | min(end - index, (pgoff_t)PAGEVEC_SIZE), | |
762 | pvec.pages, indices); | |
7a5d0fbb HD |
763 | if (!pvec.nr) |
764 | break; | |
bda97eab HD |
765 | for (i = 0; i < pagevec_count(&pvec); i++) { |
766 | struct page *page = pvec.pages[i]; | |
767 | ||
7a5d0fbb | 768 | index = indices[i]; |
83e4fa9c | 769 | if (index >= end) |
bda97eab HD |
770 | break; |
771 | ||
7a5d0fbb | 772 | if (radix_tree_exceptional_entry(page)) { |
1635f6a7 HD |
773 | if (unfalloc) |
774 | continue; | |
7a5d0fbb HD |
775 | nr_swaps_freed += !shmem_free_swap(mapping, |
776 | index, page); | |
bda97eab | 777 | continue; |
7a5d0fbb HD |
778 | } |
779 | ||
800d8c63 KS |
780 | VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page); |
781 | ||
7a5d0fbb | 782 | if (!trylock_page(page)) |
bda97eab | 783 | continue; |
800d8c63 KS |
784 | |
785 | if (PageTransTail(page)) { | |
786 | /* Middle of THP: zero out the page */ | |
787 | clear_highpage(page); | |
788 | unlock_page(page); | |
789 | continue; | |
790 | } else if (PageTransHuge(page)) { | |
791 | if (index == round_down(end, HPAGE_PMD_NR)) { | |
792 | /* | |
793 | * Range ends in the middle of THP: | |
794 | * zero out the page | |
795 | */ | |
796 | clear_highpage(page); | |
797 | unlock_page(page); | |
798 | continue; | |
799 | } | |
800 | index += HPAGE_PMD_NR - 1; | |
801 | i += HPAGE_PMD_NR - 1; | |
802 | } | |
803 | ||
1635f6a7 | 804 | if (!unfalloc || !PageUptodate(page)) { |
800d8c63 KS |
805 | VM_BUG_ON_PAGE(PageTail(page), page); |
806 | if (page_mapping(page) == mapping) { | |
309381fe | 807 | VM_BUG_ON_PAGE(PageWriteback(page), page); |
1635f6a7 HD |
808 | truncate_inode_page(mapping, page); |
809 | } | |
bda97eab | 810 | } |
bda97eab HD |
811 | unlock_page(page); |
812 | } | |
0cd6144a | 813 | pagevec_remove_exceptionals(&pvec); |
24513264 | 814 | pagevec_release(&pvec); |
bda97eab HD |
815 | cond_resched(); |
816 | index++; | |
817 | } | |
1da177e4 | 818 | |
83e4fa9c | 819 | if (partial_start) { |
bda97eab | 820 | struct page *page = NULL; |
9e18eb29 | 821 | shmem_getpage(inode, start - 1, &page, SGP_READ); |
bda97eab | 822 | if (page) { |
09cbfeaf | 823 | unsigned int top = PAGE_SIZE; |
83e4fa9c HD |
824 | if (start > end) { |
825 | top = partial_end; | |
826 | partial_end = 0; | |
827 | } | |
828 | zero_user_segment(page, partial_start, top); | |
829 | set_page_dirty(page); | |
830 | unlock_page(page); | |
09cbfeaf | 831 | put_page(page); |
83e4fa9c HD |
832 | } |
833 | } | |
834 | if (partial_end) { | |
835 | struct page *page = NULL; | |
9e18eb29 | 836 | shmem_getpage(inode, end, &page, SGP_READ); |
83e4fa9c HD |
837 | if (page) { |
838 | zero_user_segment(page, 0, partial_end); | |
bda97eab HD |
839 | set_page_dirty(page); |
840 | unlock_page(page); | |
09cbfeaf | 841 | put_page(page); |
bda97eab HD |
842 | } |
843 | } | |
83e4fa9c HD |
844 | if (start >= end) |
845 | return; | |
bda97eab HD |
846 | |
847 | index = start; | |
b1a36650 | 848 | while (index < end) { |
bda97eab | 849 | cond_resched(); |
0cd6144a JW |
850 | |
851 | pvec.nr = find_get_entries(mapping, index, | |
83e4fa9c | 852 | min(end - index, (pgoff_t)PAGEVEC_SIZE), |
0cd6144a | 853 | pvec.pages, indices); |
7a5d0fbb | 854 | if (!pvec.nr) { |
b1a36650 HD |
855 | /* If all gone or hole-punch or unfalloc, we're done */ |
856 | if (index == start || end != -1) | |
bda97eab | 857 | break; |
b1a36650 | 858 | /* But if truncating, restart to make sure all gone */ |
bda97eab HD |
859 | index = start; |
860 | continue; | |
861 | } | |
bda97eab HD |
862 | for (i = 0; i < pagevec_count(&pvec); i++) { |
863 | struct page *page = pvec.pages[i]; | |
864 | ||
7a5d0fbb | 865 | index = indices[i]; |
83e4fa9c | 866 | if (index >= end) |
bda97eab HD |
867 | break; |
868 | ||
7a5d0fbb | 869 | if (radix_tree_exceptional_entry(page)) { |
1635f6a7 HD |
870 | if (unfalloc) |
871 | continue; | |
b1a36650 HD |
872 | if (shmem_free_swap(mapping, index, page)) { |
873 | /* Swap was replaced by page: retry */ | |
874 | index--; | |
875 | break; | |
876 | } | |
877 | nr_swaps_freed++; | |
7a5d0fbb HD |
878 | continue; |
879 | } | |
880 | ||
bda97eab | 881 | lock_page(page); |
800d8c63 KS |
882 | |
883 | if (PageTransTail(page)) { | |
884 | /* Middle of THP: zero out the page */ | |
885 | clear_highpage(page); | |
886 | unlock_page(page); | |
887 | /* | |
888 | * Partial thp truncate due 'start' in middle | |
889 | * of THP: don't need to look on these pages | |
890 | * again on !pvec.nr restart. | |
891 | */ | |
892 | if (index != round_down(end, HPAGE_PMD_NR)) | |
893 | start++; | |
894 | continue; | |
895 | } else if (PageTransHuge(page)) { | |
896 | if (index == round_down(end, HPAGE_PMD_NR)) { | |
897 | /* | |
898 | * Range ends in the middle of THP: | |
899 | * zero out the page | |
900 | */ | |
901 | clear_highpage(page); | |
902 | unlock_page(page); | |
903 | continue; | |
904 | } | |
905 | index += HPAGE_PMD_NR - 1; | |
906 | i += HPAGE_PMD_NR - 1; | |
907 | } | |
908 | ||
1635f6a7 | 909 | if (!unfalloc || !PageUptodate(page)) { |
800d8c63 KS |
910 | VM_BUG_ON_PAGE(PageTail(page), page); |
911 | if (page_mapping(page) == mapping) { | |
309381fe | 912 | VM_BUG_ON_PAGE(PageWriteback(page), page); |
1635f6a7 | 913 | truncate_inode_page(mapping, page); |
b1a36650 HD |
914 | } else { |
915 | /* Page was replaced by swap: retry */ | |
916 | unlock_page(page); | |
917 | index--; | |
918 | break; | |
1635f6a7 | 919 | } |
7a5d0fbb | 920 | } |
bda97eab HD |
921 | unlock_page(page); |
922 | } | |
0cd6144a | 923 | pagevec_remove_exceptionals(&pvec); |
24513264 | 924 | pagevec_release(&pvec); |
bda97eab HD |
925 | index++; |
926 | } | |
94c1e62d | 927 | |
4595ef88 | 928 | spin_lock_irq(&info->lock); |
7a5d0fbb | 929 | info->swapped -= nr_swaps_freed; |
1da177e4 | 930 | shmem_recalc_inode(inode); |
4595ef88 | 931 | spin_unlock_irq(&info->lock); |
1635f6a7 | 932 | } |
1da177e4 | 933 | |
1635f6a7 HD |
934 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
935 | { | |
936 | shmem_undo_range(inode, lstart, lend, false); | |
078cd827 | 937 | inode->i_ctime = inode->i_mtime = current_time(inode); |
1da177e4 | 938 | } |
94c1e62d | 939 | EXPORT_SYMBOL_GPL(shmem_truncate_range); |
1da177e4 | 940 | |
44a30220 YZ |
941 | static int shmem_getattr(struct vfsmount *mnt, struct dentry *dentry, |
942 | struct kstat *stat) | |
943 | { | |
944 | struct inode *inode = dentry->d_inode; | |
945 | struct shmem_inode_info *info = SHMEM_I(inode); | |
946 | ||
d0424c42 | 947 | if (info->alloced - info->swapped != inode->i_mapping->nrpages) { |
4595ef88 | 948 | spin_lock_irq(&info->lock); |
d0424c42 | 949 | shmem_recalc_inode(inode); |
4595ef88 | 950 | spin_unlock_irq(&info->lock); |
d0424c42 | 951 | } |
44a30220 | 952 | generic_fillattr(inode, stat); |
44a30220 YZ |
953 | return 0; |
954 | } | |
955 | ||
94c1e62d | 956 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) |
1da177e4 | 957 | { |
75c3cfa8 | 958 | struct inode *inode = d_inode(dentry); |
40e041a2 | 959 | struct shmem_inode_info *info = SHMEM_I(inode); |
779750d2 | 960 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
1da177e4 LT |
961 | int error; |
962 | ||
31051c85 | 963 | error = setattr_prepare(dentry, attr); |
db78b877 CH |
964 | if (error) |
965 | return error; | |
966 | ||
94c1e62d HD |
967 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { |
968 | loff_t oldsize = inode->i_size; | |
969 | loff_t newsize = attr->ia_size; | |
3889e6e7 | 970 | |
40e041a2 DH |
971 | /* protected by i_mutex */ |
972 | if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) || | |
973 | (newsize > oldsize && (info->seals & F_SEAL_GROW))) | |
974 | return -EPERM; | |
975 | ||
94c1e62d | 976 | if (newsize != oldsize) { |
77142517 KK |
977 | error = shmem_reacct_size(SHMEM_I(inode)->flags, |
978 | oldsize, newsize); | |
979 | if (error) | |
980 | return error; | |
94c1e62d | 981 | i_size_write(inode, newsize); |
078cd827 | 982 | inode->i_ctime = inode->i_mtime = current_time(inode); |
94c1e62d | 983 | } |
afa2db2f | 984 | if (newsize <= oldsize) { |
94c1e62d | 985 | loff_t holebegin = round_up(newsize, PAGE_SIZE); |
d0424c42 HD |
986 | if (oldsize > holebegin) |
987 | unmap_mapping_range(inode->i_mapping, | |
988 | holebegin, 0, 1); | |
989 | if (info->alloced) | |
990 | shmem_truncate_range(inode, | |
991 | newsize, (loff_t)-1); | |
94c1e62d | 992 | /* unmap again to remove racily COWed private pages */ |
d0424c42 HD |
993 | if (oldsize > holebegin) |
994 | unmap_mapping_range(inode->i_mapping, | |
995 | holebegin, 0, 1); | |
779750d2 KS |
996 | |
997 | /* | |
998 | * Part of the huge page can be beyond i_size: subject | |
999 | * to shrink under memory pressure. | |
1000 | */ | |
1001 | if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) { | |
1002 | spin_lock(&sbinfo->shrinklist_lock); | |
1003 | if (list_empty(&info->shrinklist)) { | |
1004 | list_add_tail(&info->shrinklist, | |
1005 | &sbinfo->shrinklist); | |
1006 | sbinfo->shrinklist_len++; | |
1007 | } | |
1008 | spin_unlock(&sbinfo->shrinklist_lock); | |
1009 | } | |
94c1e62d | 1010 | } |
1da177e4 LT |
1011 | } |
1012 | ||
db78b877 | 1013 | setattr_copy(inode, attr); |
db78b877 | 1014 | if (attr->ia_valid & ATTR_MODE) |
feda821e | 1015 | error = posix_acl_chmod(inode, inode->i_mode); |
1da177e4 LT |
1016 | return error; |
1017 | } | |
1018 | ||
1f895f75 | 1019 | static void shmem_evict_inode(struct inode *inode) |
1da177e4 | 1020 | { |
1da177e4 | 1021 | struct shmem_inode_info *info = SHMEM_I(inode); |
779750d2 | 1022 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
1da177e4 | 1023 | |
3889e6e7 | 1024 | if (inode->i_mapping->a_ops == &shmem_aops) { |
1da177e4 LT |
1025 | shmem_unacct_size(info->flags, inode->i_size); |
1026 | inode->i_size = 0; | |
3889e6e7 | 1027 | shmem_truncate_range(inode, 0, (loff_t)-1); |
779750d2 KS |
1028 | if (!list_empty(&info->shrinklist)) { |
1029 | spin_lock(&sbinfo->shrinklist_lock); | |
1030 | if (!list_empty(&info->shrinklist)) { | |
1031 | list_del_init(&info->shrinklist); | |
1032 | sbinfo->shrinklist_len--; | |
1033 | } | |
1034 | spin_unlock(&sbinfo->shrinklist_lock); | |
1035 | } | |
1da177e4 | 1036 | if (!list_empty(&info->swaplist)) { |
cb5f7b9a | 1037 | mutex_lock(&shmem_swaplist_mutex); |
1da177e4 | 1038 | list_del_init(&info->swaplist); |
cb5f7b9a | 1039 | mutex_unlock(&shmem_swaplist_mutex); |
1da177e4 | 1040 | } |
3ed47db3 | 1041 | } |
b09e0fa4 | 1042 | |
38f38657 | 1043 | simple_xattrs_free(&info->xattrs); |
0f3c42f5 | 1044 | WARN_ON(inode->i_blocks); |
5b04c689 | 1045 | shmem_free_inode(inode->i_sb); |
dbd5768f | 1046 | clear_inode(inode); |
1da177e4 LT |
1047 | } |
1048 | ||
46f65ec1 HD |
1049 | /* |
1050 | * If swap found in inode, free it and move page from swapcache to filecache. | |
1051 | */ | |
41ffe5d5 | 1052 | static int shmem_unuse_inode(struct shmem_inode_info *info, |
bde05d1c | 1053 | swp_entry_t swap, struct page **pagep) |
1da177e4 | 1054 | { |
285b2c4f | 1055 | struct address_space *mapping = info->vfs_inode.i_mapping; |
46f65ec1 | 1056 | void *radswap; |
41ffe5d5 | 1057 | pgoff_t index; |
bde05d1c HD |
1058 | gfp_t gfp; |
1059 | int error = 0; | |
1da177e4 | 1060 | |
46f65ec1 | 1061 | radswap = swp_to_radix_entry(swap); |
e504f3fd | 1062 | index = radix_tree_locate_item(&mapping->page_tree, radswap); |
46f65ec1 | 1063 | if (index == -1) |
00501b53 | 1064 | return -EAGAIN; /* tell shmem_unuse we found nothing */ |
2e0e26c7 | 1065 | |
1b1b32f2 HD |
1066 | /* |
1067 | * Move _head_ to start search for next from here. | |
1f895f75 | 1068 | * But be careful: shmem_evict_inode checks list_empty without taking |
1b1b32f2 | 1069 | * mutex, and there's an instant in list_move_tail when info->swaplist |
285b2c4f | 1070 | * would appear empty, if it were the only one on shmem_swaplist. |
1b1b32f2 HD |
1071 | */ |
1072 | if (shmem_swaplist.next != &info->swaplist) | |
1073 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
2e0e26c7 | 1074 | |
bde05d1c HD |
1075 | gfp = mapping_gfp_mask(mapping); |
1076 | if (shmem_should_replace_page(*pagep, gfp)) { | |
1077 | mutex_unlock(&shmem_swaplist_mutex); | |
1078 | error = shmem_replace_page(pagep, gfp, info, index); | |
1079 | mutex_lock(&shmem_swaplist_mutex); | |
1080 | /* | |
1081 | * We needed to drop mutex to make that restrictive page | |
0142ef6c HD |
1082 | * allocation, but the inode might have been freed while we |
1083 | * dropped it: although a racing shmem_evict_inode() cannot | |
1084 | * complete without emptying the radix_tree, our page lock | |
1085 | * on this swapcache page is not enough to prevent that - | |
1086 | * free_swap_and_cache() of our swap entry will only | |
1087 | * trylock_page(), removing swap from radix_tree whatever. | |
1088 | * | |
1089 | * We must not proceed to shmem_add_to_page_cache() if the | |
1090 | * inode has been freed, but of course we cannot rely on | |
1091 | * inode or mapping or info to check that. However, we can | |
1092 | * safely check if our swap entry is still in use (and here | |
1093 | * it can't have got reused for another page): if it's still | |
1094 | * in use, then the inode cannot have been freed yet, and we | |
1095 | * can safely proceed (if it's no longer in use, that tells | |
1096 | * nothing about the inode, but we don't need to unuse swap). | |
bde05d1c HD |
1097 | */ |
1098 | if (!page_swapcount(*pagep)) | |
1099 | error = -ENOENT; | |
1100 | } | |
1101 | ||
d13d1443 | 1102 | /* |
778dd893 HD |
1103 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, |
1104 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
1105 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
d13d1443 | 1106 | */ |
bde05d1c HD |
1107 | if (!error) |
1108 | error = shmem_add_to_page_cache(*pagep, mapping, index, | |
fed400a1 | 1109 | radswap); |
48f170fb | 1110 | if (error != -ENOMEM) { |
46f65ec1 HD |
1111 | /* |
1112 | * Truncation and eviction use free_swap_and_cache(), which | |
1113 | * only does trylock page: if we raced, best clean up here. | |
1114 | */ | |
bde05d1c HD |
1115 | delete_from_swap_cache(*pagep); |
1116 | set_page_dirty(*pagep); | |
46f65ec1 | 1117 | if (!error) { |
4595ef88 | 1118 | spin_lock_irq(&info->lock); |
46f65ec1 | 1119 | info->swapped--; |
4595ef88 | 1120 | spin_unlock_irq(&info->lock); |
46f65ec1 HD |
1121 | swap_free(swap); |
1122 | } | |
1da177e4 | 1123 | } |
2e0e26c7 | 1124 | return error; |
1da177e4 LT |
1125 | } |
1126 | ||
1127 | /* | |
46f65ec1 | 1128 | * Search through swapped inodes to find and replace swap by page. |
1da177e4 | 1129 | */ |
41ffe5d5 | 1130 | int shmem_unuse(swp_entry_t swap, struct page *page) |
1da177e4 | 1131 | { |
41ffe5d5 | 1132 | struct list_head *this, *next; |
1da177e4 | 1133 | struct shmem_inode_info *info; |
00501b53 | 1134 | struct mem_cgroup *memcg; |
bde05d1c HD |
1135 | int error = 0; |
1136 | ||
1137 | /* | |
1138 | * There's a faint possibility that swap page was replaced before | |
0142ef6c | 1139 | * caller locked it: caller will come back later with the right page. |
bde05d1c | 1140 | */ |
0142ef6c | 1141 | if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val)) |
bde05d1c | 1142 | goto out; |
778dd893 HD |
1143 | |
1144 | /* | |
1145 | * Charge page using GFP_KERNEL while we can wait, before taking | |
1146 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
1147 | * Charged back to the user (not to caller) when swap account is used. | |
778dd893 | 1148 | */ |
f627c2f5 KS |
1149 | error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg, |
1150 | false); | |
778dd893 HD |
1151 | if (error) |
1152 | goto out; | |
46f65ec1 | 1153 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ |
00501b53 | 1154 | error = -EAGAIN; |
1da177e4 | 1155 | |
cb5f7b9a | 1156 | mutex_lock(&shmem_swaplist_mutex); |
41ffe5d5 HD |
1157 | list_for_each_safe(this, next, &shmem_swaplist) { |
1158 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
285b2c4f | 1159 | if (info->swapped) |
00501b53 | 1160 | error = shmem_unuse_inode(info, swap, &page); |
6922c0c7 HD |
1161 | else |
1162 | list_del_init(&info->swaplist); | |
cb5f7b9a | 1163 | cond_resched(); |
00501b53 | 1164 | if (error != -EAGAIN) |
778dd893 | 1165 | break; |
00501b53 | 1166 | /* found nothing in this: move on to search the next */ |
1da177e4 | 1167 | } |
cb5f7b9a | 1168 | mutex_unlock(&shmem_swaplist_mutex); |
778dd893 | 1169 | |
00501b53 JW |
1170 | if (error) { |
1171 | if (error != -ENOMEM) | |
1172 | error = 0; | |
f627c2f5 | 1173 | mem_cgroup_cancel_charge(page, memcg, false); |
00501b53 | 1174 | } else |
f627c2f5 | 1175 | mem_cgroup_commit_charge(page, memcg, true, false); |
778dd893 | 1176 | out: |
aaa46865 | 1177 | unlock_page(page); |
09cbfeaf | 1178 | put_page(page); |
778dd893 | 1179 | return error; |
1da177e4 LT |
1180 | } |
1181 | ||
1182 | /* | |
1183 | * Move the page from the page cache to the swap cache. | |
1184 | */ | |
1185 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
1186 | { | |
1187 | struct shmem_inode_info *info; | |
1da177e4 | 1188 | struct address_space *mapping; |
1da177e4 | 1189 | struct inode *inode; |
6922c0c7 HD |
1190 | swp_entry_t swap; |
1191 | pgoff_t index; | |
1da177e4 | 1192 | |
800d8c63 | 1193 | VM_BUG_ON_PAGE(PageCompound(page), page); |
1da177e4 | 1194 | BUG_ON(!PageLocked(page)); |
1da177e4 LT |
1195 | mapping = page->mapping; |
1196 | index = page->index; | |
1197 | inode = mapping->host; | |
1198 | info = SHMEM_I(inode); | |
1199 | if (info->flags & VM_LOCKED) | |
1200 | goto redirty; | |
d9fe526a | 1201 | if (!total_swap_pages) |
1da177e4 LT |
1202 | goto redirty; |
1203 | ||
d9fe526a | 1204 | /* |
97b713ba CH |
1205 | * Our capabilities prevent regular writeback or sync from ever calling |
1206 | * shmem_writepage; but a stacking filesystem might use ->writepage of | |
1207 | * its underlying filesystem, in which case tmpfs should write out to | |
1208 | * swap only in response to memory pressure, and not for the writeback | |
1209 | * threads or sync. | |
d9fe526a | 1210 | */ |
48f170fb HD |
1211 | if (!wbc->for_reclaim) { |
1212 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
1213 | goto redirty; | |
1214 | } | |
1635f6a7 HD |
1215 | |
1216 | /* | |
1217 | * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC | |
1218 | * value into swapfile.c, the only way we can correctly account for a | |
1219 | * fallocated page arriving here is now to initialize it and write it. | |
1aac1400 HD |
1220 | * |
1221 | * That's okay for a page already fallocated earlier, but if we have | |
1222 | * not yet completed the fallocation, then (a) we want to keep track | |
1223 | * of this page in case we have to undo it, and (b) it may not be a | |
1224 | * good idea to continue anyway, once we're pushing into swap. So | |
1225 | * reactivate the page, and let shmem_fallocate() quit when too many. | |
1635f6a7 HD |
1226 | */ |
1227 | if (!PageUptodate(page)) { | |
1aac1400 HD |
1228 | if (inode->i_private) { |
1229 | struct shmem_falloc *shmem_falloc; | |
1230 | spin_lock(&inode->i_lock); | |
1231 | shmem_falloc = inode->i_private; | |
1232 | if (shmem_falloc && | |
8e205f77 | 1233 | !shmem_falloc->waitq && |
1aac1400 HD |
1234 | index >= shmem_falloc->start && |
1235 | index < shmem_falloc->next) | |
1236 | shmem_falloc->nr_unswapped++; | |
1237 | else | |
1238 | shmem_falloc = NULL; | |
1239 | spin_unlock(&inode->i_lock); | |
1240 | if (shmem_falloc) | |
1241 | goto redirty; | |
1242 | } | |
1635f6a7 HD |
1243 | clear_highpage(page); |
1244 | flush_dcache_page(page); | |
1245 | SetPageUptodate(page); | |
1246 | } | |
1247 | ||
48f170fb HD |
1248 | swap = get_swap_page(); |
1249 | if (!swap.val) | |
1250 | goto redirty; | |
d9fe526a | 1251 | |
37e84351 VD |
1252 | if (mem_cgroup_try_charge_swap(page, swap)) |
1253 | goto free_swap; | |
1254 | ||
b1dea800 HD |
1255 | /* |
1256 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
6922c0c7 HD |
1257 | * if it's not already there. Do it now before the page is |
1258 | * moved to swap cache, when its pagelock no longer protects | |
b1dea800 | 1259 | * the inode from eviction. But don't unlock the mutex until |
6922c0c7 HD |
1260 | * we've incremented swapped, because shmem_unuse_inode() will |
1261 | * prune a !swapped inode from the swaplist under this mutex. | |
b1dea800 | 1262 | */ |
48f170fb HD |
1263 | mutex_lock(&shmem_swaplist_mutex); |
1264 | if (list_empty(&info->swaplist)) | |
1265 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
b1dea800 | 1266 | |
48f170fb | 1267 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { |
4595ef88 | 1268 | spin_lock_irq(&info->lock); |
6922c0c7 | 1269 | shmem_recalc_inode(inode); |
267a4c76 | 1270 | info->swapped++; |
4595ef88 | 1271 | spin_unlock_irq(&info->lock); |
6922c0c7 | 1272 | |
267a4c76 HD |
1273 | swap_shmem_alloc(swap); |
1274 | shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); | |
1275 | ||
6922c0c7 | 1276 | mutex_unlock(&shmem_swaplist_mutex); |
d9fe526a | 1277 | BUG_ON(page_mapped(page)); |
9fab5619 | 1278 | swap_writepage(page, wbc); |
1da177e4 LT |
1279 | return 0; |
1280 | } | |
1281 | ||
6922c0c7 | 1282 | mutex_unlock(&shmem_swaplist_mutex); |
37e84351 | 1283 | free_swap: |
0a31bc97 | 1284 | swapcache_free(swap); |
1da177e4 LT |
1285 | redirty: |
1286 | set_page_dirty(page); | |
d9fe526a HD |
1287 | if (wbc->for_reclaim) |
1288 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1289 | unlock_page(page); | |
1290 | return 0; | |
1da177e4 LT |
1291 | } |
1292 | ||
75edd345 | 1293 | #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS) |
71fe804b | 1294 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) |
680d794b | 1295 | { |
095f1fc4 | 1296 | char buffer[64]; |
680d794b | 1297 | |
71fe804b | 1298 | if (!mpol || mpol->mode == MPOL_DEFAULT) |
095f1fc4 | 1299 | return; /* show nothing */ |
680d794b | 1300 | |
a7a88b23 | 1301 | mpol_to_str(buffer, sizeof(buffer), mpol); |
095f1fc4 LS |
1302 | |
1303 | seq_printf(seq, ",mpol=%s", buffer); | |
680d794b | 1304 | } |
71fe804b LS |
1305 | |
1306 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1307 | { | |
1308 | struct mempolicy *mpol = NULL; | |
1309 | if (sbinfo->mpol) { | |
1310 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
1311 | mpol = sbinfo->mpol; | |
1312 | mpol_get(mpol); | |
1313 | spin_unlock(&sbinfo->stat_lock); | |
1314 | } | |
1315 | return mpol; | |
1316 | } | |
75edd345 HD |
1317 | #else /* !CONFIG_NUMA || !CONFIG_TMPFS */ |
1318 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) | |
1319 | { | |
1320 | } | |
1321 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1322 | { | |
1323 | return NULL; | |
1324 | } | |
1325 | #endif /* CONFIG_NUMA && CONFIG_TMPFS */ | |
1326 | #ifndef CONFIG_NUMA | |
1327 | #define vm_policy vm_private_data | |
1328 | #endif | |
680d794b | 1329 | |
800d8c63 KS |
1330 | static void shmem_pseudo_vma_init(struct vm_area_struct *vma, |
1331 | struct shmem_inode_info *info, pgoff_t index) | |
1332 | { | |
1333 | /* Create a pseudo vma that just contains the policy */ | |
1334 | vma->vm_start = 0; | |
1335 | /* Bias interleave by inode number to distribute better across nodes */ | |
1336 | vma->vm_pgoff = index + info->vfs_inode.i_ino; | |
1337 | vma->vm_ops = NULL; | |
1338 | vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index); | |
1339 | } | |
1340 | ||
1341 | static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma) | |
1342 | { | |
1343 | /* Drop reference taken by mpol_shared_policy_lookup() */ | |
1344 | mpol_cond_put(vma->vm_policy); | |
1345 | } | |
1346 | ||
41ffe5d5 HD |
1347 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, |
1348 | struct shmem_inode_info *info, pgoff_t index) | |
1da177e4 | 1349 | { |
1da177e4 | 1350 | struct vm_area_struct pvma; |
18a2f371 | 1351 | struct page *page; |
52cd3b07 | 1352 | |
800d8c63 | 1353 | shmem_pseudo_vma_init(&pvma, info, index); |
18a2f371 | 1354 | page = swapin_readahead(swap, gfp, &pvma, 0); |
800d8c63 | 1355 | shmem_pseudo_vma_destroy(&pvma); |
18a2f371 | 1356 | |
800d8c63 KS |
1357 | return page; |
1358 | } | |
1359 | ||
1360 | static struct page *shmem_alloc_hugepage(gfp_t gfp, | |
1361 | struct shmem_inode_info *info, pgoff_t index) | |
1362 | { | |
1363 | struct vm_area_struct pvma; | |
1364 | struct inode *inode = &info->vfs_inode; | |
1365 | struct address_space *mapping = inode->i_mapping; | |
4620a06e | 1366 | pgoff_t idx, hindex; |
800d8c63 KS |
1367 | void __rcu **results; |
1368 | struct page *page; | |
1369 | ||
e496cf3d | 1370 | if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) |
800d8c63 KS |
1371 | return NULL; |
1372 | ||
4620a06e | 1373 | hindex = round_down(index, HPAGE_PMD_NR); |
800d8c63 KS |
1374 | rcu_read_lock(); |
1375 | if (radix_tree_gang_lookup_slot(&mapping->page_tree, &results, &idx, | |
1376 | hindex, 1) && idx < hindex + HPAGE_PMD_NR) { | |
1377 | rcu_read_unlock(); | |
1378 | return NULL; | |
1379 | } | |
1380 | rcu_read_unlock(); | |
18a2f371 | 1381 | |
800d8c63 KS |
1382 | shmem_pseudo_vma_init(&pvma, info, hindex); |
1383 | page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN, | |
1384 | HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), true); | |
1385 | shmem_pseudo_vma_destroy(&pvma); | |
1386 | if (page) | |
1387 | prep_transhuge_page(page); | |
18a2f371 | 1388 | return page; |
1da177e4 LT |
1389 | } |
1390 | ||
02098fea | 1391 | static struct page *shmem_alloc_page(gfp_t gfp, |
41ffe5d5 | 1392 | struct shmem_inode_info *info, pgoff_t index) |
1da177e4 LT |
1393 | { |
1394 | struct vm_area_struct pvma; | |
18a2f371 | 1395 | struct page *page; |
1da177e4 | 1396 | |
800d8c63 KS |
1397 | shmem_pseudo_vma_init(&pvma, info, index); |
1398 | page = alloc_page_vma(gfp, &pvma, 0); | |
1399 | shmem_pseudo_vma_destroy(&pvma); | |
1400 | ||
1401 | return page; | |
1402 | } | |
1403 | ||
1404 | static struct page *shmem_alloc_and_acct_page(gfp_t gfp, | |
1405 | struct shmem_inode_info *info, struct shmem_sb_info *sbinfo, | |
1406 | pgoff_t index, bool huge) | |
1407 | { | |
1408 | struct page *page; | |
1409 | int nr; | |
1410 | int err = -ENOSPC; | |
52cd3b07 | 1411 | |
e496cf3d | 1412 | if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) |
800d8c63 KS |
1413 | huge = false; |
1414 | nr = huge ? HPAGE_PMD_NR : 1; | |
1415 | ||
1416 | if (shmem_acct_block(info->flags, nr)) | |
1417 | goto failed; | |
1418 | if (sbinfo->max_blocks) { | |
1419 | if (percpu_counter_compare(&sbinfo->used_blocks, | |
1420 | sbinfo->max_blocks - nr) > 0) | |
1421 | goto unacct; | |
1422 | percpu_counter_add(&sbinfo->used_blocks, nr); | |
1423 | } | |
1424 | ||
1425 | if (huge) | |
1426 | page = shmem_alloc_hugepage(gfp, info, index); | |
1427 | else | |
1428 | page = shmem_alloc_page(gfp, info, index); | |
75edd345 HD |
1429 | if (page) { |
1430 | __SetPageLocked(page); | |
1431 | __SetPageSwapBacked(page); | |
800d8c63 | 1432 | return page; |
75edd345 | 1433 | } |
18a2f371 | 1434 | |
800d8c63 KS |
1435 | err = -ENOMEM; |
1436 | if (sbinfo->max_blocks) | |
1437 | percpu_counter_add(&sbinfo->used_blocks, -nr); | |
1438 | unacct: | |
1439 | shmem_unacct_blocks(info->flags, nr); | |
1440 | failed: | |
1441 | return ERR_PTR(err); | |
1da177e4 | 1442 | } |
71fe804b | 1443 | |
bde05d1c HD |
1444 | /* |
1445 | * When a page is moved from swapcache to shmem filecache (either by the | |
1446 | * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of | |
1447 | * shmem_unuse_inode()), it may have been read in earlier from swap, in | |
1448 | * ignorance of the mapping it belongs to. If that mapping has special | |
1449 | * constraints (like the gma500 GEM driver, which requires RAM below 4GB), | |
1450 | * we may need to copy to a suitable page before moving to filecache. | |
1451 | * | |
1452 | * In a future release, this may well be extended to respect cpuset and | |
1453 | * NUMA mempolicy, and applied also to anonymous pages in do_swap_page(); | |
1454 | * but for now it is a simple matter of zone. | |
1455 | */ | |
1456 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp) | |
1457 | { | |
1458 | return page_zonenum(page) > gfp_zone(gfp); | |
1459 | } | |
1460 | ||
1461 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
1462 | struct shmem_inode_info *info, pgoff_t index) | |
1463 | { | |
1464 | struct page *oldpage, *newpage; | |
1465 | struct address_space *swap_mapping; | |
1466 | pgoff_t swap_index; | |
1467 | int error; | |
1468 | ||
1469 | oldpage = *pagep; | |
1470 | swap_index = page_private(oldpage); | |
1471 | swap_mapping = page_mapping(oldpage); | |
1472 | ||
1473 | /* | |
1474 | * We have arrived here because our zones are constrained, so don't | |
1475 | * limit chance of success by further cpuset and node constraints. | |
1476 | */ | |
1477 | gfp &= ~GFP_CONSTRAINT_MASK; | |
1478 | newpage = shmem_alloc_page(gfp, info, index); | |
1479 | if (!newpage) | |
1480 | return -ENOMEM; | |
bde05d1c | 1481 | |
09cbfeaf | 1482 | get_page(newpage); |
bde05d1c | 1483 | copy_highpage(newpage, oldpage); |
0142ef6c | 1484 | flush_dcache_page(newpage); |
bde05d1c | 1485 | |
9956edf3 HD |
1486 | __SetPageLocked(newpage); |
1487 | __SetPageSwapBacked(newpage); | |
bde05d1c | 1488 | SetPageUptodate(newpage); |
bde05d1c | 1489 | set_page_private(newpage, swap_index); |
bde05d1c HD |
1490 | SetPageSwapCache(newpage); |
1491 | ||
1492 | /* | |
1493 | * Our caller will very soon move newpage out of swapcache, but it's | |
1494 | * a nice clean interface for us to replace oldpage by newpage there. | |
1495 | */ | |
1496 | spin_lock_irq(&swap_mapping->tree_lock); | |
1497 | error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage, | |
1498 | newpage); | |
0142ef6c | 1499 | if (!error) { |
11fb9989 MG |
1500 | __inc_node_page_state(newpage, NR_FILE_PAGES); |
1501 | __dec_node_page_state(oldpage, NR_FILE_PAGES); | |
0142ef6c | 1502 | } |
bde05d1c | 1503 | spin_unlock_irq(&swap_mapping->tree_lock); |
bde05d1c | 1504 | |
0142ef6c HD |
1505 | if (unlikely(error)) { |
1506 | /* | |
1507 | * Is this possible? I think not, now that our callers check | |
1508 | * both PageSwapCache and page_private after getting page lock; | |
1509 | * but be defensive. Reverse old to newpage for clear and free. | |
1510 | */ | |
1511 | oldpage = newpage; | |
1512 | } else { | |
6a93ca8f | 1513 | mem_cgroup_migrate(oldpage, newpage); |
0142ef6c HD |
1514 | lru_cache_add_anon(newpage); |
1515 | *pagep = newpage; | |
1516 | } | |
bde05d1c HD |
1517 | |
1518 | ClearPageSwapCache(oldpage); | |
1519 | set_page_private(oldpage, 0); | |
1520 | ||
1521 | unlock_page(oldpage); | |
09cbfeaf KS |
1522 | put_page(oldpage); |
1523 | put_page(oldpage); | |
0142ef6c | 1524 | return error; |
bde05d1c HD |
1525 | } |
1526 | ||
1da177e4 | 1527 | /* |
68da9f05 | 1528 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate |
1da177e4 LT |
1529 | * |
1530 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1531 | * vm. If we swap it in we mark it dirty since we also free the swap | |
9e18eb29 ALC |
1532 | * entry since a page cannot live in both the swap and page cache. |
1533 | * | |
1534 | * fault_mm and fault_type are only supplied by shmem_fault: | |
1535 | * otherwise they are NULL. | |
1da177e4 | 1536 | */ |
41ffe5d5 | 1537 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, |
9e18eb29 ALC |
1538 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, |
1539 | struct mm_struct *fault_mm, int *fault_type) | |
1da177e4 LT |
1540 | { |
1541 | struct address_space *mapping = inode->i_mapping; | |
54af6042 | 1542 | struct shmem_inode_info *info; |
1da177e4 | 1543 | struct shmem_sb_info *sbinfo; |
9e18eb29 | 1544 | struct mm_struct *charge_mm; |
00501b53 | 1545 | struct mem_cgroup *memcg; |
27ab7006 | 1546 | struct page *page; |
1da177e4 | 1547 | swp_entry_t swap; |
657e3038 | 1548 | enum sgp_type sgp_huge = sgp; |
800d8c63 | 1549 | pgoff_t hindex = index; |
1da177e4 | 1550 | int error; |
54af6042 | 1551 | int once = 0; |
1635f6a7 | 1552 | int alloced = 0; |
1da177e4 | 1553 | |
09cbfeaf | 1554 | if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT)) |
1da177e4 | 1555 | return -EFBIG; |
657e3038 KS |
1556 | if (sgp == SGP_NOHUGE || sgp == SGP_HUGE) |
1557 | sgp = SGP_CACHE; | |
1da177e4 | 1558 | repeat: |
54af6042 | 1559 | swap.val = 0; |
0cd6144a | 1560 | page = find_lock_entry(mapping, index); |
54af6042 HD |
1561 | if (radix_tree_exceptional_entry(page)) { |
1562 | swap = radix_to_swp_entry(page); | |
1563 | page = NULL; | |
1564 | } | |
1565 | ||
75edd345 | 1566 | if (sgp <= SGP_CACHE && |
09cbfeaf | 1567 | ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { |
54af6042 | 1568 | error = -EINVAL; |
267a4c76 | 1569 | goto unlock; |
54af6042 HD |
1570 | } |
1571 | ||
66d2f4d2 HD |
1572 | if (page && sgp == SGP_WRITE) |
1573 | mark_page_accessed(page); | |
1574 | ||
1635f6a7 HD |
1575 | /* fallocated page? */ |
1576 | if (page && !PageUptodate(page)) { | |
1577 | if (sgp != SGP_READ) | |
1578 | goto clear; | |
1579 | unlock_page(page); | |
09cbfeaf | 1580 | put_page(page); |
1635f6a7 HD |
1581 | page = NULL; |
1582 | } | |
54af6042 | 1583 | if (page || (sgp == SGP_READ && !swap.val)) { |
54af6042 HD |
1584 | *pagep = page; |
1585 | return 0; | |
27ab7006 HD |
1586 | } |
1587 | ||
1588 | /* | |
54af6042 HD |
1589 | * Fast cache lookup did not find it: |
1590 | * bring it back from swap or allocate. | |
27ab7006 | 1591 | */ |
54af6042 HD |
1592 | info = SHMEM_I(inode); |
1593 | sbinfo = SHMEM_SB(inode->i_sb); | |
9e18eb29 | 1594 | charge_mm = fault_mm ? : current->mm; |
1da177e4 | 1595 | |
1da177e4 LT |
1596 | if (swap.val) { |
1597 | /* Look it up and read it in.. */ | |
27ab7006 HD |
1598 | page = lookup_swap_cache(swap); |
1599 | if (!page) { | |
9e18eb29 ALC |
1600 | /* Or update major stats only when swapin succeeds?? */ |
1601 | if (fault_type) { | |
68da9f05 | 1602 | *fault_type |= VM_FAULT_MAJOR; |
9e18eb29 ALC |
1603 | count_vm_event(PGMAJFAULT); |
1604 | mem_cgroup_count_vm_event(fault_mm, PGMAJFAULT); | |
1605 | } | |
1606 | /* Here we actually start the io */ | |
41ffe5d5 | 1607 | page = shmem_swapin(swap, gfp, info, index); |
27ab7006 | 1608 | if (!page) { |
54af6042 HD |
1609 | error = -ENOMEM; |
1610 | goto failed; | |
1da177e4 | 1611 | } |
1da177e4 LT |
1612 | } |
1613 | ||
1614 | /* We have to do this with page locked to prevent races */ | |
54af6042 | 1615 | lock_page(page); |
0142ef6c | 1616 | if (!PageSwapCache(page) || page_private(page) != swap.val || |
d1899228 | 1617 | !shmem_confirm_swap(mapping, index, swap)) { |
bde05d1c | 1618 | error = -EEXIST; /* try again */ |
d1899228 | 1619 | goto unlock; |
bde05d1c | 1620 | } |
27ab7006 | 1621 | if (!PageUptodate(page)) { |
1da177e4 | 1622 | error = -EIO; |
54af6042 | 1623 | goto failed; |
1da177e4 | 1624 | } |
54af6042 HD |
1625 | wait_on_page_writeback(page); |
1626 | ||
bde05d1c HD |
1627 | if (shmem_should_replace_page(page, gfp)) { |
1628 | error = shmem_replace_page(&page, gfp, info, index); | |
1629 | if (error) | |
1630 | goto failed; | |
1da177e4 | 1631 | } |
27ab7006 | 1632 | |
9e18eb29 | 1633 | error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg, |
f627c2f5 | 1634 | false); |
d1899228 | 1635 | if (!error) { |
aa3b1895 | 1636 | error = shmem_add_to_page_cache(page, mapping, index, |
fed400a1 | 1637 | swp_to_radix_entry(swap)); |
215c02bc HD |
1638 | /* |
1639 | * We already confirmed swap under page lock, and make | |
1640 | * no memory allocation here, so usually no possibility | |
1641 | * of error; but free_swap_and_cache() only trylocks a | |
1642 | * page, so it is just possible that the entry has been | |
1643 | * truncated or holepunched since swap was confirmed. | |
1644 | * shmem_undo_range() will have done some of the | |
1645 | * unaccounting, now delete_from_swap_cache() will do | |
93aa7d95 | 1646 | * the rest. |
215c02bc HD |
1647 | * Reset swap.val? No, leave it so "failed" goes back to |
1648 | * "repeat": reading a hole and writing should succeed. | |
1649 | */ | |
00501b53 | 1650 | if (error) { |
f627c2f5 | 1651 | mem_cgroup_cancel_charge(page, memcg, false); |
215c02bc | 1652 | delete_from_swap_cache(page); |
00501b53 | 1653 | } |
d1899228 | 1654 | } |
54af6042 HD |
1655 | if (error) |
1656 | goto failed; | |
1657 | ||
f627c2f5 | 1658 | mem_cgroup_commit_charge(page, memcg, true, false); |
00501b53 | 1659 | |
4595ef88 | 1660 | spin_lock_irq(&info->lock); |
285b2c4f | 1661 | info->swapped--; |
54af6042 | 1662 | shmem_recalc_inode(inode); |
4595ef88 | 1663 | spin_unlock_irq(&info->lock); |
54af6042 | 1664 | |
66d2f4d2 HD |
1665 | if (sgp == SGP_WRITE) |
1666 | mark_page_accessed(page); | |
1667 | ||
54af6042 | 1668 | delete_from_swap_cache(page); |
27ab7006 HD |
1669 | set_page_dirty(page); |
1670 | swap_free(swap); | |
1671 | ||
54af6042 | 1672 | } else { |
800d8c63 KS |
1673 | /* shmem_symlink() */ |
1674 | if (mapping->a_ops != &shmem_aops) | |
1675 | goto alloc_nohuge; | |
657e3038 | 1676 | if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE) |
800d8c63 KS |
1677 | goto alloc_nohuge; |
1678 | if (shmem_huge == SHMEM_HUGE_FORCE) | |
1679 | goto alloc_huge; | |
1680 | switch (sbinfo->huge) { | |
1681 | loff_t i_size; | |
1682 | pgoff_t off; | |
1683 | case SHMEM_HUGE_NEVER: | |
1684 | goto alloc_nohuge; | |
1685 | case SHMEM_HUGE_WITHIN_SIZE: | |
1686 | off = round_up(index, HPAGE_PMD_NR); | |
1687 | i_size = round_up(i_size_read(inode), PAGE_SIZE); | |
1688 | if (i_size >= HPAGE_PMD_SIZE && | |
1689 | i_size >> PAGE_SHIFT >= off) | |
1690 | goto alloc_huge; | |
1691 | /* fallthrough */ | |
1692 | case SHMEM_HUGE_ADVISE: | |
657e3038 KS |
1693 | if (sgp_huge == SGP_HUGE) |
1694 | goto alloc_huge; | |
1695 | /* TODO: implement fadvise() hints */ | |
800d8c63 | 1696 | goto alloc_nohuge; |
54af6042 | 1697 | } |
1da177e4 | 1698 | |
800d8c63 KS |
1699 | alloc_huge: |
1700 | page = shmem_alloc_and_acct_page(gfp, info, sbinfo, | |
1701 | index, true); | |
1702 | if (IS_ERR(page)) { | |
1703 | alloc_nohuge: page = shmem_alloc_and_acct_page(gfp, info, sbinfo, | |
1704 | index, false); | |
1da177e4 | 1705 | } |
800d8c63 | 1706 | if (IS_ERR(page)) { |
779750d2 | 1707 | int retry = 5; |
800d8c63 KS |
1708 | error = PTR_ERR(page); |
1709 | page = NULL; | |
779750d2 KS |
1710 | if (error != -ENOSPC) |
1711 | goto failed; | |
1712 | /* | |
1713 | * Try to reclaim some spece by splitting a huge page | |
1714 | * beyond i_size on the filesystem. | |
1715 | */ | |
1716 | while (retry--) { | |
1717 | int ret; | |
1718 | ret = shmem_unused_huge_shrink(sbinfo, NULL, 1); | |
1719 | if (ret == SHRINK_STOP) | |
1720 | break; | |
1721 | if (ret) | |
1722 | goto alloc_nohuge; | |
1723 | } | |
800d8c63 KS |
1724 | goto failed; |
1725 | } | |
1726 | ||
1727 | if (PageTransHuge(page)) | |
1728 | hindex = round_down(index, HPAGE_PMD_NR); | |
1729 | else | |
1730 | hindex = index; | |
1731 | ||
66d2f4d2 | 1732 | if (sgp == SGP_WRITE) |
eb39d618 | 1733 | __SetPageReferenced(page); |
66d2f4d2 | 1734 | |
9e18eb29 | 1735 | error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg, |
800d8c63 | 1736 | PageTransHuge(page)); |
54af6042 | 1737 | if (error) |
800d8c63 KS |
1738 | goto unacct; |
1739 | error = radix_tree_maybe_preload_order(gfp & GFP_RECLAIM_MASK, | |
1740 | compound_order(page)); | |
b065b432 | 1741 | if (!error) { |
800d8c63 | 1742 | error = shmem_add_to_page_cache(page, mapping, hindex, |
fed400a1 | 1743 | NULL); |
b065b432 HD |
1744 | radix_tree_preload_end(); |
1745 | } | |
1746 | if (error) { | |
800d8c63 KS |
1747 | mem_cgroup_cancel_charge(page, memcg, |
1748 | PageTransHuge(page)); | |
1749 | goto unacct; | |
b065b432 | 1750 | } |
800d8c63 KS |
1751 | mem_cgroup_commit_charge(page, memcg, false, |
1752 | PageTransHuge(page)); | |
54af6042 HD |
1753 | lru_cache_add_anon(page); |
1754 | ||
4595ef88 | 1755 | spin_lock_irq(&info->lock); |
800d8c63 KS |
1756 | info->alloced += 1 << compound_order(page); |
1757 | inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page); | |
54af6042 | 1758 | shmem_recalc_inode(inode); |
4595ef88 | 1759 | spin_unlock_irq(&info->lock); |
1635f6a7 | 1760 | alloced = true; |
54af6042 | 1761 | |
779750d2 KS |
1762 | if (PageTransHuge(page) && |
1763 | DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < | |
1764 | hindex + HPAGE_PMD_NR - 1) { | |
1765 | /* | |
1766 | * Part of the huge page is beyond i_size: subject | |
1767 | * to shrink under memory pressure. | |
1768 | */ | |
1769 | spin_lock(&sbinfo->shrinklist_lock); | |
1770 | if (list_empty(&info->shrinklist)) { | |
1771 | list_add_tail(&info->shrinklist, | |
1772 | &sbinfo->shrinklist); | |
1773 | sbinfo->shrinklist_len++; | |
1774 | } | |
1775 | spin_unlock(&sbinfo->shrinklist_lock); | |
1776 | } | |
1777 | ||
ec9516fb | 1778 | /* |
1635f6a7 HD |
1779 | * Let SGP_FALLOC use the SGP_WRITE optimization on a new page. |
1780 | */ | |
1781 | if (sgp == SGP_FALLOC) | |
1782 | sgp = SGP_WRITE; | |
1783 | clear: | |
1784 | /* | |
1785 | * Let SGP_WRITE caller clear ends if write does not fill page; | |
1786 | * but SGP_FALLOC on a page fallocated earlier must initialize | |
1787 | * it now, lest undo on failure cancel our earlier guarantee. | |
ec9516fb | 1788 | */ |
800d8c63 KS |
1789 | if (sgp != SGP_WRITE && !PageUptodate(page)) { |
1790 | struct page *head = compound_head(page); | |
1791 | int i; | |
1792 | ||
1793 | for (i = 0; i < (1 << compound_order(head)); i++) { | |
1794 | clear_highpage(head + i); | |
1795 | flush_dcache_page(head + i); | |
1796 | } | |
1797 | SetPageUptodate(head); | |
ec9516fb | 1798 | } |
1da177e4 | 1799 | } |
bde05d1c | 1800 | |
54af6042 | 1801 | /* Perhaps the file has been truncated since we checked */ |
75edd345 | 1802 | if (sgp <= SGP_CACHE && |
09cbfeaf | 1803 | ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { |
267a4c76 HD |
1804 | if (alloced) { |
1805 | ClearPageDirty(page); | |
1806 | delete_from_page_cache(page); | |
4595ef88 | 1807 | spin_lock_irq(&info->lock); |
267a4c76 | 1808 | shmem_recalc_inode(inode); |
4595ef88 | 1809 | spin_unlock_irq(&info->lock); |
267a4c76 | 1810 | } |
54af6042 | 1811 | error = -EINVAL; |
267a4c76 | 1812 | goto unlock; |
e83c32e8 | 1813 | } |
800d8c63 | 1814 | *pagep = page + index - hindex; |
54af6042 | 1815 | return 0; |
1da177e4 | 1816 | |
59a16ead | 1817 | /* |
54af6042 | 1818 | * Error recovery. |
59a16ead | 1819 | */ |
54af6042 | 1820 | unacct: |
800d8c63 KS |
1821 | if (sbinfo->max_blocks) |
1822 | percpu_counter_sub(&sbinfo->used_blocks, | |
1823 | 1 << compound_order(page)); | |
1824 | shmem_unacct_blocks(info->flags, 1 << compound_order(page)); | |
1825 | ||
1826 | if (PageTransHuge(page)) { | |
1827 | unlock_page(page); | |
1828 | put_page(page); | |
1829 | goto alloc_nohuge; | |
1830 | } | |
54af6042 | 1831 | failed: |
267a4c76 | 1832 | if (swap.val && !shmem_confirm_swap(mapping, index, swap)) |
d1899228 HD |
1833 | error = -EEXIST; |
1834 | unlock: | |
27ab7006 | 1835 | if (page) { |
54af6042 | 1836 | unlock_page(page); |
09cbfeaf | 1837 | put_page(page); |
54af6042 HD |
1838 | } |
1839 | if (error == -ENOSPC && !once++) { | |
1840 | info = SHMEM_I(inode); | |
4595ef88 | 1841 | spin_lock_irq(&info->lock); |
54af6042 | 1842 | shmem_recalc_inode(inode); |
4595ef88 | 1843 | spin_unlock_irq(&info->lock); |
27ab7006 | 1844 | goto repeat; |
ff36b801 | 1845 | } |
d1899228 | 1846 | if (error == -EEXIST) /* from above or from radix_tree_insert */ |
54af6042 HD |
1847 | goto repeat; |
1848 | return error; | |
1da177e4 LT |
1849 | } |
1850 | ||
10d20bd2 LT |
1851 | /* |
1852 | * This is like autoremove_wake_function, but it removes the wait queue | |
1853 | * entry unconditionally - even if something else had already woken the | |
1854 | * target. | |
1855 | */ | |
1856 | static int synchronous_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key) | |
1857 | { | |
1858 | int ret = default_wake_function(wait, mode, sync, key); | |
1859 | list_del_init(&wait->task_list); | |
1860 | return ret; | |
1861 | } | |
1862 | ||
d0217ac0 | 1863 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1da177e4 | 1864 | { |
496ad9aa | 1865 | struct inode *inode = file_inode(vma->vm_file); |
9e18eb29 | 1866 | gfp_t gfp = mapping_gfp_mask(inode->i_mapping); |
657e3038 | 1867 | enum sgp_type sgp; |
1da177e4 | 1868 | int error; |
68da9f05 | 1869 | int ret = VM_FAULT_LOCKED; |
1da177e4 | 1870 | |
f00cdc6d HD |
1871 | /* |
1872 | * Trinity finds that probing a hole which tmpfs is punching can | |
1873 | * prevent the hole-punch from ever completing: which in turn | |
1874 | * locks writers out with its hold on i_mutex. So refrain from | |
8e205f77 HD |
1875 | * faulting pages into the hole while it's being punched. Although |
1876 | * shmem_undo_range() does remove the additions, it may be unable to | |
1877 | * keep up, as each new page needs its own unmap_mapping_range() call, | |
1878 | * and the i_mmap tree grows ever slower to scan if new vmas are added. | |
1879 | * | |
1880 | * It does not matter if we sometimes reach this check just before the | |
1881 | * hole-punch begins, so that one fault then races with the punch: | |
1882 | * we just need to make racing faults a rare case. | |
1883 | * | |
1884 | * The implementation below would be much simpler if we just used a | |
1885 | * standard mutex or completion: but we cannot take i_mutex in fault, | |
1886 | * and bloating every shmem inode for this unlikely case would be sad. | |
f00cdc6d HD |
1887 | */ |
1888 | if (unlikely(inode->i_private)) { | |
1889 | struct shmem_falloc *shmem_falloc; | |
1890 | ||
1891 | spin_lock(&inode->i_lock); | |
1892 | shmem_falloc = inode->i_private; | |
8e205f77 HD |
1893 | if (shmem_falloc && |
1894 | shmem_falloc->waitq && | |
1895 | vmf->pgoff >= shmem_falloc->start && | |
1896 | vmf->pgoff < shmem_falloc->next) { | |
1897 | wait_queue_head_t *shmem_falloc_waitq; | |
10d20bd2 | 1898 | DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function); |
8e205f77 HD |
1899 | |
1900 | ret = VM_FAULT_NOPAGE; | |
f00cdc6d HD |
1901 | if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && |
1902 | !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { | |
8e205f77 | 1903 | /* It's polite to up mmap_sem if we can */ |
f00cdc6d | 1904 | up_read(&vma->vm_mm->mmap_sem); |
8e205f77 | 1905 | ret = VM_FAULT_RETRY; |
f00cdc6d | 1906 | } |
8e205f77 HD |
1907 | |
1908 | shmem_falloc_waitq = shmem_falloc->waitq; | |
1909 | prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, | |
1910 | TASK_UNINTERRUPTIBLE); | |
1911 | spin_unlock(&inode->i_lock); | |
1912 | schedule(); | |
1913 | ||
1914 | /* | |
1915 | * shmem_falloc_waitq points into the shmem_fallocate() | |
1916 | * stack of the hole-punching task: shmem_falloc_waitq | |
1917 | * is usually invalid by the time we reach here, but | |
1918 | * finish_wait() does not dereference it in that case; | |
1919 | * though i_lock needed lest racing with wake_up_all(). | |
1920 | */ | |
1921 | spin_lock(&inode->i_lock); | |
1922 | finish_wait(shmem_falloc_waitq, &shmem_fault_wait); | |
1923 | spin_unlock(&inode->i_lock); | |
1924 | return ret; | |
f00cdc6d | 1925 | } |
8e205f77 | 1926 | spin_unlock(&inode->i_lock); |
f00cdc6d HD |
1927 | } |
1928 | ||
657e3038 KS |
1929 | sgp = SGP_CACHE; |
1930 | if (vma->vm_flags & VM_HUGEPAGE) | |
1931 | sgp = SGP_HUGE; | |
1932 | else if (vma->vm_flags & VM_NOHUGEPAGE) | |
1933 | sgp = SGP_NOHUGE; | |
1934 | ||
1935 | error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp, | |
9e18eb29 | 1936 | gfp, vma->vm_mm, &ret); |
d0217ac0 NP |
1937 | if (error) |
1938 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
68da9f05 | 1939 | return ret; |
1da177e4 LT |
1940 | } |
1941 | ||
c01d5b30 HD |
1942 | unsigned long shmem_get_unmapped_area(struct file *file, |
1943 | unsigned long uaddr, unsigned long len, | |
1944 | unsigned long pgoff, unsigned long flags) | |
1945 | { | |
1946 | unsigned long (*get_area)(struct file *, | |
1947 | unsigned long, unsigned long, unsigned long, unsigned long); | |
1948 | unsigned long addr; | |
1949 | unsigned long offset; | |
1950 | unsigned long inflated_len; | |
1951 | unsigned long inflated_addr; | |
1952 | unsigned long inflated_offset; | |
1953 | ||
1954 | if (len > TASK_SIZE) | |
1955 | return -ENOMEM; | |
1956 | ||
1957 | get_area = current->mm->get_unmapped_area; | |
1958 | addr = get_area(file, uaddr, len, pgoff, flags); | |
1959 | ||
e496cf3d | 1960 | if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) |
c01d5b30 HD |
1961 | return addr; |
1962 | if (IS_ERR_VALUE(addr)) | |
1963 | return addr; | |
1964 | if (addr & ~PAGE_MASK) | |
1965 | return addr; | |
1966 | if (addr > TASK_SIZE - len) | |
1967 | return addr; | |
1968 | ||
1969 | if (shmem_huge == SHMEM_HUGE_DENY) | |
1970 | return addr; | |
1971 | if (len < HPAGE_PMD_SIZE) | |
1972 | return addr; | |
1973 | if (flags & MAP_FIXED) | |
1974 | return addr; | |
1975 | /* | |
1976 | * Our priority is to support MAP_SHARED mapped hugely; | |
1977 | * and support MAP_PRIVATE mapped hugely too, until it is COWed. | |
1978 | * But if caller specified an address hint, respect that as before. | |
1979 | */ | |
1980 | if (uaddr) | |
1981 | return addr; | |
1982 | ||
1983 | if (shmem_huge != SHMEM_HUGE_FORCE) { | |
1984 | struct super_block *sb; | |
1985 | ||
1986 | if (file) { | |
1987 | VM_BUG_ON(file->f_op != &shmem_file_operations); | |
1988 | sb = file_inode(file)->i_sb; | |
1989 | } else { | |
1990 | /* | |
1991 | * Called directly from mm/mmap.c, or drivers/char/mem.c | |
1992 | * for "/dev/zero", to create a shared anonymous object. | |
1993 | */ | |
1994 | if (IS_ERR(shm_mnt)) | |
1995 | return addr; | |
1996 | sb = shm_mnt->mnt_sb; | |
1997 | } | |
3089bf61 | 1998 | if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER) |
c01d5b30 HD |
1999 | return addr; |
2000 | } | |
2001 | ||
2002 | offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1); | |
2003 | if (offset && offset + len < 2 * HPAGE_PMD_SIZE) | |
2004 | return addr; | |
2005 | if ((addr & (HPAGE_PMD_SIZE-1)) == offset) | |
2006 | return addr; | |
2007 | ||
2008 | inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE; | |
2009 | if (inflated_len > TASK_SIZE) | |
2010 | return addr; | |
2011 | if (inflated_len < len) | |
2012 | return addr; | |
2013 | ||
2014 | inflated_addr = get_area(NULL, 0, inflated_len, 0, flags); | |
2015 | if (IS_ERR_VALUE(inflated_addr)) | |
2016 | return addr; | |
2017 | if (inflated_addr & ~PAGE_MASK) | |
2018 | return addr; | |
2019 | ||
2020 | inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1); | |
2021 | inflated_addr += offset - inflated_offset; | |
2022 | if (inflated_offset > offset) | |
2023 | inflated_addr += HPAGE_PMD_SIZE; | |
2024 | ||
2025 | if (inflated_addr > TASK_SIZE - len) | |
2026 | return addr; | |
2027 | return inflated_addr; | |
2028 | } | |
2029 | ||
1da177e4 | 2030 | #ifdef CONFIG_NUMA |
41ffe5d5 | 2031 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) |
1da177e4 | 2032 | { |
496ad9aa | 2033 | struct inode *inode = file_inode(vma->vm_file); |
41ffe5d5 | 2034 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); |
1da177e4 LT |
2035 | } |
2036 | ||
d8dc74f2 AB |
2037 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, |
2038 | unsigned long addr) | |
1da177e4 | 2039 | { |
496ad9aa | 2040 | struct inode *inode = file_inode(vma->vm_file); |
41ffe5d5 | 2041 | pgoff_t index; |
1da177e4 | 2042 | |
41ffe5d5 HD |
2043 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
2044 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
1da177e4 LT |
2045 | } |
2046 | #endif | |
2047 | ||
2048 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
2049 | { | |
496ad9aa | 2050 | struct inode *inode = file_inode(file); |
1da177e4 LT |
2051 | struct shmem_inode_info *info = SHMEM_I(inode); |
2052 | int retval = -ENOMEM; | |
2053 | ||
4595ef88 | 2054 | spin_lock_irq(&info->lock); |
1da177e4 LT |
2055 | if (lock && !(info->flags & VM_LOCKED)) { |
2056 | if (!user_shm_lock(inode->i_size, user)) | |
2057 | goto out_nomem; | |
2058 | info->flags |= VM_LOCKED; | |
89e004ea | 2059 | mapping_set_unevictable(file->f_mapping); |
1da177e4 LT |
2060 | } |
2061 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
2062 | user_shm_unlock(inode->i_size, user); | |
2063 | info->flags &= ~VM_LOCKED; | |
89e004ea | 2064 | mapping_clear_unevictable(file->f_mapping); |
1da177e4 LT |
2065 | } |
2066 | retval = 0; | |
89e004ea | 2067 | |
1da177e4 | 2068 | out_nomem: |
4595ef88 | 2069 | spin_unlock_irq(&info->lock); |
1da177e4 LT |
2070 | return retval; |
2071 | } | |
2072 | ||
9b83a6a8 | 2073 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) |
1da177e4 LT |
2074 | { |
2075 | file_accessed(file); | |
2076 | vma->vm_ops = &shmem_vm_ops; | |
e496cf3d | 2077 | if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && |
f3f0e1d2 KS |
2078 | ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) < |
2079 | (vma->vm_end & HPAGE_PMD_MASK)) { | |
2080 | khugepaged_enter(vma, vma->vm_flags); | |
2081 | } | |
1da177e4 LT |
2082 | return 0; |
2083 | } | |
2084 | ||
454abafe | 2085 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, |
09208d15 | 2086 | umode_t mode, dev_t dev, unsigned long flags) |
1da177e4 LT |
2087 | { |
2088 | struct inode *inode; | |
2089 | struct shmem_inode_info *info; | |
2090 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
2091 | ||
5b04c689 PE |
2092 | if (shmem_reserve_inode(sb)) |
2093 | return NULL; | |
1da177e4 LT |
2094 | |
2095 | inode = new_inode(sb); | |
2096 | if (inode) { | |
85fe4025 | 2097 | inode->i_ino = get_next_ino(); |
454abafe | 2098 | inode_init_owner(inode, dir, mode); |
1da177e4 | 2099 | inode->i_blocks = 0; |
078cd827 | 2100 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); |
91828a40 | 2101 | inode->i_generation = get_seconds(); |
1da177e4 LT |
2102 | info = SHMEM_I(inode); |
2103 | memset(info, 0, (char *)inode - (char *)info); | |
2104 | spin_lock_init(&info->lock); | |
40e041a2 | 2105 | info->seals = F_SEAL_SEAL; |
0b0a0806 | 2106 | info->flags = flags & VM_NORESERVE; |
779750d2 | 2107 | INIT_LIST_HEAD(&info->shrinklist); |
1da177e4 | 2108 | INIT_LIST_HEAD(&info->swaplist); |
38f38657 | 2109 | simple_xattrs_init(&info->xattrs); |
72c04902 | 2110 | cache_no_acl(inode); |
1da177e4 LT |
2111 | |
2112 | switch (mode & S_IFMT) { | |
2113 | default: | |
39f0247d | 2114 | inode->i_op = &shmem_special_inode_operations; |
1da177e4 LT |
2115 | init_special_inode(inode, mode, dev); |
2116 | break; | |
2117 | case S_IFREG: | |
14fcc23f | 2118 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 LT |
2119 | inode->i_op = &shmem_inode_operations; |
2120 | inode->i_fop = &shmem_file_operations; | |
71fe804b LS |
2121 | mpol_shared_policy_init(&info->policy, |
2122 | shmem_get_sbmpol(sbinfo)); | |
1da177e4 LT |
2123 | break; |
2124 | case S_IFDIR: | |
d8c76e6f | 2125 | inc_nlink(inode); |
1da177e4 LT |
2126 | /* Some things misbehave if size == 0 on a directory */ |
2127 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
2128 | inode->i_op = &shmem_dir_inode_operations; | |
2129 | inode->i_fop = &simple_dir_operations; | |
2130 | break; | |
2131 | case S_IFLNK: | |
2132 | /* | |
2133 | * Must not load anything in the rbtree, | |
2134 | * mpol_free_shared_policy will not be called. | |
2135 | */ | |
71fe804b | 2136 | mpol_shared_policy_init(&info->policy, NULL); |
1da177e4 LT |
2137 | break; |
2138 | } | |
5b04c689 PE |
2139 | } else |
2140 | shmem_free_inode(sb); | |
1da177e4 LT |
2141 | return inode; |
2142 | } | |
2143 | ||
0cd6144a JW |
2144 | bool shmem_mapping(struct address_space *mapping) |
2145 | { | |
f0774d88 SL |
2146 | if (!mapping->host) |
2147 | return false; | |
2148 | ||
97b713ba | 2149 | return mapping->host->i_sb->s_op == &shmem_ops; |
0cd6144a JW |
2150 | } |
2151 | ||
1da177e4 | 2152 | #ifdef CONFIG_TMPFS |
92e1d5be | 2153 | static const struct inode_operations shmem_symlink_inode_operations; |
69f07ec9 | 2154 | static const struct inode_operations shmem_short_symlink_operations; |
1da177e4 | 2155 | |
6d9d88d0 JS |
2156 | #ifdef CONFIG_TMPFS_XATTR |
2157 | static int shmem_initxattrs(struct inode *, const struct xattr *, void *); | |
2158 | #else | |
2159 | #define shmem_initxattrs NULL | |
2160 | #endif | |
2161 | ||
1da177e4 | 2162 | static int |
800d15a5 NP |
2163 | shmem_write_begin(struct file *file, struct address_space *mapping, |
2164 | loff_t pos, unsigned len, unsigned flags, | |
2165 | struct page **pagep, void **fsdata) | |
1da177e4 | 2166 | { |
800d15a5 | 2167 | struct inode *inode = mapping->host; |
40e041a2 | 2168 | struct shmem_inode_info *info = SHMEM_I(inode); |
09cbfeaf | 2169 | pgoff_t index = pos >> PAGE_SHIFT; |
40e041a2 DH |
2170 | |
2171 | /* i_mutex is held by caller */ | |
2172 | if (unlikely(info->seals)) { | |
2173 | if (info->seals & F_SEAL_WRITE) | |
2174 | return -EPERM; | |
2175 | if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size) | |
2176 | return -EPERM; | |
2177 | } | |
2178 | ||
9e18eb29 | 2179 | return shmem_getpage(inode, index, pagep, SGP_WRITE); |
800d15a5 NP |
2180 | } |
2181 | ||
2182 | static int | |
2183 | shmem_write_end(struct file *file, struct address_space *mapping, | |
2184 | loff_t pos, unsigned len, unsigned copied, | |
2185 | struct page *page, void *fsdata) | |
2186 | { | |
2187 | struct inode *inode = mapping->host; | |
2188 | ||
d3602444 HD |
2189 | if (pos + copied > inode->i_size) |
2190 | i_size_write(inode, pos + copied); | |
2191 | ||
ec9516fb | 2192 | if (!PageUptodate(page)) { |
800d8c63 KS |
2193 | struct page *head = compound_head(page); |
2194 | if (PageTransCompound(page)) { | |
2195 | int i; | |
2196 | ||
2197 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2198 | if (head + i == page) | |
2199 | continue; | |
2200 | clear_highpage(head + i); | |
2201 | flush_dcache_page(head + i); | |
2202 | } | |
2203 | } | |
09cbfeaf KS |
2204 | if (copied < PAGE_SIZE) { |
2205 | unsigned from = pos & (PAGE_SIZE - 1); | |
ec9516fb | 2206 | zero_user_segments(page, 0, from, |
09cbfeaf | 2207 | from + copied, PAGE_SIZE); |
ec9516fb | 2208 | } |
800d8c63 | 2209 | SetPageUptodate(head); |
ec9516fb | 2210 | } |
800d15a5 | 2211 | set_page_dirty(page); |
6746aff7 | 2212 | unlock_page(page); |
09cbfeaf | 2213 | put_page(page); |
800d15a5 | 2214 | |
800d15a5 | 2215 | return copied; |
1da177e4 LT |
2216 | } |
2217 | ||
2ba5bbed | 2218 | static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) |
1da177e4 | 2219 | { |
6e58e79d AV |
2220 | struct file *file = iocb->ki_filp; |
2221 | struct inode *inode = file_inode(file); | |
1da177e4 | 2222 | struct address_space *mapping = inode->i_mapping; |
41ffe5d5 HD |
2223 | pgoff_t index; |
2224 | unsigned long offset; | |
a0ee5ec5 | 2225 | enum sgp_type sgp = SGP_READ; |
f7c1d074 | 2226 | int error = 0; |
cb66a7a1 | 2227 | ssize_t retval = 0; |
6e58e79d | 2228 | loff_t *ppos = &iocb->ki_pos; |
a0ee5ec5 HD |
2229 | |
2230 | /* | |
2231 | * Might this read be for a stacking filesystem? Then when reading | |
2232 | * holes of a sparse file, we actually need to allocate those pages, | |
2233 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
2234 | */ | |
777eda2c | 2235 | if (!iter_is_iovec(to)) |
75edd345 | 2236 | sgp = SGP_CACHE; |
1da177e4 | 2237 | |
09cbfeaf KS |
2238 | index = *ppos >> PAGE_SHIFT; |
2239 | offset = *ppos & ~PAGE_MASK; | |
1da177e4 LT |
2240 | |
2241 | for (;;) { | |
2242 | struct page *page = NULL; | |
41ffe5d5 HD |
2243 | pgoff_t end_index; |
2244 | unsigned long nr, ret; | |
1da177e4 LT |
2245 | loff_t i_size = i_size_read(inode); |
2246 | ||
09cbfeaf | 2247 | end_index = i_size >> PAGE_SHIFT; |
1da177e4 LT |
2248 | if (index > end_index) |
2249 | break; | |
2250 | if (index == end_index) { | |
09cbfeaf | 2251 | nr = i_size & ~PAGE_MASK; |
1da177e4 LT |
2252 | if (nr <= offset) |
2253 | break; | |
2254 | } | |
2255 | ||
9e18eb29 | 2256 | error = shmem_getpage(inode, index, &page, sgp); |
6e58e79d AV |
2257 | if (error) { |
2258 | if (error == -EINVAL) | |
2259 | error = 0; | |
1da177e4 LT |
2260 | break; |
2261 | } | |
75edd345 HD |
2262 | if (page) { |
2263 | if (sgp == SGP_CACHE) | |
2264 | set_page_dirty(page); | |
d3602444 | 2265 | unlock_page(page); |
75edd345 | 2266 | } |
1da177e4 LT |
2267 | |
2268 | /* | |
2269 | * We must evaluate after, since reads (unlike writes) | |
1b1dcc1b | 2270 | * are called without i_mutex protection against truncate |
1da177e4 | 2271 | */ |
09cbfeaf | 2272 | nr = PAGE_SIZE; |
1da177e4 | 2273 | i_size = i_size_read(inode); |
09cbfeaf | 2274 | end_index = i_size >> PAGE_SHIFT; |
1da177e4 | 2275 | if (index == end_index) { |
09cbfeaf | 2276 | nr = i_size & ~PAGE_MASK; |
1da177e4 LT |
2277 | if (nr <= offset) { |
2278 | if (page) | |
09cbfeaf | 2279 | put_page(page); |
1da177e4 LT |
2280 | break; |
2281 | } | |
2282 | } | |
2283 | nr -= offset; | |
2284 | ||
2285 | if (page) { | |
2286 | /* | |
2287 | * If users can be writing to this page using arbitrary | |
2288 | * virtual addresses, take care about potential aliasing | |
2289 | * before reading the page on the kernel side. | |
2290 | */ | |
2291 | if (mapping_writably_mapped(mapping)) | |
2292 | flush_dcache_page(page); | |
2293 | /* | |
2294 | * Mark the page accessed if we read the beginning. | |
2295 | */ | |
2296 | if (!offset) | |
2297 | mark_page_accessed(page); | |
b5810039 | 2298 | } else { |
1da177e4 | 2299 | page = ZERO_PAGE(0); |
09cbfeaf | 2300 | get_page(page); |
b5810039 | 2301 | } |
1da177e4 LT |
2302 | |
2303 | /* | |
2304 | * Ok, we have the page, and it's up-to-date, so | |
2305 | * now we can copy it to user space... | |
1da177e4 | 2306 | */ |
2ba5bbed | 2307 | ret = copy_page_to_iter(page, offset, nr, to); |
6e58e79d | 2308 | retval += ret; |
1da177e4 | 2309 | offset += ret; |
09cbfeaf KS |
2310 | index += offset >> PAGE_SHIFT; |
2311 | offset &= ~PAGE_MASK; | |
1da177e4 | 2312 | |
09cbfeaf | 2313 | put_page(page); |
2ba5bbed | 2314 | if (!iov_iter_count(to)) |
1da177e4 | 2315 | break; |
6e58e79d AV |
2316 | if (ret < nr) { |
2317 | error = -EFAULT; | |
2318 | break; | |
2319 | } | |
1da177e4 LT |
2320 | cond_resched(); |
2321 | } | |
2322 | ||
09cbfeaf | 2323 | *ppos = ((loff_t) index << PAGE_SHIFT) + offset; |
6e58e79d AV |
2324 | file_accessed(file); |
2325 | return retval ? retval : error; | |
1da177e4 LT |
2326 | } |
2327 | ||
220f2ac9 HD |
2328 | /* |
2329 | * llseek SEEK_DATA or SEEK_HOLE through the radix_tree. | |
2330 | */ | |
2331 | static pgoff_t shmem_seek_hole_data(struct address_space *mapping, | |
965c8e59 | 2332 | pgoff_t index, pgoff_t end, int whence) |
220f2ac9 HD |
2333 | { |
2334 | struct page *page; | |
2335 | struct pagevec pvec; | |
2336 | pgoff_t indices[PAGEVEC_SIZE]; | |
2337 | bool done = false; | |
2338 | int i; | |
2339 | ||
2340 | pagevec_init(&pvec, 0); | |
2341 | pvec.nr = 1; /* start small: we may be there already */ | |
2342 | while (!done) { | |
0cd6144a | 2343 | pvec.nr = find_get_entries(mapping, index, |
220f2ac9 HD |
2344 | pvec.nr, pvec.pages, indices); |
2345 | if (!pvec.nr) { | |
965c8e59 | 2346 | if (whence == SEEK_DATA) |
220f2ac9 HD |
2347 | index = end; |
2348 | break; | |
2349 | } | |
2350 | for (i = 0; i < pvec.nr; i++, index++) { | |
2351 | if (index < indices[i]) { | |
965c8e59 | 2352 | if (whence == SEEK_HOLE) { |
220f2ac9 HD |
2353 | done = true; |
2354 | break; | |
2355 | } | |
2356 | index = indices[i]; | |
2357 | } | |
2358 | page = pvec.pages[i]; | |
2359 | if (page && !radix_tree_exceptional_entry(page)) { | |
2360 | if (!PageUptodate(page)) | |
2361 | page = NULL; | |
2362 | } | |
2363 | if (index >= end || | |
965c8e59 AM |
2364 | (page && whence == SEEK_DATA) || |
2365 | (!page && whence == SEEK_HOLE)) { | |
220f2ac9 HD |
2366 | done = true; |
2367 | break; | |
2368 | } | |
2369 | } | |
0cd6144a | 2370 | pagevec_remove_exceptionals(&pvec); |
220f2ac9 HD |
2371 | pagevec_release(&pvec); |
2372 | pvec.nr = PAGEVEC_SIZE; | |
2373 | cond_resched(); | |
2374 | } | |
2375 | return index; | |
2376 | } | |
2377 | ||
965c8e59 | 2378 | static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence) |
220f2ac9 HD |
2379 | { |
2380 | struct address_space *mapping = file->f_mapping; | |
2381 | struct inode *inode = mapping->host; | |
2382 | pgoff_t start, end; | |
2383 | loff_t new_offset; | |
2384 | ||
965c8e59 AM |
2385 | if (whence != SEEK_DATA && whence != SEEK_HOLE) |
2386 | return generic_file_llseek_size(file, offset, whence, | |
220f2ac9 | 2387 | MAX_LFS_FILESIZE, i_size_read(inode)); |
5955102c | 2388 | inode_lock(inode); |
220f2ac9 HD |
2389 | /* We're holding i_mutex so we can access i_size directly */ |
2390 | ||
2391 | if (offset < 0) | |
2392 | offset = -EINVAL; | |
2393 | else if (offset >= inode->i_size) | |
2394 | offset = -ENXIO; | |
2395 | else { | |
09cbfeaf KS |
2396 | start = offset >> PAGE_SHIFT; |
2397 | end = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
965c8e59 | 2398 | new_offset = shmem_seek_hole_data(mapping, start, end, whence); |
09cbfeaf | 2399 | new_offset <<= PAGE_SHIFT; |
220f2ac9 HD |
2400 | if (new_offset > offset) { |
2401 | if (new_offset < inode->i_size) | |
2402 | offset = new_offset; | |
965c8e59 | 2403 | else if (whence == SEEK_DATA) |
220f2ac9 HD |
2404 | offset = -ENXIO; |
2405 | else | |
2406 | offset = inode->i_size; | |
2407 | } | |
2408 | } | |
2409 | ||
387aae6f HD |
2410 | if (offset >= 0) |
2411 | offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE); | |
5955102c | 2412 | inode_unlock(inode); |
220f2ac9 HD |
2413 | return offset; |
2414 | } | |
2415 | ||
05f65b5c DH |
2416 | /* |
2417 | * We need a tag: a new tag would expand every radix_tree_node by 8 bytes, | |
2418 | * so reuse a tag which we firmly believe is never set or cleared on shmem. | |
2419 | */ | |
2420 | #define SHMEM_TAG_PINNED PAGECACHE_TAG_TOWRITE | |
2421 | #define LAST_SCAN 4 /* about 150ms max */ | |
2422 | ||
2423 | static void shmem_tag_pins(struct address_space *mapping) | |
2424 | { | |
2425 | struct radix_tree_iter iter; | |
2426 | void **slot; | |
2427 | pgoff_t start; | |
2428 | struct page *page; | |
2429 | ||
2430 | lru_add_drain(); | |
2431 | start = 0; | |
2432 | rcu_read_lock(); | |
2433 | ||
05f65b5c DH |
2434 | radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { |
2435 | page = radix_tree_deref_slot(slot); | |
2436 | if (!page || radix_tree_exception(page)) { | |
2cf938aa MW |
2437 | if (radix_tree_deref_retry(page)) { |
2438 | slot = radix_tree_iter_retry(&iter); | |
2439 | continue; | |
2440 | } | |
05f65b5c DH |
2441 | } else if (page_count(page) - page_mapcount(page) > 1) { |
2442 | spin_lock_irq(&mapping->tree_lock); | |
2443 | radix_tree_tag_set(&mapping->page_tree, iter.index, | |
2444 | SHMEM_TAG_PINNED); | |
2445 | spin_unlock_irq(&mapping->tree_lock); | |
2446 | } | |
2447 | ||
2448 | if (need_resched()) { | |
2449 | cond_resched_rcu(); | |
7165092f | 2450 | slot = radix_tree_iter_next(&iter); |
05f65b5c DH |
2451 | } |
2452 | } | |
2453 | rcu_read_unlock(); | |
2454 | } | |
2455 | ||
2456 | /* | |
2457 | * Setting SEAL_WRITE requires us to verify there's no pending writer. However, | |
2458 | * via get_user_pages(), drivers might have some pending I/O without any active | |
2459 | * user-space mappings (eg., direct-IO, AIO). Therefore, we look at all pages | |
2460 | * and see whether it has an elevated ref-count. If so, we tag them and wait for | |
2461 | * them to be dropped. | |
2462 | * The caller must guarantee that no new user will acquire writable references | |
2463 | * to those pages to avoid races. | |
2464 | */ | |
40e041a2 DH |
2465 | static int shmem_wait_for_pins(struct address_space *mapping) |
2466 | { | |
05f65b5c DH |
2467 | struct radix_tree_iter iter; |
2468 | void **slot; | |
2469 | pgoff_t start; | |
2470 | struct page *page; | |
2471 | int error, scan; | |
2472 | ||
2473 | shmem_tag_pins(mapping); | |
2474 | ||
2475 | error = 0; | |
2476 | for (scan = 0; scan <= LAST_SCAN; scan++) { | |
2477 | if (!radix_tree_tagged(&mapping->page_tree, SHMEM_TAG_PINNED)) | |
2478 | break; | |
2479 | ||
2480 | if (!scan) | |
2481 | lru_add_drain_all(); | |
2482 | else if (schedule_timeout_killable((HZ << scan) / 200)) | |
2483 | scan = LAST_SCAN; | |
2484 | ||
2485 | start = 0; | |
2486 | rcu_read_lock(); | |
05f65b5c DH |
2487 | radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, |
2488 | start, SHMEM_TAG_PINNED) { | |
2489 | ||
2490 | page = radix_tree_deref_slot(slot); | |
2491 | if (radix_tree_exception(page)) { | |
2cf938aa MW |
2492 | if (radix_tree_deref_retry(page)) { |
2493 | slot = radix_tree_iter_retry(&iter); | |
2494 | continue; | |
2495 | } | |
05f65b5c DH |
2496 | |
2497 | page = NULL; | |
2498 | } | |
2499 | ||
2500 | if (page && | |
2501 | page_count(page) - page_mapcount(page) != 1) { | |
2502 | if (scan < LAST_SCAN) | |
2503 | goto continue_resched; | |
2504 | ||
2505 | /* | |
2506 | * On the last scan, we clean up all those tags | |
2507 | * we inserted; but make a note that we still | |
2508 | * found pages pinned. | |
2509 | */ | |
2510 | error = -EBUSY; | |
2511 | } | |
2512 | ||
2513 | spin_lock_irq(&mapping->tree_lock); | |
2514 | radix_tree_tag_clear(&mapping->page_tree, | |
2515 | iter.index, SHMEM_TAG_PINNED); | |
2516 | spin_unlock_irq(&mapping->tree_lock); | |
2517 | continue_resched: | |
2518 | if (need_resched()) { | |
2519 | cond_resched_rcu(); | |
7165092f | 2520 | slot = radix_tree_iter_next(&iter); |
05f65b5c DH |
2521 | } |
2522 | } | |
2523 | rcu_read_unlock(); | |
2524 | } | |
2525 | ||
2526 | return error; | |
40e041a2 DH |
2527 | } |
2528 | ||
2529 | #define F_ALL_SEALS (F_SEAL_SEAL | \ | |
2530 | F_SEAL_SHRINK | \ | |
2531 | F_SEAL_GROW | \ | |
2532 | F_SEAL_WRITE) | |
2533 | ||
2534 | int shmem_add_seals(struct file *file, unsigned int seals) | |
2535 | { | |
2536 | struct inode *inode = file_inode(file); | |
2537 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2538 | int error; | |
2539 | ||
2540 | /* | |
2541 | * SEALING | |
2542 | * Sealing allows multiple parties to share a shmem-file but restrict | |
2543 | * access to a specific subset of file operations. Seals can only be | |
2544 | * added, but never removed. This way, mutually untrusted parties can | |
2545 | * share common memory regions with a well-defined policy. A malicious | |
2546 | * peer can thus never perform unwanted operations on a shared object. | |
2547 | * | |
2548 | * Seals are only supported on special shmem-files and always affect | |
2549 | * the whole underlying inode. Once a seal is set, it may prevent some | |
2550 | * kinds of access to the file. Currently, the following seals are | |
2551 | * defined: | |
2552 | * SEAL_SEAL: Prevent further seals from being set on this file | |
2553 | * SEAL_SHRINK: Prevent the file from shrinking | |
2554 | * SEAL_GROW: Prevent the file from growing | |
2555 | * SEAL_WRITE: Prevent write access to the file | |
2556 | * | |
2557 | * As we don't require any trust relationship between two parties, we | |
2558 | * must prevent seals from being removed. Therefore, sealing a file | |
2559 | * only adds a given set of seals to the file, it never touches | |
2560 | * existing seals. Furthermore, the "setting seals"-operation can be | |
2561 | * sealed itself, which basically prevents any further seal from being | |
2562 | * added. | |
2563 | * | |
2564 | * Semantics of sealing are only defined on volatile files. Only | |
2565 | * anonymous shmem files support sealing. More importantly, seals are | |
2566 | * never written to disk. Therefore, there's no plan to support it on | |
2567 | * other file types. | |
2568 | */ | |
2569 | ||
2570 | if (file->f_op != &shmem_file_operations) | |
2571 | return -EINVAL; | |
2572 | if (!(file->f_mode & FMODE_WRITE)) | |
2573 | return -EPERM; | |
2574 | if (seals & ~(unsigned int)F_ALL_SEALS) | |
2575 | return -EINVAL; | |
2576 | ||
5955102c | 2577 | inode_lock(inode); |
40e041a2 DH |
2578 | |
2579 | if (info->seals & F_SEAL_SEAL) { | |
2580 | error = -EPERM; | |
2581 | goto unlock; | |
2582 | } | |
2583 | ||
2584 | if ((seals & F_SEAL_WRITE) && !(info->seals & F_SEAL_WRITE)) { | |
2585 | error = mapping_deny_writable(file->f_mapping); | |
2586 | if (error) | |
2587 | goto unlock; | |
2588 | ||
2589 | error = shmem_wait_for_pins(file->f_mapping); | |
2590 | if (error) { | |
2591 | mapping_allow_writable(file->f_mapping); | |
2592 | goto unlock; | |
2593 | } | |
2594 | } | |
2595 | ||
2596 | info->seals |= seals; | |
2597 | error = 0; | |
2598 | ||
2599 | unlock: | |
5955102c | 2600 | inode_unlock(inode); |
40e041a2 DH |
2601 | return error; |
2602 | } | |
2603 | EXPORT_SYMBOL_GPL(shmem_add_seals); | |
2604 | ||
2605 | int shmem_get_seals(struct file *file) | |
2606 | { | |
2607 | if (file->f_op != &shmem_file_operations) | |
2608 | return -EINVAL; | |
2609 | ||
2610 | return SHMEM_I(file_inode(file))->seals; | |
2611 | } | |
2612 | EXPORT_SYMBOL_GPL(shmem_get_seals); | |
2613 | ||
2614 | long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg) | |
2615 | { | |
2616 | long error; | |
2617 | ||
2618 | switch (cmd) { | |
2619 | case F_ADD_SEALS: | |
2620 | /* disallow upper 32bit */ | |
2621 | if (arg > UINT_MAX) | |
2622 | return -EINVAL; | |
2623 | ||
2624 | error = shmem_add_seals(file, arg); | |
2625 | break; | |
2626 | case F_GET_SEALS: | |
2627 | error = shmem_get_seals(file); | |
2628 | break; | |
2629 | default: | |
2630 | error = -EINVAL; | |
2631 | break; | |
2632 | } | |
2633 | ||
2634 | return error; | |
2635 | } | |
2636 | ||
83e4fa9c HD |
2637 | static long shmem_fallocate(struct file *file, int mode, loff_t offset, |
2638 | loff_t len) | |
2639 | { | |
496ad9aa | 2640 | struct inode *inode = file_inode(file); |
e2d12e22 | 2641 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); |
40e041a2 | 2642 | struct shmem_inode_info *info = SHMEM_I(inode); |
1aac1400 | 2643 | struct shmem_falloc shmem_falloc; |
e2d12e22 HD |
2644 | pgoff_t start, index, end; |
2645 | int error; | |
83e4fa9c | 2646 | |
13ace4d0 HD |
2647 | if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) |
2648 | return -EOPNOTSUPP; | |
2649 | ||
5955102c | 2650 | inode_lock(inode); |
83e4fa9c HD |
2651 | |
2652 | if (mode & FALLOC_FL_PUNCH_HOLE) { | |
2653 | struct address_space *mapping = file->f_mapping; | |
2654 | loff_t unmap_start = round_up(offset, PAGE_SIZE); | |
2655 | loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1; | |
8e205f77 | 2656 | DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq); |
83e4fa9c | 2657 | |
40e041a2 DH |
2658 | /* protected by i_mutex */ |
2659 | if (info->seals & F_SEAL_WRITE) { | |
2660 | error = -EPERM; | |
2661 | goto out; | |
2662 | } | |
2663 | ||
8e205f77 | 2664 | shmem_falloc.waitq = &shmem_falloc_waitq; |
f00cdc6d HD |
2665 | shmem_falloc.start = unmap_start >> PAGE_SHIFT; |
2666 | shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT; | |
2667 | spin_lock(&inode->i_lock); | |
2668 | inode->i_private = &shmem_falloc; | |
2669 | spin_unlock(&inode->i_lock); | |
2670 | ||
83e4fa9c HD |
2671 | if ((u64)unmap_end > (u64)unmap_start) |
2672 | unmap_mapping_range(mapping, unmap_start, | |
2673 | 1 + unmap_end - unmap_start, 0); | |
2674 | shmem_truncate_range(inode, offset, offset + len - 1); | |
2675 | /* No need to unmap again: hole-punching leaves COWed pages */ | |
8e205f77 HD |
2676 | |
2677 | spin_lock(&inode->i_lock); | |
2678 | inode->i_private = NULL; | |
2679 | wake_up_all(&shmem_falloc_waitq); | |
10d20bd2 | 2680 | WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.task_list)); |
8e205f77 | 2681 | spin_unlock(&inode->i_lock); |
83e4fa9c | 2682 | error = 0; |
8e205f77 | 2683 | goto out; |
e2d12e22 HD |
2684 | } |
2685 | ||
2686 | /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ | |
2687 | error = inode_newsize_ok(inode, offset + len); | |
2688 | if (error) | |
2689 | goto out; | |
2690 | ||
40e041a2 DH |
2691 | if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) { |
2692 | error = -EPERM; | |
2693 | goto out; | |
2694 | } | |
2695 | ||
09cbfeaf KS |
2696 | start = offset >> PAGE_SHIFT; |
2697 | end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
e2d12e22 HD |
2698 | /* Try to avoid a swapstorm if len is impossible to satisfy */ |
2699 | if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) { | |
2700 | error = -ENOSPC; | |
2701 | goto out; | |
83e4fa9c HD |
2702 | } |
2703 | ||
8e205f77 | 2704 | shmem_falloc.waitq = NULL; |
1aac1400 HD |
2705 | shmem_falloc.start = start; |
2706 | shmem_falloc.next = start; | |
2707 | shmem_falloc.nr_falloced = 0; | |
2708 | shmem_falloc.nr_unswapped = 0; | |
2709 | spin_lock(&inode->i_lock); | |
2710 | inode->i_private = &shmem_falloc; | |
2711 | spin_unlock(&inode->i_lock); | |
2712 | ||
e2d12e22 HD |
2713 | for (index = start; index < end; index++) { |
2714 | struct page *page; | |
2715 | ||
2716 | /* | |
2717 | * Good, the fallocate(2) manpage permits EINTR: we may have | |
2718 | * been interrupted because we are using up too much memory. | |
2719 | */ | |
2720 | if (signal_pending(current)) | |
2721 | error = -EINTR; | |
1aac1400 HD |
2722 | else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced) |
2723 | error = -ENOMEM; | |
e2d12e22 | 2724 | else |
9e18eb29 | 2725 | error = shmem_getpage(inode, index, &page, SGP_FALLOC); |
e2d12e22 | 2726 | if (error) { |
1635f6a7 | 2727 | /* Remove the !PageUptodate pages we added */ |
7f556567 HD |
2728 | if (index > start) { |
2729 | shmem_undo_range(inode, | |
2730 | (loff_t)start << PAGE_SHIFT, | |
2731 | ((loff_t)index << PAGE_SHIFT) - 1, true); | |
2732 | } | |
1aac1400 | 2733 | goto undone; |
e2d12e22 HD |
2734 | } |
2735 | ||
1aac1400 HD |
2736 | /* |
2737 | * Inform shmem_writepage() how far we have reached. | |
2738 | * No need for lock or barrier: we have the page lock. | |
2739 | */ | |
2740 | shmem_falloc.next++; | |
2741 | if (!PageUptodate(page)) | |
2742 | shmem_falloc.nr_falloced++; | |
2743 | ||
e2d12e22 | 2744 | /* |
1635f6a7 HD |
2745 | * If !PageUptodate, leave it that way so that freeable pages |
2746 | * can be recognized if we need to rollback on error later. | |
2747 | * But set_page_dirty so that memory pressure will swap rather | |
e2d12e22 HD |
2748 | * than free the pages we are allocating (and SGP_CACHE pages |
2749 | * might still be clean: we now need to mark those dirty too). | |
2750 | */ | |
2751 | set_page_dirty(page); | |
2752 | unlock_page(page); | |
09cbfeaf | 2753 | put_page(page); |
e2d12e22 HD |
2754 | cond_resched(); |
2755 | } | |
2756 | ||
2757 | if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) | |
2758 | i_size_write(inode, offset + len); | |
078cd827 | 2759 | inode->i_ctime = current_time(inode); |
1aac1400 HD |
2760 | undone: |
2761 | spin_lock(&inode->i_lock); | |
2762 | inode->i_private = NULL; | |
2763 | spin_unlock(&inode->i_lock); | |
e2d12e22 | 2764 | out: |
5955102c | 2765 | inode_unlock(inode); |
83e4fa9c HD |
2766 | return error; |
2767 | } | |
2768 | ||
726c3342 | 2769 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) |
1da177e4 | 2770 | { |
726c3342 | 2771 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); |
1da177e4 LT |
2772 | |
2773 | buf->f_type = TMPFS_MAGIC; | |
09cbfeaf | 2774 | buf->f_bsize = PAGE_SIZE; |
1da177e4 | 2775 | buf->f_namelen = NAME_MAX; |
0edd73b3 | 2776 | if (sbinfo->max_blocks) { |
1da177e4 | 2777 | buf->f_blocks = sbinfo->max_blocks; |
41ffe5d5 HD |
2778 | buf->f_bavail = |
2779 | buf->f_bfree = sbinfo->max_blocks - | |
2780 | percpu_counter_sum(&sbinfo->used_blocks); | |
0edd73b3 HD |
2781 | } |
2782 | if (sbinfo->max_inodes) { | |
1da177e4 LT |
2783 | buf->f_files = sbinfo->max_inodes; |
2784 | buf->f_ffree = sbinfo->free_inodes; | |
1da177e4 LT |
2785 | } |
2786 | /* else leave those fields 0 like simple_statfs */ | |
2787 | return 0; | |
2788 | } | |
2789 | ||
2790 | /* | |
2791 | * File creation. Allocate an inode, and we're done.. | |
2792 | */ | |
2793 | static int | |
1a67aafb | 2794 | shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
1da177e4 | 2795 | { |
0b0a0806 | 2796 | struct inode *inode; |
1da177e4 LT |
2797 | int error = -ENOSPC; |
2798 | ||
454abafe | 2799 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); |
1da177e4 | 2800 | if (inode) { |
feda821e CH |
2801 | error = simple_acl_create(dir, inode); |
2802 | if (error) | |
2803 | goto out_iput; | |
2a7dba39 | 2804 | error = security_inode_init_security(inode, dir, |
9d8f13ba | 2805 | &dentry->d_name, |
6d9d88d0 | 2806 | shmem_initxattrs, NULL); |
feda821e CH |
2807 | if (error && error != -EOPNOTSUPP) |
2808 | goto out_iput; | |
37ec43cd | 2809 | |
718deb6b | 2810 | error = 0; |
1da177e4 | 2811 | dir->i_size += BOGO_DIRENT_SIZE; |
078cd827 | 2812 | dir->i_ctime = dir->i_mtime = current_time(dir); |
1da177e4 LT |
2813 | d_instantiate(dentry, inode); |
2814 | dget(dentry); /* Extra count - pin the dentry in core */ | |
1da177e4 LT |
2815 | } |
2816 | return error; | |
feda821e CH |
2817 | out_iput: |
2818 | iput(inode); | |
2819 | return error; | |
1da177e4 LT |
2820 | } |
2821 | ||
60545d0d AV |
2822 | static int |
2823 | shmem_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) | |
2824 | { | |
2825 | struct inode *inode; | |
2826 | int error = -ENOSPC; | |
2827 | ||
2828 | inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE); | |
2829 | if (inode) { | |
2830 | error = security_inode_init_security(inode, dir, | |
2831 | NULL, | |
2832 | shmem_initxattrs, NULL); | |
feda821e CH |
2833 | if (error && error != -EOPNOTSUPP) |
2834 | goto out_iput; | |
2835 | error = simple_acl_create(dir, inode); | |
2836 | if (error) | |
2837 | goto out_iput; | |
60545d0d AV |
2838 | d_tmpfile(dentry, inode); |
2839 | } | |
2840 | return error; | |
feda821e CH |
2841 | out_iput: |
2842 | iput(inode); | |
2843 | return error; | |
60545d0d AV |
2844 | } |
2845 | ||
18bb1db3 | 2846 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
2847 | { |
2848 | int error; | |
2849 | ||
2850 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
2851 | return error; | |
d8c76e6f | 2852 | inc_nlink(dir); |
1da177e4 LT |
2853 | return 0; |
2854 | } | |
2855 | ||
4acdaf27 | 2856 | static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
ebfc3b49 | 2857 | bool excl) |
1da177e4 LT |
2858 | { |
2859 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
2860 | } | |
2861 | ||
2862 | /* | |
2863 | * Link a file.. | |
2864 | */ | |
2865 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
2866 | { | |
75c3cfa8 | 2867 | struct inode *inode = d_inode(old_dentry); |
5b04c689 | 2868 | int ret; |
1da177e4 LT |
2869 | |
2870 | /* | |
2871 | * No ordinary (disk based) filesystem counts links as inodes; | |
2872 | * but each new link needs a new dentry, pinning lowmem, and | |
2873 | * tmpfs dentries cannot be pruned until they are unlinked. | |
2874 | */ | |
5b04c689 PE |
2875 | ret = shmem_reserve_inode(inode->i_sb); |
2876 | if (ret) | |
2877 | goto out; | |
1da177e4 LT |
2878 | |
2879 | dir->i_size += BOGO_DIRENT_SIZE; | |
078cd827 | 2880 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
d8c76e6f | 2881 | inc_nlink(inode); |
7de9c6ee | 2882 | ihold(inode); /* New dentry reference */ |
1da177e4 LT |
2883 | dget(dentry); /* Extra pinning count for the created dentry */ |
2884 | d_instantiate(dentry, inode); | |
5b04c689 PE |
2885 | out: |
2886 | return ret; | |
1da177e4 LT |
2887 | } |
2888 | ||
2889 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
2890 | { | |
75c3cfa8 | 2891 | struct inode *inode = d_inode(dentry); |
1da177e4 | 2892 | |
5b04c689 PE |
2893 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) |
2894 | shmem_free_inode(inode->i_sb); | |
1da177e4 LT |
2895 | |
2896 | dir->i_size -= BOGO_DIRENT_SIZE; | |
078cd827 | 2897 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); |
9a53c3a7 | 2898 | drop_nlink(inode); |
1da177e4 LT |
2899 | dput(dentry); /* Undo the count from "create" - this does all the work */ |
2900 | return 0; | |
2901 | } | |
2902 | ||
2903 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
2904 | { | |
2905 | if (!simple_empty(dentry)) | |
2906 | return -ENOTEMPTY; | |
2907 | ||
75c3cfa8 | 2908 | drop_nlink(d_inode(dentry)); |
9a53c3a7 | 2909 | drop_nlink(dir); |
1da177e4 LT |
2910 | return shmem_unlink(dir, dentry); |
2911 | } | |
2912 | ||
37456771 MS |
2913 | static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) |
2914 | { | |
e36cb0b8 DH |
2915 | bool old_is_dir = d_is_dir(old_dentry); |
2916 | bool new_is_dir = d_is_dir(new_dentry); | |
37456771 MS |
2917 | |
2918 | if (old_dir != new_dir && old_is_dir != new_is_dir) { | |
2919 | if (old_is_dir) { | |
2920 | drop_nlink(old_dir); | |
2921 | inc_nlink(new_dir); | |
2922 | } else { | |
2923 | drop_nlink(new_dir); | |
2924 | inc_nlink(old_dir); | |
2925 | } | |
2926 | } | |
2927 | old_dir->i_ctime = old_dir->i_mtime = | |
2928 | new_dir->i_ctime = new_dir->i_mtime = | |
75c3cfa8 | 2929 | d_inode(old_dentry)->i_ctime = |
078cd827 | 2930 | d_inode(new_dentry)->i_ctime = current_time(old_dir); |
37456771 MS |
2931 | |
2932 | return 0; | |
2933 | } | |
2934 | ||
46fdb794 MS |
2935 | static int shmem_whiteout(struct inode *old_dir, struct dentry *old_dentry) |
2936 | { | |
2937 | struct dentry *whiteout; | |
2938 | int error; | |
2939 | ||
2940 | whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name); | |
2941 | if (!whiteout) | |
2942 | return -ENOMEM; | |
2943 | ||
2944 | error = shmem_mknod(old_dir, whiteout, | |
2945 | S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV); | |
2946 | dput(whiteout); | |
2947 | if (error) | |
2948 | return error; | |
2949 | ||
2950 | /* | |
2951 | * Cheat and hash the whiteout while the old dentry is still in | |
2952 | * place, instead of playing games with FS_RENAME_DOES_D_MOVE. | |
2953 | * | |
2954 | * d_lookup() will consistently find one of them at this point, | |
2955 | * not sure which one, but that isn't even important. | |
2956 | */ | |
2957 | d_rehash(whiteout); | |
2958 | return 0; | |
2959 | } | |
2960 | ||
1da177e4 LT |
2961 | /* |
2962 | * The VFS layer already does all the dentry stuff for rename, | |
2963 | * we just have to decrement the usage count for the target if | |
2964 | * it exists so that the VFS layer correctly free's it when it | |
2965 | * gets overwritten. | |
2966 | */ | |
3b69ff51 | 2967 | static int shmem_rename2(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) |
1da177e4 | 2968 | { |
75c3cfa8 | 2969 | struct inode *inode = d_inode(old_dentry); |
1da177e4 LT |
2970 | int they_are_dirs = S_ISDIR(inode->i_mode); |
2971 | ||
46fdb794 | 2972 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT)) |
3b69ff51 MS |
2973 | return -EINVAL; |
2974 | ||
37456771 MS |
2975 | if (flags & RENAME_EXCHANGE) |
2976 | return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry); | |
2977 | ||
1da177e4 LT |
2978 | if (!simple_empty(new_dentry)) |
2979 | return -ENOTEMPTY; | |
2980 | ||
46fdb794 MS |
2981 | if (flags & RENAME_WHITEOUT) { |
2982 | int error; | |
2983 | ||
2984 | error = shmem_whiteout(old_dir, old_dentry); | |
2985 | if (error) | |
2986 | return error; | |
2987 | } | |
2988 | ||
75c3cfa8 | 2989 | if (d_really_is_positive(new_dentry)) { |
1da177e4 | 2990 | (void) shmem_unlink(new_dir, new_dentry); |
b928095b | 2991 | if (they_are_dirs) { |
75c3cfa8 | 2992 | drop_nlink(d_inode(new_dentry)); |
9a53c3a7 | 2993 | drop_nlink(old_dir); |
b928095b | 2994 | } |
1da177e4 | 2995 | } else if (they_are_dirs) { |
9a53c3a7 | 2996 | drop_nlink(old_dir); |
d8c76e6f | 2997 | inc_nlink(new_dir); |
1da177e4 LT |
2998 | } |
2999 | ||
3000 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
3001 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
3002 | old_dir->i_ctime = old_dir->i_mtime = | |
3003 | new_dir->i_ctime = new_dir->i_mtime = | |
078cd827 | 3004 | inode->i_ctime = current_time(old_dir); |
1da177e4 LT |
3005 | return 0; |
3006 | } | |
3007 | ||
3008 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
3009 | { | |
3010 | int error; | |
3011 | int len; | |
3012 | struct inode *inode; | |
9276aad6 | 3013 | struct page *page; |
1da177e4 LT |
3014 | struct shmem_inode_info *info; |
3015 | ||
3016 | len = strlen(symname) + 1; | |
09cbfeaf | 3017 | if (len > PAGE_SIZE) |
1da177e4 LT |
3018 | return -ENAMETOOLONG; |
3019 | ||
454abafe | 3020 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); |
1da177e4 LT |
3021 | if (!inode) |
3022 | return -ENOSPC; | |
3023 | ||
9d8f13ba | 3024 | error = security_inode_init_security(inode, dir, &dentry->d_name, |
6d9d88d0 | 3025 | shmem_initxattrs, NULL); |
570bc1c2 SS |
3026 | if (error) { |
3027 | if (error != -EOPNOTSUPP) { | |
3028 | iput(inode); | |
3029 | return error; | |
3030 | } | |
3031 | error = 0; | |
3032 | } | |
3033 | ||
1da177e4 LT |
3034 | info = SHMEM_I(inode); |
3035 | inode->i_size = len-1; | |
69f07ec9 | 3036 | if (len <= SHORT_SYMLINK_LEN) { |
3ed47db3 AV |
3037 | inode->i_link = kmemdup(symname, len, GFP_KERNEL); |
3038 | if (!inode->i_link) { | |
69f07ec9 HD |
3039 | iput(inode); |
3040 | return -ENOMEM; | |
3041 | } | |
3042 | inode->i_op = &shmem_short_symlink_operations; | |
1da177e4 | 3043 | } else { |
e8ecde25 | 3044 | inode_nohighmem(inode); |
9e18eb29 | 3045 | error = shmem_getpage(inode, 0, &page, SGP_WRITE); |
1da177e4 LT |
3046 | if (error) { |
3047 | iput(inode); | |
3048 | return error; | |
3049 | } | |
14fcc23f | 3050 | inode->i_mapping->a_ops = &shmem_aops; |
1da177e4 | 3051 | inode->i_op = &shmem_symlink_inode_operations; |
21fc61c7 | 3052 | memcpy(page_address(page), symname, len); |
ec9516fb | 3053 | SetPageUptodate(page); |
1da177e4 | 3054 | set_page_dirty(page); |
6746aff7 | 3055 | unlock_page(page); |
09cbfeaf | 3056 | put_page(page); |
1da177e4 | 3057 | } |
1da177e4 | 3058 | dir->i_size += BOGO_DIRENT_SIZE; |
078cd827 | 3059 | dir->i_ctime = dir->i_mtime = current_time(dir); |
1da177e4 LT |
3060 | d_instantiate(dentry, inode); |
3061 | dget(dentry); | |
3062 | return 0; | |
3063 | } | |
3064 | ||
fceef393 | 3065 | static void shmem_put_link(void *arg) |
1da177e4 | 3066 | { |
fceef393 AV |
3067 | mark_page_accessed(arg); |
3068 | put_page(arg); | |
1da177e4 LT |
3069 | } |
3070 | ||
6b255391 | 3071 | static const char *shmem_get_link(struct dentry *dentry, |
fceef393 AV |
3072 | struct inode *inode, |
3073 | struct delayed_call *done) | |
1da177e4 | 3074 | { |
1da177e4 | 3075 | struct page *page = NULL; |
6b255391 | 3076 | int error; |
6a6c9904 AV |
3077 | if (!dentry) { |
3078 | page = find_get_page(inode->i_mapping, 0); | |
3079 | if (!page) | |
3080 | return ERR_PTR(-ECHILD); | |
3081 | if (!PageUptodate(page)) { | |
3082 | put_page(page); | |
3083 | return ERR_PTR(-ECHILD); | |
3084 | } | |
3085 | } else { | |
9e18eb29 | 3086 | error = shmem_getpage(inode, 0, &page, SGP_READ); |
6a6c9904 AV |
3087 | if (error) |
3088 | return ERR_PTR(error); | |
3089 | unlock_page(page); | |
3090 | } | |
fceef393 | 3091 | set_delayed_call(done, shmem_put_link, page); |
21fc61c7 | 3092 | return page_address(page); |
1da177e4 LT |
3093 | } |
3094 | ||
b09e0fa4 | 3095 | #ifdef CONFIG_TMPFS_XATTR |
46711810 | 3096 | /* |
b09e0fa4 EP |
3097 | * Superblocks without xattr inode operations may get some security.* xattr |
3098 | * support from the LSM "for free". As soon as we have any other xattrs | |
39f0247d AG |
3099 | * like ACLs, we also need to implement the security.* handlers at |
3100 | * filesystem level, though. | |
3101 | */ | |
3102 | ||
6d9d88d0 JS |
3103 | /* |
3104 | * Callback for security_inode_init_security() for acquiring xattrs. | |
3105 | */ | |
3106 | static int shmem_initxattrs(struct inode *inode, | |
3107 | const struct xattr *xattr_array, | |
3108 | void *fs_info) | |
3109 | { | |
3110 | struct shmem_inode_info *info = SHMEM_I(inode); | |
3111 | const struct xattr *xattr; | |
38f38657 | 3112 | struct simple_xattr *new_xattr; |
6d9d88d0 JS |
3113 | size_t len; |
3114 | ||
3115 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { | |
38f38657 | 3116 | new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); |
6d9d88d0 JS |
3117 | if (!new_xattr) |
3118 | return -ENOMEM; | |
3119 | ||
3120 | len = strlen(xattr->name) + 1; | |
3121 | new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len, | |
3122 | GFP_KERNEL); | |
3123 | if (!new_xattr->name) { | |
3124 | kfree(new_xattr); | |
3125 | return -ENOMEM; | |
3126 | } | |
3127 | ||
3128 | memcpy(new_xattr->name, XATTR_SECURITY_PREFIX, | |
3129 | XATTR_SECURITY_PREFIX_LEN); | |
3130 | memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, | |
3131 | xattr->name, len); | |
3132 | ||
38f38657 | 3133 | simple_xattr_list_add(&info->xattrs, new_xattr); |
6d9d88d0 JS |
3134 | } |
3135 | ||
3136 | return 0; | |
3137 | } | |
3138 | ||
aa7c5241 | 3139 | static int shmem_xattr_handler_get(const struct xattr_handler *handler, |
b296821a AV |
3140 | struct dentry *unused, struct inode *inode, |
3141 | const char *name, void *buffer, size_t size) | |
b09e0fa4 | 3142 | { |
b296821a | 3143 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 3144 | |
aa7c5241 | 3145 | name = xattr_full_name(handler, name); |
38f38657 | 3146 | return simple_xattr_get(&info->xattrs, name, buffer, size); |
b09e0fa4 EP |
3147 | } |
3148 | ||
aa7c5241 | 3149 | static int shmem_xattr_handler_set(const struct xattr_handler *handler, |
59301226 AV |
3150 | struct dentry *unused, struct inode *inode, |
3151 | const char *name, const void *value, | |
3152 | size_t size, int flags) | |
b09e0fa4 | 3153 | { |
59301226 | 3154 | struct shmem_inode_info *info = SHMEM_I(inode); |
b09e0fa4 | 3155 | |
aa7c5241 | 3156 | name = xattr_full_name(handler, name); |
38f38657 | 3157 | return simple_xattr_set(&info->xattrs, name, value, size, flags); |
b09e0fa4 EP |
3158 | } |
3159 | ||
aa7c5241 AG |
3160 | static const struct xattr_handler shmem_security_xattr_handler = { |
3161 | .prefix = XATTR_SECURITY_PREFIX, | |
3162 | .get = shmem_xattr_handler_get, | |
3163 | .set = shmem_xattr_handler_set, | |
3164 | }; | |
b09e0fa4 | 3165 | |
aa7c5241 AG |
3166 | static const struct xattr_handler shmem_trusted_xattr_handler = { |
3167 | .prefix = XATTR_TRUSTED_PREFIX, | |
3168 | .get = shmem_xattr_handler_get, | |
3169 | .set = shmem_xattr_handler_set, | |
3170 | }; | |
b09e0fa4 | 3171 | |
aa7c5241 AG |
3172 | static const struct xattr_handler *shmem_xattr_handlers[] = { |
3173 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
3174 | &posix_acl_access_xattr_handler, | |
3175 | &posix_acl_default_xattr_handler, | |
3176 | #endif | |
3177 | &shmem_security_xattr_handler, | |
3178 | &shmem_trusted_xattr_handler, | |
3179 | NULL | |
3180 | }; | |
b09e0fa4 EP |
3181 | |
3182 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
3183 | { | |
75c3cfa8 | 3184 | struct shmem_inode_info *info = SHMEM_I(d_inode(dentry)); |
786534b9 | 3185 | return simple_xattr_list(d_inode(dentry), &info->xattrs, buffer, size); |
b09e0fa4 EP |
3186 | } |
3187 | #endif /* CONFIG_TMPFS_XATTR */ | |
3188 | ||
69f07ec9 | 3189 | static const struct inode_operations shmem_short_symlink_operations = { |
b09e0fa4 | 3190 | .readlink = generic_readlink, |
6b255391 | 3191 | .get_link = simple_get_link, |
b09e0fa4 | 3192 | #ifdef CONFIG_TMPFS_XATTR |
b09e0fa4 | 3193 | .listxattr = shmem_listxattr, |
b09e0fa4 EP |
3194 | #endif |
3195 | }; | |
3196 | ||
3197 | static const struct inode_operations shmem_symlink_inode_operations = { | |
3198 | .readlink = generic_readlink, | |
6b255391 | 3199 | .get_link = shmem_get_link, |
b09e0fa4 | 3200 | #ifdef CONFIG_TMPFS_XATTR |
b09e0fa4 | 3201 | .listxattr = shmem_listxattr, |
39f0247d | 3202 | #endif |
b09e0fa4 | 3203 | }; |
39f0247d | 3204 | |
91828a40 DG |
3205 | static struct dentry *shmem_get_parent(struct dentry *child) |
3206 | { | |
3207 | return ERR_PTR(-ESTALE); | |
3208 | } | |
3209 | ||
3210 | static int shmem_match(struct inode *ino, void *vfh) | |
3211 | { | |
3212 | __u32 *fh = vfh; | |
3213 | __u64 inum = fh[2]; | |
3214 | inum = (inum << 32) | fh[1]; | |
3215 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
3216 | } | |
3217 | ||
480b116c CH |
3218 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, |
3219 | struct fid *fid, int fh_len, int fh_type) | |
91828a40 | 3220 | { |
91828a40 | 3221 | struct inode *inode; |
480b116c | 3222 | struct dentry *dentry = NULL; |
35c2a7f4 | 3223 | u64 inum; |
480b116c CH |
3224 | |
3225 | if (fh_len < 3) | |
3226 | return NULL; | |
91828a40 | 3227 | |
35c2a7f4 HD |
3228 | inum = fid->raw[2]; |
3229 | inum = (inum << 32) | fid->raw[1]; | |
3230 | ||
480b116c CH |
3231 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), |
3232 | shmem_match, fid->raw); | |
91828a40 | 3233 | if (inode) { |
480b116c | 3234 | dentry = d_find_alias(inode); |
91828a40 DG |
3235 | iput(inode); |
3236 | } | |
3237 | ||
480b116c | 3238 | return dentry; |
91828a40 DG |
3239 | } |
3240 | ||
b0b0382b AV |
3241 | static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len, |
3242 | struct inode *parent) | |
91828a40 | 3243 | { |
5fe0c237 AK |
3244 | if (*len < 3) { |
3245 | *len = 3; | |
94e07a75 | 3246 | return FILEID_INVALID; |
5fe0c237 | 3247 | } |
91828a40 | 3248 | |
1d3382cb | 3249 | if (inode_unhashed(inode)) { |
91828a40 DG |
3250 | /* Unfortunately insert_inode_hash is not idempotent, |
3251 | * so as we hash inodes here rather than at creation | |
3252 | * time, we need a lock to ensure we only try | |
3253 | * to do it once | |
3254 | */ | |
3255 | static DEFINE_SPINLOCK(lock); | |
3256 | spin_lock(&lock); | |
1d3382cb | 3257 | if (inode_unhashed(inode)) |
91828a40 DG |
3258 | __insert_inode_hash(inode, |
3259 | inode->i_ino + inode->i_generation); | |
3260 | spin_unlock(&lock); | |
3261 | } | |
3262 | ||
3263 | fh[0] = inode->i_generation; | |
3264 | fh[1] = inode->i_ino; | |
3265 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
3266 | ||
3267 | *len = 3; | |
3268 | return 1; | |
3269 | } | |
3270 | ||
39655164 | 3271 | static const struct export_operations shmem_export_ops = { |
91828a40 | 3272 | .get_parent = shmem_get_parent, |
91828a40 | 3273 | .encode_fh = shmem_encode_fh, |
480b116c | 3274 | .fh_to_dentry = shmem_fh_to_dentry, |
91828a40 DG |
3275 | }; |
3276 | ||
680d794b AM |
3277 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, |
3278 | bool remount) | |
1da177e4 LT |
3279 | { |
3280 | char *this_char, *value, *rest; | |
49cd0a5c | 3281 | struct mempolicy *mpol = NULL; |
8751e039 EB |
3282 | uid_t uid; |
3283 | gid_t gid; | |
1da177e4 | 3284 | |
b00dc3ad HD |
3285 | while (options != NULL) { |
3286 | this_char = options; | |
3287 | for (;;) { | |
3288 | /* | |
3289 | * NUL-terminate this option: unfortunately, | |
3290 | * mount options form a comma-separated list, | |
3291 | * but mpol's nodelist may also contain commas. | |
3292 | */ | |
3293 | options = strchr(options, ','); | |
3294 | if (options == NULL) | |
3295 | break; | |
3296 | options++; | |
3297 | if (!isdigit(*options)) { | |
3298 | options[-1] = '\0'; | |
3299 | break; | |
3300 | } | |
3301 | } | |
1da177e4 LT |
3302 | if (!*this_char) |
3303 | continue; | |
3304 | if ((value = strchr(this_char,'=')) != NULL) { | |
3305 | *value++ = 0; | |
3306 | } else { | |
1170532b JP |
3307 | pr_err("tmpfs: No value for mount option '%s'\n", |
3308 | this_char); | |
49cd0a5c | 3309 | goto error; |
1da177e4 LT |
3310 | } |
3311 | ||
3312 | if (!strcmp(this_char,"size")) { | |
3313 | unsigned long long size; | |
3314 | size = memparse(value,&rest); | |
3315 | if (*rest == '%') { | |
3316 | size <<= PAGE_SHIFT; | |
3317 | size *= totalram_pages; | |
3318 | do_div(size, 100); | |
3319 | rest++; | |
3320 | } | |
3321 | if (*rest) | |
3322 | goto bad_val; | |
680d794b | 3323 | sbinfo->max_blocks = |
09cbfeaf | 3324 | DIV_ROUND_UP(size, PAGE_SIZE); |
1da177e4 | 3325 | } else if (!strcmp(this_char,"nr_blocks")) { |
680d794b | 3326 | sbinfo->max_blocks = memparse(value, &rest); |
1da177e4 LT |
3327 | if (*rest) |
3328 | goto bad_val; | |
3329 | } else if (!strcmp(this_char,"nr_inodes")) { | |
680d794b | 3330 | sbinfo->max_inodes = memparse(value, &rest); |
1da177e4 LT |
3331 | if (*rest) |
3332 | goto bad_val; | |
3333 | } else if (!strcmp(this_char,"mode")) { | |
680d794b | 3334 | if (remount) |
1da177e4 | 3335 | continue; |
680d794b | 3336 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; |
1da177e4 LT |
3337 | if (*rest) |
3338 | goto bad_val; | |
3339 | } else if (!strcmp(this_char,"uid")) { | |
680d794b | 3340 | if (remount) |
1da177e4 | 3341 | continue; |
8751e039 | 3342 | uid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
3343 | if (*rest) |
3344 | goto bad_val; | |
8751e039 EB |
3345 | sbinfo->uid = make_kuid(current_user_ns(), uid); |
3346 | if (!uid_valid(sbinfo->uid)) | |
3347 | goto bad_val; | |
1da177e4 | 3348 | } else if (!strcmp(this_char,"gid")) { |
680d794b | 3349 | if (remount) |
1da177e4 | 3350 | continue; |
8751e039 | 3351 | gid = simple_strtoul(value, &rest, 0); |
1da177e4 LT |
3352 | if (*rest) |
3353 | goto bad_val; | |
8751e039 EB |
3354 | sbinfo->gid = make_kgid(current_user_ns(), gid); |
3355 | if (!gid_valid(sbinfo->gid)) | |
3356 | goto bad_val; | |
e496cf3d | 3357 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
5a6e75f8 KS |
3358 | } else if (!strcmp(this_char, "huge")) { |
3359 | int huge; | |
3360 | huge = shmem_parse_huge(value); | |
3361 | if (huge < 0) | |
3362 | goto bad_val; | |
3363 | if (!has_transparent_hugepage() && | |
3364 | huge != SHMEM_HUGE_NEVER) | |
3365 | goto bad_val; | |
3366 | sbinfo->huge = huge; | |
3367 | #endif | |
3368 | #ifdef CONFIG_NUMA | |
7339ff83 | 3369 | } else if (!strcmp(this_char,"mpol")) { |
49cd0a5c GT |
3370 | mpol_put(mpol); |
3371 | mpol = NULL; | |
3372 | if (mpol_parse_str(value, &mpol)) | |
7339ff83 | 3373 | goto bad_val; |
5a6e75f8 | 3374 | #endif |
1da177e4 | 3375 | } else { |
1170532b | 3376 | pr_err("tmpfs: Bad mount option %s\n", this_char); |
49cd0a5c | 3377 | goto error; |
1da177e4 LT |
3378 | } |
3379 | } | |
49cd0a5c | 3380 | sbinfo->mpol = mpol; |
1da177e4 LT |
3381 | return 0; |
3382 | ||
3383 | bad_val: | |
1170532b | 3384 | pr_err("tmpfs: Bad value '%s' for mount option '%s'\n", |
1da177e4 | 3385 | value, this_char); |
49cd0a5c GT |
3386 | error: |
3387 | mpol_put(mpol); | |
1da177e4 LT |
3388 | return 1; |
3389 | ||
3390 | } | |
3391 | ||
3392 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
3393 | { | |
3394 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
680d794b | 3395 | struct shmem_sb_info config = *sbinfo; |
0edd73b3 HD |
3396 | unsigned long inodes; |
3397 | int error = -EINVAL; | |
3398 | ||
5f00110f | 3399 | config.mpol = NULL; |
680d794b | 3400 | if (shmem_parse_options(data, &config, true)) |
0edd73b3 | 3401 | return error; |
1da177e4 | 3402 | |
0edd73b3 | 3403 | spin_lock(&sbinfo->stat_lock); |
0edd73b3 | 3404 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; |
7e496299 | 3405 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) |
0edd73b3 | 3406 | goto out; |
680d794b | 3407 | if (config.max_inodes < inodes) |
0edd73b3 HD |
3408 | goto out; |
3409 | /* | |
54af6042 | 3410 | * Those tests disallow limited->unlimited while any are in use; |
0edd73b3 HD |
3411 | * but we must separately disallow unlimited->limited, because |
3412 | * in that case we have no record of how much is already in use. | |
3413 | */ | |
680d794b | 3414 | if (config.max_blocks && !sbinfo->max_blocks) |
0edd73b3 | 3415 | goto out; |
680d794b | 3416 | if (config.max_inodes && !sbinfo->max_inodes) |
0edd73b3 HD |
3417 | goto out; |
3418 | ||
3419 | error = 0; | |
5a6e75f8 | 3420 | sbinfo->huge = config.huge; |
680d794b | 3421 | sbinfo->max_blocks = config.max_blocks; |
680d794b AM |
3422 | sbinfo->max_inodes = config.max_inodes; |
3423 | sbinfo->free_inodes = config.max_inodes - inodes; | |
71fe804b | 3424 | |
5f00110f GT |
3425 | /* |
3426 | * Preserve previous mempolicy unless mpol remount option was specified. | |
3427 | */ | |
3428 | if (config.mpol) { | |
3429 | mpol_put(sbinfo->mpol); | |
3430 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
3431 | } | |
0edd73b3 HD |
3432 | out: |
3433 | spin_unlock(&sbinfo->stat_lock); | |
3434 | return error; | |
1da177e4 | 3435 | } |
680d794b | 3436 | |
34c80b1d | 3437 | static int shmem_show_options(struct seq_file *seq, struct dentry *root) |
680d794b | 3438 | { |
34c80b1d | 3439 | struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); |
680d794b AM |
3440 | |
3441 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
3442 | seq_printf(seq, ",size=%luk", | |
09cbfeaf | 3443 | sbinfo->max_blocks << (PAGE_SHIFT - 10)); |
680d794b AM |
3444 | if (sbinfo->max_inodes != shmem_default_max_inodes()) |
3445 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
3446 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
09208d15 | 3447 | seq_printf(seq, ",mode=%03ho", sbinfo->mode); |
8751e039 EB |
3448 | if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) |
3449 | seq_printf(seq, ",uid=%u", | |
3450 | from_kuid_munged(&init_user_ns, sbinfo->uid)); | |
3451 | if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) | |
3452 | seq_printf(seq, ",gid=%u", | |
3453 | from_kgid_munged(&init_user_ns, sbinfo->gid)); | |
e496cf3d | 3454 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
5a6e75f8 KS |
3455 | /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */ |
3456 | if (sbinfo->huge) | |
3457 | seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge)); | |
3458 | #endif | |
71fe804b | 3459 | shmem_show_mpol(seq, sbinfo->mpol); |
680d794b AM |
3460 | return 0; |
3461 | } | |
9183df25 DH |
3462 | |
3463 | #define MFD_NAME_PREFIX "memfd:" | |
3464 | #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1) | |
3465 | #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN) | |
3466 | ||
3467 | #define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING) | |
3468 | ||
3469 | SYSCALL_DEFINE2(memfd_create, | |
3470 | const char __user *, uname, | |
3471 | unsigned int, flags) | |
3472 | { | |
3473 | struct shmem_inode_info *info; | |
3474 | struct file *file; | |
3475 | int fd, error; | |
3476 | char *name; | |
3477 | long len; | |
3478 | ||
3479 | if (flags & ~(unsigned int)MFD_ALL_FLAGS) | |
3480 | return -EINVAL; | |
3481 | ||
3482 | /* length includes terminating zero */ | |
3483 | len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1); | |
3484 | if (len <= 0) | |
3485 | return -EFAULT; | |
3486 | if (len > MFD_NAME_MAX_LEN + 1) | |
3487 | return -EINVAL; | |
3488 | ||
3489 | name = kmalloc(len + MFD_NAME_PREFIX_LEN, GFP_TEMPORARY); | |
3490 | if (!name) | |
3491 | return -ENOMEM; | |
3492 | ||
3493 | strcpy(name, MFD_NAME_PREFIX); | |
3494 | if (copy_from_user(&name[MFD_NAME_PREFIX_LEN], uname, len)) { | |
3495 | error = -EFAULT; | |
3496 | goto err_name; | |
3497 | } | |
3498 | ||
3499 | /* terminating-zero may have changed after strnlen_user() returned */ | |
3500 | if (name[len + MFD_NAME_PREFIX_LEN - 1]) { | |
3501 | error = -EFAULT; | |
3502 | goto err_name; | |
3503 | } | |
3504 | ||
3505 | fd = get_unused_fd_flags((flags & MFD_CLOEXEC) ? O_CLOEXEC : 0); | |
3506 | if (fd < 0) { | |
3507 | error = fd; | |
3508 | goto err_name; | |
3509 | } | |
3510 | ||
3511 | file = shmem_file_setup(name, 0, VM_NORESERVE); | |
3512 | if (IS_ERR(file)) { | |
3513 | error = PTR_ERR(file); | |
3514 | goto err_fd; | |
3515 | } | |
3516 | info = SHMEM_I(file_inode(file)); | |
3517 | file->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; | |
3518 | file->f_flags |= O_RDWR | O_LARGEFILE; | |
3519 | if (flags & MFD_ALLOW_SEALING) | |
3520 | info->seals &= ~F_SEAL_SEAL; | |
3521 | ||
3522 | fd_install(fd, file); | |
3523 | kfree(name); | |
3524 | return fd; | |
3525 | ||
3526 | err_fd: | |
3527 | put_unused_fd(fd); | |
3528 | err_name: | |
3529 | kfree(name); | |
3530 | return error; | |
3531 | } | |
3532 | ||
680d794b | 3533 | #endif /* CONFIG_TMPFS */ |
1da177e4 LT |
3534 | |
3535 | static void shmem_put_super(struct super_block *sb) | |
3536 | { | |
602586a8 HD |
3537 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); |
3538 | ||
3539 | percpu_counter_destroy(&sbinfo->used_blocks); | |
49cd0a5c | 3540 | mpol_put(sbinfo->mpol); |
602586a8 | 3541 | kfree(sbinfo); |
1da177e4 LT |
3542 | sb->s_fs_info = NULL; |
3543 | } | |
3544 | ||
2b2af54a | 3545 | int shmem_fill_super(struct super_block *sb, void *data, int silent) |
1da177e4 LT |
3546 | { |
3547 | struct inode *inode; | |
0edd73b3 | 3548 | struct shmem_sb_info *sbinfo; |
680d794b AM |
3549 | int err = -ENOMEM; |
3550 | ||
3551 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
425fbf04 | 3552 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), |
680d794b AM |
3553 | L1_CACHE_BYTES), GFP_KERNEL); |
3554 | if (!sbinfo) | |
3555 | return -ENOMEM; | |
3556 | ||
680d794b | 3557 | sbinfo->mode = S_IRWXUGO | S_ISVTX; |
76aac0e9 DH |
3558 | sbinfo->uid = current_fsuid(); |
3559 | sbinfo->gid = current_fsgid(); | |
680d794b | 3560 | sb->s_fs_info = sbinfo; |
1da177e4 | 3561 | |
0edd73b3 | 3562 | #ifdef CONFIG_TMPFS |
1da177e4 LT |
3563 | /* |
3564 | * Per default we only allow half of the physical ram per | |
3565 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
3566 | * but the internal instance is left unlimited. | |
3567 | */ | |
ca4e0519 | 3568 | if (!(sb->s_flags & MS_KERNMOUNT)) { |
680d794b AM |
3569 | sbinfo->max_blocks = shmem_default_max_blocks(); |
3570 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
3571 | if (shmem_parse_options(data, sbinfo, false)) { | |
3572 | err = -EINVAL; | |
3573 | goto failed; | |
3574 | } | |
ca4e0519 AV |
3575 | } else { |
3576 | sb->s_flags |= MS_NOUSER; | |
1da177e4 | 3577 | } |
91828a40 | 3578 | sb->s_export_op = &shmem_export_ops; |
2f6e38f3 | 3579 | sb->s_flags |= MS_NOSEC; |
1da177e4 LT |
3580 | #else |
3581 | sb->s_flags |= MS_NOUSER; | |
3582 | #endif | |
3583 | ||
0edd73b3 | 3584 | spin_lock_init(&sbinfo->stat_lock); |
908c7f19 | 3585 | if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL)) |
602586a8 | 3586 | goto failed; |
680d794b | 3587 | sbinfo->free_inodes = sbinfo->max_inodes; |
779750d2 KS |
3588 | spin_lock_init(&sbinfo->shrinklist_lock); |
3589 | INIT_LIST_HEAD(&sbinfo->shrinklist); | |
0edd73b3 | 3590 | |
285b2c4f | 3591 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
09cbfeaf KS |
3592 | sb->s_blocksize = PAGE_SIZE; |
3593 | sb->s_blocksize_bits = PAGE_SHIFT; | |
1da177e4 LT |
3594 | sb->s_magic = TMPFS_MAGIC; |
3595 | sb->s_op = &shmem_ops; | |
cfd95a9c | 3596 | sb->s_time_gran = 1; |
b09e0fa4 | 3597 | #ifdef CONFIG_TMPFS_XATTR |
39f0247d | 3598 | sb->s_xattr = shmem_xattr_handlers; |
b09e0fa4 EP |
3599 | #endif |
3600 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
39f0247d AG |
3601 | sb->s_flags |= MS_POSIXACL; |
3602 | #endif | |
0edd73b3 | 3603 | |
454abafe | 3604 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); |
1da177e4 LT |
3605 | if (!inode) |
3606 | goto failed; | |
680d794b AM |
3607 | inode->i_uid = sbinfo->uid; |
3608 | inode->i_gid = sbinfo->gid; | |
318ceed0 AV |
3609 | sb->s_root = d_make_root(inode); |
3610 | if (!sb->s_root) | |
48fde701 | 3611 | goto failed; |
1da177e4 LT |
3612 | return 0; |
3613 | ||
1da177e4 LT |
3614 | failed: |
3615 | shmem_put_super(sb); | |
3616 | return err; | |
3617 | } | |
3618 | ||
fcc234f8 | 3619 | static struct kmem_cache *shmem_inode_cachep; |
1da177e4 LT |
3620 | |
3621 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
3622 | { | |
41ffe5d5 HD |
3623 | struct shmem_inode_info *info; |
3624 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
3625 | if (!info) | |
1da177e4 | 3626 | return NULL; |
41ffe5d5 | 3627 | return &info->vfs_inode; |
1da177e4 LT |
3628 | } |
3629 | ||
41ffe5d5 | 3630 | static void shmem_destroy_callback(struct rcu_head *head) |
fa0d7e3d NP |
3631 | { |
3632 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
84e710da AV |
3633 | if (S_ISLNK(inode->i_mode)) |
3634 | kfree(inode->i_link); | |
fa0d7e3d NP |
3635 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); |
3636 | } | |
3637 | ||
1da177e4 LT |
3638 | static void shmem_destroy_inode(struct inode *inode) |
3639 | { | |
09208d15 | 3640 | if (S_ISREG(inode->i_mode)) |
1da177e4 | 3641 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); |
41ffe5d5 | 3642 | call_rcu(&inode->i_rcu, shmem_destroy_callback); |
1da177e4 LT |
3643 | } |
3644 | ||
41ffe5d5 | 3645 | static void shmem_init_inode(void *foo) |
1da177e4 | 3646 | { |
41ffe5d5 HD |
3647 | struct shmem_inode_info *info = foo; |
3648 | inode_init_once(&info->vfs_inode); | |
1da177e4 LT |
3649 | } |
3650 | ||
41ffe5d5 | 3651 | static int shmem_init_inodecache(void) |
1da177e4 LT |
3652 | { |
3653 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
3654 | sizeof(struct shmem_inode_info), | |
5d097056 | 3655 | 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); |
1da177e4 LT |
3656 | return 0; |
3657 | } | |
3658 | ||
41ffe5d5 | 3659 | static void shmem_destroy_inodecache(void) |
1da177e4 | 3660 | { |
1a1d92c1 | 3661 | kmem_cache_destroy(shmem_inode_cachep); |
1da177e4 LT |
3662 | } |
3663 | ||
f5e54d6e | 3664 | static const struct address_space_operations shmem_aops = { |
1da177e4 | 3665 | .writepage = shmem_writepage, |
76719325 | 3666 | .set_page_dirty = __set_page_dirty_no_writeback, |
1da177e4 | 3667 | #ifdef CONFIG_TMPFS |
800d15a5 NP |
3668 | .write_begin = shmem_write_begin, |
3669 | .write_end = shmem_write_end, | |
1da177e4 | 3670 | #endif |
1c93923c | 3671 | #ifdef CONFIG_MIGRATION |
304dbdb7 | 3672 | .migratepage = migrate_page, |
1c93923c | 3673 | #endif |
aa261f54 | 3674 | .error_remove_page = generic_error_remove_page, |
1da177e4 LT |
3675 | }; |
3676 | ||
15ad7cdc | 3677 | static const struct file_operations shmem_file_operations = { |
1da177e4 | 3678 | .mmap = shmem_mmap, |
c01d5b30 | 3679 | .get_unmapped_area = shmem_get_unmapped_area, |
1da177e4 | 3680 | #ifdef CONFIG_TMPFS |
220f2ac9 | 3681 | .llseek = shmem_file_llseek, |
2ba5bbed | 3682 | .read_iter = shmem_file_read_iter, |
8174202b | 3683 | .write_iter = generic_file_write_iter, |
1b061d92 | 3684 | .fsync = noop_fsync, |
82c156f8 | 3685 | .splice_read = generic_file_splice_read, |
f6cb85d0 | 3686 | .splice_write = iter_file_splice_write, |
83e4fa9c | 3687 | .fallocate = shmem_fallocate, |
1da177e4 LT |
3688 | #endif |
3689 | }; | |
3690 | ||
92e1d5be | 3691 | static const struct inode_operations shmem_inode_operations = { |
44a30220 | 3692 | .getattr = shmem_getattr, |
94c1e62d | 3693 | .setattr = shmem_setattr, |
b09e0fa4 | 3694 | #ifdef CONFIG_TMPFS_XATTR |
b09e0fa4 | 3695 | .listxattr = shmem_listxattr, |
feda821e | 3696 | .set_acl = simple_set_acl, |
b09e0fa4 | 3697 | #endif |
1da177e4 LT |
3698 | }; |
3699 | ||
92e1d5be | 3700 | static const struct inode_operations shmem_dir_inode_operations = { |
1da177e4 LT |
3701 | #ifdef CONFIG_TMPFS |
3702 | .create = shmem_create, | |
3703 | .lookup = simple_lookup, | |
3704 | .link = shmem_link, | |
3705 | .unlink = shmem_unlink, | |
3706 | .symlink = shmem_symlink, | |
3707 | .mkdir = shmem_mkdir, | |
3708 | .rmdir = shmem_rmdir, | |
3709 | .mknod = shmem_mknod, | |
2773bf00 | 3710 | .rename = shmem_rename2, |
60545d0d | 3711 | .tmpfile = shmem_tmpfile, |
1da177e4 | 3712 | #endif |
b09e0fa4 | 3713 | #ifdef CONFIG_TMPFS_XATTR |
b09e0fa4 | 3714 | .listxattr = shmem_listxattr, |
b09e0fa4 | 3715 | #endif |
39f0247d | 3716 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 3717 | .setattr = shmem_setattr, |
feda821e | 3718 | .set_acl = simple_set_acl, |
39f0247d AG |
3719 | #endif |
3720 | }; | |
3721 | ||
92e1d5be | 3722 | static const struct inode_operations shmem_special_inode_operations = { |
b09e0fa4 | 3723 | #ifdef CONFIG_TMPFS_XATTR |
b09e0fa4 | 3724 | .listxattr = shmem_listxattr, |
b09e0fa4 | 3725 | #endif |
39f0247d | 3726 | #ifdef CONFIG_TMPFS_POSIX_ACL |
94c1e62d | 3727 | .setattr = shmem_setattr, |
feda821e | 3728 | .set_acl = simple_set_acl, |
39f0247d | 3729 | #endif |
1da177e4 LT |
3730 | }; |
3731 | ||
759b9775 | 3732 | static const struct super_operations shmem_ops = { |
1da177e4 LT |
3733 | .alloc_inode = shmem_alloc_inode, |
3734 | .destroy_inode = shmem_destroy_inode, | |
3735 | #ifdef CONFIG_TMPFS | |
3736 | .statfs = shmem_statfs, | |
3737 | .remount_fs = shmem_remount_fs, | |
680d794b | 3738 | .show_options = shmem_show_options, |
1da177e4 | 3739 | #endif |
1f895f75 | 3740 | .evict_inode = shmem_evict_inode, |
1da177e4 LT |
3741 | .drop_inode = generic_delete_inode, |
3742 | .put_super = shmem_put_super, | |
779750d2 KS |
3743 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
3744 | .nr_cached_objects = shmem_unused_huge_count, | |
3745 | .free_cached_objects = shmem_unused_huge_scan, | |
3746 | #endif | |
1da177e4 LT |
3747 | }; |
3748 | ||
f0f37e2f | 3749 | static const struct vm_operations_struct shmem_vm_ops = { |
54cb8821 | 3750 | .fault = shmem_fault, |
d7c17551 | 3751 | .map_pages = filemap_map_pages, |
1da177e4 LT |
3752 | #ifdef CONFIG_NUMA |
3753 | .set_policy = shmem_set_policy, | |
3754 | .get_policy = shmem_get_policy, | |
3755 | #endif | |
3756 | }; | |
3757 | ||
3c26ff6e AV |
3758 | static struct dentry *shmem_mount(struct file_system_type *fs_type, |
3759 | int flags, const char *dev_name, void *data) | |
1da177e4 | 3760 | { |
3c26ff6e | 3761 | return mount_nodev(fs_type, flags, data, shmem_fill_super); |
1da177e4 LT |
3762 | } |
3763 | ||
41ffe5d5 | 3764 | static struct file_system_type shmem_fs_type = { |
1da177e4 LT |
3765 | .owner = THIS_MODULE, |
3766 | .name = "tmpfs", | |
3c26ff6e | 3767 | .mount = shmem_mount, |
1da177e4 | 3768 | .kill_sb = kill_litter_super, |
2b8576cb | 3769 | .fs_flags = FS_USERNS_MOUNT, |
1da177e4 | 3770 | }; |
1da177e4 | 3771 | |
41ffe5d5 | 3772 | int __init shmem_init(void) |
1da177e4 LT |
3773 | { |
3774 | int error; | |
3775 | ||
16203a7a RL |
3776 | /* If rootfs called this, don't re-init */ |
3777 | if (shmem_inode_cachep) | |
3778 | return 0; | |
3779 | ||
41ffe5d5 | 3780 | error = shmem_init_inodecache(); |
1da177e4 LT |
3781 | if (error) |
3782 | goto out3; | |
3783 | ||
41ffe5d5 | 3784 | error = register_filesystem(&shmem_fs_type); |
1da177e4 | 3785 | if (error) { |
1170532b | 3786 | pr_err("Could not register tmpfs\n"); |
1da177e4 LT |
3787 | goto out2; |
3788 | } | |
95dc112a | 3789 | |
ca4e0519 | 3790 | shm_mnt = kern_mount(&shmem_fs_type); |
1da177e4 LT |
3791 | if (IS_ERR(shm_mnt)) { |
3792 | error = PTR_ERR(shm_mnt); | |
1170532b | 3793 | pr_err("Could not kern_mount tmpfs\n"); |
1da177e4 LT |
3794 | goto out1; |
3795 | } | |
5a6e75f8 | 3796 | |
e496cf3d | 3797 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
5a6e75f8 KS |
3798 | if (has_transparent_hugepage() && shmem_huge < SHMEM_HUGE_DENY) |
3799 | SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; | |
3800 | else | |
3801 | shmem_huge = 0; /* just in case it was patched */ | |
3802 | #endif | |
1da177e4 LT |
3803 | return 0; |
3804 | ||
3805 | out1: | |
41ffe5d5 | 3806 | unregister_filesystem(&shmem_fs_type); |
1da177e4 | 3807 | out2: |
41ffe5d5 | 3808 | shmem_destroy_inodecache(); |
1da177e4 LT |
3809 | out3: |
3810 | shm_mnt = ERR_PTR(error); | |
3811 | return error; | |
3812 | } | |
853ac43a | 3813 | |
e496cf3d | 3814 | #if defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && defined(CONFIG_SYSFS) |
5a6e75f8 KS |
3815 | static ssize_t shmem_enabled_show(struct kobject *kobj, |
3816 | struct kobj_attribute *attr, char *buf) | |
3817 | { | |
3818 | int values[] = { | |
3819 | SHMEM_HUGE_ALWAYS, | |
3820 | SHMEM_HUGE_WITHIN_SIZE, | |
3821 | SHMEM_HUGE_ADVISE, | |
3822 | SHMEM_HUGE_NEVER, | |
3823 | SHMEM_HUGE_DENY, | |
3824 | SHMEM_HUGE_FORCE, | |
3825 | }; | |
3826 | int i, count; | |
3827 | ||
3828 | for (i = 0, count = 0; i < ARRAY_SIZE(values); i++) { | |
3829 | const char *fmt = shmem_huge == values[i] ? "[%s] " : "%s "; | |
3830 | ||
3831 | count += sprintf(buf + count, fmt, | |
3832 | shmem_format_huge(values[i])); | |
3833 | } | |
3834 | buf[count - 1] = '\n'; | |
3835 | return count; | |
3836 | } | |
3837 | ||
3838 | static ssize_t shmem_enabled_store(struct kobject *kobj, | |
3839 | struct kobj_attribute *attr, const char *buf, size_t count) | |
3840 | { | |
3841 | char tmp[16]; | |
3842 | int huge; | |
3843 | ||
3844 | if (count + 1 > sizeof(tmp)) | |
3845 | return -EINVAL; | |
3846 | memcpy(tmp, buf, count); | |
3847 | tmp[count] = '\0'; | |
3848 | if (count && tmp[count - 1] == '\n') | |
3849 | tmp[count - 1] = '\0'; | |
3850 | ||
3851 | huge = shmem_parse_huge(tmp); | |
3852 | if (huge == -EINVAL) | |
3853 | return -EINVAL; | |
3854 | if (!has_transparent_hugepage() && | |
3855 | huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY) | |
3856 | return -EINVAL; | |
3857 | ||
3858 | shmem_huge = huge; | |
3859 | if (shmem_huge < SHMEM_HUGE_DENY) | |
3860 | SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; | |
3861 | return count; | |
3862 | } | |
3863 | ||
3864 | struct kobj_attribute shmem_enabled_attr = | |
3865 | __ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store); | |
3b33719c | 3866 | #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE && CONFIG_SYSFS */ |
f3f0e1d2 | 3867 | |
3b33719c | 3868 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
f3f0e1d2 KS |
3869 | bool shmem_huge_enabled(struct vm_area_struct *vma) |
3870 | { | |
3871 | struct inode *inode = file_inode(vma->vm_file); | |
3872 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
3873 | loff_t i_size; | |
3874 | pgoff_t off; | |
3875 | ||
3876 | if (shmem_huge == SHMEM_HUGE_FORCE) | |
3877 | return true; | |
3878 | if (shmem_huge == SHMEM_HUGE_DENY) | |
3879 | return false; | |
3880 | switch (sbinfo->huge) { | |
3881 | case SHMEM_HUGE_NEVER: | |
3882 | return false; | |
3883 | case SHMEM_HUGE_ALWAYS: | |
3884 | return true; | |
3885 | case SHMEM_HUGE_WITHIN_SIZE: | |
3886 | off = round_up(vma->vm_pgoff, HPAGE_PMD_NR); | |
3887 | i_size = round_up(i_size_read(inode), PAGE_SIZE); | |
3888 | if (i_size >= HPAGE_PMD_SIZE && | |
3889 | i_size >> PAGE_SHIFT >= off) | |
3890 | return true; | |
3891 | case SHMEM_HUGE_ADVISE: | |
3892 | /* TODO: implement fadvise() hints */ | |
3893 | return (vma->vm_flags & VM_HUGEPAGE); | |
3894 | default: | |
3895 | VM_BUG_ON(1); | |
3896 | return false; | |
3897 | } | |
3898 | } | |
3b33719c | 3899 | #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */ |
5a6e75f8 | 3900 | |
853ac43a MM |
3901 | #else /* !CONFIG_SHMEM */ |
3902 | ||
3903 | /* | |
3904 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
3905 | * | |
3906 | * This is intended for small system where the benefits of the full | |
3907 | * shmem code (swap-backed and resource-limited) are outweighed by | |
3908 | * their complexity. On systems without swap this code should be | |
3909 | * effectively equivalent, but much lighter weight. | |
3910 | */ | |
3911 | ||
41ffe5d5 | 3912 | static struct file_system_type shmem_fs_type = { |
853ac43a | 3913 | .name = "tmpfs", |
3c26ff6e | 3914 | .mount = ramfs_mount, |
853ac43a | 3915 | .kill_sb = kill_litter_super, |
2b8576cb | 3916 | .fs_flags = FS_USERNS_MOUNT, |
853ac43a MM |
3917 | }; |
3918 | ||
41ffe5d5 | 3919 | int __init shmem_init(void) |
853ac43a | 3920 | { |
41ffe5d5 | 3921 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); |
853ac43a | 3922 | |
41ffe5d5 | 3923 | shm_mnt = kern_mount(&shmem_fs_type); |
853ac43a MM |
3924 | BUG_ON(IS_ERR(shm_mnt)); |
3925 | ||
3926 | return 0; | |
3927 | } | |
3928 | ||
41ffe5d5 | 3929 | int shmem_unuse(swp_entry_t swap, struct page *page) |
853ac43a MM |
3930 | { |
3931 | return 0; | |
3932 | } | |
3933 | ||
3f96b79a HD |
3934 | int shmem_lock(struct file *file, int lock, struct user_struct *user) |
3935 | { | |
3936 | return 0; | |
3937 | } | |
3938 | ||
24513264 HD |
3939 | void shmem_unlock_mapping(struct address_space *mapping) |
3940 | { | |
3941 | } | |
3942 | ||
c01d5b30 HD |
3943 | #ifdef CONFIG_MMU |
3944 | unsigned long shmem_get_unmapped_area(struct file *file, | |
3945 | unsigned long addr, unsigned long len, | |
3946 | unsigned long pgoff, unsigned long flags) | |
3947 | { | |
3948 | return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); | |
3949 | } | |
3950 | #endif | |
3951 | ||
41ffe5d5 | 3952 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) |
94c1e62d | 3953 | { |
41ffe5d5 | 3954 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); |
94c1e62d HD |
3955 | } |
3956 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
3957 | ||
0b0a0806 HD |
3958 | #define shmem_vm_ops generic_file_vm_ops |
3959 | #define shmem_file_operations ramfs_file_operations | |
454abafe | 3960 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) |
0b0a0806 HD |
3961 | #define shmem_acct_size(flags, size) 0 |
3962 | #define shmem_unacct_size(flags, size) do {} while (0) | |
853ac43a MM |
3963 | |
3964 | #endif /* CONFIG_SHMEM */ | |
3965 | ||
3966 | /* common code */ | |
1da177e4 | 3967 | |
19938e35 | 3968 | static const struct dentry_operations anon_ops = { |
118b2302 | 3969 | .d_dname = simple_dname |
3451538a AV |
3970 | }; |
3971 | ||
c7277090 EP |
3972 | static struct file *__shmem_file_setup(const char *name, loff_t size, |
3973 | unsigned long flags, unsigned int i_flags) | |
1da177e4 | 3974 | { |
6b4d0b27 | 3975 | struct file *res; |
1da177e4 | 3976 | struct inode *inode; |
2c48b9c4 | 3977 | struct path path; |
3451538a | 3978 | struct super_block *sb; |
1da177e4 LT |
3979 | struct qstr this; |
3980 | ||
3981 | if (IS_ERR(shm_mnt)) | |
6b4d0b27 | 3982 | return ERR_CAST(shm_mnt); |
1da177e4 | 3983 | |
285b2c4f | 3984 | if (size < 0 || size > MAX_LFS_FILESIZE) |
1da177e4 LT |
3985 | return ERR_PTR(-EINVAL); |
3986 | ||
3987 | if (shmem_acct_size(flags, size)) | |
3988 | return ERR_PTR(-ENOMEM); | |
3989 | ||
6b4d0b27 | 3990 | res = ERR_PTR(-ENOMEM); |
1da177e4 LT |
3991 | this.name = name; |
3992 | this.len = strlen(name); | |
3993 | this.hash = 0; /* will go */ | |
3451538a | 3994 | sb = shm_mnt->mnt_sb; |
66ee4b88 | 3995 | path.mnt = mntget(shm_mnt); |
3451538a | 3996 | path.dentry = d_alloc_pseudo(sb, &this); |
2c48b9c4 | 3997 | if (!path.dentry) |
1da177e4 | 3998 | goto put_memory; |
3451538a | 3999 | d_set_d_op(path.dentry, &anon_ops); |
1da177e4 | 4000 | |
6b4d0b27 | 4001 | res = ERR_PTR(-ENOSPC); |
3451538a | 4002 | inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); |
1da177e4 | 4003 | if (!inode) |
66ee4b88 | 4004 | goto put_memory; |
1da177e4 | 4005 | |
c7277090 | 4006 | inode->i_flags |= i_flags; |
2c48b9c4 | 4007 | d_instantiate(path.dentry, inode); |
1da177e4 | 4008 | inode->i_size = size; |
6d6b77f1 | 4009 | clear_nlink(inode); /* It is unlinked */ |
26567cdb AV |
4010 | res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size)); |
4011 | if (IS_ERR(res)) | |
66ee4b88 | 4012 | goto put_path; |
4b42af81 | 4013 | |
6b4d0b27 | 4014 | res = alloc_file(&path, FMODE_WRITE | FMODE_READ, |
4b42af81 | 4015 | &shmem_file_operations); |
6b4d0b27 | 4016 | if (IS_ERR(res)) |
66ee4b88 | 4017 | goto put_path; |
4b42af81 | 4018 | |
6b4d0b27 | 4019 | return res; |
1da177e4 | 4020 | |
1da177e4 LT |
4021 | put_memory: |
4022 | shmem_unacct_size(flags, size); | |
66ee4b88 KK |
4023 | put_path: |
4024 | path_put(&path); | |
6b4d0b27 | 4025 | return res; |
1da177e4 | 4026 | } |
c7277090 EP |
4027 | |
4028 | /** | |
4029 | * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be | |
4030 | * kernel internal. There will be NO LSM permission checks against the | |
4031 | * underlying inode. So users of this interface must do LSM checks at a | |
e1832f29 SS |
4032 | * higher layer. The users are the big_key and shm implementations. LSM |
4033 | * checks are provided at the key or shm level rather than the inode. | |
c7277090 EP |
4034 | * @name: name for dentry (to be seen in /proc/<pid>/maps |
4035 | * @size: size to be set for the file | |
4036 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
4037 | */ | |
4038 | struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags) | |
4039 | { | |
4040 | return __shmem_file_setup(name, size, flags, S_PRIVATE); | |
4041 | } | |
4042 | ||
4043 | /** | |
4044 | * shmem_file_setup - get an unlinked file living in tmpfs | |
4045 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
4046 | * @size: size to be set for the file | |
4047 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
4048 | */ | |
4049 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) | |
4050 | { | |
4051 | return __shmem_file_setup(name, size, flags, 0); | |
4052 | } | |
395e0ddc | 4053 | EXPORT_SYMBOL_GPL(shmem_file_setup); |
1da177e4 | 4054 | |
46711810 | 4055 | /** |
1da177e4 | 4056 | * shmem_zero_setup - setup a shared anonymous mapping |
1da177e4 LT |
4057 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff |
4058 | */ | |
4059 | int shmem_zero_setup(struct vm_area_struct *vma) | |
4060 | { | |
4061 | struct file *file; | |
4062 | loff_t size = vma->vm_end - vma->vm_start; | |
4063 | ||
66fc1303 HD |
4064 | /* |
4065 | * Cloning a new file under mmap_sem leads to a lock ordering conflict | |
4066 | * between XFS directory reading and selinux: since this file is only | |
4067 | * accessible to the user through its mapping, use S_PRIVATE flag to | |
4068 | * bypass file security, in the same way as shmem_kernel_file_setup(). | |
4069 | */ | |
4070 | file = __shmem_file_setup("dev/zero", size, vma->vm_flags, S_PRIVATE); | |
1da177e4 LT |
4071 | if (IS_ERR(file)) |
4072 | return PTR_ERR(file); | |
4073 | ||
4074 | if (vma->vm_file) | |
4075 | fput(vma->vm_file); | |
4076 | vma->vm_file = file; | |
4077 | vma->vm_ops = &shmem_vm_ops; | |
f3f0e1d2 | 4078 | |
e496cf3d | 4079 | if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && |
f3f0e1d2 KS |
4080 | ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) < |
4081 | (vma->vm_end & HPAGE_PMD_MASK)) { | |
4082 | khugepaged_enter(vma, vma->vm_flags); | |
4083 | } | |
4084 | ||
1da177e4 LT |
4085 | return 0; |
4086 | } | |
d9d90e5e HD |
4087 | |
4088 | /** | |
4089 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
4090 | * @mapping: the page's address_space | |
4091 | * @index: the page index | |
4092 | * @gfp: the page allocator flags to use if allocating | |
4093 | * | |
4094 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
4095 | * with any new page allocations done using the specified allocation flags. | |
4096 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
4097 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
4098 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
4099 | * | |
68da9f05 HD |
4100 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in |
4101 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
d9d90e5e HD |
4102 | */ |
4103 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
4104 | pgoff_t index, gfp_t gfp) | |
4105 | { | |
68da9f05 HD |
4106 | #ifdef CONFIG_SHMEM |
4107 | struct inode *inode = mapping->host; | |
9276aad6 | 4108 | struct page *page; |
68da9f05 HD |
4109 | int error; |
4110 | ||
4111 | BUG_ON(mapping->a_ops != &shmem_aops); | |
9e18eb29 ALC |
4112 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, |
4113 | gfp, NULL, NULL); | |
68da9f05 HD |
4114 | if (error) |
4115 | page = ERR_PTR(error); | |
4116 | else | |
4117 | unlock_page(page); | |
4118 | return page; | |
4119 | #else | |
4120 | /* | |
4121 | * The tiny !SHMEM case uses ramfs without swap | |
4122 | */ | |
d9d90e5e | 4123 | return read_cache_page_gfp(mapping, index, gfp); |
68da9f05 | 4124 | #endif |
d9d90e5e HD |
4125 | } |
4126 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |