]>
Commit | Line | Data |
---|---|---|
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. | |
9 | * Copyright (C) 2002-2011 Hugh Dickins. | |
10 | * Copyright (C) 2011 Google Inc. | |
11 | * Copyright (C) 2002-2005 VERITAS Software Corporation. | |
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 | * | |
18 | * tiny-shmem: | |
19 | * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com> | |
20 | * | |
21 | * This file is released under the GPL. | |
22 | */ | |
23 | ||
24 | #include <linux/fs.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/vfs.h> | |
27 | #include <linux/mount.h> | |
28 | #include <linux/ramfs.h> | |
29 | #include <linux/pagemap.h> | |
30 | #include <linux/file.h> | |
31 | #include <linux/mm.h> | |
32 | #include <linux/export.h> | |
33 | #include <linux/swap.h> | |
34 | #include <linux/uio.h> | |
35 | #include <linux/khugepaged.h> | |
36 | ||
37 | static struct vfsmount *shm_mnt; | |
38 | ||
39 | #ifdef CONFIG_SHMEM | |
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 | ||
46 | #include <linux/xattr.h> | |
47 | #include <linux/exportfs.h> | |
48 | #include <linux/posix_acl.h> | |
49 | #include <linux/posix_acl_xattr.h> | |
50 | #include <linux/mman.h> | |
51 | #include <linux/string.h> | |
52 | #include <linux/slab.h> | |
53 | #include <linux/backing-dev.h> | |
54 | #include <linux/shmem_fs.h> | |
55 | #include <linux/writeback.h> | |
56 | #include <linux/blkdev.h> | |
57 | #include <linux/pagevec.h> | |
58 | #include <linux/percpu_counter.h> | |
59 | #include <linux/falloc.h> | |
60 | #include <linux/splice.h> | |
61 | #include <linux/security.h> | |
62 | #include <linux/swapops.h> | |
63 | #include <linux/mempolicy.h> | |
64 | #include <linux/namei.h> | |
65 | #include <linux/ctype.h> | |
66 | #include <linux/migrate.h> | |
67 | #include <linux/highmem.h> | |
68 | #include <linux/seq_file.h> | |
69 | #include <linux/magic.h> | |
70 | #include <linux/syscalls.h> | |
71 | #include <linux/fcntl.h> | |
72 | #include <uapi/linux/memfd.h> | |
73 | ||
74 | #include <linux/uaccess.h> | |
75 | #include <asm/pgtable.h> | |
76 | ||
77 | #include "internal.h" | |
78 | ||
79 | #define BLOCKS_PER_PAGE (PAGE_SIZE/512) | |
80 | #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT) | |
81 | ||
82 | /* Pretend that each entry is of this size in directory's i_size */ | |
83 | #define BOGO_DIRENT_SIZE 20 | |
84 | ||
85 | /* Symlink up to this size is kmalloc'ed instead of using a swappable page */ | |
86 | #define SHORT_SYMLINK_LEN 128 | |
87 | ||
88 | /* | |
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. | |
92 | */ | |
93 | struct shmem_falloc { | |
94 | wait_queue_head_t *waitq; /* faults into hole wait for punch to end */ | |
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 | ||
101 | #ifdef CONFIG_TMPFS | |
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 | } | |
111 | #endif | |
112 | ||
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); | |
116 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, | |
117 | struct page **pagep, enum sgp_type sgp, | |
118 | gfp_t gfp, struct mm_struct *fault_mm, int *fault_type); | |
119 | ||
120 | int shmem_getpage(struct inode *inode, pgoff_t index, | |
121 | struct page **pagep, enum sgp_type sgp) | |
122 | { | |
123 | return shmem_getpage_gfp(inode, index, pagep, sgp, | |
124 | mapping_gfp_mask(inode->i_mapping), NULL, NULL); | |
125 | } | |
126 | ||
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 | { | |
140 | return (flags & VM_NORESERVE) ? | |
141 | 0 : security_vm_enough_memory_mm(current->mm, VM_ACCT(size)); | |
142 | } | |
143 | ||
144 | static inline void shmem_unacct_size(unsigned long flags, loff_t size) | |
145 | { | |
146 | if (!(flags & VM_NORESERVE)) | |
147 | vm_unacct_memory(VM_ACCT(size)); | |
148 | } | |
149 | ||
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 | ||
163 | /* | |
164 | * ... whereas tmpfs objects are accounted incrementally as | |
165 | * pages are allocated, in order to allow large sparse files. | |
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 | */ | |
169 | static inline int shmem_acct_block(unsigned long flags, long pages) | |
170 | { | |
171 | if (!(flags & VM_NORESERVE)) | |
172 | return 0; | |
173 | ||
174 | return security_vm_enough_memory_mm(current->mm, | |
175 | pages * VM_ACCT(PAGE_SIZE)); | |
176 | } | |
177 | ||
178 | static inline void shmem_unacct_blocks(unsigned long flags, long pages) | |
179 | { | |
180 | if (flags & VM_NORESERVE) | |
181 | vm_unacct_memory(pages * VM_ACCT(PAGE_SIZE)); | |
182 | } | |
183 | ||
184 | static const struct super_operations shmem_ops; | |
185 | static const struct address_space_operations shmem_aops; | |
186 | static const struct file_operations shmem_file_operations; | |
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; | |
190 | static const struct vm_operations_struct shmem_vm_ops; | |
191 | static struct file_system_type shmem_fs_type; | |
192 | ||
193 | static LIST_HEAD(shmem_swaplist); | |
194 | static DEFINE_MUTEX(shmem_swaplist_mutex); | |
195 | ||
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 | ||
221 | /** | |
222 | * shmem_recalc_inode - recalculate the block usage of an inode | |
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) { | |
240 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
241 | if (sbinfo->max_blocks) | |
242 | percpu_counter_add(&sbinfo->used_blocks, -freed); | |
243 | info->alloced -= freed; | |
244 | inode->i_blocks -= freed * BLOCKS_PER_PAGE; | |
245 | shmem_unacct_blocks(info->flags, freed); | |
246 | } | |
247 | } | |
248 | ||
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); | |
253 | unsigned long flags; | |
254 | ||
255 | if (shmem_acct_block(info->flags, pages)) | |
256 | return false; | |
257 | spin_lock_irqsave(&info->lock, flags); | |
258 | info->alloced += pages; | |
259 | inode->i_blocks += pages * BLOCKS_PER_PAGE; | |
260 | shmem_recalc_inode(inode); | |
261 | spin_unlock_irqrestore(&info->lock, flags); | |
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; | |
269 | spin_lock_irqsave(&info->lock, flags); | |
270 | info->alloced -= pages; | |
271 | shmem_recalc_inode(inode); | |
272 | spin_unlock_irqrestore(&info->lock, flags); | |
273 | shmem_unacct_blocks(info->flags, pages); | |
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); | |
284 | unsigned long flags; | |
285 | ||
286 | spin_lock_irqsave(&info->lock, flags); | |
287 | info->alloced -= pages; | |
288 | inode->i_blocks -= pages * BLOCKS_PER_PAGE; | |
289 | shmem_recalc_inode(inode); | |
290 | spin_unlock_irqrestore(&info->lock, flags); | |
291 | ||
292 | if (sbinfo->max_blocks) | |
293 | percpu_counter_sub(&sbinfo->used_blocks, pages); | |
294 | shmem_unacct_blocks(info->flags, pages); | |
295 | } | |
296 | ||
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 | struct radix_tree_node *node; | |
304 | void **pslot; | |
305 | void *item; | |
306 | ||
307 | VM_BUG_ON(!expected); | |
308 | VM_BUG_ON(!replacement); | |
309 | item = __radix_tree_lookup(&mapping->page_tree, index, &node, &pslot); | |
310 | if (!item) | |
311 | return -ENOENT; | |
312 | if (item != expected) | |
313 | return -ENOENT; | |
314 | __radix_tree_replace(&mapping->page_tree, node, pslot, | |
315 | replacement, NULL, NULL); | |
316 | return 0; | |
317 | } | |
318 | ||
319 | /* | |
320 | * Sometimes, before we decide whether to proceed or to fail, we must check | |
321 | * that an entry was not already brought back from swap by a racing thread. | |
322 | * | |
323 | * Checking page is not enough: by the time a SwapCache page is locked, it | |
324 | * might be reused, and again be SwapCache, using the same swap as before. | |
325 | */ | |
326 | static bool shmem_confirm_swap(struct address_space *mapping, | |
327 | pgoff_t index, swp_entry_t swap) | |
328 | { | |
329 | void *item; | |
330 | ||
331 | rcu_read_lock(); | |
332 | item = radix_tree_lookup(&mapping->page_tree, index); | |
333 | rcu_read_unlock(); | |
334 | return item == swp_to_radix_entry(swap); | |
335 | } | |
336 | ||
337 | /* | |
338 | * Definitions for "huge tmpfs": tmpfs mounted with the huge= option | |
339 | * | |
340 | * SHMEM_HUGE_NEVER: | |
341 | * disables huge pages for the mount; | |
342 | * SHMEM_HUGE_ALWAYS: | |
343 | * enables huge pages for the mount; | |
344 | * SHMEM_HUGE_WITHIN_SIZE: | |
345 | * only allocate huge pages if the page will be fully within i_size, | |
346 | * also respect fadvise()/madvise() hints; | |
347 | * SHMEM_HUGE_ADVISE: | |
348 | * only allocate huge pages if requested with fadvise()/madvise(); | |
349 | */ | |
350 | ||
351 | #define SHMEM_HUGE_NEVER 0 | |
352 | #define SHMEM_HUGE_ALWAYS 1 | |
353 | #define SHMEM_HUGE_WITHIN_SIZE 2 | |
354 | #define SHMEM_HUGE_ADVISE 3 | |
355 | ||
356 | /* | |
357 | * Special values. | |
358 | * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled: | |
359 | * | |
360 | * SHMEM_HUGE_DENY: | |
361 | * disables huge on shm_mnt and all mounts, for emergency use; | |
362 | * SHMEM_HUGE_FORCE: | |
363 | * enables huge on shm_mnt and all mounts, w/o needing option, for testing; | |
364 | * | |
365 | */ | |
366 | #define SHMEM_HUGE_DENY (-1) | |
367 | #define SHMEM_HUGE_FORCE (-2) | |
368 | ||
369 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE | |
370 | /* ifdef here to avoid bloating shmem.o when not necessary */ | |
371 | ||
372 | int shmem_huge __read_mostly; | |
373 | ||
374 | #if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS) | |
375 | static int shmem_parse_huge(const char *str) | |
376 | { | |
377 | if (!strcmp(str, "never")) | |
378 | return SHMEM_HUGE_NEVER; | |
379 | if (!strcmp(str, "always")) | |
380 | return SHMEM_HUGE_ALWAYS; | |
381 | if (!strcmp(str, "within_size")) | |
382 | return SHMEM_HUGE_WITHIN_SIZE; | |
383 | if (!strcmp(str, "advise")) | |
384 | return SHMEM_HUGE_ADVISE; | |
385 | if (!strcmp(str, "deny")) | |
386 | return SHMEM_HUGE_DENY; | |
387 | if (!strcmp(str, "force")) | |
388 | return SHMEM_HUGE_FORCE; | |
389 | return -EINVAL; | |
390 | } | |
391 | ||
392 | static const char *shmem_format_huge(int huge) | |
393 | { | |
394 | switch (huge) { | |
395 | case SHMEM_HUGE_NEVER: | |
396 | return "never"; | |
397 | case SHMEM_HUGE_ALWAYS: | |
398 | return "always"; | |
399 | case SHMEM_HUGE_WITHIN_SIZE: | |
400 | return "within_size"; | |
401 | case SHMEM_HUGE_ADVISE: | |
402 | return "advise"; | |
403 | case SHMEM_HUGE_DENY: | |
404 | return "deny"; | |
405 | case SHMEM_HUGE_FORCE: | |
406 | return "force"; | |
407 | default: | |
408 | VM_BUG_ON(1); | |
409 | return "bad_val"; | |
410 | } | |
411 | } | |
412 | #endif | |
413 | ||
414 | static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, | |
415 | struct shrink_control *sc, unsigned long nr_to_split) | |
416 | { | |
417 | LIST_HEAD(list), *pos, *next; | |
418 | LIST_HEAD(to_remove); | |
419 | struct inode *inode; | |
420 | struct shmem_inode_info *info; | |
421 | struct page *page; | |
422 | unsigned long batch = sc ? sc->nr_to_scan : 128; | |
423 | int removed = 0, split = 0; | |
424 | ||
425 | if (list_empty(&sbinfo->shrinklist)) | |
426 | return SHRINK_STOP; | |
427 | ||
428 | spin_lock(&sbinfo->shrinklist_lock); | |
429 | list_for_each_safe(pos, next, &sbinfo->shrinklist) { | |
430 | info = list_entry(pos, struct shmem_inode_info, shrinklist); | |
431 | ||
432 | /* pin the inode */ | |
433 | inode = igrab(&info->vfs_inode); | |
434 | ||
435 | /* inode is about to be evicted */ | |
436 | if (!inode) { | |
437 | list_del_init(&info->shrinklist); | |
438 | removed++; | |
439 | goto next; | |
440 | } | |
441 | ||
442 | /* Check if there's anything to gain */ | |
443 | if (round_up(inode->i_size, PAGE_SIZE) == | |
444 | round_up(inode->i_size, HPAGE_PMD_SIZE)) { | |
445 | list_move(&info->shrinklist, &to_remove); | |
446 | removed++; | |
447 | goto next; | |
448 | } | |
449 | ||
450 | list_move(&info->shrinklist, &list); | |
451 | next: | |
452 | if (!--batch) | |
453 | break; | |
454 | } | |
455 | spin_unlock(&sbinfo->shrinklist_lock); | |
456 | ||
457 | list_for_each_safe(pos, next, &to_remove) { | |
458 | info = list_entry(pos, struct shmem_inode_info, shrinklist); | |
459 | inode = &info->vfs_inode; | |
460 | list_del_init(&info->shrinklist); | |
461 | iput(inode); | |
462 | } | |
463 | ||
464 | list_for_each_safe(pos, next, &list) { | |
465 | int ret; | |
466 | ||
467 | info = list_entry(pos, struct shmem_inode_info, shrinklist); | |
468 | inode = &info->vfs_inode; | |
469 | ||
470 | if (nr_to_split && split >= nr_to_split) { | |
471 | iput(inode); | |
472 | continue; | |
473 | } | |
474 | ||
475 | page = find_lock_page(inode->i_mapping, | |
476 | (inode->i_size & HPAGE_PMD_MASK) >> PAGE_SHIFT); | |
477 | if (!page) | |
478 | goto drop; | |
479 | ||
480 | if (!PageTransHuge(page)) { | |
481 | unlock_page(page); | |
482 | put_page(page); | |
483 | goto drop; | |
484 | } | |
485 | ||
486 | ret = split_huge_page(page); | |
487 | unlock_page(page); | |
488 | put_page(page); | |
489 | ||
490 | if (ret) { | |
491 | /* split failed: leave it on the list */ | |
492 | iput(inode); | |
493 | continue; | |
494 | } | |
495 | ||
496 | split++; | |
497 | drop: | |
498 | list_del_init(&info->shrinklist); | |
499 | removed++; | |
500 | iput(inode); | |
501 | } | |
502 | ||
503 | spin_lock(&sbinfo->shrinklist_lock); | |
504 | list_splice_tail(&list, &sbinfo->shrinklist); | |
505 | sbinfo->shrinklist_len -= removed; | |
506 | spin_unlock(&sbinfo->shrinklist_lock); | |
507 | ||
508 | return split; | |
509 | } | |
510 | ||
511 | static long shmem_unused_huge_scan(struct super_block *sb, | |
512 | struct shrink_control *sc) | |
513 | { | |
514 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
515 | ||
516 | if (!READ_ONCE(sbinfo->shrinklist_len)) | |
517 | return SHRINK_STOP; | |
518 | ||
519 | return shmem_unused_huge_shrink(sbinfo, sc, 0); | |
520 | } | |
521 | ||
522 | static long shmem_unused_huge_count(struct super_block *sb, | |
523 | struct shrink_control *sc) | |
524 | { | |
525 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
526 | return READ_ONCE(sbinfo->shrinklist_len); | |
527 | } | |
528 | #else /* !CONFIG_TRANSPARENT_HUGE_PAGECACHE */ | |
529 | ||
530 | #define shmem_huge SHMEM_HUGE_DENY | |
531 | ||
532 | static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info *sbinfo, | |
533 | struct shrink_control *sc, unsigned long nr_to_split) | |
534 | { | |
535 | return 0; | |
536 | } | |
537 | #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */ | |
538 | ||
539 | /* | |
540 | * Like add_to_page_cache_locked, but error if expected item has gone. | |
541 | */ | |
542 | static int shmem_add_to_page_cache(struct page *page, | |
543 | struct address_space *mapping, | |
544 | pgoff_t index, void *expected) | |
545 | { | |
546 | int error, nr = hpage_nr_pages(page); | |
547 | ||
548 | VM_BUG_ON_PAGE(PageTail(page), page); | |
549 | VM_BUG_ON_PAGE(index != round_down(index, nr), page); | |
550 | VM_BUG_ON_PAGE(!PageLocked(page), page); | |
551 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); | |
552 | VM_BUG_ON(expected && PageTransHuge(page)); | |
553 | ||
554 | page_ref_add(page, nr); | |
555 | page->mapping = mapping; | |
556 | page->index = index; | |
557 | ||
558 | spin_lock_irq(&mapping->tree_lock); | |
559 | if (PageTransHuge(page)) { | |
560 | void __rcu **results; | |
561 | pgoff_t idx; | |
562 | int i; | |
563 | ||
564 | error = 0; | |
565 | if (radix_tree_gang_lookup_slot(&mapping->page_tree, | |
566 | &results, &idx, index, 1) && | |
567 | idx < index + HPAGE_PMD_NR) { | |
568 | error = -EEXIST; | |
569 | } | |
570 | ||
571 | if (!error) { | |
572 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
573 | error = radix_tree_insert(&mapping->page_tree, | |
574 | index + i, page + i); | |
575 | VM_BUG_ON(error); | |
576 | } | |
577 | count_vm_event(THP_FILE_ALLOC); | |
578 | } | |
579 | } else if (!expected) { | |
580 | error = radix_tree_insert(&mapping->page_tree, index, page); | |
581 | } else { | |
582 | error = shmem_radix_tree_replace(mapping, index, expected, | |
583 | page); | |
584 | } | |
585 | ||
586 | if (!error) { | |
587 | mapping->nrpages += nr; | |
588 | if (PageTransHuge(page)) | |
589 | __inc_node_page_state(page, NR_SHMEM_THPS); | |
590 | __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr); | |
591 | __mod_node_page_state(page_pgdat(page), NR_SHMEM, nr); | |
592 | spin_unlock_irq(&mapping->tree_lock); | |
593 | } else { | |
594 | page->mapping = NULL; | |
595 | spin_unlock_irq(&mapping->tree_lock); | |
596 | page_ref_sub(page, nr); | |
597 | } | |
598 | return error; | |
599 | } | |
600 | ||
601 | /* | |
602 | * Like delete_from_page_cache, but substitutes swap for page. | |
603 | */ | |
604 | static void shmem_delete_from_page_cache(struct page *page, void *radswap) | |
605 | { | |
606 | struct address_space *mapping = page->mapping; | |
607 | int error; | |
608 | ||
609 | VM_BUG_ON_PAGE(PageCompound(page), page); | |
610 | ||
611 | spin_lock_irq(&mapping->tree_lock); | |
612 | error = shmem_radix_tree_replace(mapping, page->index, page, radswap); | |
613 | page->mapping = NULL; | |
614 | mapping->nrpages--; | |
615 | __dec_node_page_state(page, NR_FILE_PAGES); | |
616 | __dec_node_page_state(page, NR_SHMEM); | |
617 | spin_unlock_irq(&mapping->tree_lock); | |
618 | put_page(page); | |
619 | BUG_ON(error); | |
620 | } | |
621 | ||
622 | /* | |
623 | * Remove swap entry from radix tree, free the swap and its page cache. | |
624 | */ | |
625 | static int shmem_free_swap(struct address_space *mapping, | |
626 | pgoff_t index, void *radswap) | |
627 | { | |
628 | void *old; | |
629 | ||
630 | spin_lock_irq(&mapping->tree_lock); | |
631 | old = radix_tree_delete_item(&mapping->page_tree, index, radswap); | |
632 | spin_unlock_irq(&mapping->tree_lock); | |
633 | if (old != radswap) | |
634 | return -ENOENT; | |
635 | free_swap_and_cache(radix_to_swp_entry(radswap)); | |
636 | return 0; | |
637 | } | |
638 | ||
639 | /* | |
640 | * Determine (in bytes) how many of the shmem object's pages mapped by the | |
641 | * given offsets are swapped out. | |
642 | * | |
643 | * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, | |
644 | * as long as the inode doesn't go away and racy results are not a problem. | |
645 | */ | |
646 | unsigned long shmem_partial_swap_usage(struct address_space *mapping, | |
647 | pgoff_t start, pgoff_t end) | |
648 | { | |
649 | struct radix_tree_iter iter; | |
650 | void **slot; | |
651 | struct page *page; | |
652 | unsigned long swapped = 0; | |
653 | ||
654 | rcu_read_lock(); | |
655 | ||
656 | radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { | |
657 | if (iter.index >= end) | |
658 | break; | |
659 | ||
660 | page = radix_tree_deref_slot(slot); | |
661 | ||
662 | if (radix_tree_deref_retry(page)) { | |
663 | slot = radix_tree_iter_retry(&iter); | |
664 | continue; | |
665 | } | |
666 | ||
667 | if (radix_tree_exceptional_entry(page)) | |
668 | swapped++; | |
669 | ||
670 | if (need_resched()) { | |
671 | slot = radix_tree_iter_resume(slot, &iter); | |
672 | cond_resched_rcu(); | |
673 | } | |
674 | } | |
675 | ||
676 | rcu_read_unlock(); | |
677 | ||
678 | return swapped << PAGE_SHIFT; | |
679 | } | |
680 | ||
681 | /* | |
682 | * Determine (in bytes) how many of the shmem object's pages mapped by the | |
683 | * given vma is swapped out. | |
684 | * | |
685 | * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, | |
686 | * as long as the inode doesn't go away and racy results are not a problem. | |
687 | */ | |
688 | unsigned long shmem_swap_usage(struct vm_area_struct *vma) | |
689 | { | |
690 | struct inode *inode = file_inode(vma->vm_file); | |
691 | struct shmem_inode_info *info = SHMEM_I(inode); | |
692 | struct address_space *mapping = inode->i_mapping; | |
693 | unsigned long swapped; | |
694 | ||
695 | /* Be careful as we don't hold info->lock */ | |
696 | swapped = READ_ONCE(info->swapped); | |
697 | ||
698 | /* | |
699 | * The easier cases are when the shmem object has nothing in swap, or | |
700 | * the vma maps it whole. Then we can simply use the stats that we | |
701 | * already track. | |
702 | */ | |
703 | if (!swapped) | |
704 | return 0; | |
705 | ||
706 | if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size) | |
707 | return swapped << PAGE_SHIFT; | |
708 | ||
709 | /* Here comes the more involved part */ | |
710 | return shmem_partial_swap_usage(mapping, | |
711 | linear_page_index(vma, vma->vm_start), | |
712 | linear_page_index(vma, vma->vm_end)); | |
713 | } | |
714 | ||
715 | /* | |
716 | * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. | |
717 | */ | |
718 | void shmem_unlock_mapping(struct address_space *mapping) | |
719 | { | |
720 | struct pagevec pvec; | |
721 | pgoff_t indices[PAGEVEC_SIZE]; | |
722 | pgoff_t index = 0; | |
723 | ||
724 | pagevec_init(&pvec, 0); | |
725 | /* | |
726 | * Minor point, but we might as well stop if someone else SHM_LOCKs it. | |
727 | */ | |
728 | while (!mapping_unevictable(mapping)) { | |
729 | /* | |
730 | * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it | |
731 | * has finished, if it hits a row of PAGEVEC_SIZE swap entries. | |
732 | */ | |
733 | pvec.nr = find_get_entries(mapping, index, | |
734 | PAGEVEC_SIZE, pvec.pages, indices); | |
735 | if (!pvec.nr) | |
736 | break; | |
737 | index = indices[pvec.nr - 1] + 1; | |
738 | pagevec_remove_exceptionals(&pvec); | |
739 | check_move_unevictable_pages(pvec.pages, pvec.nr); | |
740 | pagevec_release(&pvec); | |
741 | cond_resched(); | |
742 | } | |
743 | } | |
744 | ||
745 | /* | |
746 | * Remove range of pages and swap entries from radix tree, and free them. | |
747 | * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate. | |
748 | */ | |
749 | static void shmem_undo_range(struct inode *inode, loff_t lstart, loff_t lend, | |
750 | bool unfalloc) | |
751 | { | |
752 | struct address_space *mapping = inode->i_mapping; | |
753 | struct shmem_inode_info *info = SHMEM_I(inode); | |
754 | pgoff_t start = (lstart + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
755 | pgoff_t end = (lend + 1) >> PAGE_SHIFT; | |
756 | unsigned int partial_start = lstart & (PAGE_SIZE - 1); | |
757 | unsigned int partial_end = (lend + 1) & (PAGE_SIZE - 1); | |
758 | struct pagevec pvec; | |
759 | pgoff_t indices[PAGEVEC_SIZE]; | |
760 | long nr_swaps_freed = 0; | |
761 | pgoff_t index; | |
762 | int i; | |
763 | ||
764 | if (lend == -1) | |
765 | end = -1; /* unsigned, so actually very big */ | |
766 | ||
767 | pagevec_init(&pvec, 0); | |
768 | index = start; | |
769 | while (index < end) { | |
770 | pvec.nr = find_get_entries(mapping, index, | |
771 | min(end - index, (pgoff_t)PAGEVEC_SIZE), | |
772 | pvec.pages, indices); | |
773 | if (!pvec.nr) | |
774 | break; | |
775 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
776 | struct page *page = pvec.pages[i]; | |
777 | ||
778 | index = indices[i]; | |
779 | if (index >= end) | |
780 | break; | |
781 | ||
782 | if (radix_tree_exceptional_entry(page)) { | |
783 | if (unfalloc) | |
784 | continue; | |
785 | nr_swaps_freed += !shmem_free_swap(mapping, | |
786 | index, page); | |
787 | continue; | |
788 | } | |
789 | ||
790 | VM_BUG_ON_PAGE(page_to_pgoff(page) != index, page); | |
791 | ||
792 | if (!trylock_page(page)) | |
793 | continue; | |
794 | ||
795 | if (PageTransTail(page)) { | |
796 | /* Middle of THP: zero out the page */ | |
797 | clear_highpage(page); | |
798 | unlock_page(page); | |
799 | continue; | |
800 | } else if (PageTransHuge(page)) { | |
801 | if (index == round_down(end, HPAGE_PMD_NR)) { | |
802 | /* | |
803 | * Range ends in the middle of THP: | |
804 | * zero out the page | |
805 | */ | |
806 | clear_highpage(page); | |
807 | unlock_page(page); | |
808 | continue; | |
809 | } | |
810 | index += HPAGE_PMD_NR - 1; | |
811 | i += HPAGE_PMD_NR - 1; | |
812 | } | |
813 | ||
814 | if (!unfalloc || !PageUptodate(page)) { | |
815 | VM_BUG_ON_PAGE(PageTail(page), page); | |
816 | if (page_mapping(page) == mapping) { | |
817 | VM_BUG_ON_PAGE(PageWriteback(page), page); | |
818 | truncate_inode_page(mapping, page); | |
819 | } | |
820 | } | |
821 | unlock_page(page); | |
822 | } | |
823 | pagevec_remove_exceptionals(&pvec); | |
824 | pagevec_release(&pvec); | |
825 | cond_resched(); | |
826 | index++; | |
827 | } | |
828 | ||
829 | if (partial_start) { | |
830 | struct page *page = NULL; | |
831 | shmem_getpage(inode, start - 1, &page, SGP_READ); | |
832 | if (page) { | |
833 | unsigned int top = PAGE_SIZE; | |
834 | if (start > end) { | |
835 | top = partial_end; | |
836 | partial_end = 0; | |
837 | } | |
838 | zero_user_segment(page, partial_start, top); | |
839 | set_page_dirty(page); | |
840 | unlock_page(page); | |
841 | put_page(page); | |
842 | } | |
843 | } | |
844 | if (partial_end) { | |
845 | struct page *page = NULL; | |
846 | shmem_getpage(inode, end, &page, SGP_READ); | |
847 | if (page) { | |
848 | zero_user_segment(page, 0, partial_end); | |
849 | set_page_dirty(page); | |
850 | unlock_page(page); | |
851 | put_page(page); | |
852 | } | |
853 | } | |
854 | if (start >= end) | |
855 | return; | |
856 | ||
857 | index = start; | |
858 | while (index < end) { | |
859 | cond_resched(); | |
860 | ||
861 | pvec.nr = find_get_entries(mapping, index, | |
862 | min(end - index, (pgoff_t)PAGEVEC_SIZE), | |
863 | pvec.pages, indices); | |
864 | if (!pvec.nr) { | |
865 | /* If all gone or hole-punch or unfalloc, we're done */ | |
866 | if (index == start || end != -1) | |
867 | break; | |
868 | /* But if truncating, restart to make sure all gone */ | |
869 | index = start; | |
870 | continue; | |
871 | } | |
872 | for (i = 0; i < pagevec_count(&pvec); i++) { | |
873 | struct page *page = pvec.pages[i]; | |
874 | ||
875 | index = indices[i]; | |
876 | if (index >= end) | |
877 | break; | |
878 | ||
879 | if (radix_tree_exceptional_entry(page)) { | |
880 | if (unfalloc) | |
881 | continue; | |
882 | if (shmem_free_swap(mapping, index, page)) { | |
883 | /* Swap was replaced by page: retry */ | |
884 | index--; | |
885 | break; | |
886 | } | |
887 | nr_swaps_freed++; | |
888 | continue; | |
889 | } | |
890 | ||
891 | lock_page(page); | |
892 | ||
893 | if (PageTransTail(page)) { | |
894 | /* Middle of THP: zero out the page */ | |
895 | clear_highpage(page); | |
896 | unlock_page(page); | |
897 | /* | |
898 | * Partial thp truncate due 'start' in middle | |
899 | * of THP: don't need to look on these pages | |
900 | * again on !pvec.nr restart. | |
901 | */ | |
902 | if (index != round_down(end, HPAGE_PMD_NR)) | |
903 | start++; | |
904 | continue; | |
905 | } else if (PageTransHuge(page)) { | |
906 | if (index == round_down(end, HPAGE_PMD_NR)) { | |
907 | /* | |
908 | * Range ends in the middle of THP: | |
909 | * zero out the page | |
910 | */ | |
911 | clear_highpage(page); | |
912 | unlock_page(page); | |
913 | continue; | |
914 | } | |
915 | index += HPAGE_PMD_NR - 1; | |
916 | i += HPAGE_PMD_NR - 1; | |
917 | } | |
918 | ||
919 | if (!unfalloc || !PageUptodate(page)) { | |
920 | VM_BUG_ON_PAGE(PageTail(page), page); | |
921 | if (page_mapping(page) == mapping) { | |
922 | VM_BUG_ON_PAGE(PageWriteback(page), page); | |
923 | truncate_inode_page(mapping, page); | |
924 | } else { | |
925 | /* Page was replaced by swap: retry */ | |
926 | unlock_page(page); | |
927 | index--; | |
928 | break; | |
929 | } | |
930 | } | |
931 | unlock_page(page); | |
932 | } | |
933 | pagevec_remove_exceptionals(&pvec); | |
934 | pagevec_release(&pvec); | |
935 | index++; | |
936 | } | |
937 | ||
938 | spin_lock_irq(&info->lock); | |
939 | info->swapped -= nr_swaps_freed; | |
940 | shmem_recalc_inode(inode); | |
941 | spin_unlock_irq(&info->lock); | |
942 | } | |
943 | ||
944 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) | |
945 | { | |
946 | shmem_undo_range(inode, lstart, lend, false); | |
947 | inode->i_ctime = inode->i_mtime = current_time(inode); | |
948 | } | |
949 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
950 | ||
951 | static int shmem_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
952 | struct kstat *stat) | |
953 | { | |
954 | struct inode *inode = dentry->d_inode; | |
955 | struct shmem_inode_info *info = SHMEM_I(inode); | |
956 | ||
957 | if (info->alloced - info->swapped != inode->i_mapping->nrpages) { | |
958 | spin_lock_irq(&info->lock); | |
959 | shmem_recalc_inode(inode); | |
960 | spin_unlock_irq(&info->lock); | |
961 | } | |
962 | generic_fillattr(inode, stat); | |
963 | return 0; | |
964 | } | |
965 | ||
966 | static int shmem_setattr(struct dentry *dentry, struct iattr *attr) | |
967 | { | |
968 | struct inode *inode = d_inode(dentry); | |
969 | struct shmem_inode_info *info = SHMEM_I(inode); | |
970 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
971 | int error; | |
972 | ||
973 | error = setattr_prepare(dentry, attr); | |
974 | if (error) | |
975 | return error; | |
976 | ||
977 | if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { | |
978 | loff_t oldsize = inode->i_size; | |
979 | loff_t newsize = attr->ia_size; | |
980 | ||
981 | /* protected by i_mutex */ | |
982 | if ((newsize < oldsize && (info->seals & F_SEAL_SHRINK)) || | |
983 | (newsize > oldsize && (info->seals & F_SEAL_GROW))) | |
984 | return -EPERM; | |
985 | ||
986 | if (newsize != oldsize) { | |
987 | error = shmem_reacct_size(SHMEM_I(inode)->flags, | |
988 | oldsize, newsize); | |
989 | if (error) | |
990 | return error; | |
991 | i_size_write(inode, newsize); | |
992 | inode->i_ctime = inode->i_mtime = current_time(inode); | |
993 | } | |
994 | if (newsize <= oldsize) { | |
995 | loff_t holebegin = round_up(newsize, PAGE_SIZE); | |
996 | if (oldsize > holebegin) | |
997 | unmap_mapping_range(inode->i_mapping, | |
998 | holebegin, 0, 1); | |
999 | if (info->alloced) | |
1000 | shmem_truncate_range(inode, | |
1001 | newsize, (loff_t)-1); | |
1002 | /* unmap again to remove racily COWed private pages */ | |
1003 | if (oldsize > holebegin) | |
1004 | unmap_mapping_range(inode->i_mapping, | |
1005 | holebegin, 0, 1); | |
1006 | ||
1007 | /* | |
1008 | * Part of the huge page can be beyond i_size: subject | |
1009 | * to shrink under memory pressure. | |
1010 | */ | |
1011 | if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) { | |
1012 | spin_lock(&sbinfo->shrinklist_lock); | |
1013 | if (list_empty(&info->shrinklist)) { | |
1014 | list_add_tail(&info->shrinklist, | |
1015 | &sbinfo->shrinklist); | |
1016 | sbinfo->shrinklist_len++; | |
1017 | } | |
1018 | spin_unlock(&sbinfo->shrinklist_lock); | |
1019 | } | |
1020 | } | |
1021 | } | |
1022 | ||
1023 | setattr_copy(inode, attr); | |
1024 | if (attr->ia_valid & ATTR_MODE) | |
1025 | error = posix_acl_chmod(inode, inode->i_mode); | |
1026 | return error; | |
1027 | } | |
1028 | ||
1029 | static void shmem_evict_inode(struct inode *inode) | |
1030 | { | |
1031 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1032 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
1033 | ||
1034 | if (inode->i_mapping->a_ops == &shmem_aops) { | |
1035 | shmem_unacct_size(info->flags, inode->i_size); | |
1036 | inode->i_size = 0; | |
1037 | shmem_truncate_range(inode, 0, (loff_t)-1); | |
1038 | if (!list_empty(&info->shrinklist)) { | |
1039 | spin_lock(&sbinfo->shrinklist_lock); | |
1040 | if (!list_empty(&info->shrinklist)) { | |
1041 | list_del_init(&info->shrinklist); | |
1042 | sbinfo->shrinklist_len--; | |
1043 | } | |
1044 | spin_unlock(&sbinfo->shrinklist_lock); | |
1045 | } | |
1046 | if (!list_empty(&info->swaplist)) { | |
1047 | mutex_lock(&shmem_swaplist_mutex); | |
1048 | list_del_init(&info->swaplist); | |
1049 | mutex_unlock(&shmem_swaplist_mutex); | |
1050 | } | |
1051 | } | |
1052 | ||
1053 | simple_xattrs_free(&info->xattrs); | |
1054 | WARN_ON(inode->i_blocks); | |
1055 | shmem_free_inode(inode->i_sb); | |
1056 | clear_inode(inode); | |
1057 | } | |
1058 | ||
1059 | static unsigned long find_swap_entry(struct radix_tree_root *root, void *item) | |
1060 | { | |
1061 | struct radix_tree_iter iter; | |
1062 | void **slot; | |
1063 | unsigned long found = -1; | |
1064 | unsigned int checked = 0; | |
1065 | ||
1066 | rcu_read_lock(); | |
1067 | radix_tree_for_each_slot(slot, root, &iter, 0) { | |
1068 | if (*slot == item) { | |
1069 | found = iter.index; | |
1070 | break; | |
1071 | } | |
1072 | checked++; | |
1073 | if ((checked % 4096) != 0) | |
1074 | continue; | |
1075 | slot = radix_tree_iter_resume(slot, &iter); | |
1076 | cond_resched_rcu(); | |
1077 | } | |
1078 | ||
1079 | rcu_read_unlock(); | |
1080 | return found; | |
1081 | } | |
1082 | ||
1083 | /* | |
1084 | * If swap found in inode, free it and move page from swapcache to filecache. | |
1085 | */ | |
1086 | static int shmem_unuse_inode(struct shmem_inode_info *info, | |
1087 | swp_entry_t swap, struct page **pagep) | |
1088 | { | |
1089 | struct address_space *mapping = info->vfs_inode.i_mapping; | |
1090 | void *radswap; | |
1091 | pgoff_t index; | |
1092 | gfp_t gfp; | |
1093 | int error = 0; | |
1094 | ||
1095 | radswap = swp_to_radix_entry(swap); | |
1096 | index = find_swap_entry(&mapping->page_tree, radswap); | |
1097 | if (index == -1) | |
1098 | return -EAGAIN; /* tell shmem_unuse we found nothing */ | |
1099 | ||
1100 | /* | |
1101 | * Move _head_ to start search for next from here. | |
1102 | * But be careful: shmem_evict_inode checks list_empty without taking | |
1103 | * mutex, and there's an instant in list_move_tail when info->swaplist | |
1104 | * would appear empty, if it were the only one on shmem_swaplist. | |
1105 | */ | |
1106 | if (shmem_swaplist.next != &info->swaplist) | |
1107 | list_move_tail(&shmem_swaplist, &info->swaplist); | |
1108 | ||
1109 | gfp = mapping_gfp_mask(mapping); | |
1110 | if (shmem_should_replace_page(*pagep, gfp)) { | |
1111 | mutex_unlock(&shmem_swaplist_mutex); | |
1112 | error = shmem_replace_page(pagep, gfp, info, index); | |
1113 | mutex_lock(&shmem_swaplist_mutex); | |
1114 | /* | |
1115 | * We needed to drop mutex to make that restrictive page | |
1116 | * allocation, but the inode might have been freed while we | |
1117 | * dropped it: although a racing shmem_evict_inode() cannot | |
1118 | * complete without emptying the radix_tree, our page lock | |
1119 | * on this swapcache page is not enough to prevent that - | |
1120 | * free_swap_and_cache() of our swap entry will only | |
1121 | * trylock_page(), removing swap from radix_tree whatever. | |
1122 | * | |
1123 | * We must not proceed to shmem_add_to_page_cache() if the | |
1124 | * inode has been freed, but of course we cannot rely on | |
1125 | * inode or mapping or info to check that. However, we can | |
1126 | * safely check if our swap entry is still in use (and here | |
1127 | * it can't have got reused for another page): if it's still | |
1128 | * in use, then the inode cannot have been freed yet, and we | |
1129 | * can safely proceed (if it's no longer in use, that tells | |
1130 | * nothing about the inode, but we don't need to unuse swap). | |
1131 | */ | |
1132 | if (!page_swapcount(*pagep)) | |
1133 | error = -ENOENT; | |
1134 | } | |
1135 | ||
1136 | /* | |
1137 | * We rely on shmem_swaplist_mutex, not only to protect the swaplist, | |
1138 | * but also to hold up shmem_evict_inode(): so inode cannot be freed | |
1139 | * beneath us (pagelock doesn't help until the page is in pagecache). | |
1140 | */ | |
1141 | if (!error) | |
1142 | error = shmem_add_to_page_cache(*pagep, mapping, index, | |
1143 | radswap); | |
1144 | if (error != -ENOMEM) { | |
1145 | /* | |
1146 | * Truncation and eviction use free_swap_and_cache(), which | |
1147 | * only does trylock page: if we raced, best clean up here. | |
1148 | */ | |
1149 | delete_from_swap_cache(*pagep); | |
1150 | set_page_dirty(*pagep); | |
1151 | if (!error) { | |
1152 | spin_lock_irq(&info->lock); | |
1153 | info->swapped--; | |
1154 | spin_unlock_irq(&info->lock); | |
1155 | swap_free(swap); | |
1156 | } | |
1157 | } | |
1158 | return error; | |
1159 | } | |
1160 | ||
1161 | /* | |
1162 | * Search through swapped inodes to find and replace swap by page. | |
1163 | */ | |
1164 | int shmem_unuse(swp_entry_t swap, struct page *page) | |
1165 | { | |
1166 | struct list_head *this, *next; | |
1167 | struct shmem_inode_info *info; | |
1168 | struct mem_cgroup *memcg; | |
1169 | int error = 0; | |
1170 | ||
1171 | /* | |
1172 | * There's a faint possibility that swap page was replaced before | |
1173 | * caller locked it: caller will come back later with the right page. | |
1174 | */ | |
1175 | if (unlikely(!PageSwapCache(page) || page_private(page) != swap.val)) | |
1176 | goto out; | |
1177 | ||
1178 | /* | |
1179 | * Charge page using GFP_KERNEL while we can wait, before taking | |
1180 | * the shmem_swaplist_mutex which might hold up shmem_writepage(). | |
1181 | * Charged back to the user (not to caller) when swap account is used. | |
1182 | */ | |
1183 | error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg, | |
1184 | false); | |
1185 | if (error) | |
1186 | goto out; | |
1187 | /* No radix_tree_preload: swap entry keeps a place for page in tree */ | |
1188 | error = -EAGAIN; | |
1189 | ||
1190 | mutex_lock(&shmem_swaplist_mutex); | |
1191 | list_for_each_safe(this, next, &shmem_swaplist) { | |
1192 | info = list_entry(this, struct shmem_inode_info, swaplist); | |
1193 | if (info->swapped) | |
1194 | error = shmem_unuse_inode(info, swap, &page); | |
1195 | else | |
1196 | list_del_init(&info->swaplist); | |
1197 | cond_resched(); | |
1198 | if (error != -EAGAIN) | |
1199 | break; | |
1200 | /* found nothing in this: move on to search the next */ | |
1201 | } | |
1202 | mutex_unlock(&shmem_swaplist_mutex); | |
1203 | ||
1204 | if (error) { | |
1205 | if (error != -ENOMEM) | |
1206 | error = 0; | |
1207 | mem_cgroup_cancel_charge(page, memcg, false); | |
1208 | } else | |
1209 | mem_cgroup_commit_charge(page, memcg, true, false); | |
1210 | out: | |
1211 | unlock_page(page); | |
1212 | put_page(page); | |
1213 | return error; | |
1214 | } | |
1215 | ||
1216 | /* | |
1217 | * Move the page from the page cache to the swap cache. | |
1218 | */ | |
1219 | static int shmem_writepage(struct page *page, struct writeback_control *wbc) | |
1220 | { | |
1221 | struct shmem_inode_info *info; | |
1222 | struct address_space *mapping; | |
1223 | struct inode *inode; | |
1224 | swp_entry_t swap; | |
1225 | pgoff_t index; | |
1226 | ||
1227 | VM_BUG_ON_PAGE(PageCompound(page), page); | |
1228 | BUG_ON(!PageLocked(page)); | |
1229 | mapping = page->mapping; | |
1230 | index = page->index; | |
1231 | inode = mapping->host; | |
1232 | info = SHMEM_I(inode); | |
1233 | if (info->flags & VM_LOCKED) | |
1234 | goto redirty; | |
1235 | if (!total_swap_pages) | |
1236 | goto redirty; | |
1237 | ||
1238 | /* | |
1239 | * Our capabilities prevent regular writeback or sync from ever calling | |
1240 | * shmem_writepage; but a stacking filesystem might use ->writepage of | |
1241 | * its underlying filesystem, in which case tmpfs should write out to | |
1242 | * swap only in response to memory pressure, and not for the writeback | |
1243 | * threads or sync. | |
1244 | */ | |
1245 | if (!wbc->for_reclaim) { | |
1246 | WARN_ON_ONCE(1); /* Still happens? Tell us about it! */ | |
1247 | goto redirty; | |
1248 | } | |
1249 | ||
1250 | /* | |
1251 | * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC | |
1252 | * value into swapfile.c, the only way we can correctly account for a | |
1253 | * fallocated page arriving here is now to initialize it and write it. | |
1254 | * | |
1255 | * That's okay for a page already fallocated earlier, but if we have | |
1256 | * not yet completed the fallocation, then (a) we want to keep track | |
1257 | * of this page in case we have to undo it, and (b) it may not be a | |
1258 | * good idea to continue anyway, once we're pushing into swap. So | |
1259 | * reactivate the page, and let shmem_fallocate() quit when too many. | |
1260 | */ | |
1261 | if (!PageUptodate(page)) { | |
1262 | if (inode->i_private) { | |
1263 | struct shmem_falloc *shmem_falloc; | |
1264 | spin_lock(&inode->i_lock); | |
1265 | shmem_falloc = inode->i_private; | |
1266 | if (shmem_falloc && | |
1267 | !shmem_falloc->waitq && | |
1268 | index >= shmem_falloc->start && | |
1269 | index < shmem_falloc->next) | |
1270 | shmem_falloc->nr_unswapped++; | |
1271 | else | |
1272 | shmem_falloc = NULL; | |
1273 | spin_unlock(&inode->i_lock); | |
1274 | if (shmem_falloc) | |
1275 | goto redirty; | |
1276 | } | |
1277 | clear_highpage(page); | |
1278 | flush_dcache_page(page); | |
1279 | SetPageUptodate(page); | |
1280 | } | |
1281 | ||
1282 | swap = get_swap_page(); | |
1283 | if (!swap.val) | |
1284 | goto redirty; | |
1285 | ||
1286 | if (mem_cgroup_try_charge_swap(page, swap)) | |
1287 | goto free_swap; | |
1288 | ||
1289 | /* | |
1290 | * Add inode to shmem_unuse()'s list of swapped-out inodes, | |
1291 | * if it's not already there. Do it now before the page is | |
1292 | * moved to swap cache, when its pagelock no longer protects | |
1293 | * the inode from eviction. But don't unlock the mutex until | |
1294 | * we've incremented swapped, because shmem_unuse_inode() will | |
1295 | * prune a !swapped inode from the swaplist under this mutex. | |
1296 | */ | |
1297 | mutex_lock(&shmem_swaplist_mutex); | |
1298 | if (list_empty(&info->swaplist)) | |
1299 | list_add_tail(&info->swaplist, &shmem_swaplist); | |
1300 | ||
1301 | if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) { | |
1302 | spin_lock_irq(&info->lock); | |
1303 | shmem_recalc_inode(inode); | |
1304 | info->swapped++; | |
1305 | spin_unlock_irq(&info->lock); | |
1306 | ||
1307 | swap_shmem_alloc(swap); | |
1308 | shmem_delete_from_page_cache(page, swp_to_radix_entry(swap)); | |
1309 | ||
1310 | mutex_unlock(&shmem_swaplist_mutex); | |
1311 | BUG_ON(page_mapped(page)); | |
1312 | swap_writepage(page, wbc); | |
1313 | return 0; | |
1314 | } | |
1315 | ||
1316 | mutex_unlock(&shmem_swaplist_mutex); | |
1317 | free_swap: | |
1318 | swapcache_free(swap); | |
1319 | redirty: | |
1320 | set_page_dirty(page); | |
1321 | if (wbc->for_reclaim) | |
1322 | return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */ | |
1323 | unlock_page(page); | |
1324 | return 0; | |
1325 | } | |
1326 | ||
1327 | #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS) | |
1328 | static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) | |
1329 | { | |
1330 | char buffer[64]; | |
1331 | ||
1332 | if (!mpol || mpol->mode == MPOL_DEFAULT) | |
1333 | return; /* show nothing */ | |
1334 | ||
1335 | mpol_to_str(buffer, sizeof(buffer), mpol); | |
1336 | ||
1337 | seq_printf(seq, ",mpol=%s", buffer); | |
1338 | } | |
1339 | ||
1340 | static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1341 | { | |
1342 | struct mempolicy *mpol = NULL; | |
1343 | if (sbinfo->mpol) { | |
1344 | spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */ | |
1345 | mpol = sbinfo->mpol; | |
1346 | mpol_get(mpol); | |
1347 | spin_unlock(&sbinfo->stat_lock); | |
1348 | } | |
1349 | return mpol; | |
1350 | } | |
1351 | #else /* !CONFIG_NUMA || !CONFIG_TMPFS */ | |
1352 | static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol) | |
1353 | { | |
1354 | } | |
1355 | static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo) | |
1356 | { | |
1357 | return NULL; | |
1358 | } | |
1359 | #endif /* CONFIG_NUMA && CONFIG_TMPFS */ | |
1360 | #ifndef CONFIG_NUMA | |
1361 | #define vm_policy vm_private_data | |
1362 | #endif | |
1363 | ||
1364 | static void shmem_pseudo_vma_init(struct vm_area_struct *vma, | |
1365 | struct shmem_inode_info *info, pgoff_t index) | |
1366 | { | |
1367 | /* Create a pseudo vma that just contains the policy */ | |
1368 | vma->vm_start = 0; | |
1369 | /* Bias interleave by inode number to distribute better across nodes */ | |
1370 | vma->vm_pgoff = index + info->vfs_inode.i_ino; | |
1371 | vma->vm_ops = NULL; | |
1372 | vma->vm_policy = mpol_shared_policy_lookup(&info->policy, index); | |
1373 | } | |
1374 | ||
1375 | static void shmem_pseudo_vma_destroy(struct vm_area_struct *vma) | |
1376 | { | |
1377 | /* Drop reference taken by mpol_shared_policy_lookup() */ | |
1378 | mpol_cond_put(vma->vm_policy); | |
1379 | } | |
1380 | ||
1381 | static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp, | |
1382 | struct shmem_inode_info *info, pgoff_t index) | |
1383 | { | |
1384 | struct vm_area_struct pvma; | |
1385 | struct page *page; | |
1386 | ||
1387 | shmem_pseudo_vma_init(&pvma, info, index); | |
1388 | page = swapin_readahead(swap, gfp, &pvma, 0); | |
1389 | shmem_pseudo_vma_destroy(&pvma); | |
1390 | ||
1391 | return page; | |
1392 | } | |
1393 | ||
1394 | static struct page *shmem_alloc_hugepage(gfp_t gfp, | |
1395 | struct shmem_inode_info *info, pgoff_t index) | |
1396 | { | |
1397 | struct vm_area_struct pvma; | |
1398 | struct inode *inode = &info->vfs_inode; | |
1399 | struct address_space *mapping = inode->i_mapping; | |
1400 | pgoff_t idx, hindex; | |
1401 | void __rcu **results; | |
1402 | struct page *page; | |
1403 | ||
1404 | if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) | |
1405 | return NULL; | |
1406 | ||
1407 | hindex = round_down(index, HPAGE_PMD_NR); | |
1408 | rcu_read_lock(); | |
1409 | if (radix_tree_gang_lookup_slot(&mapping->page_tree, &results, &idx, | |
1410 | hindex, 1) && idx < hindex + HPAGE_PMD_NR) { | |
1411 | rcu_read_unlock(); | |
1412 | return NULL; | |
1413 | } | |
1414 | rcu_read_unlock(); | |
1415 | ||
1416 | shmem_pseudo_vma_init(&pvma, info, hindex); | |
1417 | page = alloc_pages_vma(gfp | __GFP_COMP | __GFP_NORETRY | __GFP_NOWARN, | |
1418 | HPAGE_PMD_ORDER, &pvma, 0, numa_node_id(), true); | |
1419 | shmem_pseudo_vma_destroy(&pvma); | |
1420 | if (page) | |
1421 | prep_transhuge_page(page); | |
1422 | return page; | |
1423 | } | |
1424 | ||
1425 | static struct page *shmem_alloc_page(gfp_t gfp, | |
1426 | struct shmem_inode_info *info, pgoff_t index) | |
1427 | { | |
1428 | struct vm_area_struct pvma; | |
1429 | struct page *page; | |
1430 | ||
1431 | shmem_pseudo_vma_init(&pvma, info, index); | |
1432 | page = alloc_page_vma(gfp, &pvma, 0); | |
1433 | shmem_pseudo_vma_destroy(&pvma); | |
1434 | ||
1435 | return page; | |
1436 | } | |
1437 | ||
1438 | static struct page *shmem_alloc_and_acct_page(gfp_t gfp, | |
1439 | struct shmem_inode_info *info, struct shmem_sb_info *sbinfo, | |
1440 | pgoff_t index, bool huge) | |
1441 | { | |
1442 | struct page *page; | |
1443 | int nr; | |
1444 | int err = -ENOSPC; | |
1445 | ||
1446 | if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) | |
1447 | huge = false; | |
1448 | nr = huge ? HPAGE_PMD_NR : 1; | |
1449 | ||
1450 | if (shmem_acct_block(info->flags, nr)) | |
1451 | goto failed; | |
1452 | if (sbinfo->max_blocks) { | |
1453 | if (percpu_counter_compare(&sbinfo->used_blocks, | |
1454 | sbinfo->max_blocks - nr) > 0) | |
1455 | goto unacct; | |
1456 | percpu_counter_add(&sbinfo->used_blocks, nr); | |
1457 | } | |
1458 | ||
1459 | if (huge) | |
1460 | page = shmem_alloc_hugepage(gfp, info, index); | |
1461 | else | |
1462 | page = shmem_alloc_page(gfp, info, index); | |
1463 | if (page) { | |
1464 | __SetPageLocked(page); | |
1465 | __SetPageSwapBacked(page); | |
1466 | return page; | |
1467 | } | |
1468 | ||
1469 | err = -ENOMEM; | |
1470 | if (sbinfo->max_blocks) | |
1471 | percpu_counter_add(&sbinfo->used_blocks, -nr); | |
1472 | unacct: | |
1473 | shmem_unacct_blocks(info->flags, nr); | |
1474 | failed: | |
1475 | return ERR_PTR(err); | |
1476 | } | |
1477 | ||
1478 | /* | |
1479 | * When a page is moved from swapcache to shmem filecache (either by the | |
1480 | * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of | |
1481 | * shmem_unuse_inode()), it may have been read in earlier from swap, in | |
1482 | * ignorance of the mapping it belongs to. If that mapping has special | |
1483 | * constraints (like the gma500 GEM driver, which requires RAM below 4GB), | |
1484 | * we may need to copy to a suitable page before moving to filecache. | |
1485 | * | |
1486 | * In a future release, this may well be extended to respect cpuset and | |
1487 | * NUMA mempolicy, and applied also to anonymous pages in do_swap_page(); | |
1488 | * but for now it is a simple matter of zone. | |
1489 | */ | |
1490 | static bool shmem_should_replace_page(struct page *page, gfp_t gfp) | |
1491 | { | |
1492 | return page_zonenum(page) > gfp_zone(gfp); | |
1493 | } | |
1494 | ||
1495 | static int shmem_replace_page(struct page **pagep, gfp_t gfp, | |
1496 | struct shmem_inode_info *info, pgoff_t index) | |
1497 | { | |
1498 | struct page *oldpage, *newpage; | |
1499 | struct address_space *swap_mapping; | |
1500 | pgoff_t swap_index; | |
1501 | int error; | |
1502 | ||
1503 | oldpage = *pagep; | |
1504 | swap_index = page_private(oldpage); | |
1505 | swap_mapping = page_mapping(oldpage); | |
1506 | ||
1507 | /* | |
1508 | * We have arrived here because our zones are constrained, so don't | |
1509 | * limit chance of success by further cpuset and node constraints. | |
1510 | */ | |
1511 | gfp &= ~GFP_CONSTRAINT_MASK; | |
1512 | newpage = shmem_alloc_page(gfp, info, index); | |
1513 | if (!newpage) | |
1514 | return -ENOMEM; | |
1515 | ||
1516 | get_page(newpage); | |
1517 | copy_highpage(newpage, oldpage); | |
1518 | flush_dcache_page(newpage); | |
1519 | ||
1520 | __SetPageLocked(newpage); | |
1521 | __SetPageSwapBacked(newpage); | |
1522 | SetPageUptodate(newpage); | |
1523 | set_page_private(newpage, swap_index); | |
1524 | SetPageSwapCache(newpage); | |
1525 | ||
1526 | /* | |
1527 | * Our caller will very soon move newpage out of swapcache, but it's | |
1528 | * a nice clean interface for us to replace oldpage by newpage there. | |
1529 | */ | |
1530 | spin_lock_irq(&swap_mapping->tree_lock); | |
1531 | error = shmem_radix_tree_replace(swap_mapping, swap_index, oldpage, | |
1532 | newpage); | |
1533 | if (!error) { | |
1534 | __inc_node_page_state(newpage, NR_FILE_PAGES); | |
1535 | __dec_node_page_state(oldpage, NR_FILE_PAGES); | |
1536 | } | |
1537 | spin_unlock_irq(&swap_mapping->tree_lock); | |
1538 | ||
1539 | if (unlikely(error)) { | |
1540 | /* | |
1541 | * Is this possible? I think not, now that our callers check | |
1542 | * both PageSwapCache and page_private after getting page lock; | |
1543 | * but be defensive. Reverse old to newpage for clear and free. | |
1544 | */ | |
1545 | oldpage = newpage; | |
1546 | } else { | |
1547 | mem_cgroup_migrate(oldpage, newpage); | |
1548 | lru_cache_add_anon(newpage); | |
1549 | *pagep = newpage; | |
1550 | } | |
1551 | ||
1552 | ClearPageSwapCache(oldpage); | |
1553 | set_page_private(oldpage, 0); | |
1554 | ||
1555 | unlock_page(oldpage); | |
1556 | put_page(oldpage); | |
1557 | put_page(oldpage); | |
1558 | return error; | |
1559 | } | |
1560 | ||
1561 | /* | |
1562 | * shmem_getpage_gfp - find page in cache, or get from swap, or allocate | |
1563 | * | |
1564 | * If we allocate a new one we do not mark it dirty. That's up to the | |
1565 | * vm. If we swap it in we mark it dirty since we also free the swap | |
1566 | * entry since a page cannot live in both the swap and page cache. | |
1567 | * | |
1568 | * fault_mm and fault_type are only supplied by shmem_fault: | |
1569 | * otherwise they are NULL. | |
1570 | */ | |
1571 | static int shmem_getpage_gfp(struct inode *inode, pgoff_t index, | |
1572 | struct page **pagep, enum sgp_type sgp, gfp_t gfp, | |
1573 | struct mm_struct *fault_mm, int *fault_type) | |
1574 | { | |
1575 | struct address_space *mapping = inode->i_mapping; | |
1576 | struct shmem_inode_info *info = SHMEM_I(inode); | |
1577 | struct shmem_sb_info *sbinfo; | |
1578 | struct mm_struct *charge_mm; | |
1579 | struct mem_cgroup *memcg; | |
1580 | struct page *page; | |
1581 | swp_entry_t swap; | |
1582 | enum sgp_type sgp_huge = sgp; | |
1583 | pgoff_t hindex = index; | |
1584 | int error; | |
1585 | int once = 0; | |
1586 | int alloced = 0; | |
1587 | ||
1588 | if (index > (MAX_LFS_FILESIZE >> PAGE_SHIFT)) | |
1589 | return -EFBIG; | |
1590 | if (sgp == SGP_NOHUGE || sgp == SGP_HUGE) | |
1591 | sgp = SGP_CACHE; | |
1592 | repeat: | |
1593 | swap.val = 0; | |
1594 | page = find_lock_entry(mapping, index); | |
1595 | if (radix_tree_exceptional_entry(page)) { | |
1596 | swap = radix_to_swp_entry(page); | |
1597 | page = NULL; | |
1598 | } | |
1599 | ||
1600 | if (sgp <= SGP_CACHE && | |
1601 | ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { | |
1602 | error = -EINVAL; | |
1603 | goto unlock; | |
1604 | } | |
1605 | ||
1606 | if (page && sgp == SGP_WRITE) | |
1607 | mark_page_accessed(page); | |
1608 | ||
1609 | /* fallocated page? */ | |
1610 | if (page && !PageUptodate(page)) { | |
1611 | if (sgp != SGP_READ) | |
1612 | goto clear; | |
1613 | unlock_page(page); | |
1614 | put_page(page); | |
1615 | page = NULL; | |
1616 | } | |
1617 | if (page || (sgp == SGP_READ && !swap.val)) { | |
1618 | *pagep = page; | |
1619 | return 0; | |
1620 | } | |
1621 | ||
1622 | /* | |
1623 | * Fast cache lookup did not find it: | |
1624 | * bring it back from swap or allocate. | |
1625 | */ | |
1626 | sbinfo = SHMEM_SB(inode->i_sb); | |
1627 | charge_mm = fault_mm ? : current->mm; | |
1628 | ||
1629 | if (swap.val) { | |
1630 | /* Look it up and read it in.. */ | |
1631 | page = lookup_swap_cache(swap); | |
1632 | if (!page) { | |
1633 | /* Or update major stats only when swapin succeeds?? */ | |
1634 | if (fault_type) { | |
1635 | *fault_type |= VM_FAULT_MAJOR; | |
1636 | count_vm_event(PGMAJFAULT); | |
1637 | mem_cgroup_count_vm_event(fault_mm, PGMAJFAULT); | |
1638 | } | |
1639 | /* Here we actually start the io */ | |
1640 | page = shmem_swapin(swap, gfp, info, index); | |
1641 | if (!page) { | |
1642 | error = -ENOMEM; | |
1643 | goto failed; | |
1644 | } | |
1645 | } | |
1646 | ||
1647 | /* We have to do this with page locked to prevent races */ | |
1648 | lock_page(page); | |
1649 | if (!PageSwapCache(page) || page_private(page) != swap.val || | |
1650 | !shmem_confirm_swap(mapping, index, swap)) { | |
1651 | error = -EEXIST; /* try again */ | |
1652 | goto unlock; | |
1653 | } | |
1654 | if (!PageUptodate(page)) { | |
1655 | error = -EIO; | |
1656 | goto failed; | |
1657 | } | |
1658 | wait_on_page_writeback(page); | |
1659 | ||
1660 | if (shmem_should_replace_page(page, gfp)) { | |
1661 | error = shmem_replace_page(&page, gfp, info, index); | |
1662 | if (error) | |
1663 | goto failed; | |
1664 | } | |
1665 | ||
1666 | error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg, | |
1667 | false); | |
1668 | if (!error) { | |
1669 | error = shmem_add_to_page_cache(page, mapping, index, | |
1670 | swp_to_radix_entry(swap)); | |
1671 | /* | |
1672 | * We already confirmed swap under page lock, and make | |
1673 | * no memory allocation here, so usually no possibility | |
1674 | * of error; but free_swap_and_cache() only trylocks a | |
1675 | * page, so it is just possible that the entry has been | |
1676 | * truncated or holepunched since swap was confirmed. | |
1677 | * shmem_undo_range() will have done some of the | |
1678 | * unaccounting, now delete_from_swap_cache() will do | |
1679 | * the rest. | |
1680 | * Reset swap.val? No, leave it so "failed" goes back to | |
1681 | * "repeat": reading a hole and writing should succeed. | |
1682 | */ | |
1683 | if (error) { | |
1684 | mem_cgroup_cancel_charge(page, memcg, false); | |
1685 | delete_from_swap_cache(page); | |
1686 | } | |
1687 | } | |
1688 | if (error) | |
1689 | goto failed; | |
1690 | ||
1691 | mem_cgroup_commit_charge(page, memcg, true, false); | |
1692 | ||
1693 | spin_lock_irq(&info->lock); | |
1694 | info->swapped--; | |
1695 | shmem_recalc_inode(inode); | |
1696 | spin_unlock_irq(&info->lock); | |
1697 | ||
1698 | if (sgp == SGP_WRITE) | |
1699 | mark_page_accessed(page); | |
1700 | ||
1701 | delete_from_swap_cache(page); | |
1702 | set_page_dirty(page); | |
1703 | swap_free(swap); | |
1704 | ||
1705 | } else { | |
1706 | /* shmem_symlink() */ | |
1707 | if (mapping->a_ops != &shmem_aops) | |
1708 | goto alloc_nohuge; | |
1709 | if (shmem_huge == SHMEM_HUGE_DENY || sgp_huge == SGP_NOHUGE) | |
1710 | goto alloc_nohuge; | |
1711 | if (shmem_huge == SHMEM_HUGE_FORCE) | |
1712 | goto alloc_huge; | |
1713 | switch (sbinfo->huge) { | |
1714 | loff_t i_size; | |
1715 | pgoff_t off; | |
1716 | case SHMEM_HUGE_NEVER: | |
1717 | goto alloc_nohuge; | |
1718 | case SHMEM_HUGE_WITHIN_SIZE: | |
1719 | off = round_up(index, HPAGE_PMD_NR); | |
1720 | i_size = round_up(i_size_read(inode), PAGE_SIZE); | |
1721 | if (i_size >= HPAGE_PMD_SIZE && | |
1722 | i_size >> PAGE_SHIFT >= off) | |
1723 | goto alloc_huge; | |
1724 | /* fallthrough */ | |
1725 | case SHMEM_HUGE_ADVISE: | |
1726 | if (sgp_huge == SGP_HUGE) | |
1727 | goto alloc_huge; | |
1728 | /* TODO: implement fadvise() hints */ | |
1729 | goto alloc_nohuge; | |
1730 | } | |
1731 | ||
1732 | alloc_huge: | |
1733 | page = shmem_alloc_and_acct_page(gfp, info, sbinfo, | |
1734 | index, true); | |
1735 | if (IS_ERR(page)) { | |
1736 | alloc_nohuge: page = shmem_alloc_and_acct_page(gfp, info, sbinfo, | |
1737 | index, false); | |
1738 | } | |
1739 | if (IS_ERR(page)) { | |
1740 | int retry = 5; | |
1741 | error = PTR_ERR(page); | |
1742 | page = NULL; | |
1743 | if (error != -ENOSPC) | |
1744 | goto failed; | |
1745 | /* | |
1746 | * Try to reclaim some spece by splitting a huge page | |
1747 | * beyond i_size on the filesystem. | |
1748 | */ | |
1749 | while (retry--) { | |
1750 | int ret; | |
1751 | ret = shmem_unused_huge_shrink(sbinfo, NULL, 1); | |
1752 | if (ret == SHRINK_STOP) | |
1753 | break; | |
1754 | if (ret) | |
1755 | goto alloc_nohuge; | |
1756 | } | |
1757 | goto failed; | |
1758 | } | |
1759 | ||
1760 | if (PageTransHuge(page)) | |
1761 | hindex = round_down(index, HPAGE_PMD_NR); | |
1762 | else | |
1763 | hindex = index; | |
1764 | ||
1765 | if (sgp == SGP_WRITE) | |
1766 | __SetPageReferenced(page); | |
1767 | ||
1768 | error = mem_cgroup_try_charge(page, charge_mm, gfp, &memcg, | |
1769 | PageTransHuge(page)); | |
1770 | if (error) | |
1771 | goto unacct; | |
1772 | error = radix_tree_maybe_preload_order(gfp & GFP_RECLAIM_MASK, | |
1773 | compound_order(page)); | |
1774 | if (!error) { | |
1775 | error = shmem_add_to_page_cache(page, mapping, hindex, | |
1776 | NULL); | |
1777 | radix_tree_preload_end(); | |
1778 | } | |
1779 | if (error) { | |
1780 | mem_cgroup_cancel_charge(page, memcg, | |
1781 | PageTransHuge(page)); | |
1782 | goto unacct; | |
1783 | } | |
1784 | mem_cgroup_commit_charge(page, memcg, false, | |
1785 | PageTransHuge(page)); | |
1786 | lru_cache_add_anon(page); | |
1787 | ||
1788 | spin_lock_irq(&info->lock); | |
1789 | info->alloced += 1 << compound_order(page); | |
1790 | inode->i_blocks += BLOCKS_PER_PAGE << compound_order(page); | |
1791 | shmem_recalc_inode(inode); | |
1792 | spin_unlock_irq(&info->lock); | |
1793 | alloced = true; | |
1794 | ||
1795 | if (PageTransHuge(page) && | |
1796 | DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE) < | |
1797 | hindex + HPAGE_PMD_NR - 1) { | |
1798 | /* | |
1799 | * Part of the huge page is beyond i_size: subject | |
1800 | * to shrink under memory pressure. | |
1801 | */ | |
1802 | spin_lock(&sbinfo->shrinklist_lock); | |
1803 | if (list_empty(&info->shrinklist)) { | |
1804 | list_add_tail(&info->shrinklist, | |
1805 | &sbinfo->shrinklist); | |
1806 | sbinfo->shrinklist_len++; | |
1807 | } | |
1808 | spin_unlock(&sbinfo->shrinklist_lock); | |
1809 | } | |
1810 | ||
1811 | /* | |
1812 | * Let SGP_FALLOC use the SGP_WRITE optimization on a new page. | |
1813 | */ | |
1814 | if (sgp == SGP_FALLOC) | |
1815 | sgp = SGP_WRITE; | |
1816 | clear: | |
1817 | /* | |
1818 | * Let SGP_WRITE caller clear ends if write does not fill page; | |
1819 | * but SGP_FALLOC on a page fallocated earlier must initialize | |
1820 | * it now, lest undo on failure cancel our earlier guarantee. | |
1821 | */ | |
1822 | if (sgp != SGP_WRITE && !PageUptodate(page)) { | |
1823 | struct page *head = compound_head(page); | |
1824 | int i; | |
1825 | ||
1826 | for (i = 0; i < (1 << compound_order(head)); i++) { | |
1827 | clear_highpage(head + i); | |
1828 | flush_dcache_page(head + i); | |
1829 | } | |
1830 | SetPageUptodate(head); | |
1831 | } | |
1832 | } | |
1833 | ||
1834 | /* Perhaps the file has been truncated since we checked */ | |
1835 | if (sgp <= SGP_CACHE && | |
1836 | ((loff_t)index << PAGE_SHIFT) >= i_size_read(inode)) { | |
1837 | if (alloced) { | |
1838 | ClearPageDirty(page); | |
1839 | delete_from_page_cache(page); | |
1840 | spin_lock_irq(&info->lock); | |
1841 | shmem_recalc_inode(inode); | |
1842 | spin_unlock_irq(&info->lock); | |
1843 | } | |
1844 | error = -EINVAL; | |
1845 | goto unlock; | |
1846 | } | |
1847 | *pagep = page + index - hindex; | |
1848 | return 0; | |
1849 | ||
1850 | /* | |
1851 | * Error recovery. | |
1852 | */ | |
1853 | unacct: | |
1854 | if (sbinfo->max_blocks) | |
1855 | percpu_counter_sub(&sbinfo->used_blocks, | |
1856 | 1 << compound_order(page)); | |
1857 | shmem_unacct_blocks(info->flags, 1 << compound_order(page)); | |
1858 | ||
1859 | if (PageTransHuge(page)) { | |
1860 | unlock_page(page); | |
1861 | put_page(page); | |
1862 | goto alloc_nohuge; | |
1863 | } | |
1864 | failed: | |
1865 | if (swap.val && !shmem_confirm_swap(mapping, index, swap)) | |
1866 | error = -EEXIST; | |
1867 | unlock: | |
1868 | if (page) { | |
1869 | unlock_page(page); | |
1870 | put_page(page); | |
1871 | } | |
1872 | if (error == -ENOSPC && !once++) { | |
1873 | spin_lock_irq(&info->lock); | |
1874 | shmem_recalc_inode(inode); | |
1875 | spin_unlock_irq(&info->lock); | |
1876 | goto repeat; | |
1877 | } | |
1878 | if (error == -EEXIST) /* from above or from radix_tree_insert */ | |
1879 | goto repeat; | |
1880 | return error; | |
1881 | } | |
1882 | ||
1883 | /* | |
1884 | * This is like autoremove_wake_function, but it removes the wait queue | |
1885 | * entry unconditionally - even if something else had already woken the | |
1886 | * target. | |
1887 | */ | |
1888 | static int synchronous_wake_function(wait_queue_t *wait, unsigned mode, int sync, void *key) | |
1889 | { | |
1890 | int ret = default_wake_function(wait, mode, sync, key); | |
1891 | list_del_init(&wait->task_list); | |
1892 | return ret; | |
1893 | } | |
1894 | ||
1895 | static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
1896 | { | |
1897 | struct inode *inode = file_inode(vma->vm_file); | |
1898 | gfp_t gfp = mapping_gfp_mask(inode->i_mapping); | |
1899 | enum sgp_type sgp; | |
1900 | int error; | |
1901 | int ret = VM_FAULT_LOCKED; | |
1902 | ||
1903 | /* | |
1904 | * Trinity finds that probing a hole which tmpfs is punching can | |
1905 | * prevent the hole-punch from ever completing: which in turn | |
1906 | * locks writers out with its hold on i_mutex. So refrain from | |
1907 | * faulting pages into the hole while it's being punched. Although | |
1908 | * shmem_undo_range() does remove the additions, it may be unable to | |
1909 | * keep up, as each new page needs its own unmap_mapping_range() call, | |
1910 | * and the i_mmap tree grows ever slower to scan if new vmas are added. | |
1911 | * | |
1912 | * It does not matter if we sometimes reach this check just before the | |
1913 | * hole-punch begins, so that one fault then races with the punch: | |
1914 | * we just need to make racing faults a rare case. | |
1915 | * | |
1916 | * The implementation below would be much simpler if we just used a | |
1917 | * standard mutex or completion: but we cannot take i_mutex in fault, | |
1918 | * and bloating every shmem inode for this unlikely case would be sad. | |
1919 | */ | |
1920 | if (unlikely(inode->i_private)) { | |
1921 | struct shmem_falloc *shmem_falloc; | |
1922 | ||
1923 | spin_lock(&inode->i_lock); | |
1924 | shmem_falloc = inode->i_private; | |
1925 | if (shmem_falloc && | |
1926 | shmem_falloc->waitq && | |
1927 | vmf->pgoff >= shmem_falloc->start && | |
1928 | vmf->pgoff < shmem_falloc->next) { | |
1929 | wait_queue_head_t *shmem_falloc_waitq; | |
1930 | DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function); | |
1931 | ||
1932 | ret = VM_FAULT_NOPAGE; | |
1933 | if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) && | |
1934 | !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) { | |
1935 | /* It's polite to up mmap_sem if we can */ | |
1936 | up_read(&vma->vm_mm->mmap_sem); | |
1937 | ret = VM_FAULT_RETRY; | |
1938 | } | |
1939 | ||
1940 | shmem_falloc_waitq = shmem_falloc->waitq; | |
1941 | prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait, | |
1942 | TASK_UNINTERRUPTIBLE); | |
1943 | spin_unlock(&inode->i_lock); | |
1944 | schedule(); | |
1945 | ||
1946 | /* | |
1947 | * shmem_falloc_waitq points into the shmem_fallocate() | |
1948 | * stack of the hole-punching task: shmem_falloc_waitq | |
1949 | * is usually invalid by the time we reach here, but | |
1950 | * finish_wait() does not dereference it in that case; | |
1951 | * though i_lock needed lest racing with wake_up_all(). | |
1952 | */ | |
1953 | spin_lock(&inode->i_lock); | |
1954 | finish_wait(shmem_falloc_waitq, &shmem_fault_wait); | |
1955 | spin_unlock(&inode->i_lock); | |
1956 | return ret; | |
1957 | } | |
1958 | spin_unlock(&inode->i_lock); | |
1959 | } | |
1960 | ||
1961 | sgp = SGP_CACHE; | |
1962 | if (vma->vm_flags & VM_HUGEPAGE) | |
1963 | sgp = SGP_HUGE; | |
1964 | else if (vma->vm_flags & VM_NOHUGEPAGE) | |
1965 | sgp = SGP_NOHUGE; | |
1966 | ||
1967 | error = shmem_getpage_gfp(inode, vmf->pgoff, &vmf->page, sgp, | |
1968 | gfp, vma->vm_mm, &ret); | |
1969 | if (error) | |
1970 | return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS); | |
1971 | return ret; | |
1972 | } | |
1973 | ||
1974 | unsigned long shmem_get_unmapped_area(struct file *file, | |
1975 | unsigned long uaddr, unsigned long len, | |
1976 | unsigned long pgoff, unsigned long flags) | |
1977 | { | |
1978 | unsigned long (*get_area)(struct file *, | |
1979 | unsigned long, unsigned long, unsigned long, unsigned long); | |
1980 | unsigned long addr; | |
1981 | unsigned long offset; | |
1982 | unsigned long inflated_len; | |
1983 | unsigned long inflated_addr; | |
1984 | unsigned long inflated_offset; | |
1985 | ||
1986 | if (len > TASK_SIZE) | |
1987 | return -ENOMEM; | |
1988 | ||
1989 | get_area = current->mm->get_unmapped_area; | |
1990 | addr = get_area(file, uaddr, len, pgoff, flags); | |
1991 | ||
1992 | if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) | |
1993 | return addr; | |
1994 | if (IS_ERR_VALUE(addr)) | |
1995 | return addr; | |
1996 | if (addr & ~PAGE_MASK) | |
1997 | return addr; | |
1998 | if (addr > TASK_SIZE - len) | |
1999 | return addr; | |
2000 | ||
2001 | if (shmem_huge == SHMEM_HUGE_DENY) | |
2002 | return addr; | |
2003 | if (len < HPAGE_PMD_SIZE) | |
2004 | return addr; | |
2005 | if (flags & MAP_FIXED) | |
2006 | return addr; | |
2007 | /* | |
2008 | * Our priority is to support MAP_SHARED mapped hugely; | |
2009 | * and support MAP_PRIVATE mapped hugely too, until it is COWed. | |
2010 | * But if caller specified an address hint, respect that as before. | |
2011 | */ | |
2012 | if (uaddr) | |
2013 | return addr; | |
2014 | ||
2015 | if (shmem_huge != SHMEM_HUGE_FORCE) { | |
2016 | struct super_block *sb; | |
2017 | ||
2018 | if (file) { | |
2019 | VM_BUG_ON(file->f_op != &shmem_file_operations); | |
2020 | sb = file_inode(file)->i_sb; | |
2021 | } else { | |
2022 | /* | |
2023 | * Called directly from mm/mmap.c, or drivers/char/mem.c | |
2024 | * for "/dev/zero", to create a shared anonymous object. | |
2025 | */ | |
2026 | if (IS_ERR(shm_mnt)) | |
2027 | return addr; | |
2028 | sb = shm_mnt->mnt_sb; | |
2029 | } | |
2030 | if (SHMEM_SB(sb)->huge == SHMEM_HUGE_NEVER) | |
2031 | return addr; | |
2032 | } | |
2033 | ||
2034 | offset = (pgoff << PAGE_SHIFT) & (HPAGE_PMD_SIZE-1); | |
2035 | if (offset && offset + len < 2 * HPAGE_PMD_SIZE) | |
2036 | return addr; | |
2037 | if ((addr & (HPAGE_PMD_SIZE-1)) == offset) | |
2038 | return addr; | |
2039 | ||
2040 | inflated_len = len + HPAGE_PMD_SIZE - PAGE_SIZE; | |
2041 | if (inflated_len > TASK_SIZE) | |
2042 | return addr; | |
2043 | if (inflated_len < len) | |
2044 | return addr; | |
2045 | ||
2046 | inflated_addr = get_area(NULL, 0, inflated_len, 0, flags); | |
2047 | if (IS_ERR_VALUE(inflated_addr)) | |
2048 | return addr; | |
2049 | if (inflated_addr & ~PAGE_MASK) | |
2050 | return addr; | |
2051 | ||
2052 | inflated_offset = inflated_addr & (HPAGE_PMD_SIZE-1); | |
2053 | inflated_addr += offset - inflated_offset; | |
2054 | if (inflated_offset > offset) | |
2055 | inflated_addr += HPAGE_PMD_SIZE; | |
2056 | ||
2057 | if (inflated_addr > TASK_SIZE - len) | |
2058 | return addr; | |
2059 | return inflated_addr; | |
2060 | } | |
2061 | ||
2062 | #ifdef CONFIG_NUMA | |
2063 | static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *mpol) | |
2064 | { | |
2065 | struct inode *inode = file_inode(vma->vm_file); | |
2066 | return mpol_set_shared_policy(&SHMEM_I(inode)->policy, vma, mpol); | |
2067 | } | |
2068 | ||
2069 | static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma, | |
2070 | unsigned long addr) | |
2071 | { | |
2072 | struct inode *inode = file_inode(vma->vm_file); | |
2073 | pgoff_t index; | |
2074 | ||
2075 | index = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; | |
2076 | return mpol_shared_policy_lookup(&SHMEM_I(inode)->policy, index); | |
2077 | } | |
2078 | #endif | |
2079 | ||
2080 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
2081 | { | |
2082 | struct inode *inode = file_inode(file); | |
2083 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2084 | int retval = -ENOMEM; | |
2085 | ||
2086 | spin_lock_irq(&info->lock); | |
2087 | if (lock && !(info->flags & VM_LOCKED)) { | |
2088 | if (!user_shm_lock(inode->i_size, user)) | |
2089 | goto out_nomem; | |
2090 | info->flags |= VM_LOCKED; | |
2091 | mapping_set_unevictable(file->f_mapping); | |
2092 | } | |
2093 | if (!lock && (info->flags & VM_LOCKED) && user) { | |
2094 | user_shm_unlock(inode->i_size, user); | |
2095 | info->flags &= ~VM_LOCKED; | |
2096 | mapping_clear_unevictable(file->f_mapping); | |
2097 | } | |
2098 | retval = 0; | |
2099 | ||
2100 | out_nomem: | |
2101 | spin_unlock_irq(&info->lock); | |
2102 | return retval; | |
2103 | } | |
2104 | ||
2105 | static int shmem_mmap(struct file *file, struct vm_area_struct *vma) | |
2106 | { | |
2107 | file_accessed(file); | |
2108 | vma->vm_ops = &shmem_vm_ops; | |
2109 | if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && | |
2110 | ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) < | |
2111 | (vma->vm_end & HPAGE_PMD_MASK)) { | |
2112 | khugepaged_enter(vma, vma->vm_flags); | |
2113 | } | |
2114 | return 0; | |
2115 | } | |
2116 | ||
2117 | static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, | |
2118 | umode_t mode, dev_t dev, unsigned long flags) | |
2119 | { | |
2120 | struct inode *inode; | |
2121 | struct shmem_inode_info *info; | |
2122 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
2123 | ||
2124 | if (shmem_reserve_inode(sb)) | |
2125 | return NULL; | |
2126 | ||
2127 | inode = new_inode(sb); | |
2128 | if (inode) { | |
2129 | inode->i_ino = get_next_ino(); | |
2130 | inode_init_owner(inode, dir, mode); | |
2131 | inode->i_blocks = 0; | |
2132 | inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode); | |
2133 | inode->i_generation = get_seconds(); | |
2134 | info = SHMEM_I(inode); | |
2135 | memset(info, 0, (char *)inode - (char *)info); | |
2136 | spin_lock_init(&info->lock); | |
2137 | info->seals = F_SEAL_SEAL; | |
2138 | info->flags = flags & VM_NORESERVE; | |
2139 | INIT_LIST_HEAD(&info->shrinklist); | |
2140 | INIT_LIST_HEAD(&info->swaplist); | |
2141 | simple_xattrs_init(&info->xattrs); | |
2142 | cache_no_acl(inode); | |
2143 | ||
2144 | switch (mode & S_IFMT) { | |
2145 | default: | |
2146 | inode->i_op = &shmem_special_inode_operations; | |
2147 | init_special_inode(inode, mode, dev); | |
2148 | break; | |
2149 | case S_IFREG: | |
2150 | inode->i_mapping->a_ops = &shmem_aops; | |
2151 | inode->i_op = &shmem_inode_operations; | |
2152 | inode->i_fop = &shmem_file_operations; | |
2153 | mpol_shared_policy_init(&info->policy, | |
2154 | shmem_get_sbmpol(sbinfo)); | |
2155 | break; | |
2156 | case S_IFDIR: | |
2157 | inc_nlink(inode); | |
2158 | /* Some things misbehave if size == 0 on a directory */ | |
2159 | inode->i_size = 2 * BOGO_DIRENT_SIZE; | |
2160 | inode->i_op = &shmem_dir_inode_operations; | |
2161 | inode->i_fop = &simple_dir_operations; | |
2162 | break; | |
2163 | case S_IFLNK: | |
2164 | /* | |
2165 | * Must not load anything in the rbtree, | |
2166 | * mpol_free_shared_policy will not be called. | |
2167 | */ | |
2168 | mpol_shared_policy_init(&info->policy, NULL); | |
2169 | break; | |
2170 | } | |
2171 | } else | |
2172 | shmem_free_inode(sb); | |
2173 | return inode; | |
2174 | } | |
2175 | ||
2176 | bool shmem_mapping(struct address_space *mapping) | |
2177 | { | |
2178 | if (!mapping->host) | |
2179 | return false; | |
2180 | ||
2181 | return mapping->host->i_sb->s_op == &shmem_ops; | |
2182 | } | |
2183 | ||
2184 | #ifdef CONFIG_TMPFS | |
2185 | static const struct inode_operations shmem_symlink_inode_operations; | |
2186 | static const struct inode_operations shmem_short_symlink_operations; | |
2187 | ||
2188 | #ifdef CONFIG_TMPFS_XATTR | |
2189 | static int shmem_initxattrs(struct inode *, const struct xattr *, void *); | |
2190 | #else | |
2191 | #define shmem_initxattrs NULL | |
2192 | #endif | |
2193 | ||
2194 | static int | |
2195 | shmem_write_begin(struct file *file, struct address_space *mapping, | |
2196 | loff_t pos, unsigned len, unsigned flags, | |
2197 | struct page **pagep, void **fsdata) | |
2198 | { | |
2199 | struct inode *inode = mapping->host; | |
2200 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2201 | pgoff_t index = pos >> PAGE_SHIFT; | |
2202 | ||
2203 | /* i_mutex is held by caller */ | |
2204 | if (unlikely(info->seals)) { | |
2205 | if (info->seals & F_SEAL_WRITE) | |
2206 | return -EPERM; | |
2207 | if ((info->seals & F_SEAL_GROW) && pos + len > inode->i_size) | |
2208 | return -EPERM; | |
2209 | } | |
2210 | ||
2211 | return shmem_getpage(inode, index, pagep, SGP_WRITE); | |
2212 | } | |
2213 | ||
2214 | static int | |
2215 | shmem_write_end(struct file *file, struct address_space *mapping, | |
2216 | loff_t pos, unsigned len, unsigned copied, | |
2217 | struct page *page, void *fsdata) | |
2218 | { | |
2219 | struct inode *inode = mapping->host; | |
2220 | ||
2221 | if (pos + copied > inode->i_size) | |
2222 | i_size_write(inode, pos + copied); | |
2223 | ||
2224 | if (!PageUptodate(page)) { | |
2225 | struct page *head = compound_head(page); | |
2226 | if (PageTransCompound(page)) { | |
2227 | int i; | |
2228 | ||
2229 | for (i = 0; i < HPAGE_PMD_NR; i++) { | |
2230 | if (head + i == page) | |
2231 | continue; | |
2232 | clear_highpage(head + i); | |
2233 | flush_dcache_page(head + i); | |
2234 | } | |
2235 | } | |
2236 | if (copied < PAGE_SIZE) { | |
2237 | unsigned from = pos & (PAGE_SIZE - 1); | |
2238 | zero_user_segments(page, 0, from, | |
2239 | from + copied, PAGE_SIZE); | |
2240 | } | |
2241 | SetPageUptodate(head); | |
2242 | } | |
2243 | set_page_dirty(page); | |
2244 | unlock_page(page); | |
2245 | put_page(page); | |
2246 | ||
2247 | return copied; | |
2248 | } | |
2249 | ||
2250 | static ssize_t shmem_file_read_iter(struct kiocb *iocb, struct iov_iter *to) | |
2251 | { | |
2252 | struct file *file = iocb->ki_filp; | |
2253 | struct inode *inode = file_inode(file); | |
2254 | struct address_space *mapping = inode->i_mapping; | |
2255 | pgoff_t index; | |
2256 | unsigned long offset; | |
2257 | enum sgp_type sgp = SGP_READ; | |
2258 | int error = 0; | |
2259 | ssize_t retval = 0; | |
2260 | loff_t *ppos = &iocb->ki_pos; | |
2261 | ||
2262 | /* | |
2263 | * Might this read be for a stacking filesystem? Then when reading | |
2264 | * holes of a sparse file, we actually need to allocate those pages, | |
2265 | * and even mark them dirty, so it cannot exceed the max_blocks limit. | |
2266 | */ | |
2267 | if (!iter_is_iovec(to)) | |
2268 | sgp = SGP_CACHE; | |
2269 | ||
2270 | index = *ppos >> PAGE_SHIFT; | |
2271 | offset = *ppos & ~PAGE_MASK; | |
2272 | ||
2273 | for (;;) { | |
2274 | struct page *page = NULL; | |
2275 | pgoff_t end_index; | |
2276 | unsigned long nr, ret; | |
2277 | loff_t i_size = i_size_read(inode); | |
2278 | ||
2279 | end_index = i_size >> PAGE_SHIFT; | |
2280 | if (index > end_index) | |
2281 | break; | |
2282 | if (index == end_index) { | |
2283 | nr = i_size & ~PAGE_MASK; | |
2284 | if (nr <= offset) | |
2285 | break; | |
2286 | } | |
2287 | ||
2288 | error = shmem_getpage(inode, index, &page, sgp); | |
2289 | if (error) { | |
2290 | if (error == -EINVAL) | |
2291 | error = 0; | |
2292 | break; | |
2293 | } | |
2294 | if (page) { | |
2295 | if (sgp == SGP_CACHE) | |
2296 | set_page_dirty(page); | |
2297 | unlock_page(page); | |
2298 | } | |
2299 | ||
2300 | /* | |
2301 | * We must evaluate after, since reads (unlike writes) | |
2302 | * are called without i_mutex protection against truncate | |
2303 | */ | |
2304 | nr = PAGE_SIZE; | |
2305 | i_size = i_size_read(inode); | |
2306 | end_index = i_size >> PAGE_SHIFT; | |
2307 | if (index == end_index) { | |
2308 | nr = i_size & ~PAGE_MASK; | |
2309 | if (nr <= offset) { | |
2310 | if (page) | |
2311 | put_page(page); | |
2312 | break; | |
2313 | } | |
2314 | } | |
2315 | nr -= offset; | |
2316 | ||
2317 | if (page) { | |
2318 | /* | |
2319 | * If users can be writing to this page using arbitrary | |
2320 | * virtual addresses, take care about potential aliasing | |
2321 | * before reading the page on the kernel side. | |
2322 | */ | |
2323 | if (mapping_writably_mapped(mapping)) | |
2324 | flush_dcache_page(page); | |
2325 | /* | |
2326 | * Mark the page accessed if we read the beginning. | |
2327 | */ | |
2328 | if (!offset) | |
2329 | mark_page_accessed(page); | |
2330 | } else { | |
2331 | page = ZERO_PAGE(0); | |
2332 | get_page(page); | |
2333 | } | |
2334 | ||
2335 | /* | |
2336 | * Ok, we have the page, and it's up-to-date, so | |
2337 | * now we can copy it to user space... | |
2338 | */ | |
2339 | ret = copy_page_to_iter(page, offset, nr, to); | |
2340 | retval += ret; | |
2341 | offset += ret; | |
2342 | index += offset >> PAGE_SHIFT; | |
2343 | offset &= ~PAGE_MASK; | |
2344 | ||
2345 | put_page(page); | |
2346 | if (!iov_iter_count(to)) | |
2347 | break; | |
2348 | if (ret < nr) { | |
2349 | error = -EFAULT; | |
2350 | break; | |
2351 | } | |
2352 | cond_resched(); | |
2353 | } | |
2354 | ||
2355 | *ppos = ((loff_t) index << PAGE_SHIFT) + offset; | |
2356 | file_accessed(file); | |
2357 | return retval ? retval : error; | |
2358 | } | |
2359 | ||
2360 | /* | |
2361 | * llseek SEEK_DATA or SEEK_HOLE through the radix_tree. | |
2362 | */ | |
2363 | static pgoff_t shmem_seek_hole_data(struct address_space *mapping, | |
2364 | pgoff_t index, pgoff_t end, int whence) | |
2365 | { | |
2366 | struct page *page; | |
2367 | struct pagevec pvec; | |
2368 | pgoff_t indices[PAGEVEC_SIZE]; | |
2369 | bool done = false; | |
2370 | int i; | |
2371 | ||
2372 | pagevec_init(&pvec, 0); | |
2373 | pvec.nr = 1; /* start small: we may be there already */ | |
2374 | while (!done) { | |
2375 | pvec.nr = find_get_entries(mapping, index, | |
2376 | pvec.nr, pvec.pages, indices); | |
2377 | if (!pvec.nr) { | |
2378 | if (whence == SEEK_DATA) | |
2379 | index = end; | |
2380 | break; | |
2381 | } | |
2382 | for (i = 0; i < pvec.nr; i++, index++) { | |
2383 | if (index < indices[i]) { | |
2384 | if (whence == SEEK_HOLE) { | |
2385 | done = true; | |
2386 | break; | |
2387 | } | |
2388 | index = indices[i]; | |
2389 | } | |
2390 | page = pvec.pages[i]; | |
2391 | if (page && !radix_tree_exceptional_entry(page)) { | |
2392 | if (!PageUptodate(page)) | |
2393 | page = NULL; | |
2394 | } | |
2395 | if (index >= end || | |
2396 | (page && whence == SEEK_DATA) || | |
2397 | (!page && whence == SEEK_HOLE)) { | |
2398 | done = true; | |
2399 | break; | |
2400 | } | |
2401 | } | |
2402 | pagevec_remove_exceptionals(&pvec); | |
2403 | pagevec_release(&pvec); | |
2404 | pvec.nr = PAGEVEC_SIZE; | |
2405 | cond_resched(); | |
2406 | } | |
2407 | return index; | |
2408 | } | |
2409 | ||
2410 | static loff_t shmem_file_llseek(struct file *file, loff_t offset, int whence) | |
2411 | { | |
2412 | struct address_space *mapping = file->f_mapping; | |
2413 | struct inode *inode = mapping->host; | |
2414 | pgoff_t start, end; | |
2415 | loff_t new_offset; | |
2416 | ||
2417 | if (whence != SEEK_DATA && whence != SEEK_HOLE) | |
2418 | return generic_file_llseek_size(file, offset, whence, | |
2419 | MAX_LFS_FILESIZE, i_size_read(inode)); | |
2420 | inode_lock(inode); | |
2421 | /* We're holding i_mutex so we can access i_size directly */ | |
2422 | ||
2423 | if (offset < 0) | |
2424 | offset = -EINVAL; | |
2425 | else if (offset >= inode->i_size) | |
2426 | offset = -ENXIO; | |
2427 | else { | |
2428 | start = offset >> PAGE_SHIFT; | |
2429 | end = (inode->i_size + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2430 | new_offset = shmem_seek_hole_data(mapping, start, end, whence); | |
2431 | new_offset <<= PAGE_SHIFT; | |
2432 | if (new_offset > offset) { | |
2433 | if (new_offset < inode->i_size) | |
2434 | offset = new_offset; | |
2435 | else if (whence == SEEK_DATA) | |
2436 | offset = -ENXIO; | |
2437 | else | |
2438 | offset = inode->i_size; | |
2439 | } | |
2440 | } | |
2441 | ||
2442 | if (offset >= 0) | |
2443 | offset = vfs_setpos(file, offset, MAX_LFS_FILESIZE); | |
2444 | inode_unlock(inode); | |
2445 | return offset; | |
2446 | } | |
2447 | ||
2448 | /* | |
2449 | * We need a tag: a new tag would expand every radix_tree_node by 8 bytes, | |
2450 | * so reuse a tag which we firmly believe is never set or cleared on shmem. | |
2451 | */ | |
2452 | #define SHMEM_TAG_PINNED PAGECACHE_TAG_TOWRITE | |
2453 | #define LAST_SCAN 4 /* about 150ms max */ | |
2454 | ||
2455 | static void shmem_tag_pins(struct address_space *mapping) | |
2456 | { | |
2457 | struct radix_tree_iter iter; | |
2458 | void **slot; | |
2459 | pgoff_t start; | |
2460 | struct page *page; | |
2461 | ||
2462 | lru_add_drain(); | |
2463 | start = 0; | |
2464 | rcu_read_lock(); | |
2465 | ||
2466 | radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { | |
2467 | page = radix_tree_deref_slot(slot); | |
2468 | if (!page || radix_tree_exception(page)) { | |
2469 | if (radix_tree_deref_retry(page)) { | |
2470 | slot = radix_tree_iter_retry(&iter); | |
2471 | continue; | |
2472 | } | |
2473 | } else if (page_count(page) - page_mapcount(page) > 1) { | |
2474 | spin_lock_irq(&mapping->tree_lock); | |
2475 | radix_tree_tag_set(&mapping->page_tree, iter.index, | |
2476 | SHMEM_TAG_PINNED); | |
2477 | spin_unlock_irq(&mapping->tree_lock); | |
2478 | } | |
2479 | ||
2480 | if (need_resched()) { | |
2481 | slot = radix_tree_iter_resume(slot, &iter); | |
2482 | cond_resched_rcu(); | |
2483 | } | |
2484 | } | |
2485 | rcu_read_unlock(); | |
2486 | } | |
2487 | ||
2488 | /* | |
2489 | * Setting SEAL_WRITE requires us to verify there's no pending writer. However, | |
2490 | * via get_user_pages(), drivers might have some pending I/O without any active | |
2491 | * user-space mappings (eg., direct-IO, AIO). Therefore, we look at all pages | |
2492 | * and see whether it has an elevated ref-count. If so, we tag them and wait for | |
2493 | * them to be dropped. | |
2494 | * The caller must guarantee that no new user will acquire writable references | |
2495 | * to those pages to avoid races. | |
2496 | */ | |
2497 | static int shmem_wait_for_pins(struct address_space *mapping) | |
2498 | { | |
2499 | struct radix_tree_iter iter; | |
2500 | void **slot; | |
2501 | pgoff_t start; | |
2502 | struct page *page; | |
2503 | int error, scan; | |
2504 | ||
2505 | shmem_tag_pins(mapping); | |
2506 | ||
2507 | error = 0; | |
2508 | for (scan = 0; scan <= LAST_SCAN; scan++) { | |
2509 | if (!radix_tree_tagged(&mapping->page_tree, SHMEM_TAG_PINNED)) | |
2510 | break; | |
2511 | ||
2512 | if (!scan) | |
2513 | lru_add_drain_all(); | |
2514 | else if (schedule_timeout_killable((HZ << scan) / 200)) | |
2515 | scan = LAST_SCAN; | |
2516 | ||
2517 | start = 0; | |
2518 | rcu_read_lock(); | |
2519 | radix_tree_for_each_tagged(slot, &mapping->page_tree, &iter, | |
2520 | start, SHMEM_TAG_PINNED) { | |
2521 | ||
2522 | page = radix_tree_deref_slot(slot); | |
2523 | if (radix_tree_exception(page)) { | |
2524 | if (radix_tree_deref_retry(page)) { | |
2525 | slot = radix_tree_iter_retry(&iter); | |
2526 | continue; | |
2527 | } | |
2528 | ||
2529 | page = NULL; | |
2530 | } | |
2531 | ||
2532 | if (page && | |
2533 | page_count(page) - page_mapcount(page) != 1) { | |
2534 | if (scan < LAST_SCAN) | |
2535 | goto continue_resched; | |
2536 | ||
2537 | /* | |
2538 | * On the last scan, we clean up all those tags | |
2539 | * we inserted; but make a note that we still | |
2540 | * found pages pinned. | |
2541 | */ | |
2542 | error = -EBUSY; | |
2543 | } | |
2544 | ||
2545 | spin_lock_irq(&mapping->tree_lock); | |
2546 | radix_tree_tag_clear(&mapping->page_tree, | |
2547 | iter.index, SHMEM_TAG_PINNED); | |
2548 | spin_unlock_irq(&mapping->tree_lock); | |
2549 | continue_resched: | |
2550 | if (need_resched()) { | |
2551 | slot = radix_tree_iter_resume(slot, &iter); | |
2552 | cond_resched_rcu(); | |
2553 | } | |
2554 | } | |
2555 | rcu_read_unlock(); | |
2556 | } | |
2557 | ||
2558 | return error; | |
2559 | } | |
2560 | ||
2561 | #define F_ALL_SEALS (F_SEAL_SEAL | \ | |
2562 | F_SEAL_SHRINK | \ | |
2563 | F_SEAL_GROW | \ | |
2564 | F_SEAL_WRITE) | |
2565 | ||
2566 | int shmem_add_seals(struct file *file, unsigned int seals) | |
2567 | { | |
2568 | struct inode *inode = file_inode(file); | |
2569 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2570 | int error; | |
2571 | ||
2572 | /* | |
2573 | * SEALING | |
2574 | * Sealing allows multiple parties to share a shmem-file but restrict | |
2575 | * access to a specific subset of file operations. Seals can only be | |
2576 | * added, but never removed. This way, mutually untrusted parties can | |
2577 | * share common memory regions with a well-defined policy. A malicious | |
2578 | * peer can thus never perform unwanted operations on a shared object. | |
2579 | * | |
2580 | * Seals are only supported on special shmem-files and always affect | |
2581 | * the whole underlying inode. Once a seal is set, it may prevent some | |
2582 | * kinds of access to the file. Currently, the following seals are | |
2583 | * defined: | |
2584 | * SEAL_SEAL: Prevent further seals from being set on this file | |
2585 | * SEAL_SHRINK: Prevent the file from shrinking | |
2586 | * SEAL_GROW: Prevent the file from growing | |
2587 | * SEAL_WRITE: Prevent write access to the file | |
2588 | * | |
2589 | * As we don't require any trust relationship between two parties, we | |
2590 | * must prevent seals from being removed. Therefore, sealing a file | |
2591 | * only adds a given set of seals to the file, it never touches | |
2592 | * existing seals. Furthermore, the "setting seals"-operation can be | |
2593 | * sealed itself, which basically prevents any further seal from being | |
2594 | * added. | |
2595 | * | |
2596 | * Semantics of sealing are only defined on volatile files. Only | |
2597 | * anonymous shmem files support sealing. More importantly, seals are | |
2598 | * never written to disk. Therefore, there's no plan to support it on | |
2599 | * other file types. | |
2600 | */ | |
2601 | ||
2602 | if (file->f_op != &shmem_file_operations) | |
2603 | return -EINVAL; | |
2604 | if (!(file->f_mode & FMODE_WRITE)) | |
2605 | return -EPERM; | |
2606 | if (seals & ~(unsigned int)F_ALL_SEALS) | |
2607 | return -EINVAL; | |
2608 | ||
2609 | inode_lock(inode); | |
2610 | ||
2611 | if (info->seals & F_SEAL_SEAL) { | |
2612 | error = -EPERM; | |
2613 | goto unlock; | |
2614 | } | |
2615 | ||
2616 | if ((seals & F_SEAL_WRITE) && !(info->seals & F_SEAL_WRITE)) { | |
2617 | error = mapping_deny_writable(file->f_mapping); | |
2618 | if (error) | |
2619 | goto unlock; | |
2620 | ||
2621 | error = shmem_wait_for_pins(file->f_mapping); | |
2622 | if (error) { | |
2623 | mapping_allow_writable(file->f_mapping); | |
2624 | goto unlock; | |
2625 | } | |
2626 | } | |
2627 | ||
2628 | info->seals |= seals; | |
2629 | error = 0; | |
2630 | ||
2631 | unlock: | |
2632 | inode_unlock(inode); | |
2633 | return error; | |
2634 | } | |
2635 | EXPORT_SYMBOL_GPL(shmem_add_seals); | |
2636 | ||
2637 | int shmem_get_seals(struct file *file) | |
2638 | { | |
2639 | if (file->f_op != &shmem_file_operations) | |
2640 | return -EINVAL; | |
2641 | ||
2642 | return SHMEM_I(file_inode(file))->seals; | |
2643 | } | |
2644 | EXPORT_SYMBOL_GPL(shmem_get_seals); | |
2645 | ||
2646 | long shmem_fcntl(struct file *file, unsigned int cmd, unsigned long arg) | |
2647 | { | |
2648 | long error; | |
2649 | ||
2650 | switch (cmd) { | |
2651 | case F_ADD_SEALS: | |
2652 | /* disallow upper 32bit */ | |
2653 | if (arg > UINT_MAX) | |
2654 | return -EINVAL; | |
2655 | ||
2656 | error = shmem_add_seals(file, arg); | |
2657 | break; | |
2658 | case F_GET_SEALS: | |
2659 | error = shmem_get_seals(file); | |
2660 | break; | |
2661 | default: | |
2662 | error = -EINVAL; | |
2663 | break; | |
2664 | } | |
2665 | ||
2666 | return error; | |
2667 | } | |
2668 | ||
2669 | static long shmem_fallocate(struct file *file, int mode, loff_t offset, | |
2670 | loff_t len) | |
2671 | { | |
2672 | struct inode *inode = file_inode(file); | |
2673 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
2674 | struct shmem_inode_info *info = SHMEM_I(inode); | |
2675 | struct shmem_falloc shmem_falloc; | |
2676 | pgoff_t start, index, end; | |
2677 | int error; | |
2678 | ||
2679 | if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE)) | |
2680 | return -EOPNOTSUPP; | |
2681 | ||
2682 | inode_lock(inode); | |
2683 | ||
2684 | if (mode & FALLOC_FL_PUNCH_HOLE) { | |
2685 | struct address_space *mapping = file->f_mapping; | |
2686 | loff_t unmap_start = round_up(offset, PAGE_SIZE); | |
2687 | loff_t unmap_end = round_down(offset + len, PAGE_SIZE) - 1; | |
2688 | DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq); | |
2689 | ||
2690 | /* protected by i_mutex */ | |
2691 | if (info->seals & F_SEAL_WRITE) { | |
2692 | error = -EPERM; | |
2693 | goto out; | |
2694 | } | |
2695 | ||
2696 | shmem_falloc.waitq = &shmem_falloc_waitq; | |
2697 | shmem_falloc.start = unmap_start >> PAGE_SHIFT; | |
2698 | shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT; | |
2699 | spin_lock(&inode->i_lock); | |
2700 | inode->i_private = &shmem_falloc; | |
2701 | spin_unlock(&inode->i_lock); | |
2702 | ||
2703 | if ((u64)unmap_end > (u64)unmap_start) | |
2704 | unmap_mapping_range(mapping, unmap_start, | |
2705 | 1 + unmap_end - unmap_start, 0); | |
2706 | shmem_truncate_range(inode, offset, offset + len - 1); | |
2707 | /* No need to unmap again: hole-punching leaves COWed pages */ | |
2708 | ||
2709 | spin_lock(&inode->i_lock); | |
2710 | inode->i_private = NULL; | |
2711 | wake_up_all(&shmem_falloc_waitq); | |
2712 | WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq.task_list)); | |
2713 | spin_unlock(&inode->i_lock); | |
2714 | error = 0; | |
2715 | goto out; | |
2716 | } | |
2717 | ||
2718 | /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ | |
2719 | error = inode_newsize_ok(inode, offset + len); | |
2720 | if (error) | |
2721 | goto out; | |
2722 | ||
2723 | if ((info->seals & F_SEAL_GROW) && offset + len > inode->i_size) { | |
2724 | error = -EPERM; | |
2725 | goto out; | |
2726 | } | |
2727 | ||
2728 | start = offset >> PAGE_SHIFT; | |
2729 | end = (offset + len + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2730 | /* Try to avoid a swapstorm if len is impossible to satisfy */ | |
2731 | if (sbinfo->max_blocks && end - start > sbinfo->max_blocks) { | |
2732 | error = -ENOSPC; | |
2733 | goto out; | |
2734 | } | |
2735 | ||
2736 | shmem_falloc.waitq = NULL; | |
2737 | shmem_falloc.start = start; | |
2738 | shmem_falloc.next = start; | |
2739 | shmem_falloc.nr_falloced = 0; | |
2740 | shmem_falloc.nr_unswapped = 0; | |
2741 | spin_lock(&inode->i_lock); | |
2742 | inode->i_private = &shmem_falloc; | |
2743 | spin_unlock(&inode->i_lock); | |
2744 | ||
2745 | for (index = start; index < end; index++) { | |
2746 | struct page *page; | |
2747 | ||
2748 | /* | |
2749 | * Good, the fallocate(2) manpage permits EINTR: we may have | |
2750 | * been interrupted because we are using up too much memory. | |
2751 | */ | |
2752 | if (signal_pending(current)) | |
2753 | error = -EINTR; | |
2754 | else if (shmem_falloc.nr_unswapped > shmem_falloc.nr_falloced) | |
2755 | error = -ENOMEM; | |
2756 | else | |
2757 | error = shmem_getpage(inode, index, &page, SGP_FALLOC); | |
2758 | if (error) { | |
2759 | /* Remove the !PageUptodate pages we added */ | |
2760 | if (index > start) { | |
2761 | shmem_undo_range(inode, | |
2762 | (loff_t)start << PAGE_SHIFT, | |
2763 | ((loff_t)index << PAGE_SHIFT) - 1, true); | |
2764 | } | |
2765 | goto undone; | |
2766 | } | |
2767 | ||
2768 | /* | |
2769 | * Inform shmem_writepage() how far we have reached. | |
2770 | * No need for lock or barrier: we have the page lock. | |
2771 | */ | |
2772 | shmem_falloc.next++; | |
2773 | if (!PageUptodate(page)) | |
2774 | shmem_falloc.nr_falloced++; | |
2775 | ||
2776 | /* | |
2777 | * If !PageUptodate, leave it that way so that freeable pages | |
2778 | * can be recognized if we need to rollback on error later. | |
2779 | * But set_page_dirty so that memory pressure will swap rather | |
2780 | * than free the pages we are allocating (and SGP_CACHE pages | |
2781 | * might still be clean: we now need to mark those dirty too). | |
2782 | */ | |
2783 | set_page_dirty(page); | |
2784 | unlock_page(page); | |
2785 | put_page(page); | |
2786 | cond_resched(); | |
2787 | } | |
2788 | ||
2789 | if (!(mode & FALLOC_FL_KEEP_SIZE) && offset + len > inode->i_size) | |
2790 | i_size_write(inode, offset + len); | |
2791 | inode->i_ctime = current_time(inode); | |
2792 | undone: | |
2793 | spin_lock(&inode->i_lock); | |
2794 | inode->i_private = NULL; | |
2795 | spin_unlock(&inode->i_lock); | |
2796 | out: | |
2797 | inode_unlock(inode); | |
2798 | return error; | |
2799 | } | |
2800 | ||
2801 | static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf) | |
2802 | { | |
2803 | struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb); | |
2804 | ||
2805 | buf->f_type = TMPFS_MAGIC; | |
2806 | buf->f_bsize = PAGE_SIZE; | |
2807 | buf->f_namelen = NAME_MAX; | |
2808 | if (sbinfo->max_blocks) { | |
2809 | buf->f_blocks = sbinfo->max_blocks; | |
2810 | buf->f_bavail = | |
2811 | buf->f_bfree = sbinfo->max_blocks - | |
2812 | percpu_counter_sum(&sbinfo->used_blocks); | |
2813 | } | |
2814 | if (sbinfo->max_inodes) { | |
2815 | buf->f_files = sbinfo->max_inodes; | |
2816 | buf->f_ffree = sbinfo->free_inodes; | |
2817 | } | |
2818 | /* else leave those fields 0 like simple_statfs */ | |
2819 | return 0; | |
2820 | } | |
2821 | ||
2822 | /* | |
2823 | * File creation. Allocate an inode, and we're done.. | |
2824 | */ | |
2825 | static int | |
2826 | shmem_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) | |
2827 | { | |
2828 | struct inode *inode; | |
2829 | int error = -ENOSPC; | |
2830 | ||
2831 | inode = shmem_get_inode(dir->i_sb, dir, mode, dev, VM_NORESERVE); | |
2832 | if (inode) { | |
2833 | error = simple_acl_create(dir, inode); | |
2834 | if (error) | |
2835 | goto out_iput; | |
2836 | error = security_inode_init_security(inode, dir, | |
2837 | &dentry->d_name, | |
2838 | shmem_initxattrs, NULL); | |
2839 | if (error && error != -EOPNOTSUPP) | |
2840 | goto out_iput; | |
2841 | ||
2842 | error = 0; | |
2843 | dir->i_size += BOGO_DIRENT_SIZE; | |
2844 | dir->i_ctime = dir->i_mtime = current_time(dir); | |
2845 | d_instantiate(dentry, inode); | |
2846 | dget(dentry); /* Extra count - pin the dentry in core */ | |
2847 | } | |
2848 | return error; | |
2849 | out_iput: | |
2850 | iput(inode); | |
2851 | return error; | |
2852 | } | |
2853 | ||
2854 | static int | |
2855 | shmem_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) | |
2856 | { | |
2857 | struct inode *inode; | |
2858 | int error = -ENOSPC; | |
2859 | ||
2860 | inode = shmem_get_inode(dir->i_sb, dir, mode, 0, VM_NORESERVE); | |
2861 | if (inode) { | |
2862 | error = security_inode_init_security(inode, dir, | |
2863 | NULL, | |
2864 | shmem_initxattrs, NULL); | |
2865 | if (error && error != -EOPNOTSUPP) | |
2866 | goto out_iput; | |
2867 | error = simple_acl_create(dir, inode); | |
2868 | if (error) | |
2869 | goto out_iput; | |
2870 | d_tmpfile(dentry, inode); | |
2871 | } | |
2872 | return error; | |
2873 | out_iput: | |
2874 | iput(inode); | |
2875 | return error; | |
2876 | } | |
2877 | ||
2878 | static int shmem_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
2879 | { | |
2880 | int error; | |
2881 | ||
2882 | if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0))) | |
2883 | return error; | |
2884 | inc_nlink(dir); | |
2885 | return 0; | |
2886 | } | |
2887 | ||
2888 | static int shmem_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
2889 | bool excl) | |
2890 | { | |
2891 | return shmem_mknod(dir, dentry, mode | S_IFREG, 0); | |
2892 | } | |
2893 | ||
2894 | /* | |
2895 | * Link a file.. | |
2896 | */ | |
2897 | static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry) | |
2898 | { | |
2899 | struct inode *inode = d_inode(old_dentry); | |
2900 | int ret; | |
2901 | ||
2902 | /* | |
2903 | * No ordinary (disk based) filesystem counts links as inodes; | |
2904 | * but each new link needs a new dentry, pinning lowmem, and | |
2905 | * tmpfs dentries cannot be pruned until they are unlinked. | |
2906 | */ | |
2907 | ret = shmem_reserve_inode(inode->i_sb); | |
2908 | if (ret) | |
2909 | goto out; | |
2910 | ||
2911 | dir->i_size += BOGO_DIRENT_SIZE; | |
2912 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); | |
2913 | inc_nlink(inode); | |
2914 | ihold(inode); /* New dentry reference */ | |
2915 | dget(dentry); /* Extra pinning count for the created dentry */ | |
2916 | d_instantiate(dentry, inode); | |
2917 | out: | |
2918 | return ret; | |
2919 | } | |
2920 | ||
2921 | static int shmem_unlink(struct inode *dir, struct dentry *dentry) | |
2922 | { | |
2923 | struct inode *inode = d_inode(dentry); | |
2924 | ||
2925 | if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode)) | |
2926 | shmem_free_inode(inode->i_sb); | |
2927 | ||
2928 | dir->i_size -= BOGO_DIRENT_SIZE; | |
2929 | inode->i_ctime = dir->i_ctime = dir->i_mtime = current_time(inode); | |
2930 | drop_nlink(inode); | |
2931 | dput(dentry); /* Undo the count from "create" - this does all the work */ | |
2932 | return 0; | |
2933 | } | |
2934 | ||
2935 | static int shmem_rmdir(struct inode *dir, struct dentry *dentry) | |
2936 | { | |
2937 | if (!simple_empty(dentry)) | |
2938 | return -ENOTEMPTY; | |
2939 | ||
2940 | drop_nlink(d_inode(dentry)); | |
2941 | drop_nlink(dir); | |
2942 | return shmem_unlink(dir, dentry); | |
2943 | } | |
2944 | ||
2945 | static int shmem_exchange(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry) | |
2946 | { | |
2947 | bool old_is_dir = d_is_dir(old_dentry); | |
2948 | bool new_is_dir = d_is_dir(new_dentry); | |
2949 | ||
2950 | if (old_dir != new_dir && old_is_dir != new_is_dir) { | |
2951 | if (old_is_dir) { | |
2952 | drop_nlink(old_dir); | |
2953 | inc_nlink(new_dir); | |
2954 | } else { | |
2955 | drop_nlink(new_dir); | |
2956 | inc_nlink(old_dir); | |
2957 | } | |
2958 | } | |
2959 | old_dir->i_ctime = old_dir->i_mtime = | |
2960 | new_dir->i_ctime = new_dir->i_mtime = | |
2961 | d_inode(old_dentry)->i_ctime = | |
2962 | d_inode(new_dentry)->i_ctime = current_time(old_dir); | |
2963 | ||
2964 | return 0; | |
2965 | } | |
2966 | ||
2967 | static int shmem_whiteout(struct inode *old_dir, struct dentry *old_dentry) | |
2968 | { | |
2969 | struct dentry *whiteout; | |
2970 | int error; | |
2971 | ||
2972 | whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name); | |
2973 | if (!whiteout) | |
2974 | return -ENOMEM; | |
2975 | ||
2976 | error = shmem_mknod(old_dir, whiteout, | |
2977 | S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV); | |
2978 | dput(whiteout); | |
2979 | if (error) | |
2980 | return error; | |
2981 | ||
2982 | /* | |
2983 | * Cheat and hash the whiteout while the old dentry is still in | |
2984 | * place, instead of playing games with FS_RENAME_DOES_D_MOVE. | |
2985 | * | |
2986 | * d_lookup() will consistently find one of them at this point, | |
2987 | * not sure which one, but that isn't even important. | |
2988 | */ | |
2989 | d_rehash(whiteout); | |
2990 | return 0; | |
2991 | } | |
2992 | ||
2993 | /* | |
2994 | * The VFS layer already does all the dentry stuff for rename, | |
2995 | * we just have to decrement the usage count for the target if | |
2996 | * it exists so that the VFS layer correctly free's it when it | |
2997 | * gets overwritten. | |
2998 | */ | |
2999 | static int shmem_rename2(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry, unsigned int flags) | |
3000 | { | |
3001 | struct inode *inode = d_inode(old_dentry); | |
3002 | int they_are_dirs = S_ISDIR(inode->i_mode); | |
3003 | ||
3004 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT)) | |
3005 | return -EINVAL; | |
3006 | ||
3007 | if (flags & RENAME_EXCHANGE) | |
3008 | return shmem_exchange(old_dir, old_dentry, new_dir, new_dentry); | |
3009 | ||
3010 | if (!simple_empty(new_dentry)) | |
3011 | return -ENOTEMPTY; | |
3012 | ||
3013 | if (flags & RENAME_WHITEOUT) { | |
3014 | int error; | |
3015 | ||
3016 | error = shmem_whiteout(old_dir, old_dentry); | |
3017 | if (error) | |
3018 | return error; | |
3019 | } | |
3020 | ||
3021 | if (d_really_is_positive(new_dentry)) { | |
3022 | (void) shmem_unlink(new_dir, new_dentry); | |
3023 | if (they_are_dirs) { | |
3024 | drop_nlink(d_inode(new_dentry)); | |
3025 | drop_nlink(old_dir); | |
3026 | } | |
3027 | } else if (they_are_dirs) { | |
3028 | drop_nlink(old_dir); | |
3029 | inc_nlink(new_dir); | |
3030 | } | |
3031 | ||
3032 | old_dir->i_size -= BOGO_DIRENT_SIZE; | |
3033 | new_dir->i_size += BOGO_DIRENT_SIZE; | |
3034 | old_dir->i_ctime = old_dir->i_mtime = | |
3035 | new_dir->i_ctime = new_dir->i_mtime = | |
3036 | inode->i_ctime = current_time(old_dir); | |
3037 | return 0; | |
3038 | } | |
3039 | ||
3040 | static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname) | |
3041 | { | |
3042 | int error; | |
3043 | int len; | |
3044 | struct inode *inode; | |
3045 | struct page *page; | |
3046 | struct shmem_inode_info *info; | |
3047 | ||
3048 | len = strlen(symname) + 1; | |
3049 | if (len > PAGE_SIZE) | |
3050 | return -ENAMETOOLONG; | |
3051 | ||
3052 | inode = shmem_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0, VM_NORESERVE); | |
3053 | if (!inode) | |
3054 | return -ENOSPC; | |
3055 | ||
3056 | error = security_inode_init_security(inode, dir, &dentry->d_name, | |
3057 | shmem_initxattrs, NULL); | |
3058 | if (error) { | |
3059 | if (error != -EOPNOTSUPP) { | |
3060 | iput(inode); | |
3061 | return error; | |
3062 | } | |
3063 | error = 0; | |
3064 | } | |
3065 | ||
3066 | info = SHMEM_I(inode); | |
3067 | inode->i_size = len-1; | |
3068 | if (len <= SHORT_SYMLINK_LEN) { | |
3069 | inode->i_link = kmemdup(symname, len, GFP_KERNEL); | |
3070 | if (!inode->i_link) { | |
3071 | iput(inode); | |
3072 | return -ENOMEM; | |
3073 | } | |
3074 | inode->i_op = &shmem_short_symlink_operations; | |
3075 | } else { | |
3076 | inode_nohighmem(inode); | |
3077 | error = shmem_getpage(inode, 0, &page, SGP_WRITE); | |
3078 | if (error) { | |
3079 | iput(inode); | |
3080 | return error; | |
3081 | } | |
3082 | inode->i_mapping->a_ops = &shmem_aops; | |
3083 | inode->i_op = &shmem_symlink_inode_operations; | |
3084 | memcpy(page_address(page), symname, len); | |
3085 | SetPageUptodate(page); | |
3086 | set_page_dirty(page); | |
3087 | unlock_page(page); | |
3088 | put_page(page); | |
3089 | } | |
3090 | dir->i_size += BOGO_DIRENT_SIZE; | |
3091 | dir->i_ctime = dir->i_mtime = current_time(dir); | |
3092 | d_instantiate(dentry, inode); | |
3093 | dget(dentry); | |
3094 | return 0; | |
3095 | } | |
3096 | ||
3097 | static void shmem_put_link(void *arg) | |
3098 | { | |
3099 | mark_page_accessed(arg); | |
3100 | put_page(arg); | |
3101 | } | |
3102 | ||
3103 | static const char *shmem_get_link(struct dentry *dentry, | |
3104 | struct inode *inode, | |
3105 | struct delayed_call *done) | |
3106 | { | |
3107 | struct page *page = NULL; | |
3108 | int error; | |
3109 | if (!dentry) { | |
3110 | page = find_get_page(inode->i_mapping, 0); | |
3111 | if (!page) | |
3112 | return ERR_PTR(-ECHILD); | |
3113 | if (!PageUptodate(page)) { | |
3114 | put_page(page); | |
3115 | return ERR_PTR(-ECHILD); | |
3116 | } | |
3117 | } else { | |
3118 | error = shmem_getpage(inode, 0, &page, SGP_READ); | |
3119 | if (error) | |
3120 | return ERR_PTR(error); | |
3121 | unlock_page(page); | |
3122 | } | |
3123 | set_delayed_call(done, shmem_put_link, page); | |
3124 | return page_address(page); | |
3125 | } | |
3126 | ||
3127 | #ifdef CONFIG_TMPFS_XATTR | |
3128 | /* | |
3129 | * Superblocks without xattr inode operations may get some security.* xattr | |
3130 | * support from the LSM "for free". As soon as we have any other xattrs | |
3131 | * like ACLs, we also need to implement the security.* handlers at | |
3132 | * filesystem level, though. | |
3133 | */ | |
3134 | ||
3135 | /* | |
3136 | * Callback for security_inode_init_security() for acquiring xattrs. | |
3137 | */ | |
3138 | static int shmem_initxattrs(struct inode *inode, | |
3139 | const struct xattr *xattr_array, | |
3140 | void *fs_info) | |
3141 | { | |
3142 | struct shmem_inode_info *info = SHMEM_I(inode); | |
3143 | const struct xattr *xattr; | |
3144 | struct simple_xattr *new_xattr; | |
3145 | size_t len; | |
3146 | ||
3147 | for (xattr = xattr_array; xattr->name != NULL; xattr++) { | |
3148 | new_xattr = simple_xattr_alloc(xattr->value, xattr->value_len); | |
3149 | if (!new_xattr) | |
3150 | return -ENOMEM; | |
3151 | ||
3152 | len = strlen(xattr->name) + 1; | |
3153 | new_xattr->name = kmalloc(XATTR_SECURITY_PREFIX_LEN + len, | |
3154 | GFP_KERNEL); | |
3155 | if (!new_xattr->name) { | |
3156 | kfree(new_xattr); | |
3157 | return -ENOMEM; | |
3158 | } | |
3159 | ||
3160 | memcpy(new_xattr->name, XATTR_SECURITY_PREFIX, | |
3161 | XATTR_SECURITY_PREFIX_LEN); | |
3162 | memcpy(new_xattr->name + XATTR_SECURITY_PREFIX_LEN, | |
3163 | xattr->name, len); | |
3164 | ||
3165 | simple_xattr_list_add(&info->xattrs, new_xattr); | |
3166 | } | |
3167 | ||
3168 | return 0; | |
3169 | } | |
3170 | ||
3171 | static int shmem_xattr_handler_get(const struct xattr_handler *handler, | |
3172 | struct dentry *unused, struct inode *inode, | |
3173 | const char *name, void *buffer, size_t size) | |
3174 | { | |
3175 | struct shmem_inode_info *info = SHMEM_I(inode); | |
3176 | ||
3177 | name = xattr_full_name(handler, name); | |
3178 | return simple_xattr_get(&info->xattrs, name, buffer, size); | |
3179 | } | |
3180 | ||
3181 | static int shmem_xattr_handler_set(const struct xattr_handler *handler, | |
3182 | struct dentry *unused, struct inode *inode, | |
3183 | const char *name, const void *value, | |
3184 | size_t size, int flags) | |
3185 | { | |
3186 | struct shmem_inode_info *info = SHMEM_I(inode); | |
3187 | ||
3188 | name = xattr_full_name(handler, name); | |
3189 | return simple_xattr_set(&info->xattrs, name, value, size, flags); | |
3190 | } | |
3191 | ||
3192 | static const struct xattr_handler shmem_security_xattr_handler = { | |
3193 | .prefix = XATTR_SECURITY_PREFIX, | |
3194 | .get = shmem_xattr_handler_get, | |
3195 | .set = shmem_xattr_handler_set, | |
3196 | }; | |
3197 | ||
3198 | static const struct xattr_handler shmem_trusted_xattr_handler = { | |
3199 | .prefix = XATTR_TRUSTED_PREFIX, | |
3200 | .get = shmem_xattr_handler_get, | |
3201 | .set = shmem_xattr_handler_set, | |
3202 | }; | |
3203 | ||
3204 | static const struct xattr_handler *shmem_xattr_handlers[] = { | |
3205 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
3206 | &posix_acl_access_xattr_handler, | |
3207 | &posix_acl_default_xattr_handler, | |
3208 | #endif | |
3209 | &shmem_security_xattr_handler, | |
3210 | &shmem_trusted_xattr_handler, | |
3211 | NULL | |
3212 | }; | |
3213 | ||
3214 | static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size) | |
3215 | { | |
3216 | struct shmem_inode_info *info = SHMEM_I(d_inode(dentry)); | |
3217 | return simple_xattr_list(d_inode(dentry), &info->xattrs, buffer, size); | |
3218 | } | |
3219 | #endif /* CONFIG_TMPFS_XATTR */ | |
3220 | ||
3221 | static const struct inode_operations shmem_short_symlink_operations = { | |
3222 | .get_link = simple_get_link, | |
3223 | #ifdef CONFIG_TMPFS_XATTR | |
3224 | .listxattr = shmem_listxattr, | |
3225 | #endif | |
3226 | }; | |
3227 | ||
3228 | static const struct inode_operations shmem_symlink_inode_operations = { | |
3229 | .get_link = shmem_get_link, | |
3230 | #ifdef CONFIG_TMPFS_XATTR | |
3231 | .listxattr = shmem_listxattr, | |
3232 | #endif | |
3233 | }; | |
3234 | ||
3235 | static struct dentry *shmem_get_parent(struct dentry *child) | |
3236 | { | |
3237 | return ERR_PTR(-ESTALE); | |
3238 | } | |
3239 | ||
3240 | static int shmem_match(struct inode *ino, void *vfh) | |
3241 | { | |
3242 | __u32 *fh = vfh; | |
3243 | __u64 inum = fh[2]; | |
3244 | inum = (inum << 32) | fh[1]; | |
3245 | return ino->i_ino == inum && fh[0] == ino->i_generation; | |
3246 | } | |
3247 | ||
3248 | static struct dentry *shmem_fh_to_dentry(struct super_block *sb, | |
3249 | struct fid *fid, int fh_len, int fh_type) | |
3250 | { | |
3251 | struct inode *inode; | |
3252 | struct dentry *dentry = NULL; | |
3253 | u64 inum; | |
3254 | ||
3255 | if (fh_len < 3) | |
3256 | return NULL; | |
3257 | ||
3258 | inum = fid->raw[2]; | |
3259 | inum = (inum << 32) | fid->raw[1]; | |
3260 | ||
3261 | inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]), | |
3262 | shmem_match, fid->raw); | |
3263 | if (inode) { | |
3264 | dentry = d_find_alias(inode); | |
3265 | iput(inode); | |
3266 | } | |
3267 | ||
3268 | return dentry; | |
3269 | } | |
3270 | ||
3271 | static int shmem_encode_fh(struct inode *inode, __u32 *fh, int *len, | |
3272 | struct inode *parent) | |
3273 | { | |
3274 | if (*len < 3) { | |
3275 | *len = 3; | |
3276 | return FILEID_INVALID; | |
3277 | } | |
3278 | ||
3279 | if (inode_unhashed(inode)) { | |
3280 | /* Unfortunately insert_inode_hash is not idempotent, | |
3281 | * so as we hash inodes here rather than at creation | |
3282 | * time, we need a lock to ensure we only try | |
3283 | * to do it once | |
3284 | */ | |
3285 | static DEFINE_SPINLOCK(lock); | |
3286 | spin_lock(&lock); | |
3287 | if (inode_unhashed(inode)) | |
3288 | __insert_inode_hash(inode, | |
3289 | inode->i_ino + inode->i_generation); | |
3290 | spin_unlock(&lock); | |
3291 | } | |
3292 | ||
3293 | fh[0] = inode->i_generation; | |
3294 | fh[1] = inode->i_ino; | |
3295 | fh[2] = ((__u64)inode->i_ino) >> 32; | |
3296 | ||
3297 | *len = 3; | |
3298 | return 1; | |
3299 | } | |
3300 | ||
3301 | static const struct export_operations shmem_export_ops = { | |
3302 | .get_parent = shmem_get_parent, | |
3303 | .encode_fh = shmem_encode_fh, | |
3304 | .fh_to_dentry = shmem_fh_to_dentry, | |
3305 | }; | |
3306 | ||
3307 | static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo, | |
3308 | bool remount) | |
3309 | { | |
3310 | char *this_char, *value, *rest; | |
3311 | struct mempolicy *mpol = NULL; | |
3312 | uid_t uid; | |
3313 | gid_t gid; | |
3314 | ||
3315 | while (options != NULL) { | |
3316 | this_char = options; | |
3317 | for (;;) { | |
3318 | /* | |
3319 | * NUL-terminate this option: unfortunately, | |
3320 | * mount options form a comma-separated list, | |
3321 | * but mpol's nodelist may also contain commas. | |
3322 | */ | |
3323 | options = strchr(options, ','); | |
3324 | if (options == NULL) | |
3325 | break; | |
3326 | options++; | |
3327 | if (!isdigit(*options)) { | |
3328 | options[-1] = '\0'; | |
3329 | break; | |
3330 | } | |
3331 | } | |
3332 | if (!*this_char) | |
3333 | continue; | |
3334 | if ((value = strchr(this_char,'=')) != NULL) { | |
3335 | *value++ = 0; | |
3336 | } else { | |
3337 | pr_err("tmpfs: No value for mount option '%s'\n", | |
3338 | this_char); | |
3339 | goto error; | |
3340 | } | |
3341 | ||
3342 | if (!strcmp(this_char,"size")) { | |
3343 | unsigned long long size; | |
3344 | size = memparse(value,&rest); | |
3345 | if (*rest == '%') { | |
3346 | size <<= PAGE_SHIFT; | |
3347 | size *= totalram_pages; | |
3348 | do_div(size, 100); | |
3349 | rest++; | |
3350 | } | |
3351 | if (*rest) | |
3352 | goto bad_val; | |
3353 | sbinfo->max_blocks = | |
3354 | DIV_ROUND_UP(size, PAGE_SIZE); | |
3355 | } else if (!strcmp(this_char,"nr_blocks")) { | |
3356 | sbinfo->max_blocks = memparse(value, &rest); | |
3357 | if (*rest) | |
3358 | goto bad_val; | |
3359 | } else if (!strcmp(this_char,"nr_inodes")) { | |
3360 | sbinfo->max_inodes = memparse(value, &rest); | |
3361 | if (*rest) | |
3362 | goto bad_val; | |
3363 | } else if (!strcmp(this_char,"mode")) { | |
3364 | if (remount) | |
3365 | continue; | |
3366 | sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777; | |
3367 | if (*rest) | |
3368 | goto bad_val; | |
3369 | } else if (!strcmp(this_char,"uid")) { | |
3370 | if (remount) | |
3371 | continue; | |
3372 | uid = simple_strtoul(value, &rest, 0); | |
3373 | if (*rest) | |
3374 | goto bad_val; | |
3375 | sbinfo->uid = make_kuid(current_user_ns(), uid); | |
3376 | if (!uid_valid(sbinfo->uid)) | |
3377 | goto bad_val; | |
3378 | } else if (!strcmp(this_char,"gid")) { | |
3379 | if (remount) | |
3380 | continue; | |
3381 | gid = simple_strtoul(value, &rest, 0); | |
3382 | if (*rest) | |
3383 | goto bad_val; | |
3384 | sbinfo->gid = make_kgid(current_user_ns(), gid); | |
3385 | if (!gid_valid(sbinfo->gid)) | |
3386 | goto bad_val; | |
3387 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE | |
3388 | } else if (!strcmp(this_char, "huge")) { | |
3389 | int huge; | |
3390 | huge = shmem_parse_huge(value); | |
3391 | if (huge < 0) | |
3392 | goto bad_val; | |
3393 | if (!has_transparent_hugepage() && | |
3394 | huge != SHMEM_HUGE_NEVER) | |
3395 | goto bad_val; | |
3396 | sbinfo->huge = huge; | |
3397 | #endif | |
3398 | #ifdef CONFIG_NUMA | |
3399 | } else if (!strcmp(this_char,"mpol")) { | |
3400 | mpol_put(mpol); | |
3401 | mpol = NULL; | |
3402 | if (mpol_parse_str(value, &mpol)) | |
3403 | goto bad_val; | |
3404 | #endif | |
3405 | } else { | |
3406 | pr_err("tmpfs: Bad mount option %s\n", this_char); | |
3407 | goto error; | |
3408 | } | |
3409 | } | |
3410 | sbinfo->mpol = mpol; | |
3411 | return 0; | |
3412 | ||
3413 | bad_val: | |
3414 | pr_err("tmpfs: Bad value '%s' for mount option '%s'\n", | |
3415 | value, this_char); | |
3416 | error: | |
3417 | mpol_put(mpol); | |
3418 | return 1; | |
3419 | ||
3420 | } | |
3421 | ||
3422 | static int shmem_remount_fs(struct super_block *sb, int *flags, char *data) | |
3423 | { | |
3424 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
3425 | struct shmem_sb_info config = *sbinfo; | |
3426 | unsigned long inodes; | |
3427 | int error = -EINVAL; | |
3428 | ||
3429 | config.mpol = NULL; | |
3430 | if (shmem_parse_options(data, &config, true)) | |
3431 | return error; | |
3432 | ||
3433 | spin_lock(&sbinfo->stat_lock); | |
3434 | inodes = sbinfo->max_inodes - sbinfo->free_inodes; | |
3435 | if (percpu_counter_compare(&sbinfo->used_blocks, config.max_blocks) > 0) | |
3436 | goto out; | |
3437 | if (config.max_inodes < inodes) | |
3438 | goto out; | |
3439 | /* | |
3440 | * Those tests disallow limited->unlimited while any are in use; | |
3441 | * but we must separately disallow unlimited->limited, because | |
3442 | * in that case we have no record of how much is already in use. | |
3443 | */ | |
3444 | if (config.max_blocks && !sbinfo->max_blocks) | |
3445 | goto out; | |
3446 | if (config.max_inodes && !sbinfo->max_inodes) | |
3447 | goto out; | |
3448 | ||
3449 | error = 0; | |
3450 | sbinfo->huge = config.huge; | |
3451 | sbinfo->max_blocks = config.max_blocks; | |
3452 | sbinfo->max_inodes = config.max_inodes; | |
3453 | sbinfo->free_inodes = config.max_inodes - inodes; | |
3454 | ||
3455 | /* | |
3456 | * Preserve previous mempolicy unless mpol remount option was specified. | |
3457 | */ | |
3458 | if (config.mpol) { | |
3459 | mpol_put(sbinfo->mpol); | |
3460 | sbinfo->mpol = config.mpol; /* transfers initial ref */ | |
3461 | } | |
3462 | out: | |
3463 | spin_unlock(&sbinfo->stat_lock); | |
3464 | return error; | |
3465 | } | |
3466 | ||
3467 | static int shmem_show_options(struct seq_file *seq, struct dentry *root) | |
3468 | { | |
3469 | struct shmem_sb_info *sbinfo = SHMEM_SB(root->d_sb); | |
3470 | ||
3471 | if (sbinfo->max_blocks != shmem_default_max_blocks()) | |
3472 | seq_printf(seq, ",size=%luk", | |
3473 | sbinfo->max_blocks << (PAGE_SHIFT - 10)); | |
3474 | if (sbinfo->max_inodes != shmem_default_max_inodes()) | |
3475 | seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes); | |
3476 | if (sbinfo->mode != (S_IRWXUGO | S_ISVTX)) | |
3477 | seq_printf(seq, ",mode=%03ho", sbinfo->mode); | |
3478 | if (!uid_eq(sbinfo->uid, GLOBAL_ROOT_UID)) | |
3479 | seq_printf(seq, ",uid=%u", | |
3480 | from_kuid_munged(&init_user_ns, sbinfo->uid)); | |
3481 | if (!gid_eq(sbinfo->gid, GLOBAL_ROOT_GID)) | |
3482 | seq_printf(seq, ",gid=%u", | |
3483 | from_kgid_munged(&init_user_ns, sbinfo->gid)); | |
3484 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE | |
3485 | /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */ | |
3486 | if (sbinfo->huge) | |
3487 | seq_printf(seq, ",huge=%s", shmem_format_huge(sbinfo->huge)); | |
3488 | #endif | |
3489 | shmem_show_mpol(seq, sbinfo->mpol); | |
3490 | return 0; | |
3491 | } | |
3492 | ||
3493 | #define MFD_NAME_PREFIX "memfd:" | |
3494 | #define MFD_NAME_PREFIX_LEN (sizeof(MFD_NAME_PREFIX) - 1) | |
3495 | #define MFD_NAME_MAX_LEN (NAME_MAX - MFD_NAME_PREFIX_LEN) | |
3496 | ||
3497 | #define MFD_ALL_FLAGS (MFD_CLOEXEC | MFD_ALLOW_SEALING) | |
3498 | ||
3499 | SYSCALL_DEFINE2(memfd_create, | |
3500 | const char __user *, uname, | |
3501 | unsigned int, flags) | |
3502 | { | |
3503 | struct shmem_inode_info *info; | |
3504 | struct file *file; | |
3505 | int fd, error; | |
3506 | char *name; | |
3507 | long len; | |
3508 | ||
3509 | if (flags & ~(unsigned int)MFD_ALL_FLAGS) | |
3510 | return -EINVAL; | |
3511 | ||
3512 | /* length includes terminating zero */ | |
3513 | len = strnlen_user(uname, MFD_NAME_MAX_LEN + 1); | |
3514 | if (len <= 0) | |
3515 | return -EFAULT; | |
3516 | if (len > MFD_NAME_MAX_LEN + 1) | |
3517 | return -EINVAL; | |
3518 | ||
3519 | name = kmalloc(len + MFD_NAME_PREFIX_LEN, GFP_TEMPORARY); | |
3520 | if (!name) | |
3521 | return -ENOMEM; | |
3522 | ||
3523 | strcpy(name, MFD_NAME_PREFIX); | |
3524 | if (copy_from_user(&name[MFD_NAME_PREFIX_LEN], uname, len)) { | |
3525 | error = -EFAULT; | |
3526 | goto err_name; | |
3527 | } | |
3528 | ||
3529 | /* terminating-zero may have changed after strnlen_user() returned */ | |
3530 | if (name[len + MFD_NAME_PREFIX_LEN - 1]) { | |
3531 | error = -EFAULT; | |
3532 | goto err_name; | |
3533 | } | |
3534 | ||
3535 | fd = get_unused_fd_flags((flags & MFD_CLOEXEC) ? O_CLOEXEC : 0); | |
3536 | if (fd < 0) { | |
3537 | error = fd; | |
3538 | goto err_name; | |
3539 | } | |
3540 | ||
3541 | file = shmem_file_setup(name, 0, VM_NORESERVE); | |
3542 | if (IS_ERR(file)) { | |
3543 | error = PTR_ERR(file); | |
3544 | goto err_fd; | |
3545 | } | |
3546 | info = SHMEM_I(file_inode(file)); | |
3547 | file->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE; | |
3548 | file->f_flags |= O_RDWR | O_LARGEFILE; | |
3549 | if (flags & MFD_ALLOW_SEALING) | |
3550 | info->seals &= ~F_SEAL_SEAL; | |
3551 | ||
3552 | fd_install(fd, file); | |
3553 | kfree(name); | |
3554 | return fd; | |
3555 | ||
3556 | err_fd: | |
3557 | put_unused_fd(fd); | |
3558 | err_name: | |
3559 | kfree(name); | |
3560 | return error; | |
3561 | } | |
3562 | ||
3563 | #endif /* CONFIG_TMPFS */ | |
3564 | ||
3565 | static void shmem_put_super(struct super_block *sb) | |
3566 | { | |
3567 | struct shmem_sb_info *sbinfo = SHMEM_SB(sb); | |
3568 | ||
3569 | percpu_counter_destroy(&sbinfo->used_blocks); | |
3570 | mpol_put(sbinfo->mpol); | |
3571 | kfree(sbinfo); | |
3572 | sb->s_fs_info = NULL; | |
3573 | } | |
3574 | ||
3575 | int shmem_fill_super(struct super_block *sb, void *data, int silent) | |
3576 | { | |
3577 | struct inode *inode; | |
3578 | struct shmem_sb_info *sbinfo; | |
3579 | int err = -ENOMEM; | |
3580 | ||
3581 | /* Round up to L1_CACHE_BYTES to resist false sharing */ | |
3582 | sbinfo = kzalloc(max((int)sizeof(struct shmem_sb_info), | |
3583 | L1_CACHE_BYTES), GFP_KERNEL); | |
3584 | if (!sbinfo) | |
3585 | return -ENOMEM; | |
3586 | ||
3587 | sbinfo->mode = S_IRWXUGO | S_ISVTX; | |
3588 | sbinfo->uid = current_fsuid(); | |
3589 | sbinfo->gid = current_fsgid(); | |
3590 | sb->s_fs_info = sbinfo; | |
3591 | ||
3592 | #ifdef CONFIG_TMPFS | |
3593 | /* | |
3594 | * Per default we only allow half of the physical ram per | |
3595 | * tmpfs instance, limiting inodes to one per page of lowmem; | |
3596 | * but the internal instance is left unlimited. | |
3597 | */ | |
3598 | if (!(sb->s_flags & MS_KERNMOUNT)) { | |
3599 | sbinfo->max_blocks = shmem_default_max_blocks(); | |
3600 | sbinfo->max_inodes = shmem_default_max_inodes(); | |
3601 | if (shmem_parse_options(data, sbinfo, false)) { | |
3602 | err = -EINVAL; | |
3603 | goto failed; | |
3604 | } | |
3605 | } else { | |
3606 | sb->s_flags |= MS_NOUSER; | |
3607 | } | |
3608 | sb->s_export_op = &shmem_export_ops; | |
3609 | sb->s_flags |= MS_NOSEC; | |
3610 | #else | |
3611 | sb->s_flags |= MS_NOUSER; | |
3612 | #endif | |
3613 | ||
3614 | spin_lock_init(&sbinfo->stat_lock); | |
3615 | if (percpu_counter_init(&sbinfo->used_blocks, 0, GFP_KERNEL)) | |
3616 | goto failed; | |
3617 | sbinfo->free_inodes = sbinfo->max_inodes; | |
3618 | spin_lock_init(&sbinfo->shrinklist_lock); | |
3619 | INIT_LIST_HEAD(&sbinfo->shrinklist); | |
3620 | ||
3621 | sb->s_maxbytes = MAX_LFS_FILESIZE; | |
3622 | sb->s_blocksize = PAGE_SIZE; | |
3623 | sb->s_blocksize_bits = PAGE_SHIFT; | |
3624 | sb->s_magic = TMPFS_MAGIC; | |
3625 | sb->s_op = &shmem_ops; | |
3626 | sb->s_time_gran = 1; | |
3627 | #ifdef CONFIG_TMPFS_XATTR | |
3628 | sb->s_xattr = shmem_xattr_handlers; | |
3629 | #endif | |
3630 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
3631 | sb->s_flags |= MS_POSIXACL; | |
3632 | #endif | |
3633 | ||
3634 | inode = shmem_get_inode(sb, NULL, S_IFDIR | sbinfo->mode, 0, VM_NORESERVE); | |
3635 | if (!inode) | |
3636 | goto failed; | |
3637 | inode->i_uid = sbinfo->uid; | |
3638 | inode->i_gid = sbinfo->gid; | |
3639 | sb->s_root = d_make_root(inode); | |
3640 | if (!sb->s_root) | |
3641 | goto failed; | |
3642 | return 0; | |
3643 | ||
3644 | failed: | |
3645 | shmem_put_super(sb); | |
3646 | return err; | |
3647 | } | |
3648 | ||
3649 | static struct kmem_cache *shmem_inode_cachep; | |
3650 | ||
3651 | static struct inode *shmem_alloc_inode(struct super_block *sb) | |
3652 | { | |
3653 | struct shmem_inode_info *info; | |
3654 | info = kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL); | |
3655 | if (!info) | |
3656 | return NULL; | |
3657 | return &info->vfs_inode; | |
3658 | } | |
3659 | ||
3660 | static void shmem_destroy_callback(struct rcu_head *head) | |
3661 | { | |
3662 | struct inode *inode = container_of(head, struct inode, i_rcu); | |
3663 | if (S_ISLNK(inode->i_mode)) | |
3664 | kfree(inode->i_link); | |
3665 | kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode)); | |
3666 | } | |
3667 | ||
3668 | static void shmem_destroy_inode(struct inode *inode) | |
3669 | { | |
3670 | if (S_ISREG(inode->i_mode)) | |
3671 | mpol_free_shared_policy(&SHMEM_I(inode)->policy); | |
3672 | call_rcu(&inode->i_rcu, shmem_destroy_callback); | |
3673 | } | |
3674 | ||
3675 | static void shmem_init_inode(void *foo) | |
3676 | { | |
3677 | struct shmem_inode_info *info = foo; | |
3678 | inode_init_once(&info->vfs_inode); | |
3679 | } | |
3680 | ||
3681 | static int shmem_init_inodecache(void) | |
3682 | { | |
3683 | shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", | |
3684 | sizeof(struct shmem_inode_info), | |
3685 | 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); | |
3686 | return 0; | |
3687 | } | |
3688 | ||
3689 | static void shmem_destroy_inodecache(void) | |
3690 | { | |
3691 | kmem_cache_destroy(shmem_inode_cachep); | |
3692 | } | |
3693 | ||
3694 | static const struct address_space_operations shmem_aops = { | |
3695 | .writepage = shmem_writepage, | |
3696 | .set_page_dirty = __set_page_dirty_no_writeback, | |
3697 | #ifdef CONFIG_TMPFS | |
3698 | .write_begin = shmem_write_begin, | |
3699 | .write_end = shmem_write_end, | |
3700 | #endif | |
3701 | #ifdef CONFIG_MIGRATION | |
3702 | .migratepage = migrate_page, | |
3703 | #endif | |
3704 | .error_remove_page = generic_error_remove_page, | |
3705 | }; | |
3706 | ||
3707 | static const struct file_operations shmem_file_operations = { | |
3708 | .mmap = shmem_mmap, | |
3709 | .get_unmapped_area = shmem_get_unmapped_area, | |
3710 | #ifdef CONFIG_TMPFS | |
3711 | .llseek = shmem_file_llseek, | |
3712 | .read_iter = shmem_file_read_iter, | |
3713 | .write_iter = generic_file_write_iter, | |
3714 | .fsync = noop_fsync, | |
3715 | .splice_read = generic_file_splice_read, | |
3716 | .splice_write = iter_file_splice_write, | |
3717 | .fallocate = shmem_fallocate, | |
3718 | #endif | |
3719 | }; | |
3720 | ||
3721 | static const struct inode_operations shmem_inode_operations = { | |
3722 | .getattr = shmem_getattr, | |
3723 | .setattr = shmem_setattr, | |
3724 | #ifdef CONFIG_TMPFS_XATTR | |
3725 | .listxattr = shmem_listxattr, | |
3726 | .set_acl = simple_set_acl, | |
3727 | #endif | |
3728 | }; | |
3729 | ||
3730 | static const struct inode_operations shmem_dir_inode_operations = { | |
3731 | #ifdef CONFIG_TMPFS | |
3732 | .create = shmem_create, | |
3733 | .lookup = simple_lookup, | |
3734 | .link = shmem_link, | |
3735 | .unlink = shmem_unlink, | |
3736 | .symlink = shmem_symlink, | |
3737 | .mkdir = shmem_mkdir, | |
3738 | .rmdir = shmem_rmdir, | |
3739 | .mknod = shmem_mknod, | |
3740 | .rename = shmem_rename2, | |
3741 | .tmpfile = shmem_tmpfile, | |
3742 | #endif | |
3743 | #ifdef CONFIG_TMPFS_XATTR | |
3744 | .listxattr = shmem_listxattr, | |
3745 | #endif | |
3746 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
3747 | .setattr = shmem_setattr, | |
3748 | .set_acl = simple_set_acl, | |
3749 | #endif | |
3750 | }; | |
3751 | ||
3752 | static const struct inode_operations shmem_special_inode_operations = { | |
3753 | #ifdef CONFIG_TMPFS_XATTR | |
3754 | .listxattr = shmem_listxattr, | |
3755 | #endif | |
3756 | #ifdef CONFIG_TMPFS_POSIX_ACL | |
3757 | .setattr = shmem_setattr, | |
3758 | .set_acl = simple_set_acl, | |
3759 | #endif | |
3760 | }; | |
3761 | ||
3762 | static const struct super_operations shmem_ops = { | |
3763 | .alloc_inode = shmem_alloc_inode, | |
3764 | .destroy_inode = shmem_destroy_inode, | |
3765 | #ifdef CONFIG_TMPFS | |
3766 | .statfs = shmem_statfs, | |
3767 | .remount_fs = shmem_remount_fs, | |
3768 | .show_options = shmem_show_options, | |
3769 | #endif | |
3770 | .evict_inode = shmem_evict_inode, | |
3771 | .drop_inode = generic_delete_inode, | |
3772 | .put_super = shmem_put_super, | |
3773 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE | |
3774 | .nr_cached_objects = shmem_unused_huge_count, | |
3775 | .free_cached_objects = shmem_unused_huge_scan, | |
3776 | #endif | |
3777 | }; | |
3778 | ||
3779 | static const struct vm_operations_struct shmem_vm_ops = { | |
3780 | .fault = shmem_fault, | |
3781 | .map_pages = filemap_map_pages, | |
3782 | #ifdef CONFIG_NUMA | |
3783 | .set_policy = shmem_set_policy, | |
3784 | .get_policy = shmem_get_policy, | |
3785 | #endif | |
3786 | }; | |
3787 | ||
3788 | static struct dentry *shmem_mount(struct file_system_type *fs_type, | |
3789 | int flags, const char *dev_name, void *data) | |
3790 | { | |
3791 | return mount_nodev(fs_type, flags, data, shmem_fill_super); | |
3792 | } | |
3793 | ||
3794 | static struct file_system_type shmem_fs_type = { | |
3795 | .owner = THIS_MODULE, | |
3796 | .name = "tmpfs", | |
3797 | .mount = shmem_mount, | |
3798 | .kill_sb = kill_litter_super, | |
3799 | .fs_flags = FS_USERNS_MOUNT, | |
3800 | }; | |
3801 | ||
3802 | int __init shmem_init(void) | |
3803 | { | |
3804 | int error; | |
3805 | ||
3806 | /* If rootfs called this, don't re-init */ | |
3807 | if (shmem_inode_cachep) | |
3808 | return 0; | |
3809 | ||
3810 | error = shmem_init_inodecache(); | |
3811 | if (error) | |
3812 | goto out3; | |
3813 | ||
3814 | error = register_filesystem(&shmem_fs_type); | |
3815 | if (error) { | |
3816 | pr_err("Could not register tmpfs\n"); | |
3817 | goto out2; | |
3818 | } | |
3819 | ||
3820 | shm_mnt = kern_mount(&shmem_fs_type); | |
3821 | if (IS_ERR(shm_mnt)) { | |
3822 | error = PTR_ERR(shm_mnt); | |
3823 | pr_err("Could not kern_mount tmpfs\n"); | |
3824 | goto out1; | |
3825 | } | |
3826 | ||
3827 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE | |
3828 | if (has_transparent_hugepage() && shmem_huge < SHMEM_HUGE_DENY) | |
3829 | SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; | |
3830 | else | |
3831 | shmem_huge = 0; /* just in case it was patched */ | |
3832 | #endif | |
3833 | return 0; | |
3834 | ||
3835 | out1: | |
3836 | unregister_filesystem(&shmem_fs_type); | |
3837 | out2: | |
3838 | shmem_destroy_inodecache(); | |
3839 | out3: | |
3840 | shm_mnt = ERR_PTR(error); | |
3841 | return error; | |
3842 | } | |
3843 | ||
3844 | #if defined(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && defined(CONFIG_SYSFS) | |
3845 | static ssize_t shmem_enabled_show(struct kobject *kobj, | |
3846 | struct kobj_attribute *attr, char *buf) | |
3847 | { | |
3848 | int values[] = { | |
3849 | SHMEM_HUGE_ALWAYS, | |
3850 | SHMEM_HUGE_WITHIN_SIZE, | |
3851 | SHMEM_HUGE_ADVISE, | |
3852 | SHMEM_HUGE_NEVER, | |
3853 | SHMEM_HUGE_DENY, | |
3854 | SHMEM_HUGE_FORCE, | |
3855 | }; | |
3856 | int i, count; | |
3857 | ||
3858 | for (i = 0, count = 0; i < ARRAY_SIZE(values); i++) { | |
3859 | const char *fmt = shmem_huge == values[i] ? "[%s] " : "%s "; | |
3860 | ||
3861 | count += sprintf(buf + count, fmt, | |
3862 | shmem_format_huge(values[i])); | |
3863 | } | |
3864 | buf[count - 1] = '\n'; | |
3865 | return count; | |
3866 | } | |
3867 | ||
3868 | static ssize_t shmem_enabled_store(struct kobject *kobj, | |
3869 | struct kobj_attribute *attr, const char *buf, size_t count) | |
3870 | { | |
3871 | char tmp[16]; | |
3872 | int huge; | |
3873 | ||
3874 | if (count + 1 > sizeof(tmp)) | |
3875 | return -EINVAL; | |
3876 | memcpy(tmp, buf, count); | |
3877 | tmp[count] = '\0'; | |
3878 | if (count && tmp[count - 1] == '\n') | |
3879 | tmp[count - 1] = '\0'; | |
3880 | ||
3881 | huge = shmem_parse_huge(tmp); | |
3882 | if (huge == -EINVAL) | |
3883 | return -EINVAL; | |
3884 | if (!has_transparent_hugepage() && | |
3885 | huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY) | |
3886 | return -EINVAL; | |
3887 | ||
3888 | shmem_huge = huge; | |
3889 | if (shmem_huge < SHMEM_HUGE_DENY) | |
3890 | SHMEM_SB(shm_mnt->mnt_sb)->huge = shmem_huge; | |
3891 | return count; | |
3892 | } | |
3893 | ||
3894 | struct kobj_attribute shmem_enabled_attr = | |
3895 | __ATTR(shmem_enabled, 0644, shmem_enabled_show, shmem_enabled_store); | |
3896 | #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE && CONFIG_SYSFS */ | |
3897 | ||
3898 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE | |
3899 | bool shmem_huge_enabled(struct vm_area_struct *vma) | |
3900 | { | |
3901 | struct inode *inode = file_inode(vma->vm_file); | |
3902 | struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); | |
3903 | loff_t i_size; | |
3904 | pgoff_t off; | |
3905 | ||
3906 | if (shmem_huge == SHMEM_HUGE_FORCE) | |
3907 | return true; | |
3908 | if (shmem_huge == SHMEM_HUGE_DENY) | |
3909 | return false; | |
3910 | switch (sbinfo->huge) { | |
3911 | case SHMEM_HUGE_NEVER: | |
3912 | return false; | |
3913 | case SHMEM_HUGE_ALWAYS: | |
3914 | return true; | |
3915 | case SHMEM_HUGE_WITHIN_SIZE: | |
3916 | off = round_up(vma->vm_pgoff, HPAGE_PMD_NR); | |
3917 | i_size = round_up(i_size_read(inode), PAGE_SIZE); | |
3918 | if (i_size >= HPAGE_PMD_SIZE && | |
3919 | i_size >> PAGE_SHIFT >= off) | |
3920 | return true; | |
3921 | case SHMEM_HUGE_ADVISE: | |
3922 | /* TODO: implement fadvise() hints */ | |
3923 | return (vma->vm_flags & VM_HUGEPAGE); | |
3924 | default: | |
3925 | VM_BUG_ON(1); | |
3926 | return false; | |
3927 | } | |
3928 | } | |
3929 | #endif /* CONFIG_TRANSPARENT_HUGE_PAGECACHE */ | |
3930 | ||
3931 | #else /* !CONFIG_SHMEM */ | |
3932 | ||
3933 | /* | |
3934 | * tiny-shmem: simple shmemfs and tmpfs using ramfs code | |
3935 | * | |
3936 | * This is intended for small system where the benefits of the full | |
3937 | * shmem code (swap-backed and resource-limited) are outweighed by | |
3938 | * their complexity. On systems without swap this code should be | |
3939 | * effectively equivalent, but much lighter weight. | |
3940 | */ | |
3941 | ||
3942 | static struct file_system_type shmem_fs_type = { | |
3943 | .name = "tmpfs", | |
3944 | .mount = ramfs_mount, | |
3945 | .kill_sb = kill_litter_super, | |
3946 | .fs_flags = FS_USERNS_MOUNT, | |
3947 | }; | |
3948 | ||
3949 | int __init shmem_init(void) | |
3950 | { | |
3951 | BUG_ON(register_filesystem(&shmem_fs_type) != 0); | |
3952 | ||
3953 | shm_mnt = kern_mount(&shmem_fs_type); | |
3954 | BUG_ON(IS_ERR(shm_mnt)); | |
3955 | ||
3956 | return 0; | |
3957 | } | |
3958 | ||
3959 | int shmem_unuse(swp_entry_t swap, struct page *page) | |
3960 | { | |
3961 | return 0; | |
3962 | } | |
3963 | ||
3964 | int shmem_lock(struct file *file, int lock, struct user_struct *user) | |
3965 | { | |
3966 | return 0; | |
3967 | } | |
3968 | ||
3969 | void shmem_unlock_mapping(struct address_space *mapping) | |
3970 | { | |
3971 | } | |
3972 | ||
3973 | #ifdef CONFIG_MMU | |
3974 | unsigned long shmem_get_unmapped_area(struct file *file, | |
3975 | unsigned long addr, unsigned long len, | |
3976 | unsigned long pgoff, unsigned long flags) | |
3977 | { | |
3978 | return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); | |
3979 | } | |
3980 | #endif | |
3981 | ||
3982 | void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend) | |
3983 | { | |
3984 | truncate_inode_pages_range(inode->i_mapping, lstart, lend); | |
3985 | } | |
3986 | EXPORT_SYMBOL_GPL(shmem_truncate_range); | |
3987 | ||
3988 | #define shmem_vm_ops generic_file_vm_ops | |
3989 | #define shmem_file_operations ramfs_file_operations | |
3990 | #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev) | |
3991 | #define shmem_acct_size(flags, size) 0 | |
3992 | #define shmem_unacct_size(flags, size) do {} while (0) | |
3993 | ||
3994 | #endif /* CONFIG_SHMEM */ | |
3995 | ||
3996 | /* common code */ | |
3997 | ||
3998 | static const struct dentry_operations anon_ops = { | |
3999 | .d_dname = simple_dname | |
4000 | }; | |
4001 | ||
4002 | static struct file *__shmem_file_setup(const char *name, loff_t size, | |
4003 | unsigned long flags, unsigned int i_flags) | |
4004 | { | |
4005 | struct file *res; | |
4006 | struct inode *inode; | |
4007 | struct path path; | |
4008 | struct super_block *sb; | |
4009 | struct qstr this; | |
4010 | ||
4011 | if (IS_ERR(shm_mnt)) | |
4012 | return ERR_CAST(shm_mnt); | |
4013 | ||
4014 | if (size < 0 || size > MAX_LFS_FILESIZE) | |
4015 | return ERR_PTR(-EINVAL); | |
4016 | ||
4017 | if (shmem_acct_size(flags, size)) | |
4018 | return ERR_PTR(-ENOMEM); | |
4019 | ||
4020 | res = ERR_PTR(-ENOMEM); | |
4021 | this.name = name; | |
4022 | this.len = strlen(name); | |
4023 | this.hash = 0; /* will go */ | |
4024 | sb = shm_mnt->mnt_sb; | |
4025 | path.mnt = mntget(shm_mnt); | |
4026 | path.dentry = d_alloc_pseudo(sb, &this); | |
4027 | if (!path.dentry) | |
4028 | goto put_memory; | |
4029 | d_set_d_op(path.dentry, &anon_ops); | |
4030 | ||
4031 | res = ERR_PTR(-ENOSPC); | |
4032 | inode = shmem_get_inode(sb, NULL, S_IFREG | S_IRWXUGO, 0, flags); | |
4033 | if (!inode) | |
4034 | goto put_memory; | |
4035 | ||
4036 | inode->i_flags |= i_flags; | |
4037 | d_instantiate(path.dentry, inode); | |
4038 | inode->i_size = size; | |
4039 | clear_nlink(inode); /* It is unlinked */ | |
4040 | res = ERR_PTR(ramfs_nommu_expand_for_mapping(inode, size)); | |
4041 | if (IS_ERR(res)) | |
4042 | goto put_path; | |
4043 | ||
4044 | res = alloc_file(&path, FMODE_WRITE | FMODE_READ, | |
4045 | &shmem_file_operations); | |
4046 | if (IS_ERR(res)) | |
4047 | goto put_path; | |
4048 | ||
4049 | return res; | |
4050 | ||
4051 | put_memory: | |
4052 | shmem_unacct_size(flags, size); | |
4053 | put_path: | |
4054 | path_put(&path); | |
4055 | return res; | |
4056 | } | |
4057 | ||
4058 | /** | |
4059 | * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be | |
4060 | * kernel internal. There will be NO LSM permission checks against the | |
4061 | * underlying inode. So users of this interface must do LSM checks at a | |
4062 | * higher layer. The users are the big_key and shm implementations. LSM | |
4063 | * checks are provided at the key or shm level rather than the inode. | |
4064 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
4065 | * @size: size to be set for the file | |
4066 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
4067 | */ | |
4068 | struct file *shmem_kernel_file_setup(const char *name, loff_t size, unsigned long flags) | |
4069 | { | |
4070 | return __shmem_file_setup(name, size, flags, S_PRIVATE); | |
4071 | } | |
4072 | ||
4073 | /** | |
4074 | * shmem_file_setup - get an unlinked file living in tmpfs | |
4075 | * @name: name for dentry (to be seen in /proc/<pid>/maps | |
4076 | * @size: size to be set for the file | |
4077 | * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size | |
4078 | */ | |
4079 | struct file *shmem_file_setup(const char *name, loff_t size, unsigned long flags) | |
4080 | { | |
4081 | return __shmem_file_setup(name, size, flags, 0); | |
4082 | } | |
4083 | EXPORT_SYMBOL_GPL(shmem_file_setup); | |
4084 | ||
4085 | /** | |
4086 | * shmem_zero_setup - setup a shared anonymous mapping | |
4087 | * @vma: the vma to be mmapped is prepared by do_mmap_pgoff | |
4088 | */ | |
4089 | int shmem_zero_setup(struct vm_area_struct *vma) | |
4090 | { | |
4091 | struct file *file; | |
4092 | loff_t size = vma->vm_end - vma->vm_start; | |
4093 | ||
4094 | /* | |
4095 | * Cloning a new file under mmap_sem leads to a lock ordering conflict | |
4096 | * between XFS directory reading and selinux: since this file is only | |
4097 | * accessible to the user through its mapping, use S_PRIVATE flag to | |
4098 | * bypass file security, in the same way as shmem_kernel_file_setup(). | |
4099 | */ | |
4100 | file = __shmem_file_setup("dev/zero", size, vma->vm_flags, S_PRIVATE); | |
4101 | if (IS_ERR(file)) | |
4102 | return PTR_ERR(file); | |
4103 | ||
4104 | if (vma->vm_file) | |
4105 | fput(vma->vm_file); | |
4106 | vma->vm_file = file; | |
4107 | vma->vm_ops = &shmem_vm_ops; | |
4108 | ||
4109 | if (IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE) && | |
4110 | ((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) < | |
4111 | (vma->vm_end & HPAGE_PMD_MASK)) { | |
4112 | khugepaged_enter(vma, vma->vm_flags); | |
4113 | } | |
4114 | ||
4115 | return 0; | |
4116 | } | |
4117 | ||
4118 | /** | |
4119 | * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags. | |
4120 | * @mapping: the page's address_space | |
4121 | * @index: the page index | |
4122 | * @gfp: the page allocator flags to use if allocating | |
4123 | * | |
4124 | * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)", | |
4125 | * with any new page allocations done using the specified allocation flags. | |
4126 | * But read_cache_page_gfp() uses the ->readpage() method: which does not | |
4127 | * suit tmpfs, since it may have pages in swapcache, and needs to find those | |
4128 | * for itself; although drivers/gpu/drm i915 and ttm rely upon this support. | |
4129 | * | |
4130 | * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in | |
4131 | * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily. | |
4132 | */ | |
4133 | struct page *shmem_read_mapping_page_gfp(struct address_space *mapping, | |
4134 | pgoff_t index, gfp_t gfp) | |
4135 | { | |
4136 | #ifdef CONFIG_SHMEM | |
4137 | struct inode *inode = mapping->host; | |
4138 | struct page *page; | |
4139 | int error; | |
4140 | ||
4141 | BUG_ON(mapping->a_ops != &shmem_aops); | |
4142 | error = shmem_getpage_gfp(inode, index, &page, SGP_CACHE, | |
4143 | gfp, NULL, NULL); | |
4144 | if (error) | |
4145 | page = ERR_PTR(error); | |
4146 | else | |
4147 | unlock_page(page); | |
4148 | return page; | |
4149 | #else | |
4150 | /* | |
4151 | * The tiny !SHMEM case uses ramfs without swap | |
4152 | */ | |
4153 | return read_cache_page_gfp(mapping, index, gfp); | |
4154 | #endif | |
4155 | } | |
4156 | EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp); |