2 * Resizable virtual memory filesystem for Linux.
4 * Copyright (C) 2000 Linus Torvalds.
6 * 2000-2001 Christoph Rohland
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
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>
19 * Copyright (c) 2004, 2008 Matt Mackall <mpm@selenic.com>
21 * This file is released under the GPL.
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>
32 #include <linux/random.h>
33 #include <linux/sched/signal.h>
34 #include <linux/export.h>
35 #include <linux/swap.h>
36 #include <linux/uio.h>
37 #include <linux/khugepaged.h>
38 #include <linux/hugetlb.h>
39 #include <linux/fs_parser.h>
40 #include <linux/swapfile.h>
42 static struct vfsmount
*shm_mnt
;
46 * This virtual memory filesystem is heavily based on the ramfs. It
47 * extends ramfs by the ability to use swap and honor resource limits
48 * which makes it a completely usable filesystem.
51 #include <linux/xattr.h>
52 #include <linux/exportfs.h>
53 #include <linux/posix_acl.h>
54 #include <linux/posix_acl_xattr.h>
55 #include <linux/mman.h>
56 #include <linux/string.h>
57 #include <linux/slab.h>
58 #include <linux/backing-dev.h>
59 #include <linux/shmem_fs.h>
60 #include <linux/writeback.h>
61 #include <linux/pagevec.h>
62 #include <linux/percpu_counter.h>
63 #include <linux/falloc.h>
64 #include <linux/splice.h>
65 #include <linux/security.h>
66 #include <linux/swapops.h>
67 #include <linux/mempolicy.h>
68 #include <linux/namei.h>
69 #include <linux/ctype.h>
70 #include <linux/migrate.h>
71 #include <linux/highmem.h>
72 #include <linux/seq_file.h>
73 #include <linux/magic.h>
74 #include <linux/syscalls.h>
75 #include <linux/fcntl.h>
76 #include <uapi/linux/memfd.h>
77 #include <linux/userfaultfd_k.h>
78 #include <linux/rmap.h>
79 #include <linux/uuid.h>
81 #include <linux/uaccess.h>
85 #define BLOCKS_PER_PAGE (PAGE_SIZE/512)
86 #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
88 /* Pretend that each entry is of this size in directory's i_size */
89 #define BOGO_DIRENT_SIZE 20
91 /* Symlink up to this size is kmalloc'ed instead of using a swappable page */
92 #define SHORT_SYMLINK_LEN 128
95 * shmem_fallocate communicates with shmem_fault or shmem_writepage via
96 * inode->i_private (with i_rwsem making sure that it has only one user at
97 * a time): we would prefer not to enlarge the shmem inode just for that.
100 wait_queue_head_t
*waitq
; /* faults into hole wait for punch to end */
101 pgoff_t start
; /* start of range currently being fallocated */
102 pgoff_t next
; /* the next page offset to be fallocated */
103 pgoff_t nr_falloced
; /* how many new pages have been fallocated */
104 pgoff_t nr_unswapped
; /* how often writepage refused to swap out */
107 struct shmem_options
{
108 unsigned long long blocks
;
109 unsigned long long inodes
;
110 struct mempolicy
*mpol
;
117 #define SHMEM_SEEN_BLOCKS 1
118 #define SHMEM_SEEN_INODES 2
119 #define SHMEM_SEEN_HUGE 4
120 #define SHMEM_SEEN_INUMS 8
124 static unsigned long shmem_default_max_blocks(void)
126 return totalram_pages() / 2;
129 static unsigned long shmem_default_max_inodes(void)
131 unsigned long nr_pages
= totalram_pages();
133 return min(nr_pages
- totalhigh_pages(), nr_pages
/ 2);
137 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
138 struct page
**pagep
, enum sgp_type sgp
,
139 gfp_t gfp
, struct vm_area_struct
*vma
,
140 vm_fault_t
*fault_type
);
141 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
142 struct page
**pagep
, enum sgp_type sgp
,
143 gfp_t gfp
, struct vm_area_struct
*vma
,
144 struct vm_fault
*vmf
, vm_fault_t
*fault_type
);
146 int shmem_getpage(struct inode
*inode
, pgoff_t index
,
147 struct page
**pagep
, enum sgp_type sgp
)
149 return shmem_getpage_gfp(inode
, index
, pagep
, sgp
,
150 mapping_gfp_mask(inode
->i_mapping
), NULL
, NULL
, NULL
);
153 static inline struct shmem_sb_info
*SHMEM_SB(struct super_block
*sb
)
155 return sb
->s_fs_info
;
159 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
160 * for shared memory and for shared anonymous (/dev/zero) mappings
161 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
162 * consistent with the pre-accounting of private mappings ...
164 static inline int shmem_acct_size(unsigned long flags
, loff_t size
)
166 return (flags
& VM_NORESERVE
) ?
167 0 : security_vm_enough_memory_mm(current
->mm
, VM_ACCT(size
));
170 static inline void shmem_unacct_size(unsigned long flags
, loff_t size
)
172 if (!(flags
& VM_NORESERVE
))
173 vm_unacct_memory(VM_ACCT(size
));
176 static inline int shmem_reacct_size(unsigned long flags
,
177 loff_t oldsize
, loff_t newsize
)
179 if (!(flags
& VM_NORESERVE
)) {
180 if (VM_ACCT(newsize
) > VM_ACCT(oldsize
))
181 return security_vm_enough_memory_mm(current
->mm
,
182 VM_ACCT(newsize
) - VM_ACCT(oldsize
));
183 else if (VM_ACCT(newsize
) < VM_ACCT(oldsize
))
184 vm_unacct_memory(VM_ACCT(oldsize
) - VM_ACCT(newsize
));
190 * ... whereas tmpfs objects are accounted incrementally as
191 * pages are allocated, in order to allow large sparse files.
192 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
193 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
195 static inline int shmem_acct_block(unsigned long flags
, long pages
)
197 if (!(flags
& VM_NORESERVE
))
200 return security_vm_enough_memory_mm(current
->mm
,
201 pages
* VM_ACCT(PAGE_SIZE
));
204 static inline void shmem_unacct_blocks(unsigned long flags
, long pages
)
206 if (flags
& VM_NORESERVE
)
207 vm_unacct_memory(pages
* VM_ACCT(PAGE_SIZE
));
210 static inline bool shmem_inode_acct_block(struct inode
*inode
, long pages
)
212 struct shmem_inode_info
*info
= SHMEM_I(inode
);
213 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
215 if (shmem_acct_block(info
->flags
, pages
))
218 if (sbinfo
->max_blocks
) {
219 if (percpu_counter_compare(&sbinfo
->used_blocks
,
220 sbinfo
->max_blocks
- pages
) > 0)
222 percpu_counter_add(&sbinfo
->used_blocks
, pages
);
228 shmem_unacct_blocks(info
->flags
, pages
);
232 static inline void shmem_inode_unacct_blocks(struct inode
*inode
, long pages
)
234 struct shmem_inode_info
*info
= SHMEM_I(inode
);
235 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
237 if (sbinfo
->max_blocks
)
238 percpu_counter_sub(&sbinfo
->used_blocks
, pages
);
239 shmem_unacct_blocks(info
->flags
, pages
);
242 static const struct super_operations shmem_ops
;
243 const struct address_space_operations shmem_aops
;
244 static const struct file_operations shmem_file_operations
;
245 static const struct inode_operations shmem_inode_operations
;
246 static const struct inode_operations shmem_dir_inode_operations
;
247 static const struct inode_operations shmem_special_inode_operations
;
248 static const struct vm_operations_struct shmem_vm_ops
;
249 static struct file_system_type shmem_fs_type
;
251 bool vma_is_shmem(struct vm_area_struct
*vma
)
253 return vma
->vm_ops
== &shmem_vm_ops
;
256 static LIST_HEAD(shmem_swaplist
);
257 static DEFINE_MUTEX(shmem_swaplist_mutex
);
260 * shmem_reserve_inode() performs bookkeeping to reserve a shmem inode, and
261 * produces a novel ino for the newly allocated inode.
263 * It may also be called when making a hard link to permit the space needed by
264 * each dentry. However, in that case, no new inode number is needed since that
265 * internally draws from another pool of inode numbers (currently global
266 * get_next_ino()). This case is indicated by passing NULL as inop.
268 #define SHMEM_INO_BATCH 1024
269 static int shmem_reserve_inode(struct super_block
*sb
, ino_t
*inop
)
271 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
274 if (!(sb
->s_flags
& SB_KERNMOUNT
)) {
275 raw_spin_lock(&sbinfo
->stat_lock
);
276 if (sbinfo
->max_inodes
) {
277 if (!sbinfo
->free_inodes
) {
278 raw_spin_unlock(&sbinfo
->stat_lock
);
281 sbinfo
->free_inodes
--;
284 ino
= sbinfo
->next_ino
++;
285 if (unlikely(is_zero_ino(ino
)))
286 ino
= sbinfo
->next_ino
++;
287 if (unlikely(!sbinfo
->full_inums
&&
290 * Emulate get_next_ino uint wraparound for
293 if (IS_ENABLED(CONFIG_64BIT
))
294 pr_warn("%s: inode number overflow on device %d, consider using inode64 mount option\n",
295 __func__
, MINOR(sb
->s_dev
));
296 sbinfo
->next_ino
= 1;
297 ino
= sbinfo
->next_ino
++;
301 raw_spin_unlock(&sbinfo
->stat_lock
);
304 * __shmem_file_setup, one of our callers, is lock-free: it
305 * doesn't hold stat_lock in shmem_reserve_inode since
306 * max_inodes is always 0, and is called from potentially
307 * unknown contexts. As such, use a per-cpu batched allocator
308 * which doesn't require the per-sb stat_lock unless we are at
309 * the batch boundary.
311 * We don't need to worry about inode{32,64} since SB_KERNMOUNT
312 * shmem mounts are not exposed to userspace, so we don't need
313 * to worry about things like glibc compatibility.
317 next_ino
= per_cpu_ptr(sbinfo
->ino_batch
, get_cpu());
319 if (unlikely(ino
% SHMEM_INO_BATCH
== 0)) {
320 raw_spin_lock(&sbinfo
->stat_lock
);
321 ino
= sbinfo
->next_ino
;
322 sbinfo
->next_ino
+= SHMEM_INO_BATCH
;
323 raw_spin_unlock(&sbinfo
->stat_lock
);
324 if (unlikely(is_zero_ino(ino
)))
335 static void shmem_free_inode(struct super_block
*sb
)
337 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
338 if (sbinfo
->max_inodes
) {
339 raw_spin_lock(&sbinfo
->stat_lock
);
340 sbinfo
->free_inodes
++;
341 raw_spin_unlock(&sbinfo
->stat_lock
);
346 * shmem_recalc_inode - recalculate the block usage of an inode
347 * @inode: inode to recalc
349 * We have to calculate the free blocks since the mm can drop
350 * undirtied hole pages behind our back.
352 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
353 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
355 * It has to be called with the spinlock held.
357 static void shmem_recalc_inode(struct inode
*inode
)
359 struct shmem_inode_info
*info
= SHMEM_I(inode
);
362 freed
= info
->alloced
- info
->swapped
- inode
->i_mapping
->nrpages
;
364 info
->alloced
-= freed
;
365 inode
->i_blocks
-= freed
* BLOCKS_PER_PAGE
;
366 shmem_inode_unacct_blocks(inode
, freed
);
370 bool shmem_charge(struct inode
*inode
, long pages
)
372 struct shmem_inode_info
*info
= SHMEM_I(inode
);
375 if (!shmem_inode_acct_block(inode
, pages
))
378 /* nrpages adjustment first, then shmem_recalc_inode() when balanced */
379 inode
->i_mapping
->nrpages
+= pages
;
381 spin_lock_irqsave(&info
->lock
, flags
);
382 info
->alloced
+= pages
;
383 inode
->i_blocks
+= pages
* BLOCKS_PER_PAGE
;
384 shmem_recalc_inode(inode
);
385 spin_unlock_irqrestore(&info
->lock
, flags
);
390 void shmem_uncharge(struct inode
*inode
, long pages
)
392 struct shmem_inode_info
*info
= SHMEM_I(inode
);
395 /* nrpages adjustment done by __delete_from_page_cache() or caller */
397 spin_lock_irqsave(&info
->lock
, flags
);
398 info
->alloced
-= pages
;
399 inode
->i_blocks
-= pages
* BLOCKS_PER_PAGE
;
400 shmem_recalc_inode(inode
);
401 spin_unlock_irqrestore(&info
->lock
, flags
);
403 shmem_inode_unacct_blocks(inode
, pages
);
407 * Replace item expected in xarray by a new item, while holding xa_lock.
409 static int shmem_replace_entry(struct address_space
*mapping
,
410 pgoff_t index
, void *expected
, void *replacement
)
412 XA_STATE(xas
, &mapping
->i_pages
, index
);
415 VM_BUG_ON(!expected
);
416 VM_BUG_ON(!replacement
);
417 item
= xas_load(&xas
);
418 if (item
!= expected
)
420 xas_store(&xas
, replacement
);
425 * Sometimes, before we decide whether to proceed or to fail, we must check
426 * that an entry was not already brought back from swap by a racing thread.
428 * Checking page is not enough: by the time a SwapCache page is locked, it
429 * might be reused, and again be SwapCache, using the same swap as before.
431 static bool shmem_confirm_swap(struct address_space
*mapping
,
432 pgoff_t index
, swp_entry_t swap
)
434 return xa_load(&mapping
->i_pages
, index
) == swp_to_radix_entry(swap
);
438 * Definitions for "huge tmpfs": tmpfs mounted with the huge= option
441 * disables huge pages for the mount;
443 * enables huge pages for the mount;
444 * SHMEM_HUGE_WITHIN_SIZE:
445 * only allocate huge pages if the page will be fully within i_size,
446 * also respect fadvise()/madvise() hints;
448 * only allocate huge pages if requested with fadvise()/madvise();
451 #define SHMEM_HUGE_NEVER 0
452 #define SHMEM_HUGE_ALWAYS 1
453 #define SHMEM_HUGE_WITHIN_SIZE 2
454 #define SHMEM_HUGE_ADVISE 3
458 * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
461 * disables huge on shm_mnt and all mounts, for emergency use;
463 * enables huge on shm_mnt and all mounts, w/o needing option, for testing;
466 #define SHMEM_HUGE_DENY (-1)
467 #define SHMEM_HUGE_FORCE (-2)
469 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
470 /* ifdef here to avoid bloating shmem.o when not necessary */
472 static int shmem_huge __read_mostly
= SHMEM_HUGE_NEVER
;
474 bool shmem_is_huge(struct vm_area_struct
*vma
,
475 struct inode
*inode
, pgoff_t index
)
479 if (!S_ISREG(inode
->i_mode
))
481 if (shmem_huge
== SHMEM_HUGE_DENY
)
483 if (vma
&& ((vma
->vm_flags
& VM_NOHUGEPAGE
) ||
484 test_bit(MMF_DISABLE_THP
, &vma
->vm_mm
->flags
)))
486 if (shmem_huge
== SHMEM_HUGE_FORCE
)
489 switch (SHMEM_SB(inode
->i_sb
)->huge
) {
490 case SHMEM_HUGE_ALWAYS
:
492 case SHMEM_HUGE_WITHIN_SIZE
:
493 index
= round_up(index
+ 1, HPAGE_PMD_NR
);
494 i_size
= round_up(i_size_read(inode
), PAGE_SIZE
);
495 if (i_size
>> PAGE_SHIFT
>= index
)
498 case SHMEM_HUGE_ADVISE
:
499 if (vma
&& (vma
->vm_flags
& VM_HUGEPAGE
))
507 #if defined(CONFIG_SYSFS)
508 static int shmem_parse_huge(const char *str
)
510 if (!strcmp(str
, "never"))
511 return SHMEM_HUGE_NEVER
;
512 if (!strcmp(str
, "always"))
513 return SHMEM_HUGE_ALWAYS
;
514 if (!strcmp(str
, "within_size"))
515 return SHMEM_HUGE_WITHIN_SIZE
;
516 if (!strcmp(str
, "advise"))
517 return SHMEM_HUGE_ADVISE
;
518 if (!strcmp(str
, "deny"))
519 return SHMEM_HUGE_DENY
;
520 if (!strcmp(str
, "force"))
521 return SHMEM_HUGE_FORCE
;
526 #if defined(CONFIG_SYSFS) || defined(CONFIG_TMPFS)
527 static const char *shmem_format_huge(int huge
)
530 case SHMEM_HUGE_NEVER
:
532 case SHMEM_HUGE_ALWAYS
:
534 case SHMEM_HUGE_WITHIN_SIZE
:
535 return "within_size";
536 case SHMEM_HUGE_ADVISE
:
538 case SHMEM_HUGE_DENY
:
540 case SHMEM_HUGE_FORCE
:
549 static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info
*sbinfo
,
550 struct shrink_control
*sc
, unsigned long nr_to_split
)
552 LIST_HEAD(list
), *pos
, *next
;
553 LIST_HEAD(to_remove
);
555 struct shmem_inode_info
*info
;
557 unsigned long batch
= sc
? sc
->nr_to_scan
: 128;
560 if (list_empty(&sbinfo
->shrinklist
))
563 spin_lock(&sbinfo
->shrinklist_lock
);
564 list_for_each_safe(pos
, next
, &sbinfo
->shrinklist
) {
565 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
568 inode
= igrab(&info
->vfs_inode
);
570 /* inode is about to be evicted */
572 list_del_init(&info
->shrinklist
);
576 /* Check if there's anything to gain */
577 if (round_up(inode
->i_size
, PAGE_SIZE
) ==
578 round_up(inode
->i_size
, HPAGE_PMD_SIZE
)) {
579 list_move(&info
->shrinklist
, &to_remove
);
583 list_move(&info
->shrinklist
, &list
);
585 sbinfo
->shrinklist_len
--;
589 spin_unlock(&sbinfo
->shrinklist_lock
);
591 list_for_each_safe(pos
, next
, &to_remove
) {
592 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
593 inode
= &info
->vfs_inode
;
594 list_del_init(&info
->shrinklist
);
598 list_for_each_safe(pos
, next
, &list
) {
601 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
602 inode
= &info
->vfs_inode
;
604 if (nr_to_split
&& split
>= nr_to_split
)
607 page
= find_get_page(inode
->i_mapping
,
608 (inode
->i_size
& HPAGE_PMD_MASK
) >> PAGE_SHIFT
);
612 /* No huge page at the end of the file: nothing to split */
613 if (!PageTransHuge(page
)) {
619 * Move the inode on the list back to shrinklist if we failed
620 * to lock the page at this time.
622 * Waiting for the lock may lead to deadlock in the
625 if (!trylock_page(page
)) {
630 ret
= split_huge_page(page
);
634 /* If split failed move the inode on the list back to shrinklist */
640 list_del_init(&info
->shrinklist
);
644 * Make sure the inode is either on the global list or deleted
645 * from any local list before iput() since it could be deleted
646 * in another thread once we put the inode (then the local list
649 spin_lock(&sbinfo
->shrinklist_lock
);
650 list_move(&info
->shrinklist
, &sbinfo
->shrinklist
);
651 sbinfo
->shrinklist_len
++;
652 spin_unlock(&sbinfo
->shrinklist_lock
);
660 static long shmem_unused_huge_scan(struct super_block
*sb
,
661 struct shrink_control
*sc
)
663 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
665 if (!READ_ONCE(sbinfo
->shrinklist_len
))
668 return shmem_unused_huge_shrink(sbinfo
, sc
, 0);
671 static long shmem_unused_huge_count(struct super_block
*sb
,
672 struct shrink_control
*sc
)
674 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
675 return READ_ONCE(sbinfo
->shrinklist_len
);
677 #else /* !CONFIG_TRANSPARENT_HUGEPAGE */
679 #define shmem_huge SHMEM_HUGE_DENY
681 bool shmem_is_huge(struct vm_area_struct
*vma
,
682 struct inode
*inode
, pgoff_t index
)
687 static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info
*sbinfo
,
688 struct shrink_control
*sc
, unsigned long nr_to_split
)
692 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
695 * Like add_to_page_cache_locked, but error if expected item has gone.
697 static int shmem_add_to_page_cache(struct page
*page
,
698 struct address_space
*mapping
,
699 pgoff_t index
, void *expected
, gfp_t gfp
,
700 struct mm_struct
*charge_mm
)
702 XA_STATE_ORDER(xas
, &mapping
->i_pages
, index
, compound_order(page
));
703 unsigned long nr
= compound_nr(page
);
706 VM_BUG_ON_PAGE(PageTail(page
), page
);
707 VM_BUG_ON_PAGE(index
!= round_down(index
, nr
), page
);
708 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
709 VM_BUG_ON_PAGE(!PageSwapBacked(page
), page
);
710 VM_BUG_ON(expected
&& PageTransHuge(page
));
712 page_ref_add(page
, nr
);
713 page
->mapping
= mapping
;
716 if (!PageSwapCache(page
)) {
717 error
= mem_cgroup_charge(page_folio(page
), charge_mm
, gfp
);
719 if (PageTransHuge(page
)) {
720 count_vm_event(THP_FILE_FALLBACK
);
721 count_vm_event(THP_FILE_FALLBACK_CHARGE
);
726 cgroup_throttle_swaprate(page
, gfp
);
730 if (expected
!= xas_find_conflict(&xas
)) {
731 xas_set_err(&xas
, -EEXIST
);
734 if (expected
&& xas_find_conflict(&xas
)) {
735 xas_set_err(&xas
, -EEXIST
);
738 xas_store(&xas
, page
);
741 if (PageTransHuge(page
)) {
742 count_vm_event(THP_FILE_ALLOC
);
743 __mod_lruvec_page_state(page
, NR_SHMEM_THPS
, nr
);
745 mapping
->nrpages
+= nr
;
746 __mod_lruvec_page_state(page
, NR_FILE_PAGES
, nr
);
747 __mod_lruvec_page_state(page
, NR_SHMEM
, nr
);
749 xas_unlock_irq(&xas
);
750 } while (xas_nomem(&xas
, gfp
));
752 if (xas_error(&xas
)) {
753 error
= xas_error(&xas
);
759 page
->mapping
= NULL
;
760 page_ref_sub(page
, nr
);
765 * Like delete_from_page_cache, but substitutes swap for page.
767 static void shmem_delete_from_page_cache(struct page
*page
, void *radswap
)
769 struct address_space
*mapping
= page
->mapping
;
772 VM_BUG_ON_PAGE(PageCompound(page
), page
);
774 xa_lock_irq(&mapping
->i_pages
);
775 error
= shmem_replace_entry(mapping
, page
->index
, page
, radswap
);
776 page
->mapping
= NULL
;
778 __dec_lruvec_page_state(page
, NR_FILE_PAGES
);
779 __dec_lruvec_page_state(page
, NR_SHMEM
);
780 xa_unlock_irq(&mapping
->i_pages
);
786 * Remove swap entry from page cache, free the swap and its page cache.
788 static int shmem_free_swap(struct address_space
*mapping
,
789 pgoff_t index
, void *radswap
)
793 old
= xa_cmpxchg_irq(&mapping
->i_pages
, index
, radswap
, NULL
, 0);
796 free_swap_and_cache(radix_to_swp_entry(radswap
));
801 * Determine (in bytes) how many of the shmem object's pages mapped by the
802 * given offsets are swapped out.
804 * This is safe to call without i_rwsem or the i_pages lock thanks to RCU,
805 * as long as the inode doesn't go away and racy results are not a problem.
807 unsigned long shmem_partial_swap_usage(struct address_space
*mapping
,
808 pgoff_t start
, pgoff_t end
)
810 XA_STATE(xas
, &mapping
->i_pages
, start
);
812 unsigned long swapped
= 0;
815 xas_for_each(&xas
, page
, end
- 1) {
816 if (xas_retry(&xas
, page
))
818 if (xa_is_value(page
))
821 if (need_resched()) {
829 return swapped
<< PAGE_SHIFT
;
833 * Determine (in bytes) how many of the shmem object's pages mapped by the
834 * given vma is swapped out.
836 * This is safe to call without i_rwsem or the i_pages lock thanks to RCU,
837 * as long as the inode doesn't go away and racy results are not a problem.
839 unsigned long shmem_swap_usage(struct vm_area_struct
*vma
)
841 struct inode
*inode
= file_inode(vma
->vm_file
);
842 struct shmem_inode_info
*info
= SHMEM_I(inode
);
843 struct address_space
*mapping
= inode
->i_mapping
;
844 unsigned long swapped
;
846 /* Be careful as we don't hold info->lock */
847 swapped
= READ_ONCE(info
->swapped
);
850 * The easier cases are when the shmem object has nothing in swap, or
851 * the vma maps it whole. Then we can simply use the stats that we
857 if (!vma
->vm_pgoff
&& vma
->vm_end
- vma
->vm_start
>= inode
->i_size
)
858 return swapped
<< PAGE_SHIFT
;
860 /* Here comes the more involved part */
861 return shmem_partial_swap_usage(mapping
, vma
->vm_pgoff
,
862 vma
->vm_pgoff
+ vma_pages(vma
));
866 * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
868 void shmem_unlock_mapping(struct address_space
*mapping
)
875 * Minor point, but we might as well stop if someone else SHM_LOCKs it.
877 while (!mapping_unevictable(mapping
)) {
878 if (!pagevec_lookup(&pvec
, mapping
, &index
))
880 check_move_unevictable_pages(&pvec
);
881 pagevec_release(&pvec
);
886 static struct folio
*shmem_get_partial_folio(struct inode
*inode
, pgoff_t index
)
892 * At first avoid shmem_getpage(,,,SGP_READ): that fails
893 * beyond i_size, and reports fallocated pages as holes.
895 folio
= __filemap_get_folio(inode
->i_mapping
, index
,
896 FGP_ENTRY
| FGP_LOCK
, 0);
897 if (!xa_is_value(folio
))
900 * But read a page back from swap if any of it is within i_size
901 * (although in some cases this is just a waste of time).
904 shmem_getpage(inode
, index
, &page
, SGP_READ
);
905 return page
? page_folio(page
) : NULL
;
909 * Remove range of pages and swap entries from page cache, and free them.
910 * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
912 static void shmem_undo_range(struct inode
*inode
, loff_t lstart
, loff_t lend
,
915 struct address_space
*mapping
= inode
->i_mapping
;
916 struct shmem_inode_info
*info
= SHMEM_I(inode
);
917 pgoff_t start
= (lstart
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
918 pgoff_t end
= (lend
+ 1) >> PAGE_SHIFT
;
919 struct folio_batch fbatch
;
920 pgoff_t indices
[PAGEVEC_SIZE
];
923 long nr_swaps_freed
= 0;
928 end
= -1; /* unsigned, so actually very big */
930 if (info
->fallocend
> start
&& info
->fallocend
<= end
&& !unfalloc
)
931 info
->fallocend
= start
;
933 folio_batch_init(&fbatch
);
935 while (index
< end
&& find_lock_entries(mapping
, index
, end
- 1,
937 for (i
= 0; i
< folio_batch_count(&fbatch
); i
++) {
938 folio
= fbatch
.folios
[i
];
942 if (xa_is_value(folio
)) {
945 nr_swaps_freed
+= !shmem_free_swap(mapping
,
949 index
+= folio_nr_pages(folio
) - 1;
951 if (!unfalloc
|| !folio_test_uptodate(folio
))
952 truncate_inode_folio(mapping
, folio
);
955 folio_batch_remove_exceptionals(&fbatch
);
956 folio_batch_release(&fbatch
);
961 same_folio
= (lstart
>> PAGE_SHIFT
) == (lend
>> PAGE_SHIFT
);
962 folio
= shmem_get_partial_folio(inode
, lstart
>> PAGE_SHIFT
);
964 same_folio
= lend
< folio_pos(folio
) + folio_size(folio
);
965 folio_mark_dirty(folio
);
966 if (!truncate_inode_partial_folio(folio
, lstart
, lend
)) {
967 start
= folio
->index
+ folio_nr_pages(folio
);
977 folio
= shmem_get_partial_folio(inode
, lend
>> PAGE_SHIFT
);
979 folio_mark_dirty(folio
);
980 if (!truncate_inode_partial_folio(folio
, lstart
, lend
))
987 while (index
< end
) {
990 if (!find_get_entries(mapping
, index
, end
- 1, &fbatch
,
992 /* If all gone or hole-punch or unfalloc, we're done */
993 if (index
== start
|| end
!= -1)
995 /* But if truncating, restart to make sure all gone */
999 for (i
= 0; i
< folio_batch_count(&fbatch
); i
++) {
1000 folio
= fbatch
.folios
[i
];
1003 if (xa_is_value(folio
)) {
1006 if (shmem_free_swap(mapping
, index
, folio
)) {
1007 /* Swap was replaced by page: retry */
1017 if (!unfalloc
|| !folio_test_uptodate(folio
)) {
1018 if (folio_mapping(folio
) != mapping
) {
1019 /* Page was replaced by swap: retry */
1020 folio_unlock(folio
);
1024 VM_BUG_ON_FOLIO(folio_test_writeback(folio
),
1026 truncate_inode_folio(mapping
, folio
);
1028 index
= folio
->index
+ folio_nr_pages(folio
) - 1;
1029 folio_unlock(folio
);
1031 folio_batch_remove_exceptionals(&fbatch
);
1032 folio_batch_release(&fbatch
);
1036 spin_lock_irq(&info
->lock
);
1037 info
->swapped
-= nr_swaps_freed
;
1038 shmem_recalc_inode(inode
);
1039 spin_unlock_irq(&info
->lock
);
1042 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
1044 shmem_undo_range(inode
, lstart
, lend
, false);
1045 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
1047 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
1049 static int shmem_getattr(struct user_namespace
*mnt_userns
,
1050 const struct path
*path
, struct kstat
*stat
,
1051 u32 request_mask
, unsigned int query_flags
)
1053 struct inode
*inode
= path
->dentry
->d_inode
;
1054 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1056 if (info
->alloced
- info
->swapped
!= inode
->i_mapping
->nrpages
) {
1057 spin_lock_irq(&info
->lock
);
1058 shmem_recalc_inode(inode
);
1059 spin_unlock_irq(&info
->lock
);
1061 generic_fillattr(&init_user_ns
, inode
, stat
);
1063 if (shmem_is_huge(NULL
, inode
, 0))
1064 stat
->blksize
= HPAGE_PMD_SIZE
;
1066 if (request_mask
& STATX_BTIME
) {
1067 stat
->result_mask
|= STATX_BTIME
;
1068 stat
->btime
.tv_sec
= info
->i_crtime
.tv_sec
;
1069 stat
->btime
.tv_nsec
= info
->i_crtime
.tv_nsec
;
1075 static int shmem_setattr(struct user_namespace
*mnt_userns
,
1076 struct dentry
*dentry
, struct iattr
*attr
)
1078 struct inode
*inode
= d_inode(dentry
);
1079 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1082 error
= setattr_prepare(&init_user_ns
, dentry
, attr
);
1086 if (S_ISREG(inode
->i_mode
) && (attr
->ia_valid
& ATTR_SIZE
)) {
1087 loff_t oldsize
= inode
->i_size
;
1088 loff_t newsize
= attr
->ia_size
;
1090 /* protected by i_rwsem */
1091 if ((newsize
< oldsize
&& (info
->seals
& F_SEAL_SHRINK
)) ||
1092 (newsize
> oldsize
&& (info
->seals
& F_SEAL_GROW
)))
1095 if (newsize
!= oldsize
) {
1096 error
= shmem_reacct_size(SHMEM_I(inode
)->flags
,
1100 i_size_write(inode
, newsize
);
1101 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
1103 if (newsize
<= oldsize
) {
1104 loff_t holebegin
= round_up(newsize
, PAGE_SIZE
);
1105 if (oldsize
> holebegin
)
1106 unmap_mapping_range(inode
->i_mapping
,
1109 shmem_truncate_range(inode
,
1110 newsize
, (loff_t
)-1);
1111 /* unmap again to remove racily COWed private pages */
1112 if (oldsize
> holebegin
)
1113 unmap_mapping_range(inode
->i_mapping
,
1118 setattr_copy(&init_user_ns
, inode
, attr
);
1119 if (attr
->ia_valid
& ATTR_MODE
)
1120 error
= posix_acl_chmod(&init_user_ns
, inode
, inode
->i_mode
);
1124 static void shmem_evict_inode(struct inode
*inode
)
1126 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1127 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
1129 if (shmem_mapping(inode
->i_mapping
)) {
1130 shmem_unacct_size(info
->flags
, inode
->i_size
);
1132 mapping_set_exiting(inode
->i_mapping
);
1133 shmem_truncate_range(inode
, 0, (loff_t
)-1);
1134 if (!list_empty(&info
->shrinklist
)) {
1135 spin_lock(&sbinfo
->shrinklist_lock
);
1136 if (!list_empty(&info
->shrinklist
)) {
1137 list_del_init(&info
->shrinklist
);
1138 sbinfo
->shrinklist_len
--;
1140 spin_unlock(&sbinfo
->shrinklist_lock
);
1142 while (!list_empty(&info
->swaplist
)) {
1143 /* Wait while shmem_unuse() is scanning this inode... */
1144 wait_var_event(&info
->stop_eviction
,
1145 !atomic_read(&info
->stop_eviction
));
1146 mutex_lock(&shmem_swaplist_mutex
);
1147 /* ...but beware of the race if we peeked too early */
1148 if (!atomic_read(&info
->stop_eviction
))
1149 list_del_init(&info
->swaplist
);
1150 mutex_unlock(&shmem_swaplist_mutex
);
1154 simple_xattrs_free(&info
->xattrs
);
1155 WARN_ON(inode
->i_blocks
);
1156 shmem_free_inode(inode
->i_sb
);
1160 static int shmem_find_swap_entries(struct address_space
*mapping
,
1161 pgoff_t start
, unsigned int nr_entries
,
1162 struct page
**entries
, pgoff_t
*indices
,
1165 XA_STATE(xas
, &mapping
->i_pages
, start
);
1168 unsigned int ret
= 0;
1174 xas_for_each(&xas
, page
, ULONG_MAX
) {
1175 if (xas_retry(&xas
, page
))
1178 if (!xa_is_value(page
))
1181 entry
= radix_to_swp_entry(page
);
1182 if (swp_type(entry
) != type
)
1185 indices
[ret
] = xas
.xa_index
;
1186 entries
[ret
] = page
;
1188 if (need_resched()) {
1192 if (++ret
== nr_entries
)
1201 * Move the swapped pages for an inode to page cache. Returns the count
1202 * of pages swapped in, or the error in case of failure.
1204 static int shmem_unuse_swap_entries(struct inode
*inode
, struct pagevec pvec
,
1210 struct address_space
*mapping
= inode
->i_mapping
;
1212 for (i
= 0; i
< pvec
.nr
; i
++) {
1213 struct page
*page
= pvec
.pages
[i
];
1215 if (!xa_is_value(page
))
1217 error
= shmem_swapin_page(inode
, indices
[i
],
1219 mapping_gfp_mask(mapping
),
1226 if (error
== -ENOMEM
)
1230 return error
? error
: ret
;
1234 * If swap found in inode, free it and move page from swapcache to filecache.
1236 static int shmem_unuse_inode(struct inode
*inode
, unsigned int type
)
1238 struct address_space
*mapping
= inode
->i_mapping
;
1240 struct pagevec pvec
;
1241 pgoff_t indices
[PAGEVEC_SIZE
];
1244 pagevec_init(&pvec
);
1246 unsigned int nr_entries
= PAGEVEC_SIZE
;
1248 pvec
.nr
= shmem_find_swap_entries(mapping
, start
, nr_entries
,
1249 pvec
.pages
, indices
, type
);
1255 ret
= shmem_unuse_swap_entries(inode
, pvec
, indices
);
1259 start
= indices
[pvec
.nr
- 1];
1266 * Read all the shared memory data that resides in the swap
1267 * device 'type' back into memory, so the swap device can be
1270 int shmem_unuse(unsigned int type
)
1272 struct shmem_inode_info
*info
, *next
;
1275 if (list_empty(&shmem_swaplist
))
1278 mutex_lock(&shmem_swaplist_mutex
);
1279 list_for_each_entry_safe(info
, next
, &shmem_swaplist
, swaplist
) {
1280 if (!info
->swapped
) {
1281 list_del_init(&info
->swaplist
);
1285 * Drop the swaplist mutex while searching the inode for swap;
1286 * but before doing so, make sure shmem_evict_inode() will not
1287 * remove placeholder inode from swaplist, nor let it be freed
1288 * (igrab() would protect from unlink, but not from unmount).
1290 atomic_inc(&info
->stop_eviction
);
1291 mutex_unlock(&shmem_swaplist_mutex
);
1293 error
= shmem_unuse_inode(&info
->vfs_inode
, type
);
1296 mutex_lock(&shmem_swaplist_mutex
);
1297 next
= list_next_entry(info
, swaplist
);
1299 list_del_init(&info
->swaplist
);
1300 if (atomic_dec_and_test(&info
->stop_eviction
))
1301 wake_up_var(&info
->stop_eviction
);
1305 mutex_unlock(&shmem_swaplist_mutex
);
1311 * Move the page from the page cache to the swap cache.
1313 static int shmem_writepage(struct page
*page
, struct writeback_control
*wbc
)
1315 struct shmem_inode_info
*info
;
1316 struct address_space
*mapping
;
1317 struct inode
*inode
;
1322 * If /sys/kernel/mm/transparent_hugepage/shmem_enabled is "always" or
1323 * "force", drivers/gpu/drm/i915/gem/i915_gem_shmem.c gets huge pages,
1324 * and its shmem_writeback() needs them to be split when swapping.
1326 if (PageTransCompound(page
)) {
1327 /* Ensure the subpages are still dirty */
1329 if (split_huge_page(page
) < 0)
1331 ClearPageDirty(page
);
1334 BUG_ON(!PageLocked(page
));
1335 mapping
= page
->mapping
;
1336 index
= page
->index
;
1337 inode
= mapping
->host
;
1338 info
= SHMEM_I(inode
);
1339 if (info
->flags
& VM_LOCKED
)
1341 if (!total_swap_pages
)
1345 * Our capabilities prevent regular writeback or sync from ever calling
1346 * shmem_writepage; but a stacking filesystem might use ->writepage of
1347 * its underlying filesystem, in which case tmpfs should write out to
1348 * swap only in response to memory pressure, and not for the writeback
1351 if (!wbc
->for_reclaim
) {
1352 WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
1357 * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC
1358 * value into swapfile.c, the only way we can correctly account for a
1359 * fallocated page arriving here is now to initialize it and write it.
1361 * That's okay for a page already fallocated earlier, but if we have
1362 * not yet completed the fallocation, then (a) we want to keep track
1363 * of this page in case we have to undo it, and (b) it may not be a
1364 * good idea to continue anyway, once we're pushing into swap. So
1365 * reactivate the page, and let shmem_fallocate() quit when too many.
1367 if (!PageUptodate(page
)) {
1368 if (inode
->i_private
) {
1369 struct shmem_falloc
*shmem_falloc
;
1370 spin_lock(&inode
->i_lock
);
1371 shmem_falloc
= inode
->i_private
;
1373 !shmem_falloc
->waitq
&&
1374 index
>= shmem_falloc
->start
&&
1375 index
< shmem_falloc
->next
)
1376 shmem_falloc
->nr_unswapped
++;
1378 shmem_falloc
= NULL
;
1379 spin_unlock(&inode
->i_lock
);
1383 clear_highpage(page
);
1384 flush_dcache_page(page
);
1385 SetPageUptodate(page
);
1388 swap
= get_swap_page(page
);
1393 * Add inode to shmem_unuse()'s list of swapped-out inodes,
1394 * if it's not already there. Do it now before the page is
1395 * moved to swap cache, when its pagelock no longer protects
1396 * the inode from eviction. But don't unlock the mutex until
1397 * we've incremented swapped, because shmem_unuse_inode() will
1398 * prune a !swapped inode from the swaplist under this mutex.
1400 mutex_lock(&shmem_swaplist_mutex
);
1401 if (list_empty(&info
->swaplist
))
1402 list_add(&info
->swaplist
, &shmem_swaplist
);
1404 if (add_to_swap_cache(page
, swap
,
1405 __GFP_HIGH
| __GFP_NOMEMALLOC
| __GFP_NOWARN
,
1407 spin_lock_irq(&info
->lock
);
1408 shmem_recalc_inode(inode
);
1410 spin_unlock_irq(&info
->lock
);
1412 swap_shmem_alloc(swap
);
1413 shmem_delete_from_page_cache(page
, swp_to_radix_entry(swap
));
1415 mutex_unlock(&shmem_swaplist_mutex
);
1416 BUG_ON(page_mapped(page
));
1417 swap_writepage(page
, wbc
);
1421 mutex_unlock(&shmem_swaplist_mutex
);
1422 put_swap_page(page
, swap
);
1424 set_page_dirty(page
);
1425 if (wbc
->for_reclaim
)
1426 return AOP_WRITEPAGE_ACTIVATE
; /* Return with page locked */
1431 #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
1432 static void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1436 if (!mpol
|| mpol
->mode
== MPOL_DEFAULT
)
1437 return; /* show nothing */
1439 mpol_to_str(buffer
, sizeof(buffer
), mpol
);
1441 seq_printf(seq
, ",mpol=%s", buffer
);
1444 static struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1446 struct mempolicy
*mpol
= NULL
;
1448 raw_spin_lock(&sbinfo
->stat_lock
); /* prevent replace/use races */
1449 mpol
= sbinfo
->mpol
;
1451 raw_spin_unlock(&sbinfo
->stat_lock
);
1455 #else /* !CONFIG_NUMA || !CONFIG_TMPFS */
1456 static inline void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1459 static inline struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1463 #endif /* CONFIG_NUMA && CONFIG_TMPFS */
1465 #define vm_policy vm_private_data
1468 static void shmem_pseudo_vma_init(struct vm_area_struct
*vma
,
1469 struct shmem_inode_info
*info
, pgoff_t index
)
1471 /* Create a pseudo vma that just contains the policy */
1472 vma_init(vma
, NULL
);
1473 /* Bias interleave by inode number to distribute better across nodes */
1474 vma
->vm_pgoff
= index
+ info
->vfs_inode
.i_ino
;
1475 vma
->vm_policy
= mpol_shared_policy_lookup(&info
->policy
, index
);
1478 static void shmem_pseudo_vma_destroy(struct vm_area_struct
*vma
)
1480 /* Drop reference taken by mpol_shared_policy_lookup() */
1481 mpol_cond_put(vma
->vm_policy
);
1484 static struct page
*shmem_swapin(swp_entry_t swap
, gfp_t gfp
,
1485 struct shmem_inode_info
*info
, pgoff_t index
)
1487 struct vm_area_struct pvma
;
1489 struct vm_fault vmf
= {
1493 shmem_pseudo_vma_init(&pvma
, info
, index
);
1494 page
= swap_cluster_readahead(swap
, gfp
, &vmf
);
1495 shmem_pseudo_vma_destroy(&pvma
);
1501 * Make sure huge_gfp is always more limited than limit_gfp.
1502 * Some of the flags set permissions, while others set limitations.
1504 static gfp_t
limit_gfp_mask(gfp_t huge_gfp
, gfp_t limit_gfp
)
1506 gfp_t allowflags
= __GFP_IO
| __GFP_FS
| __GFP_RECLAIM
;
1507 gfp_t denyflags
= __GFP_NOWARN
| __GFP_NORETRY
;
1508 gfp_t zoneflags
= limit_gfp
& GFP_ZONEMASK
;
1509 gfp_t result
= huge_gfp
& ~(allowflags
| GFP_ZONEMASK
);
1511 /* Allow allocations only from the originally specified zones. */
1512 result
|= zoneflags
;
1515 * Minimize the result gfp by taking the union with the deny flags,
1516 * and the intersection of the allow flags.
1518 result
|= (limit_gfp
& denyflags
);
1519 result
|= (huge_gfp
& limit_gfp
) & allowflags
;
1524 static struct page
*shmem_alloc_hugepage(gfp_t gfp
,
1525 struct shmem_inode_info
*info
, pgoff_t index
)
1527 struct vm_area_struct pvma
;
1528 struct address_space
*mapping
= info
->vfs_inode
.i_mapping
;
1532 hindex
= round_down(index
, HPAGE_PMD_NR
);
1533 if (xa_find(&mapping
->i_pages
, &hindex
, hindex
+ HPAGE_PMD_NR
- 1,
1537 shmem_pseudo_vma_init(&pvma
, info
, hindex
);
1538 page
= alloc_pages_vma(gfp
, HPAGE_PMD_ORDER
, &pvma
, 0, true);
1539 shmem_pseudo_vma_destroy(&pvma
);
1541 prep_transhuge_page(page
);
1543 count_vm_event(THP_FILE_FALLBACK
);
1547 static struct page
*shmem_alloc_page(gfp_t gfp
,
1548 struct shmem_inode_info
*info
, pgoff_t index
)
1550 struct vm_area_struct pvma
;
1553 shmem_pseudo_vma_init(&pvma
, info
, index
);
1554 page
= alloc_page_vma(gfp
, &pvma
, 0);
1555 shmem_pseudo_vma_destroy(&pvma
);
1560 static struct page
*shmem_alloc_and_acct_page(gfp_t gfp
,
1561 struct inode
*inode
,
1562 pgoff_t index
, bool huge
)
1564 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1569 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
))
1571 nr
= huge
? HPAGE_PMD_NR
: 1;
1573 if (!shmem_inode_acct_block(inode
, nr
))
1577 page
= shmem_alloc_hugepage(gfp
, info
, index
);
1579 page
= shmem_alloc_page(gfp
, info
, index
);
1581 __SetPageLocked(page
);
1582 __SetPageSwapBacked(page
);
1587 shmem_inode_unacct_blocks(inode
, nr
);
1589 return ERR_PTR(err
);
1593 * When a page is moved from swapcache to shmem filecache (either by the
1594 * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
1595 * shmem_unuse_inode()), it may have been read in earlier from swap, in
1596 * ignorance of the mapping it belongs to. If that mapping has special
1597 * constraints (like the gma500 GEM driver, which requires RAM below 4GB),
1598 * we may need to copy to a suitable page before moving to filecache.
1600 * In a future release, this may well be extended to respect cpuset and
1601 * NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
1602 * but for now it is a simple matter of zone.
1604 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
)
1606 return page_zonenum(page
) > gfp_zone(gfp
);
1609 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
1610 struct shmem_inode_info
*info
, pgoff_t index
)
1612 struct page
*oldpage
, *newpage
;
1613 struct folio
*old
, *new;
1614 struct address_space
*swap_mapping
;
1620 entry
.val
= page_private(oldpage
);
1621 swap_index
= swp_offset(entry
);
1622 swap_mapping
= page_mapping(oldpage
);
1625 * We have arrived here because our zones are constrained, so don't
1626 * limit chance of success by further cpuset and node constraints.
1628 gfp
&= ~GFP_CONSTRAINT_MASK
;
1629 newpage
= shmem_alloc_page(gfp
, info
, index
);
1634 copy_highpage(newpage
, oldpage
);
1635 flush_dcache_page(newpage
);
1637 __SetPageLocked(newpage
);
1638 __SetPageSwapBacked(newpage
);
1639 SetPageUptodate(newpage
);
1640 set_page_private(newpage
, entry
.val
);
1641 SetPageSwapCache(newpage
);
1644 * Our caller will very soon move newpage out of swapcache, but it's
1645 * a nice clean interface for us to replace oldpage by newpage there.
1647 xa_lock_irq(&swap_mapping
->i_pages
);
1648 error
= shmem_replace_entry(swap_mapping
, swap_index
, oldpage
, newpage
);
1650 old
= page_folio(oldpage
);
1651 new = page_folio(newpage
);
1652 mem_cgroup_migrate(old
, new);
1653 __inc_lruvec_page_state(newpage
, NR_FILE_PAGES
);
1654 __dec_lruvec_page_state(oldpage
, NR_FILE_PAGES
);
1656 xa_unlock_irq(&swap_mapping
->i_pages
);
1658 if (unlikely(error
)) {
1660 * Is this possible? I think not, now that our callers check
1661 * both PageSwapCache and page_private after getting page lock;
1662 * but be defensive. Reverse old to newpage for clear and free.
1666 lru_cache_add(newpage
);
1670 ClearPageSwapCache(oldpage
);
1671 set_page_private(oldpage
, 0);
1673 unlock_page(oldpage
);
1680 * Swap in the page pointed to by *pagep.
1681 * Caller has to make sure that *pagep contains a valid swapped page.
1682 * Returns 0 and the page in pagep if success. On failure, returns the
1683 * error code and NULL in *pagep.
1685 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
1686 struct page
**pagep
, enum sgp_type sgp
,
1687 gfp_t gfp
, struct vm_area_struct
*vma
,
1688 vm_fault_t
*fault_type
)
1690 struct address_space
*mapping
= inode
->i_mapping
;
1691 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1692 struct mm_struct
*charge_mm
= vma
? vma
->vm_mm
: NULL
;
1697 VM_BUG_ON(!*pagep
|| !xa_is_value(*pagep
));
1698 swap
= radix_to_swp_entry(*pagep
);
1701 /* Look it up and read it in.. */
1702 page
= lookup_swap_cache(swap
, NULL
, 0);
1704 /* Or update major stats only when swapin succeeds?? */
1706 *fault_type
|= VM_FAULT_MAJOR
;
1707 count_vm_event(PGMAJFAULT
);
1708 count_memcg_event_mm(charge_mm
, PGMAJFAULT
);
1710 /* Here we actually start the io */
1711 page
= shmem_swapin(swap
, gfp
, info
, index
);
1718 /* We have to do this with page locked to prevent races */
1720 if (!PageSwapCache(page
) || page_private(page
) != swap
.val
||
1721 !shmem_confirm_swap(mapping
, index
, swap
)) {
1725 if (!PageUptodate(page
)) {
1729 wait_on_page_writeback(page
);
1732 * Some architectures may have to restore extra metadata to the
1733 * physical page after reading from swap.
1735 arch_swap_restore(swap
, page
);
1737 if (shmem_should_replace_page(page
, gfp
)) {
1738 error
= shmem_replace_page(&page
, gfp
, info
, index
);
1743 error
= shmem_add_to_page_cache(page
, mapping
, index
,
1744 swp_to_radix_entry(swap
), gfp
,
1749 spin_lock_irq(&info
->lock
);
1751 shmem_recalc_inode(inode
);
1752 spin_unlock_irq(&info
->lock
);
1754 if (sgp
== SGP_WRITE
)
1755 mark_page_accessed(page
);
1757 delete_from_swap_cache(page
);
1758 set_page_dirty(page
);
1764 if (!shmem_confirm_swap(mapping
, index
, swap
))
1776 * shmem_getpage_gfp - find page in cache, or get from swap, or allocate
1778 * If we allocate a new one we do not mark it dirty. That's up to the
1779 * vm. If we swap it in we mark it dirty since we also free the swap
1780 * entry since a page cannot live in both the swap and page cache.
1782 * vma, vmf, and fault_type are only supplied by shmem_fault:
1783 * otherwise they are NULL.
1785 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
1786 struct page
**pagep
, enum sgp_type sgp
, gfp_t gfp
,
1787 struct vm_area_struct
*vma
, struct vm_fault
*vmf
,
1788 vm_fault_t
*fault_type
)
1790 struct address_space
*mapping
= inode
->i_mapping
;
1791 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1792 struct shmem_sb_info
*sbinfo
;
1793 struct mm_struct
*charge_mm
;
1795 pgoff_t hindex
= index
;
1801 if (index
> (MAX_LFS_FILESIZE
>> PAGE_SHIFT
))
1804 if (sgp
<= SGP_CACHE
&&
1805 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1809 sbinfo
= SHMEM_SB(inode
->i_sb
);
1810 charge_mm
= vma
? vma
->vm_mm
: NULL
;
1812 page
= pagecache_get_page(mapping
, index
,
1813 FGP_ENTRY
| FGP_HEAD
| FGP_LOCK
, 0);
1815 if (page
&& vma
&& userfaultfd_minor(vma
)) {
1816 if (!xa_is_value(page
)) {
1820 *fault_type
= handle_userfault(vmf
, VM_UFFD_MINOR
);
1824 if (xa_is_value(page
)) {
1825 error
= shmem_swapin_page(inode
, index
, &page
,
1826 sgp
, gfp
, vma
, fault_type
);
1827 if (error
== -EEXIST
)
1835 hindex
= page
->index
;
1836 if (sgp
== SGP_WRITE
)
1837 mark_page_accessed(page
);
1838 if (PageUptodate(page
))
1840 /* fallocated page */
1841 if (sgp
!= SGP_READ
)
1848 * SGP_READ: succeed on hole, with NULL page, letting caller zero.
1849 * SGP_NOALLOC: fail on hole, with NULL page, letting caller fail.
1852 if (sgp
== SGP_READ
)
1854 if (sgp
== SGP_NOALLOC
)
1858 * Fast cache lookup and swap lookup did not find it: allocate.
1861 if (vma
&& userfaultfd_missing(vma
)) {
1862 *fault_type
= handle_userfault(vmf
, VM_UFFD_MISSING
);
1866 if (!shmem_is_huge(vma
, inode
, index
))
1869 huge_gfp
= vma_thp_gfp_mask(vma
);
1870 huge_gfp
= limit_gfp_mask(huge_gfp
, gfp
);
1871 page
= shmem_alloc_and_acct_page(huge_gfp
, inode
, index
, true);
1874 page
= shmem_alloc_and_acct_page(gfp
, inode
,
1880 error
= PTR_ERR(page
);
1882 if (error
!= -ENOSPC
)
1885 * Try to reclaim some space by splitting a huge page
1886 * beyond i_size on the filesystem.
1891 ret
= shmem_unused_huge_shrink(sbinfo
, NULL
, 1);
1892 if (ret
== SHRINK_STOP
)
1900 if (PageTransHuge(page
))
1901 hindex
= round_down(index
, HPAGE_PMD_NR
);
1905 if (sgp
== SGP_WRITE
)
1906 __SetPageReferenced(page
);
1908 error
= shmem_add_to_page_cache(page
, mapping
, hindex
,
1909 NULL
, gfp
& GFP_RECLAIM_MASK
,
1913 lru_cache_add(page
);
1915 spin_lock_irq(&info
->lock
);
1916 info
->alloced
+= compound_nr(page
);
1917 inode
->i_blocks
+= BLOCKS_PER_PAGE
<< compound_order(page
);
1918 shmem_recalc_inode(inode
);
1919 spin_unlock_irq(&info
->lock
);
1922 if (PageTransHuge(page
) &&
1923 DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
) <
1924 hindex
+ HPAGE_PMD_NR
- 1) {
1926 * Part of the huge page is beyond i_size: subject
1927 * to shrink under memory pressure.
1929 spin_lock(&sbinfo
->shrinklist_lock
);
1931 * _careful to defend against unlocked access to
1932 * ->shrink_list in shmem_unused_huge_shrink()
1934 if (list_empty_careful(&info
->shrinklist
)) {
1935 list_add_tail(&info
->shrinklist
,
1936 &sbinfo
->shrinklist
);
1937 sbinfo
->shrinklist_len
++;
1939 spin_unlock(&sbinfo
->shrinklist_lock
);
1943 * Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
1945 if (sgp
== SGP_FALLOC
)
1949 * Let SGP_WRITE caller clear ends if write does not fill page;
1950 * but SGP_FALLOC on a page fallocated earlier must initialize
1951 * it now, lest undo on failure cancel our earlier guarantee.
1953 if (sgp
!= SGP_WRITE
&& !PageUptodate(page
)) {
1956 for (i
= 0; i
< compound_nr(page
); i
++) {
1957 clear_highpage(page
+ i
);
1958 flush_dcache_page(page
+ i
);
1960 SetPageUptodate(page
);
1963 /* Perhaps the file has been truncated since we checked */
1964 if (sgp
<= SGP_CACHE
&&
1965 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1967 ClearPageDirty(page
);
1968 delete_from_page_cache(page
);
1969 spin_lock_irq(&info
->lock
);
1970 shmem_recalc_inode(inode
);
1971 spin_unlock_irq(&info
->lock
);
1977 *pagep
= page
+ index
- hindex
;
1984 shmem_inode_unacct_blocks(inode
, compound_nr(page
));
1986 if (PageTransHuge(page
)) {
1996 if (error
== -ENOSPC
&& !once
++) {
1997 spin_lock_irq(&info
->lock
);
1998 shmem_recalc_inode(inode
);
1999 spin_unlock_irq(&info
->lock
);
2002 if (error
== -EEXIST
)
2008 * This is like autoremove_wake_function, but it removes the wait queue
2009 * entry unconditionally - even if something else had already woken the
2012 static int synchronous_wake_function(wait_queue_entry_t
*wait
, unsigned mode
, int sync
, void *key
)
2014 int ret
= default_wake_function(wait
, mode
, sync
, key
);
2015 list_del_init(&wait
->entry
);
2019 static vm_fault_t
shmem_fault(struct vm_fault
*vmf
)
2021 struct vm_area_struct
*vma
= vmf
->vma
;
2022 struct inode
*inode
= file_inode(vma
->vm_file
);
2023 gfp_t gfp
= mapping_gfp_mask(inode
->i_mapping
);
2025 vm_fault_t ret
= VM_FAULT_LOCKED
;
2028 * Trinity finds that probing a hole which tmpfs is punching can
2029 * prevent the hole-punch from ever completing: which in turn
2030 * locks writers out with its hold on i_rwsem. So refrain from
2031 * faulting pages into the hole while it's being punched. Although
2032 * shmem_undo_range() does remove the additions, it may be unable to
2033 * keep up, as each new page needs its own unmap_mapping_range() call,
2034 * and the i_mmap tree grows ever slower to scan if new vmas are added.
2036 * It does not matter if we sometimes reach this check just before the
2037 * hole-punch begins, so that one fault then races with the punch:
2038 * we just need to make racing faults a rare case.
2040 * The implementation below would be much simpler if we just used a
2041 * standard mutex or completion: but we cannot take i_rwsem in fault,
2042 * and bloating every shmem inode for this unlikely case would be sad.
2044 if (unlikely(inode
->i_private
)) {
2045 struct shmem_falloc
*shmem_falloc
;
2047 spin_lock(&inode
->i_lock
);
2048 shmem_falloc
= inode
->i_private
;
2050 shmem_falloc
->waitq
&&
2051 vmf
->pgoff
>= shmem_falloc
->start
&&
2052 vmf
->pgoff
< shmem_falloc
->next
) {
2054 wait_queue_head_t
*shmem_falloc_waitq
;
2055 DEFINE_WAIT_FUNC(shmem_fault_wait
, synchronous_wake_function
);
2057 ret
= VM_FAULT_NOPAGE
;
2058 fpin
= maybe_unlock_mmap_for_io(vmf
, NULL
);
2060 ret
= VM_FAULT_RETRY
;
2062 shmem_falloc_waitq
= shmem_falloc
->waitq
;
2063 prepare_to_wait(shmem_falloc_waitq
, &shmem_fault_wait
,
2064 TASK_UNINTERRUPTIBLE
);
2065 spin_unlock(&inode
->i_lock
);
2069 * shmem_falloc_waitq points into the shmem_fallocate()
2070 * stack of the hole-punching task: shmem_falloc_waitq
2071 * is usually invalid by the time we reach here, but
2072 * finish_wait() does not dereference it in that case;
2073 * though i_lock needed lest racing with wake_up_all().
2075 spin_lock(&inode
->i_lock
);
2076 finish_wait(shmem_falloc_waitq
, &shmem_fault_wait
);
2077 spin_unlock(&inode
->i_lock
);
2083 spin_unlock(&inode
->i_lock
);
2086 err
= shmem_getpage_gfp(inode
, vmf
->pgoff
, &vmf
->page
, SGP_CACHE
,
2087 gfp
, vma
, vmf
, &ret
);
2089 return vmf_error(err
);
2093 unsigned long shmem_get_unmapped_area(struct file
*file
,
2094 unsigned long uaddr
, unsigned long len
,
2095 unsigned long pgoff
, unsigned long flags
)
2097 unsigned long (*get_area
)(struct file
*,
2098 unsigned long, unsigned long, unsigned long, unsigned long);
2100 unsigned long offset
;
2101 unsigned long inflated_len
;
2102 unsigned long inflated_addr
;
2103 unsigned long inflated_offset
;
2105 if (len
> TASK_SIZE
)
2108 get_area
= current
->mm
->get_unmapped_area
;
2109 addr
= get_area(file
, uaddr
, len
, pgoff
, flags
);
2111 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
))
2113 if (IS_ERR_VALUE(addr
))
2115 if (addr
& ~PAGE_MASK
)
2117 if (addr
> TASK_SIZE
- len
)
2120 if (shmem_huge
== SHMEM_HUGE_DENY
)
2122 if (len
< HPAGE_PMD_SIZE
)
2124 if (flags
& MAP_FIXED
)
2127 * Our priority is to support MAP_SHARED mapped hugely;
2128 * and support MAP_PRIVATE mapped hugely too, until it is COWed.
2129 * But if caller specified an address hint and we allocated area there
2130 * successfully, respect that as before.
2135 if (shmem_huge
!= SHMEM_HUGE_FORCE
) {
2136 struct super_block
*sb
;
2139 VM_BUG_ON(file
->f_op
!= &shmem_file_operations
);
2140 sb
= file_inode(file
)->i_sb
;
2143 * Called directly from mm/mmap.c, or drivers/char/mem.c
2144 * for "/dev/zero", to create a shared anonymous object.
2146 if (IS_ERR(shm_mnt
))
2148 sb
= shm_mnt
->mnt_sb
;
2150 if (SHMEM_SB(sb
)->huge
== SHMEM_HUGE_NEVER
)
2154 offset
= (pgoff
<< PAGE_SHIFT
) & (HPAGE_PMD_SIZE
-1);
2155 if (offset
&& offset
+ len
< 2 * HPAGE_PMD_SIZE
)
2157 if ((addr
& (HPAGE_PMD_SIZE
-1)) == offset
)
2160 inflated_len
= len
+ HPAGE_PMD_SIZE
- PAGE_SIZE
;
2161 if (inflated_len
> TASK_SIZE
)
2163 if (inflated_len
< len
)
2166 inflated_addr
= get_area(NULL
, uaddr
, inflated_len
, 0, flags
);
2167 if (IS_ERR_VALUE(inflated_addr
))
2169 if (inflated_addr
& ~PAGE_MASK
)
2172 inflated_offset
= inflated_addr
& (HPAGE_PMD_SIZE
-1);
2173 inflated_addr
+= offset
- inflated_offset
;
2174 if (inflated_offset
> offset
)
2175 inflated_addr
+= HPAGE_PMD_SIZE
;
2177 if (inflated_addr
> TASK_SIZE
- len
)
2179 return inflated_addr
;
2183 static int shmem_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*mpol
)
2185 struct inode
*inode
= file_inode(vma
->vm_file
);
2186 return mpol_set_shared_policy(&SHMEM_I(inode
)->policy
, vma
, mpol
);
2189 static struct mempolicy
*shmem_get_policy(struct vm_area_struct
*vma
,
2192 struct inode
*inode
= file_inode(vma
->vm_file
);
2195 index
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2196 return mpol_shared_policy_lookup(&SHMEM_I(inode
)->policy
, index
);
2200 int shmem_lock(struct file
*file
, int lock
, struct ucounts
*ucounts
)
2202 struct inode
*inode
= file_inode(file
);
2203 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2204 int retval
= -ENOMEM
;
2207 * What serializes the accesses to info->flags?
2208 * ipc_lock_object() when called from shmctl_do_lock(),
2209 * no serialization needed when called from shm_destroy().
2211 if (lock
&& !(info
->flags
& VM_LOCKED
)) {
2212 if (!user_shm_lock(inode
->i_size
, ucounts
))
2214 info
->flags
|= VM_LOCKED
;
2215 mapping_set_unevictable(file
->f_mapping
);
2217 if (!lock
&& (info
->flags
& VM_LOCKED
) && ucounts
) {
2218 user_shm_unlock(inode
->i_size
, ucounts
);
2219 info
->flags
&= ~VM_LOCKED
;
2220 mapping_clear_unevictable(file
->f_mapping
);
2228 static int shmem_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2230 struct shmem_inode_info
*info
= SHMEM_I(file_inode(file
));
2233 ret
= seal_check_future_write(info
->seals
, vma
);
2237 /* arm64 - allow memory tagging on RAM-based files */
2238 vma
->vm_flags
|= VM_MTE_ALLOWED
;
2240 file_accessed(file
);
2241 vma
->vm_ops
= &shmem_vm_ops
;
2242 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
2243 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
2244 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
2245 khugepaged_enter(vma
, vma
->vm_flags
);
2250 static struct inode
*shmem_get_inode(struct super_block
*sb
, const struct inode
*dir
,
2251 umode_t mode
, dev_t dev
, unsigned long flags
)
2253 struct inode
*inode
;
2254 struct shmem_inode_info
*info
;
2255 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
2258 if (shmem_reserve_inode(sb
, &ino
))
2261 inode
= new_inode(sb
);
2264 inode_init_owner(&init_user_ns
, inode
, dir
, mode
);
2265 inode
->i_blocks
= 0;
2266 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= current_time(inode
);
2267 inode
->i_generation
= prandom_u32();
2268 info
= SHMEM_I(inode
);
2269 memset(info
, 0, (char *)inode
- (char *)info
);
2270 spin_lock_init(&info
->lock
);
2271 atomic_set(&info
->stop_eviction
, 0);
2272 info
->seals
= F_SEAL_SEAL
;
2273 info
->flags
= flags
& VM_NORESERVE
;
2274 info
->i_crtime
= inode
->i_mtime
;
2275 INIT_LIST_HEAD(&info
->shrinklist
);
2276 INIT_LIST_HEAD(&info
->swaplist
);
2277 simple_xattrs_init(&info
->xattrs
);
2278 cache_no_acl(inode
);
2279 mapping_set_large_folios(inode
->i_mapping
);
2281 switch (mode
& S_IFMT
) {
2283 inode
->i_op
= &shmem_special_inode_operations
;
2284 init_special_inode(inode
, mode
, dev
);
2287 inode
->i_mapping
->a_ops
= &shmem_aops
;
2288 inode
->i_op
= &shmem_inode_operations
;
2289 inode
->i_fop
= &shmem_file_operations
;
2290 mpol_shared_policy_init(&info
->policy
,
2291 shmem_get_sbmpol(sbinfo
));
2295 /* Some things misbehave if size == 0 on a directory */
2296 inode
->i_size
= 2 * BOGO_DIRENT_SIZE
;
2297 inode
->i_op
= &shmem_dir_inode_operations
;
2298 inode
->i_fop
= &simple_dir_operations
;
2302 * Must not load anything in the rbtree,
2303 * mpol_free_shared_policy will not be called.
2305 mpol_shared_policy_init(&info
->policy
, NULL
);
2309 lockdep_annotate_inode_mutex_key(inode
);
2311 shmem_free_inode(sb
);
2315 #ifdef CONFIG_USERFAULTFD
2316 int shmem_mfill_atomic_pte(struct mm_struct
*dst_mm
,
2318 struct vm_area_struct
*dst_vma
,
2319 unsigned long dst_addr
,
2320 unsigned long src_addr
,
2322 struct page
**pagep
)
2324 struct inode
*inode
= file_inode(dst_vma
->vm_file
);
2325 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2326 struct address_space
*mapping
= inode
->i_mapping
;
2327 gfp_t gfp
= mapping_gfp_mask(mapping
);
2328 pgoff_t pgoff
= linear_page_index(dst_vma
, dst_addr
);
2334 if (!shmem_inode_acct_block(inode
, 1)) {
2336 * We may have got a page, returned -ENOENT triggering a retry,
2337 * and now we find ourselves with -ENOMEM. Release the page, to
2338 * avoid a BUG_ON in our caller.
2340 if (unlikely(*pagep
)) {
2349 page
= shmem_alloc_page(gfp
, info
, pgoff
);
2351 goto out_unacct_blocks
;
2353 if (!zeropage
) { /* COPY */
2354 page_kaddr
= kmap_atomic(page
);
2355 ret
= copy_from_user(page_kaddr
,
2356 (const void __user
*)src_addr
,
2358 kunmap_atomic(page_kaddr
);
2360 /* fallback to copy_from_user outside mmap_lock */
2361 if (unlikely(ret
)) {
2364 /* don't free the page */
2365 goto out_unacct_blocks
;
2368 flush_dcache_page(page
);
2369 } else { /* ZEROPAGE */
2370 clear_user_highpage(page
, dst_addr
);
2377 VM_BUG_ON(PageLocked(page
));
2378 VM_BUG_ON(PageSwapBacked(page
));
2379 __SetPageLocked(page
);
2380 __SetPageSwapBacked(page
);
2381 __SetPageUptodate(page
);
2384 max_off
= DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
);
2385 if (unlikely(pgoff
>= max_off
))
2388 ret
= shmem_add_to_page_cache(page
, mapping
, pgoff
, NULL
,
2389 gfp
& GFP_RECLAIM_MASK
, dst_mm
);
2393 ret
= mfill_atomic_install_pte(dst_mm
, dst_pmd
, dst_vma
, dst_addr
,
2396 goto out_delete_from_cache
;
2398 spin_lock_irq(&info
->lock
);
2400 inode
->i_blocks
+= BLOCKS_PER_PAGE
;
2401 shmem_recalc_inode(inode
);
2402 spin_unlock_irq(&info
->lock
);
2406 out_delete_from_cache
:
2407 delete_from_page_cache(page
);
2412 shmem_inode_unacct_blocks(inode
, 1);
2415 #endif /* CONFIG_USERFAULTFD */
2418 static const struct inode_operations shmem_symlink_inode_operations
;
2419 static const struct inode_operations shmem_short_symlink_operations
;
2421 #ifdef CONFIG_TMPFS_XATTR
2422 static int shmem_initxattrs(struct inode
*, const struct xattr
*, void *);
2424 #define shmem_initxattrs NULL
2428 shmem_write_begin(struct file
*file
, struct address_space
*mapping
,
2429 loff_t pos
, unsigned len
, unsigned flags
,
2430 struct page
**pagep
, void **fsdata
)
2432 struct inode
*inode
= mapping
->host
;
2433 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2434 pgoff_t index
= pos
>> PAGE_SHIFT
;
2437 /* i_rwsem is held by caller */
2438 if (unlikely(info
->seals
& (F_SEAL_GROW
|
2439 F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))) {
2440 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))
2442 if ((info
->seals
& F_SEAL_GROW
) && pos
+ len
> inode
->i_size
)
2446 ret
= shmem_getpage(inode
, index
, pagep
, SGP_WRITE
);
2451 if (PageHWPoison(*pagep
)) {
2452 unlock_page(*pagep
);
2462 shmem_write_end(struct file
*file
, struct address_space
*mapping
,
2463 loff_t pos
, unsigned len
, unsigned copied
,
2464 struct page
*page
, void *fsdata
)
2466 struct inode
*inode
= mapping
->host
;
2468 if (pos
+ copied
> inode
->i_size
)
2469 i_size_write(inode
, pos
+ copied
);
2471 if (!PageUptodate(page
)) {
2472 struct page
*head
= compound_head(page
);
2473 if (PageTransCompound(page
)) {
2476 for (i
= 0; i
< HPAGE_PMD_NR
; i
++) {
2477 if (head
+ i
== page
)
2479 clear_highpage(head
+ i
);
2480 flush_dcache_page(head
+ i
);
2483 if (copied
< PAGE_SIZE
) {
2484 unsigned from
= pos
& (PAGE_SIZE
- 1);
2485 zero_user_segments(page
, 0, from
,
2486 from
+ copied
, PAGE_SIZE
);
2488 SetPageUptodate(head
);
2490 set_page_dirty(page
);
2497 static ssize_t
shmem_file_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
2499 struct file
*file
= iocb
->ki_filp
;
2500 struct inode
*inode
= file_inode(file
);
2501 struct address_space
*mapping
= inode
->i_mapping
;
2503 unsigned long offset
;
2506 loff_t
*ppos
= &iocb
->ki_pos
;
2508 index
= *ppos
>> PAGE_SHIFT
;
2509 offset
= *ppos
& ~PAGE_MASK
;
2512 struct page
*page
= NULL
;
2514 unsigned long nr
, ret
;
2515 loff_t i_size
= i_size_read(inode
);
2518 end_index
= i_size
>> PAGE_SHIFT
;
2519 if (index
> end_index
)
2521 if (index
== end_index
) {
2522 nr
= i_size
& ~PAGE_MASK
;
2527 error
= shmem_getpage(inode
, index
, &page
, SGP_READ
);
2529 if (error
== -EINVAL
)
2536 if (PageHWPoison(page
)) {
2544 * We must evaluate after, since reads (unlike writes)
2545 * are called without i_rwsem protection against truncate
2548 i_size
= i_size_read(inode
);
2549 end_index
= i_size
>> PAGE_SHIFT
;
2550 if (index
== end_index
) {
2551 nr
= i_size
& ~PAGE_MASK
;
2562 * If users can be writing to this page using arbitrary
2563 * virtual addresses, take care about potential aliasing
2564 * before reading the page on the kernel side.
2566 if (mapping_writably_mapped(mapping
))
2567 flush_dcache_page(page
);
2569 * Mark the page accessed if we read the beginning.
2572 mark_page_accessed(page
);
2575 page
= ZERO_PAGE(0);
2580 * Ok, we have the page, and it's up-to-date, so
2581 * now we can copy it to user space...
2583 ret
= copy_page_to_iter(page
, offset
, nr
, to
);
2586 index
+= offset
>> PAGE_SHIFT
;
2587 offset
&= ~PAGE_MASK
;
2591 if (!iov_iter_count(to
))
2600 *ppos
= ((loff_t
) index
<< PAGE_SHIFT
) + offset
;
2601 file_accessed(file
);
2602 return retval
? retval
: error
;
2605 static loff_t
shmem_file_llseek(struct file
*file
, loff_t offset
, int whence
)
2607 struct address_space
*mapping
= file
->f_mapping
;
2608 struct inode
*inode
= mapping
->host
;
2610 if (whence
!= SEEK_DATA
&& whence
!= SEEK_HOLE
)
2611 return generic_file_llseek_size(file
, offset
, whence
,
2612 MAX_LFS_FILESIZE
, i_size_read(inode
));
2617 /* We're holding i_rwsem so we can access i_size directly */
2618 offset
= mapping_seek_hole_data(mapping
, offset
, inode
->i_size
, whence
);
2620 offset
= vfs_setpos(file
, offset
, MAX_LFS_FILESIZE
);
2621 inode_unlock(inode
);
2625 static long shmem_fallocate(struct file
*file
, int mode
, loff_t offset
,
2628 struct inode
*inode
= file_inode(file
);
2629 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
2630 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2631 struct shmem_falloc shmem_falloc
;
2632 pgoff_t start
, index
, end
, undo_fallocend
;
2635 if (mode
& ~(FALLOC_FL_KEEP_SIZE
| FALLOC_FL_PUNCH_HOLE
))
2640 if (mode
& FALLOC_FL_PUNCH_HOLE
) {
2641 struct address_space
*mapping
= file
->f_mapping
;
2642 loff_t unmap_start
= round_up(offset
, PAGE_SIZE
);
2643 loff_t unmap_end
= round_down(offset
+ len
, PAGE_SIZE
) - 1;
2644 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq
);
2646 /* protected by i_rwsem */
2647 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
)) {
2652 shmem_falloc
.waitq
= &shmem_falloc_waitq
;
2653 shmem_falloc
.start
= (u64
)unmap_start
>> PAGE_SHIFT
;
2654 shmem_falloc
.next
= (unmap_end
+ 1) >> PAGE_SHIFT
;
2655 spin_lock(&inode
->i_lock
);
2656 inode
->i_private
= &shmem_falloc
;
2657 spin_unlock(&inode
->i_lock
);
2659 if ((u64
)unmap_end
> (u64
)unmap_start
)
2660 unmap_mapping_range(mapping
, unmap_start
,
2661 1 + unmap_end
- unmap_start
, 0);
2662 shmem_truncate_range(inode
, offset
, offset
+ len
- 1);
2663 /* No need to unmap again: hole-punching leaves COWed pages */
2665 spin_lock(&inode
->i_lock
);
2666 inode
->i_private
= NULL
;
2667 wake_up_all(&shmem_falloc_waitq
);
2668 WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq
.head
));
2669 spin_unlock(&inode
->i_lock
);
2674 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
2675 error
= inode_newsize_ok(inode
, offset
+ len
);
2679 if ((info
->seals
& F_SEAL_GROW
) && offset
+ len
> inode
->i_size
) {
2684 start
= offset
>> PAGE_SHIFT
;
2685 end
= (offset
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2686 /* Try to avoid a swapstorm if len is impossible to satisfy */
2687 if (sbinfo
->max_blocks
&& end
- start
> sbinfo
->max_blocks
) {
2692 shmem_falloc
.waitq
= NULL
;
2693 shmem_falloc
.start
= start
;
2694 shmem_falloc
.next
= start
;
2695 shmem_falloc
.nr_falloced
= 0;
2696 shmem_falloc
.nr_unswapped
= 0;
2697 spin_lock(&inode
->i_lock
);
2698 inode
->i_private
= &shmem_falloc
;
2699 spin_unlock(&inode
->i_lock
);
2702 * info->fallocend is only relevant when huge pages might be
2703 * involved: to prevent split_huge_page() freeing fallocated
2704 * pages when FALLOC_FL_KEEP_SIZE committed beyond i_size.
2706 undo_fallocend
= info
->fallocend
;
2707 if (info
->fallocend
< end
)
2708 info
->fallocend
= end
;
2710 for (index
= start
; index
< end
; ) {
2714 * Good, the fallocate(2) manpage permits EINTR: we may have
2715 * been interrupted because we are using up too much memory.
2717 if (signal_pending(current
))
2719 else if (shmem_falloc
.nr_unswapped
> shmem_falloc
.nr_falloced
)
2722 error
= shmem_getpage(inode
, index
, &page
, SGP_FALLOC
);
2724 info
->fallocend
= undo_fallocend
;
2725 /* Remove the !PageUptodate pages we added */
2726 if (index
> start
) {
2727 shmem_undo_range(inode
,
2728 (loff_t
)start
<< PAGE_SHIFT
,
2729 ((loff_t
)index
<< PAGE_SHIFT
) - 1, true);
2736 * Here is a more important optimization than it appears:
2737 * a second SGP_FALLOC on the same huge page will clear it,
2738 * making it PageUptodate and un-undoable if we fail later.
2740 if (PageTransCompound(page
)) {
2741 index
= round_up(index
, HPAGE_PMD_NR
);
2742 /* Beware 32-bit wraparound */
2748 * Inform shmem_writepage() how far we have reached.
2749 * No need for lock or barrier: we have the page lock.
2751 if (!PageUptodate(page
))
2752 shmem_falloc
.nr_falloced
+= index
- shmem_falloc
.next
;
2753 shmem_falloc
.next
= index
;
2756 * If !PageUptodate, leave it that way so that freeable pages
2757 * can be recognized if we need to rollback on error later.
2758 * But set_page_dirty so that memory pressure will swap rather
2759 * than free the pages we are allocating (and SGP_CACHE pages
2760 * might still be clean: we now need to mark those dirty too).
2762 set_page_dirty(page
);
2768 if (!(mode
& FALLOC_FL_KEEP_SIZE
) && offset
+ len
> inode
->i_size
)
2769 i_size_write(inode
, offset
+ len
);
2770 inode
->i_ctime
= current_time(inode
);
2772 spin_lock(&inode
->i_lock
);
2773 inode
->i_private
= NULL
;
2774 spin_unlock(&inode
->i_lock
);
2776 inode_unlock(inode
);
2780 static int shmem_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
2782 struct shmem_sb_info
*sbinfo
= SHMEM_SB(dentry
->d_sb
);
2784 buf
->f_type
= TMPFS_MAGIC
;
2785 buf
->f_bsize
= PAGE_SIZE
;
2786 buf
->f_namelen
= NAME_MAX
;
2787 if (sbinfo
->max_blocks
) {
2788 buf
->f_blocks
= sbinfo
->max_blocks
;
2790 buf
->f_bfree
= sbinfo
->max_blocks
-
2791 percpu_counter_sum(&sbinfo
->used_blocks
);
2793 if (sbinfo
->max_inodes
) {
2794 buf
->f_files
= sbinfo
->max_inodes
;
2795 buf
->f_ffree
= sbinfo
->free_inodes
;
2797 /* else leave those fields 0 like simple_statfs */
2799 buf
->f_fsid
= uuid_to_fsid(dentry
->d_sb
->s_uuid
.b
);
2805 * File creation. Allocate an inode, and we're done..
2808 shmem_mknod(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2809 struct dentry
*dentry
, umode_t mode
, dev_t dev
)
2811 struct inode
*inode
;
2812 int error
= -ENOSPC
;
2814 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, dev
, VM_NORESERVE
);
2816 error
= simple_acl_create(dir
, inode
);
2819 error
= security_inode_init_security(inode
, dir
,
2821 shmem_initxattrs
, NULL
);
2822 if (error
&& error
!= -EOPNOTSUPP
)
2826 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2827 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
2828 d_instantiate(dentry
, inode
);
2829 dget(dentry
); /* Extra count - pin the dentry in core */
2838 shmem_tmpfile(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2839 struct dentry
*dentry
, umode_t mode
)
2841 struct inode
*inode
;
2842 int error
= -ENOSPC
;
2844 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, 0, VM_NORESERVE
);
2846 error
= security_inode_init_security(inode
, dir
,
2848 shmem_initxattrs
, NULL
);
2849 if (error
&& error
!= -EOPNOTSUPP
)
2851 error
= simple_acl_create(dir
, inode
);
2854 d_tmpfile(dentry
, inode
);
2862 static int shmem_mkdir(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2863 struct dentry
*dentry
, umode_t mode
)
2867 if ((error
= shmem_mknod(&init_user_ns
, dir
, dentry
,
2868 mode
| S_IFDIR
, 0)))
2874 static int shmem_create(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2875 struct dentry
*dentry
, umode_t mode
, bool excl
)
2877 return shmem_mknod(&init_user_ns
, dir
, dentry
, mode
| S_IFREG
, 0);
2883 static int shmem_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*dentry
)
2885 struct inode
*inode
= d_inode(old_dentry
);
2889 * No ordinary (disk based) filesystem counts links as inodes;
2890 * but each new link needs a new dentry, pinning lowmem, and
2891 * tmpfs dentries cannot be pruned until they are unlinked.
2892 * But if an O_TMPFILE file is linked into the tmpfs, the
2893 * first link must skip that, to get the accounting right.
2895 if (inode
->i_nlink
) {
2896 ret
= shmem_reserve_inode(inode
->i_sb
, NULL
);
2901 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2902 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2904 ihold(inode
); /* New dentry reference */
2905 dget(dentry
); /* Extra pinning count for the created dentry */
2906 d_instantiate(dentry
, inode
);
2911 static int shmem_unlink(struct inode
*dir
, struct dentry
*dentry
)
2913 struct inode
*inode
= d_inode(dentry
);
2915 if (inode
->i_nlink
> 1 && !S_ISDIR(inode
->i_mode
))
2916 shmem_free_inode(inode
->i_sb
);
2918 dir
->i_size
-= BOGO_DIRENT_SIZE
;
2919 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2921 dput(dentry
); /* Undo the count from "create" - this does all the work */
2925 static int shmem_rmdir(struct inode
*dir
, struct dentry
*dentry
)
2927 if (!simple_empty(dentry
))
2930 drop_nlink(d_inode(dentry
));
2932 return shmem_unlink(dir
, dentry
);
2935 static int shmem_whiteout(struct user_namespace
*mnt_userns
,
2936 struct inode
*old_dir
, struct dentry
*old_dentry
)
2938 struct dentry
*whiteout
;
2941 whiteout
= d_alloc(old_dentry
->d_parent
, &old_dentry
->d_name
);
2945 error
= shmem_mknod(&init_user_ns
, old_dir
, whiteout
,
2946 S_IFCHR
| WHITEOUT_MODE
, WHITEOUT_DEV
);
2952 * Cheat and hash the whiteout while the old dentry is still in
2953 * place, instead of playing games with FS_RENAME_DOES_D_MOVE.
2955 * d_lookup() will consistently find one of them at this point,
2956 * not sure which one, but that isn't even important.
2963 * The VFS layer already does all the dentry stuff for rename,
2964 * we just have to decrement the usage count for the target if
2965 * it exists so that the VFS layer correctly free's it when it
2968 static int shmem_rename2(struct user_namespace
*mnt_userns
,
2969 struct inode
*old_dir
, struct dentry
*old_dentry
,
2970 struct inode
*new_dir
, struct dentry
*new_dentry
,
2973 struct inode
*inode
= d_inode(old_dentry
);
2974 int they_are_dirs
= S_ISDIR(inode
->i_mode
);
2976 if (flags
& ~(RENAME_NOREPLACE
| RENAME_EXCHANGE
| RENAME_WHITEOUT
))
2979 if (flags
& RENAME_EXCHANGE
)
2980 return simple_rename_exchange(old_dir
, old_dentry
, new_dir
, new_dentry
);
2982 if (!simple_empty(new_dentry
))
2985 if (flags
& RENAME_WHITEOUT
) {
2988 error
= shmem_whiteout(&init_user_ns
, old_dir
, old_dentry
);
2993 if (d_really_is_positive(new_dentry
)) {
2994 (void) shmem_unlink(new_dir
, new_dentry
);
2995 if (they_are_dirs
) {
2996 drop_nlink(d_inode(new_dentry
));
2997 drop_nlink(old_dir
);
2999 } else if (they_are_dirs
) {
3000 drop_nlink(old_dir
);
3004 old_dir
->i_size
-= BOGO_DIRENT_SIZE
;
3005 new_dir
->i_size
+= BOGO_DIRENT_SIZE
;
3006 old_dir
->i_ctime
= old_dir
->i_mtime
=
3007 new_dir
->i_ctime
= new_dir
->i_mtime
=
3008 inode
->i_ctime
= current_time(old_dir
);
3012 static int shmem_symlink(struct user_namespace
*mnt_userns
, struct inode
*dir
,
3013 struct dentry
*dentry
, const char *symname
)
3017 struct inode
*inode
;
3020 len
= strlen(symname
) + 1;
3021 if (len
> PAGE_SIZE
)
3022 return -ENAMETOOLONG
;
3024 inode
= shmem_get_inode(dir
->i_sb
, dir
, S_IFLNK
| 0777, 0,
3029 error
= security_inode_init_security(inode
, dir
, &dentry
->d_name
,
3030 shmem_initxattrs
, NULL
);
3031 if (error
&& error
!= -EOPNOTSUPP
) {
3036 inode
->i_size
= len
-1;
3037 if (len
<= SHORT_SYMLINK_LEN
) {
3038 inode
->i_link
= kmemdup(symname
, len
, GFP_KERNEL
);
3039 if (!inode
->i_link
) {
3043 inode
->i_op
= &shmem_short_symlink_operations
;
3045 inode_nohighmem(inode
);
3046 error
= shmem_getpage(inode
, 0, &page
, SGP_WRITE
);
3051 inode
->i_mapping
->a_ops
= &shmem_aops
;
3052 inode
->i_op
= &shmem_symlink_inode_operations
;
3053 memcpy(page_address(page
), symname
, len
);
3054 SetPageUptodate(page
);
3055 set_page_dirty(page
);
3059 dir
->i_size
+= BOGO_DIRENT_SIZE
;
3060 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
3061 d_instantiate(dentry
, inode
);
3066 static void shmem_put_link(void *arg
)
3068 mark_page_accessed(arg
);
3072 static const char *shmem_get_link(struct dentry
*dentry
,
3073 struct inode
*inode
,
3074 struct delayed_call
*done
)
3076 struct page
*page
= NULL
;
3079 page
= find_get_page(inode
->i_mapping
, 0);
3081 return ERR_PTR(-ECHILD
);
3082 if (PageHWPoison(page
) ||
3083 !PageUptodate(page
)) {
3085 return ERR_PTR(-ECHILD
);
3088 error
= shmem_getpage(inode
, 0, &page
, SGP_READ
);
3090 return ERR_PTR(error
);
3092 return ERR_PTR(-ECHILD
);
3093 if (PageHWPoison(page
)) {
3096 return ERR_PTR(-ECHILD
);
3100 set_delayed_call(done
, shmem_put_link
, page
);
3101 return page_address(page
);
3104 #ifdef CONFIG_TMPFS_XATTR
3106 * Superblocks without xattr inode operations may get some security.* xattr
3107 * support from the LSM "for free". As soon as we have any other xattrs
3108 * like ACLs, we also need to implement the security.* handlers at
3109 * filesystem level, though.
3113 * Callback for security_inode_init_security() for acquiring xattrs.
3115 static int shmem_initxattrs(struct inode
*inode
,
3116 const struct xattr
*xattr_array
,
3119 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3120 const struct xattr
*xattr
;
3121 struct simple_xattr
*new_xattr
;
3124 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
3125 new_xattr
= simple_xattr_alloc(xattr
->value
, xattr
->value_len
);
3129 len
= strlen(xattr
->name
) + 1;
3130 new_xattr
->name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+ len
,
3132 if (!new_xattr
->name
) {
3137 memcpy(new_xattr
->name
, XATTR_SECURITY_PREFIX
,
3138 XATTR_SECURITY_PREFIX_LEN
);
3139 memcpy(new_xattr
->name
+ XATTR_SECURITY_PREFIX_LEN
,
3142 simple_xattr_list_add(&info
->xattrs
, new_xattr
);
3148 static int shmem_xattr_handler_get(const struct xattr_handler
*handler
,
3149 struct dentry
*unused
, struct inode
*inode
,
3150 const char *name
, void *buffer
, size_t size
)
3152 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3154 name
= xattr_full_name(handler
, name
);
3155 return simple_xattr_get(&info
->xattrs
, name
, buffer
, size
);
3158 static int shmem_xattr_handler_set(const struct xattr_handler
*handler
,
3159 struct user_namespace
*mnt_userns
,
3160 struct dentry
*unused
, struct inode
*inode
,
3161 const char *name
, const void *value
,
3162 size_t size
, int flags
)
3164 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3166 name
= xattr_full_name(handler
, name
);
3167 return simple_xattr_set(&info
->xattrs
, name
, value
, size
, flags
, NULL
);
3170 static const struct xattr_handler shmem_security_xattr_handler
= {
3171 .prefix
= XATTR_SECURITY_PREFIX
,
3172 .get
= shmem_xattr_handler_get
,
3173 .set
= shmem_xattr_handler_set
,
3176 static const struct xattr_handler shmem_trusted_xattr_handler
= {
3177 .prefix
= XATTR_TRUSTED_PREFIX
,
3178 .get
= shmem_xattr_handler_get
,
3179 .set
= shmem_xattr_handler_set
,
3182 static const struct xattr_handler
*shmem_xattr_handlers
[] = {
3183 #ifdef CONFIG_TMPFS_POSIX_ACL
3184 &posix_acl_access_xattr_handler
,
3185 &posix_acl_default_xattr_handler
,
3187 &shmem_security_xattr_handler
,
3188 &shmem_trusted_xattr_handler
,
3192 static ssize_t
shmem_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
3194 struct shmem_inode_info
*info
= SHMEM_I(d_inode(dentry
));
3195 return simple_xattr_list(d_inode(dentry
), &info
->xattrs
, buffer
, size
);
3197 #endif /* CONFIG_TMPFS_XATTR */
3199 static const struct inode_operations shmem_short_symlink_operations
= {
3200 .getattr
= shmem_getattr
,
3201 .get_link
= simple_get_link
,
3202 #ifdef CONFIG_TMPFS_XATTR
3203 .listxattr
= shmem_listxattr
,
3207 static const struct inode_operations shmem_symlink_inode_operations
= {
3208 .getattr
= shmem_getattr
,
3209 .get_link
= shmem_get_link
,
3210 #ifdef CONFIG_TMPFS_XATTR
3211 .listxattr
= shmem_listxattr
,
3215 static struct dentry
*shmem_get_parent(struct dentry
*child
)
3217 return ERR_PTR(-ESTALE
);
3220 static int shmem_match(struct inode
*ino
, void *vfh
)
3224 inum
= (inum
<< 32) | fh
[1];
3225 return ino
->i_ino
== inum
&& fh
[0] == ino
->i_generation
;
3228 /* Find any alias of inode, but prefer a hashed alias */
3229 static struct dentry
*shmem_find_alias(struct inode
*inode
)
3231 struct dentry
*alias
= d_find_alias(inode
);
3233 return alias
?: d_find_any_alias(inode
);
3237 static struct dentry
*shmem_fh_to_dentry(struct super_block
*sb
,
3238 struct fid
*fid
, int fh_len
, int fh_type
)
3240 struct inode
*inode
;
3241 struct dentry
*dentry
= NULL
;
3248 inum
= (inum
<< 32) | fid
->raw
[1];
3250 inode
= ilookup5(sb
, (unsigned long)(inum
+ fid
->raw
[0]),
3251 shmem_match
, fid
->raw
);
3253 dentry
= shmem_find_alias(inode
);
3260 static int shmem_encode_fh(struct inode
*inode
, __u32
*fh
, int *len
,
3261 struct inode
*parent
)
3265 return FILEID_INVALID
;
3268 if (inode_unhashed(inode
)) {
3269 /* Unfortunately insert_inode_hash is not idempotent,
3270 * so as we hash inodes here rather than at creation
3271 * time, we need a lock to ensure we only try
3274 static DEFINE_SPINLOCK(lock
);
3276 if (inode_unhashed(inode
))
3277 __insert_inode_hash(inode
,
3278 inode
->i_ino
+ inode
->i_generation
);
3282 fh
[0] = inode
->i_generation
;
3283 fh
[1] = inode
->i_ino
;
3284 fh
[2] = ((__u64
)inode
->i_ino
) >> 32;
3290 static const struct export_operations shmem_export_ops
= {
3291 .get_parent
= shmem_get_parent
,
3292 .encode_fh
= shmem_encode_fh
,
3293 .fh_to_dentry
= shmem_fh_to_dentry
,
3309 static const struct constant_table shmem_param_enums_huge
[] = {
3310 {"never", SHMEM_HUGE_NEVER
},
3311 {"always", SHMEM_HUGE_ALWAYS
},
3312 {"within_size", SHMEM_HUGE_WITHIN_SIZE
},
3313 {"advise", SHMEM_HUGE_ADVISE
},
3317 const struct fs_parameter_spec shmem_fs_parameters
[] = {
3318 fsparam_u32 ("gid", Opt_gid
),
3319 fsparam_enum ("huge", Opt_huge
, shmem_param_enums_huge
),
3320 fsparam_u32oct("mode", Opt_mode
),
3321 fsparam_string("mpol", Opt_mpol
),
3322 fsparam_string("nr_blocks", Opt_nr_blocks
),
3323 fsparam_string("nr_inodes", Opt_nr_inodes
),
3324 fsparam_string("size", Opt_size
),
3325 fsparam_u32 ("uid", Opt_uid
),
3326 fsparam_flag ("inode32", Opt_inode32
),
3327 fsparam_flag ("inode64", Opt_inode64
),
3331 static int shmem_parse_one(struct fs_context
*fc
, struct fs_parameter
*param
)
3333 struct shmem_options
*ctx
= fc
->fs_private
;
3334 struct fs_parse_result result
;
3335 unsigned long long size
;
3339 opt
= fs_parse(fc
, shmem_fs_parameters
, param
, &result
);
3345 size
= memparse(param
->string
, &rest
);
3347 size
<<= PAGE_SHIFT
;
3348 size
*= totalram_pages();
3354 ctx
->blocks
= DIV_ROUND_UP(size
, PAGE_SIZE
);
3355 ctx
->seen
|= SHMEM_SEEN_BLOCKS
;
3358 ctx
->blocks
= memparse(param
->string
, &rest
);
3361 ctx
->seen
|= SHMEM_SEEN_BLOCKS
;
3364 ctx
->inodes
= memparse(param
->string
, &rest
);
3367 ctx
->seen
|= SHMEM_SEEN_INODES
;
3370 ctx
->mode
= result
.uint_32
& 07777;
3373 ctx
->uid
= make_kuid(current_user_ns(), result
.uint_32
);
3374 if (!uid_valid(ctx
->uid
))
3378 ctx
->gid
= make_kgid(current_user_ns(), result
.uint_32
);
3379 if (!gid_valid(ctx
->gid
))
3383 ctx
->huge
= result
.uint_32
;
3384 if (ctx
->huge
!= SHMEM_HUGE_NEVER
&&
3385 !(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
3386 has_transparent_hugepage()))
3387 goto unsupported_parameter
;
3388 ctx
->seen
|= SHMEM_SEEN_HUGE
;
3391 if (IS_ENABLED(CONFIG_NUMA
)) {
3392 mpol_put(ctx
->mpol
);
3394 if (mpol_parse_str(param
->string
, &ctx
->mpol
))
3398 goto unsupported_parameter
;
3400 ctx
->full_inums
= false;
3401 ctx
->seen
|= SHMEM_SEEN_INUMS
;
3404 if (sizeof(ino_t
) < 8) {
3406 "Cannot use inode64 with <64bit inums in kernel\n");
3408 ctx
->full_inums
= true;
3409 ctx
->seen
|= SHMEM_SEEN_INUMS
;
3414 unsupported_parameter
:
3415 return invalfc(fc
, "Unsupported parameter '%s'", param
->key
);
3417 return invalfc(fc
, "Bad value for '%s'", param
->key
);
3420 static int shmem_parse_options(struct fs_context
*fc
, void *data
)
3422 char *options
= data
;
3425 int err
= security_sb_eat_lsm_opts(options
, &fc
->security
);
3430 while (options
!= NULL
) {
3431 char *this_char
= options
;
3434 * NUL-terminate this option: unfortunately,
3435 * mount options form a comma-separated list,
3436 * but mpol's nodelist may also contain commas.
3438 options
= strchr(options
, ',');
3439 if (options
== NULL
)
3442 if (!isdigit(*options
)) {
3448 char *value
= strchr(this_char
, '=');
3454 len
= strlen(value
);
3456 err
= vfs_parse_fs_string(fc
, this_char
, value
, len
);
3465 * Reconfigure a shmem filesystem.
3467 * Note that we disallow change from limited->unlimited blocks/inodes while any
3468 * are in use; but we must separately disallow unlimited->limited, because in
3469 * that case we have no record of how much is already in use.
3471 static int shmem_reconfigure(struct fs_context
*fc
)
3473 struct shmem_options
*ctx
= fc
->fs_private
;
3474 struct shmem_sb_info
*sbinfo
= SHMEM_SB(fc
->root
->d_sb
);
3475 unsigned long inodes
;
3476 struct mempolicy
*mpol
= NULL
;
3479 raw_spin_lock(&sbinfo
->stat_lock
);
3480 inodes
= sbinfo
->max_inodes
- sbinfo
->free_inodes
;
3481 if ((ctx
->seen
& SHMEM_SEEN_BLOCKS
) && ctx
->blocks
) {
3482 if (!sbinfo
->max_blocks
) {
3483 err
= "Cannot retroactively limit size";
3486 if (percpu_counter_compare(&sbinfo
->used_blocks
,
3488 err
= "Too small a size for current use";
3492 if ((ctx
->seen
& SHMEM_SEEN_INODES
) && ctx
->inodes
) {
3493 if (!sbinfo
->max_inodes
) {
3494 err
= "Cannot retroactively limit inodes";
3497 if (ctx
->inodes
< inodes
) {
3498 err
= "Too few inodes for current use";
3503 if ((ctx
->seen
& SHMEM_SEEN_INUMS
) && !ctx
->full_inums
&&
3504 sbinfo
->next_ino
> UINT_MAX
) {
3505 err
= "Current inum too high to switch to 32-bit inums";
3509 if (ctx
->seen
& SHMEM_SEEN_HUGE
)
3510 sbinfo
->huge
= ctx
->huge
;
3511 if (ctx
->seen
& SHMEM_SEEN_INUMS
)
3512 sbinfo
->full_inums
= ctx
->full_inums
;
3513 if (ctx
->seen
& SHMEM_SEEN_BLOCKS
)
3514 sbinfo
->max_blocks
= ctx
->blocks
;
3515 if (ctx
->seen
& SHMEM_SEEN_INODES
) {
3516 sbinfo
->max_inodes
= ctx
->inodes
;
3517 sbinfo
->free_inodes
= ctx
->inodes
- inodes
;
3521 * Preserve previous mempolicy unless mpol remount option was specified.
3524 mpol
= sbinfo
->mpol
;
3525 sbinfo
->mpol
= ctx
->mpol
; /* transfers initial ref */
3528 raw_spin_unlock(&sbinfo
->stat_lock
);
3532 raw_spin_unlock(&sbinfo
->stat_lock
);
3533 return invalfc(fc
, "%s", err
);
3536 static int shmem_show_options(struct seq_file
*seq
, struct dentry
*root
)
3538 struct shmem_sb_info
*sbinfo
= SHMEM_SB(root
->d_sb
);
3540 if (sbinfo
->max_blocks
!= shmem_default_max_blocks())
3541 seq_printf(seq
, ",size=%luk",
3542 sbinfo
->max_blocks
<< (PAGE_SHIFT
- 10));
3543 if (sbinfo
->max_inodes
!= shmem_default_max_inodes())
3544 seq_printf(seq
, ",nr_inodes=%lu", sbinfo
->max_inodes
);
3545 if (sbinfo
->mode
!= (0777 | S_ISVTX
))
3546 seq_printf(seq
, ",mode=%03ho", sbinfo
->mode
);
3547 if (!uid_eq(sbinfo
->uid
, GLOBAL_ROOT_UID
))
3548 seq_printf(seq
, ",uid=%u",
3549 from_kuid_munged(&init_user_ns
, sbinfo
->uid
));
3550 if (!gid_eq(sbinfo
->gid
, GLOBAL_ROOT_GID
))
3551 seq_printf(seq
, ",gid=%u",
3552 from_kgid_munged(&init_user_ns
, sbinfo
->gid
));
3555 * Showing inode{64,32} might be useful even if it's the system default,
3556 * since then people don't have to resort to checking both here and
3557 * /proc/config.gz to confirm 64-bit inums were successfully applied
3558 * (which may not even exist if IKCONFIG_PROC isn't enabled).
3560 * We hide it when inode64 isn't the default and we are using 32-bit
3561 * inodes, since that probably just means the feature isn't even under
3566 * +-----------------+-----------------+
3567 * | TMPFS_INODE64=y | TMPFS_INODE64=n |
3568 * +------------------+-----------------+-----------------+
3569 * | full_inums=true | show | show |
3570 * | full_inums=false | show | hide |
3571 * +------------------+-----------------+-----------------+
3574 if (IS_ENABLED(CONFIG_TMPFS_INODE64
) || sbinfo
->full_inums
)
3575 seq_printf(seq
, ",inode%d", (sbinfo
->full_inums
? 64 : 32));
3576 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3577 /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
3579 seq_printf(seq
, ",huge=%s", shmem_format_huge(sbinfo
->huge
));
3581 shmem_show_mpol(seq
, sbinfo
->mpol
);
3585 #endif /* CONFIG_TMPFS */
3587 static void shmem_put_super(struct super_block
*sb
)
3589 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
3591 free_percpu(sbinfo
->ino_batch
);
3592 percpu_counter_destroy(&sbinfo
->used_blocks
);
3593 mpol_put(sbinfo
->mpol
);
3595 sb
->s_fs_info
= NULL
;
3598 static int shmem_fill_super(struct super_block
*sb
, struct fs_context
*fc
)
3600 struct shmem_options
*ctx
= fc
->fs_private
;
3601 struct inode
*inode
;
3602 struct shmem_sb_info
*sbinfo
;
3604 /* Round up to L1_CACHE_BYTES to resist false sharing */
3605 sbinfo
= kzalloc(max((int)sizeof(struct shmem_sb_info
),
3606 L1_CACHE_BYTES
), GFP_KERNEL
);
3610 sb
->s_fs_info
= sbinfo
;
3614 * Per default we only allow half of the physical ram per
3615 * tmpfs instance, limiting inodes to one per page of lowmem;
3616 * but the internal instance is left unlimited.
3618 if (!(sb
->s_flags
& SB_KERNMOUNT
)) {
3619 if (!(ctx
->seen
& SHMEM_SEEN_BLOCKS
))
3620 ctx
->blocks
= shmem_default_max_blocks();
3621 if (!(ctx
->seen
& SHMEM_SEEN_INODES
))
3622 ctx
->inodes
= shmem_default_max_inodes();
3623 if (!(ctx
->seen
& SHMEM_SEEN_INUMS
))
3624 ctx
->full_inums
= IS_ENABLED(CONFIG_TMPFS_INODE64
);
3626 sb
->s_flags
|= SB_NOUSER
;
3628 sb
->s_export_op
= &shmem_export_ops
;
3629 sb
->s_flags
|= SB_NOSEC
;
3631 sb
->s_flags
|= SB_NOUSER
;
3633 sbinfo
->max_blocks
= ctx
->blocks
;
3634 sbinfo
->free_inodes
= sbinfo
->max_inodes
= ctx
->inodes
;
3635 if (sb
->s_flags
& SB_KERNMOUNT
) {
3636 sbinfo
->ino_batch
= alloc_percpu(ino_t
);
3637 if (!sbinfo
->ino_batch
)
3640 sbinfo
->uid
= ctx
->uid
;
3641 sbinfo
->gid
= ctx
->gid
;
3642 sbinfo
->full_inums
= ctx
->full_inums
;
3643 sbinfo
->mode
= ctx
->mode
;
3644 sbinfo
->huge
= ctx
->huge
;
3645 sbinfo
->mpol
= ctx
->mpol
;
3648 raw_spin_lock_init(&sbinfo
->stat_lock
);
3649 if (percpu_counter_init(&sbinfo
->used_blocks
, 0, GFP_KERNEL
))
3651 spin_lock_init(&sbinfo
->shrinklist_lock
);
3652 INIT_LIST_HEAD(&sbinfo
->shrinklist
);
3654 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
3655 sb
->s_blocksize
= PAGE_SIZE
;
3656 sb
->s_blocksize_bits
= PAGE_SHIFT
;
3657 sb
->s_magic
= TMPFS_MAGIC
;
3658 sb
->s_op
= &shmem_ops
;
3659 sb
->s_time_gran
= 1;
3660 #ifdef CONFIG_TMPFS_XATTR
3661 sb
->s_xattr
= shmem_xattr_handlers
;
3663 #ifdef CONFIG_TMPFS_POSIX_ACL
3664 sb
->s_flags
|= SB_POSIXACL
;
3666 uuid_gen(&sb
->s_uuid
);
3668 inode
= shmem_get_inode(sb
, NULL
, S_IFDIR
| sbinfo
->mode
, 0, VM_NORESERVE
);
3671 inode
->i_uid
= sbinfo
->uid
;
3672 inode
->i_gid
= sbinfo
->gid
;
3673 sb
->s_root
= d_make_root(inode
);
3679 shmem_put_super(sb
);
3683 static int shmem_get_tree(struct fs_context
*fc
)
3685 return get_tree_nodev(fc
, shmem_fill_super
);
3688 static void shmem_free_fc(struct fs_context
*fc
)
3690 struct shmem_options
*ctx
= fc
->fs_private
;
3693 mpol_put(ctx
->mpol
);
3698 static const struct fs_context_operations shmem_fs_context_ops
= {
3699 .free
= shmem_free_fc
,
3700 .get_tree
= shmem_get_tree
,
3702 .parse_monolithic
= shmem_parse_options
,
3703 .parse_param
= shmem_parse_one
,
3704 .reconfigure
= shmem_reconfigure
,
3708 static struct kmem_cache
*shmem_inode_cachep
;
3710 static struct inode
*shmem_alloc_inode(struct super_block
*sb
)
3712 struct shmem_inode_info
*info
;
3713 info
= alloc_inode_sb(sb
, shmem_inode_cachep
, GFP_KERNEL
);
3716 return &info
->vfs_inode
;
3719 static void shmem_free_in_core_inode(struct inode
*inode
)
3721 if (S_ISLNK(inode
->i_mode
))
3722 kfree(inode
->i_link
);
3723 kmem_cache_free(shmem_inode_cachep
, SHMEM_I(inode
));
3726 static void shmem_destroy_inode(struct inode
*inode
)
3728 if (S_ISREG(inode
->i_mode
))
3729 mpol_free_shared_policy(&SHMEM_I(inode
)->policy
);
3732 static void shmem_init_inode(void *foo
)
3734 struct shmem_inode_info
*info
= foo
;
3735 inode_init_once(&info
->vfs_inode
);
3738 static void shmem_init_inodecache(void)
3740 shmem_inode_cachep
= kmem_cache_create("shmem_inode_cache",
3741 sizeof(struct shmem_inode_info
),
3742 0, SLAB_PANIC
|SLAB_ACCOUNT
, shmem_init_inode
);
3745 static void shmem_destroy_inodecache(void)
3747 kmem_cache_destroy(shmem_inode_cachep
);
3750 /* Keep the page in page cache instead of truncating it */
3751 static int shmem_error_remove_page(struct address_space
*mapping
,
3757 const struct address_space_operations shmem_aops
= {
3758 .writepage
= shmem_writepage
,
3759 .dirty_folio
= noop_dirty_folio
,
3761 .write_begin
= shmem_write_begin
,
3762 .write_end
= shmem_write_end
,
3764 #ifdef CONFIG_MIGRATION
3765 .migratepage
= migrate_page
,
3767 .error_remove_page
= shmem_error_remove_page
,
3769 EXPORT_SYMBOL(shmem_aops
);
3771 static const struct file_operations shmem_file_operations
= {
3773 .get_unmapped_area
= shmem_get_unmapped_area
,
3775 .llseek
= shmem_file_llseek
,
3776 .read_iter
= shmem_file_read_iter
,
3777 .write_iter
= generic_file_write_iter
,
3778 .fsync
= noop_fsync
,
3779 .splice_read
= generic_file_splice_read
,
3780 .splice_write
= iter_file_splice_write
,
3781 .fallocate
= shmem_fallocate
,
3785 static const struct inode_operations shmem_inode_operations
= {
3786 .getattr
= shmem_getattr
,
3787 .setattr
= shmem_setattr
,
3788 #ifdef CONFIG_TMPFS_XATTR
3789 .listxattr
= shmem_listxattr
,
3790 .set_acl
= simple_set_acl
,
3794 static const struct inode_operations shmem_dir_inode_operations
= {
3796 .getattr
= shmem_getattr
,
3797 .create
= shmem_create
,
3798 .lookup
= simple_lookup
,
3800 .unlink
= shmem_unlink
,
3801 .symlink
= shmem_symlink
,
3802 .mkdir
= shmem_mkdir
,
3803 .rmdir
= shmem_rmdir
,
3804 .mknod
= shmem_mknod
,
3805 .rename
= shmem_rename2
,
3806 .tmpfile
= shmem_tmpfile
,
3808 #ifdef CONFIG_TMPFS_XATTR
3809 .listxattr
= shmem_listxattr
,
3811 #ifdef CONFIG_TMPFS_POSIX_ACL
3812 .setattr
= shmem_setattr
,
3813 .set_acl
= simple_set_acl
,
3817 static const struct inode_operations shmem_special_inode_operations
= {
3818 .getattr
= shmem_getattr
,
3819 #ifdef CONFIG_TMPFS_XATTR
3820 .listxattr
= shmem_listxattr
,
3822 #ifdef CONFIG_TMPFS_POSIX_ACL
3823 .setattr
= shmem_setattr
,
3824 .set_acl
= simple_set_acl
,
3828 static const struct super_operations shmem_ops
= {
3829 .alloc_inode
= shmem_alloc_inode
,
3830 .free_inode
= shmem_free_in_core_inode
,
3831 .destroy_inode
= shmem_destroy_inode
,
3833 .statfs
= shmem_statfs
,
3834 .show_options
= shmem_show_options
,
3836 .evict_inode
= shmem_evict_inode
,
3837 .drop_inode
= generic_delete_inode
,
3838 .put_super
= shmem_put_super
,
3839 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3840 .nr_cached_objects
= shmem_unused_huge_count
,
3841 .free_cached_objects
= shmem_unused_huge_scan
,
3845 static const struct vm_operations_struct shmem_vm_ops
= {
3846 .fault
= shmem_fault
,
3847 .map_pages
= filemap_map_pages
,
3849 .set_policy
= shmem_set_policy
,
3850 .get_policy
= shmem_get_policy
,
3854 int shmem_init_fs_context(struct fs_context
*fc
)
3856 struct shmem_options
*ctx
;
3858 ctx
= kzalloc(sizeof(struct shmem_options
), GFP_KERNEL
);
3862 ctx
->mode
= 0777 | S_ISVTX
;
3863 ctx
->uid
= current_fsuid();
3864 ctx
->gid
= current_fsgid();
3866 fc
->fs_private
= ctx
;
3867 fc
->ops
= &shmem_fs_context_ops
;
3871 static struct file_system_type shmem_fs_type
= {
3872 .owner
= THIS_MODULE
,
3874 .init_fs_context
= shmem_init_fs_context
,
3876 .parameters
= shmem_fs_parameters
,
3878 .kill_sb
= kill_litter_super
,
3879 .fs_flags
= FS_USERNS_MOUNT
,
3882 int __init
shmem_init(void)
3886 shmem_init_inodecache();
3888 error
= register_filesystem(&shmem_fs_type
);
3890 pr_err("Could not register tmpfs\n");
3894 shm_mnt
= kern_mount(&shmem_fs_type
);
3895 if (IS_ERR(shm_mnt
)) {
3896 error
= PTR_ERR(shm_mnt
);
3897 pr_err("Could not kern_mount tmpfs\n");
3901 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3902 if (has_transparent_hugepage() && shmem_huge
> SHMEM_HUGE_DENY
)
3903 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3905 shmem_huge
= SHMEM_HUGE_NEVER
; /* just in case it was patched */
3910 unregister_filesystem(&shmem_fs_type
);
3912 shmem_destroy_inodecache();
3913 shm_mnt
= ERR_PTR(error
);
3917 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
3918 static ssize_t
shmem_enabled_show(struct kobject
*kobj
,
3919 struct kobj_attribute
*attr
, char *buf
)
3921 static const int values
[] = {
3923 SHMEM_HUGE_WITHIN_SIZE
,
3932 for (i
= 0; i
< ARRAY_SIZE(values
); i
++) {
3933 len
+= sysfs_emit_at(buf
, len
,
3934 shmem_huge
== values
[i
] ? "%s[%s]" : "%s%s",
3936 shmem_format_huge(values
[i
]));
3939 len
+= sysfs_emit_at(buf
, len
, "\n");
3944 static ssize_t
shmem_enabled_store(struct kobject
*kobj
,
3945 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
3950 if (count
+ 1 > sizeof(tmp
))
3952 memcpy(tmp
, buf
, count
);
3954 if (count
&& tmp
[count
- 1] == '\n')
3955 tmp
[count
- 1] = '\0';
3957 huge
= shmem_parse_huge(tmp
);
3958 if (huge
== -EINVAL
)
3960 if (!has_transparent_hugepage() &&
3961 huge
!= SHMEM_HUGE_NEVER
&& huge
!= SHMEM_HUGE_DENY
)
3965 if (shmem_huge
> SHMEM_HUGE_DENY
)
3966 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3970 struct kobj_attribute shmem_enabled_attr
= __ATTR_RW(shmem_enabled
);
3971 #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_SYSFS */
3973 #else /* !CONFIG_SHMEM */
3976 * tiny-shmem: simple shmemfs and tmpfs using ramfs code
3978 * This is intended for small system where the benefits of the full
3979 * shmem code (swap-backed and resource-limited) are outweighed by
3980 * their complexity. On systems without swap this code should be
3981 * effectively equivalent, but much lighter weight.
3984 static struct file_system_type shmem_fs_type
= {
3986 .init_fs_context
= ramfs_init_fs_context
,
3987 .parameters
= ramfs_fs_parameters
,
3988 .kill_sb
= kill_litter_super
,
3989 .fs_flags
= FS_USERNS_MOUNT
,
3992 int __init
shmem_init(void)
3994 BUG_ON(register_filesystem(&shmem_fs_type
) != 0);
3996 shm_mnt
= kern_mount(&shmem_fs_type
);
3997 BUG_ON(IS_ERR(shm_mnt
));
4002 int shmem_unuse(unsigned int type
)
4007 int shmem_lock(struct file
*file
, int lock
, struct ucounts
*ucounts
)
4012 void shmem_unlock_mapping(struct address_space
*mapping
)
4017 unsigned long shmem_get_unmapped_area(struct file
*file
,
4018 unsigned long addr
, unsigned long len
,
4019 unsigned long pgoff
, unsigned long flags
)
4021 return current
->mm
->get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
4025 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
4027 truncate_inode_pages_range(inode
->i_mapping
, lstart
, lend
);
4029 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
4031 #define shmem_vm_ops generic_file_vm_ops
4032 #define shmem_file_operations ramfs_file_operations
4033 #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
4034 #define shmem_acct_size(flags, size) 0
4035 #define shmem_unacct_size(flags, size) do {} while (0)
4037 #endif /* CONFIG_SHMEM */
4041 static struct file
*__shmem_file_setup(struct vfsmount
*mnt
, const char *name
, loff_t size
,
4042 unsigned long flags
, unsigned int i_flags
)
4044 struct inode
*inode
;
4048 return ERR_CAST(mnt
);
4050 if (size
< 0 || size
> MAX_LFS_FILESIZE
)
4051 return ERR_PTR(-EINVAL
);
4053 if (shmem_acct_size(flags
, size
))
4054 return ERR_PTR(-ENOMEM
);
4056 inode
= shmem_get_inode(mnt
->mnt_sb
, NULL
, S_IFREG
| S_IRWXUGO
, 0,
4058 if (unlikely(!inode
)) {
4059 shmem_unacct_size(flags
, size
);
4060 return ERR_PTR(-ENOSPC
);
4062 inode
->i_flags
|= i_flags
;
4063 inode
->i_size
= size
;
4064 clear_nlink(inode
); /* It is unlinked */
4065 res
= ERR_PTR(ramfs_nommu_expand_for_mapping(inode
, size
));
4067 res
= alloc_file_pseudo(inode
, mnt
, name
, O_RDWR
,
4068 &shmem_file_operations
);
4075 * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be
4076 * kernel internal. There will be NO LSM permission checks against the
4077 * underlying inode. So users of this interface must do LSM checks at a
4078 * higher layer. The users are the big_key and shm implementations. LSM
4079 * checks are provided at the key or shm level rather than the inode.
4080 * @name: name for dentry (to be seen in /proc/<pid>/maps
4081 * @size: size to be set for the file
4082 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4084 struct file
*shmem_kernel_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4086 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, S_PRIVATE
);
4090 * shmem_file_setup - get an unlinked file living in tmpfs
4091 * @name: name for dentry (to be seen in /proc/<pid>/maps
4092 * @size: size to be set for the file
4093 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4095 struct file
*shmem_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4097 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, 0);
4099 EXPORT_SYMBOL_GPL(shmem_file_setup
);
4102 * shmem_file_setup_with_mnt - get an unlinked file living in tmpfs
4103 * @mnt: the tmpfs mount where the file will be created
4104 * @name: name for dentry (to be seen in /proc/<pid>/maps
4105 * @size: size to be set for the file
4106 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4108 struct file
*shmem_file_setup_with_mnt(struct vfsmount
*mnt
, const char *name
,
4109 loff_t size
, unsigned long flags
)
4111 return __shmem_file_setup(mnt
, name
, size
, flags
, 0);
4113 EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt
);
4116 * shmem_zero_setup - setup a shared anonymous mapping
4117 * @vma: the vma to be mmapped is prepared by do_mmap
4119 int shmem_zero_setup(struct vm_area_struct
*vma
)
4122 loff_t size
= vma
->vm_end
- vma
->vm_start
;
4125 * Cloning a new file under mmap_lock leads to a lock ordering conflict
4126 * between XFS directory reading and selinux: since this file is only
4127 * accessible to the user through its mapping, use S_PRIVATE flag to
4128 * bypass file security, in the same way as shmem_kernel_file_setup().
4130 file
= shmem_kernel_file_setup("dev/zero", size
, vma
->vm_flags
);
4132 return PTR_ERR(file
);
4136 vma
->vm_file
= file
;
4137 vma
->vm_ops
= &shmem_vm_ops
;
4139 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
4140 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
4141 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
4142 khugepaged_enter(vma
, vma
->vm_flags
);
4149 * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
4150 * @mapping: the page's address_space
4151 * @index: the page index
4152 * @gfp: the page allocator flags to use if allocating
4154 * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
4155 * with any new page allocations done using the specified allocation flags.
4156 * But read_cache_page_gfp() uses the ->readpage() method: which does not
4157 * suit tmpfs, since it may have pages in swapcache, and needs to find those
4158 * for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
4160 * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
4161 * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
4163 struct page
*shmem_read_mapping_page_gfp(struct address_space
*mapping
,
4164 pgoff_t index
, gfp_t gfp
)
4167 struct inode
*inode
= mapping
->host
;
4171 BUG_ON(!shmem_mapping(mapping
));
4172 error
= shmem_getpage_gfp(inode
, index
, &page
, SGP_CACHE
,
4173 gfp
, NULL
, NULL
, NULL
);
4175 return ERR_PTR(error
);
4178 if (PageHWPoison(page
)) {
4180 return ERR_PTR(-EIO
);
4186 * The tiny !SHMEM case uses ramfs without swap
4188 return read_cache_page_gfp(mapping
, index
, gfp
);
4191 EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp
);