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/frontswap.h>
40 #include <linux/fs_parser.h>
41 #include <linux/swapfile.h>
43 static struct vfsmount
*shm_mnt
;
47 * This virtual memory filesystem is heavily based on the ramfs. It
48 * extends ramfs by the ability to use swap and honor resource limits
49 * which makes it a completely usable filesystem.
52 #include <linux/xattr.h>
53 #include <linux/exportfs.h>
54 #include <linux/posix_acl.h>
55 #include <linux/posix_acl_xattr.h>
56 #include <linux/mman.h>
57 #include <linux/string.h>
58 #include <linux/slab.h>
59 #include <linux/backing-dev.h>
60 #include <linux/shmem_fs.h>
61 #include <linux/writeback.h>
62 #include <linux/blkdev.h>
63 #include <linux/pagevec.h>
64 #include <linux/percpu_counter.h>
65 #include <linux/falloc.h>
66 #include <linux/splice.h>
67 #include <linux/security.h>
68 #include <linux/swapops.h>
69 #include <linux/mempolicy.h>
70 #include <linux/namei.h>
71 #include <linux/ctype.h>
72 #include <linux/migrate.h>
73 #include <linux/highmem.h>
74 #include <linux/seq_file.h>
75 #include <linux/magic.h>
76 #include <linux/syscalls.h>
77 #include <linux/fcntl.h>
78 #include <uapi/linux/memfd.h>
79 #include <linux/userfaultfd_k.h>
80 #include <linux/rmap.h>
81 #include <linux/uuid.h>
83 #include <linux/uaccess.h>
87 #define BLOCKS_PER_PAGE (PAGE_SIZE/512)
88 #define VM_ACCT(size) (PAGE_ALIGN(size) >> PAGE_SHIFT)
90 /* Pretend that each entry is of this size in directory's i_size */
91 #define BOGO_DIRENT_SIZE 20
93 /* Symlink up to this size is kmalloc'ed instead of using a swappable page */
94 #define SHORT_SYMLINK_LEN 128
97 * shmem_fallocate communicates with shmem_fault or shmem_writepage via
98 * inode->i_private (with i_rwsem making sure that it has only one user at
99 * a time): we would prefer not to enlarge the shmem inode just for that.
101 struct shmem_falloc
{
102 wait_queue_head_t
*waitq
; /* faults into hole wait for punch to end */
103 pgoff_t start
; /* start of range currently being fallocated */
104 pgoff_t next
; /* the next page offset to be fallocated */
105 pgoff_t nr_falloced
; /* how many new pages have been fallocated */
106 pgoff_t nr_unswapped
; /* how often writepage refused to swap out */
109 struct shmem_options
{
110 unsigned long long blocks
;
111 unsigned long long inodes
;
112 struct mempolicy
*mpol
;
119 #define SHMEM_SEEN_BLOCKS 1
120 #define SHMEM_SEEN_INODES 2
121 #define SHMEM_SEEN_HUGE 4
122 #define SHMEM_SEEN_INUMS 8
126 static unsigned long shmem_default_max_blocks(void)
128 return totalram_pages() / 2;
131 static unsigned long shmem_default_max_inodes(void)
133 unsigned long nr_pages
= totalram_pages();
135 return min(nr_pages
- totalhigh_pages(), nr_pages
/ 2);
139 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
140 struct page
**pagep
, enum sgp_type sgp
,
141 gfp_t gfp
, struct vm_area_struct
*vma
,
142 vm_fault_t
*fault_type
);
143 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
144 struct page
**pagep
, enum sgp_type sgp
,
145 gfp_t gfp
, struct vm_area_struct
*vma
,
146 struct vm_fault
*vmf
, vm_fault_t
*fault_type
);
148 int shmem_getpage(struct inode
*inode
, pgoff_t index
,
149 struct page
**pagep
, enum sgp_type sgp
)
151 return shmem_getpage_gfp(inode
, index
, pagep
, sgp
,
152 mapping_gfp_mask(inode
->i_mapping
), NULL
, NULL
, NULL
);
155 static inline struct shmem_sb_info
*SHMEM_SB(struct super_block
*sb
)
157 return sb
->s_fs_info
;
161 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
162 * for shared memory and for shared anonymous (/dev/zero) mappings
163 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
164 * consistent with the pre-accounting of private mappings ...
166 static inline int shmem_acct_size(unsigned long flags
, loff_t size
)
168 return (flags
& VM_NORESERVE
) ?
169 0 : security_vm_enough_memory_mm(current
->mm
, VM_ACCT(size
));
172 static inline void shmem_unacct_size(unsigned long flags
, loff_t size
)
174 if (!(flags
& VM_NORESERVE
))
175 vm_unacct_memory(VM_ACCT(size
));
178 static inline int shmem_reacct_size(unsigned long flags
,
179 loff_t oldsize
, loff_t newsize
)
181 if (!(flags
& VM_NORESERVE
)) {
182 if (VM_ACCT(newsize
) > VM_ACCT(oldsize
))
183 return security_vm_enough_memory_mm(current
->mm
,
184 VM_ACCT(newsize
) - VM_ACCT(oldsize
));
185 else if (VM_ACCT(newsize
) < VM_ACCT(oldsize
))
186 vm_unacct_memory(VM_ACCT(oldsize
) - VM_ACCT(newsize
));
192 * ... whereas tmpfs objects are accounted incrementally as
193 * pages are allocated, in order to allow large sparse files.
194 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
195 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
197 static inline int shmem_acct_block(unsigned long flags
, long pages
)
199 if (!(flags
& VM_NORESERVE
))
202 return security_vm_enough_memory_mm(current
->mm
,
203 pages
* VM_ACCT(PAGE_SIZE
));
206 static inline void shmem_unacct_blocks(unsigned long flags
, long pages
)
208 if (flags
& VM_NORESERVE
)
209 vm_unacct_memory(pages
* VM_ACCT(PAGE_SIZE
));
212 static inline bool shmem_inode_acct_block(struct inode
*inode
, long pages
)
214 struct shmem_inode_info
*info
= SHMEM_I(inode
);
215 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
217 if (shmem_acct_block(info
->flags
, pages
))
220 if (sbinfo
->max_blocks
) {
221 if (percpu_counter_compare(&sbinfo
->used_blocks
,
222 sbinfo
->max_blocks
- pages
) > 0)
224 percpu_counter_add(&sbinfo
->used_blocks
, pages
);
230 shmem_unacct_blocks(info
->flags
, pages
);
234 static inline void shmem_inode_unacct_blocks(struct inode
*inode
, long pages
)
236 struct shmem_inode_info
*info
= SHMEM_I(inode
);
237 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
239 if (sbinfo
->max_blocks
)
240 percpu_counter_sub(&sbinfo
->used_blocks
, pages
);
241 shmem_unacct_blocks(info
->flags
, pages
);
244 static const struct super_operations shmem_ops
;
245 const struct address_space_operations shmem_aops
;
246 static const struct file_operations shmem_file_operations
;
247 static const struct inode_operations shmem_inode_operations
;
248 static const struct inode_operations shmem_dir_inode_operations
;
249 static const struct inode_operations shmem_special_inode_operations
;
250 static const struct vm_operations_struct shmem_vm_ops
;
251 static struct file_system_type shmem_fs_type
;
253 bool vma_is_shmem(struct vm_area_struct
*vma
)
255 return vma
->vm_ops
== &shmem_vm_ops
;
258 static LIST_HEAD(shmem_swaplist
);
259 static DEFINE_MUTEX(shmem_swaplist_mutex
);
262 * shmem_reserve_inode() performs bookkeeping to reserve a shmem inode, and
263 * produces a novel ino for the newly allocated inode.
265 * It may also be called when making a hard link to permit the space needed by
266 * each dentry. However, in that case, no new inode number is needed since that
267 * internally draws from another pool of inode numbers (currently global
268 * get_next_ino()). This case is indicated by passing NULL as inop.
270 #define SHMEM_INO_BATCH 1024
271 static int shmem_reserve_inode(struct super_block
*sb
, ino_t
*inop
)
273 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
276 if (!(sb
->s_flags
& SB_KERNMOUNT
)) {
277 raw_spin_lock(&sbinfo
->stat_lock
);
278 if (sbinfo
->max_inodes
) {
279 if (!sbinfo
->free_inodes
) {
280 raw_spin_unlock(&sbinfo
->stat_lock
);
283 sbinfo
->free_inodes
--;
286 ino
= sbinfo
->next_ino
++;
287 if (unlikely(is_zero_ino(ino
)))
288 ino
= sbinfo
->next_ino
++;
289 if (unlikely(!sbinfo
->full_inums
&&
292 * Emulate get_next_ino uint wraparound for
295 if (IS_ENABLED(CONFIG_64BIT
))
296 pr_warn("%s: inode number overflow on device %d, consider using inode64 mount option\n",
297 __func__
, MINOR(sb
->s_dev
));
298 sbinfo
->next_ino
= 1;
299 ino
= sbinfo
->next_ino
++;
303 raw_spin_unlock(&sbinfo
->stat_lock
);
306 * __shmem_file_setup, one of our callers, is lock-free: it
307 * doesn't hold stat_lock in shmem_reserve_inode since
308 * max_inodes is always 0, and is called from potentially
309 * unknown contexts. As such, use a per-cpu batched allocator
310 * which doesn't require the per-sb stat_lock unless we are at
311 * the batch boundary.
313 * We don't need to worry about inode{32,64} since SB_KERNMOUNT
314 * shmem mounts are not exposed to userspace, so we don't need
315 * to worry about things like glibc compatibility.
319 next_ino
= per_cpu_ptr(sbinfo
->ino_batch
, get_cpu());
321 if (unlikely(ino
% SHMEM_INO_BATCH
== 0)) {
322 raw_spin_lock(&sbinfo
->stat_lock
);
323 ino
= sbinfo
->next_ino
;
324 sbinfo
->next_ino
+= SHMEM_INO_BATCH
;
325 raw_spin_unlock(&sbinfo
->stat_lock
);
326 if (unlikely(is_zero_ino(ino
)))
337 static void shmem_free_inode(struct super_block
*sb
)
339 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
340 if (sbinfo
->max_inodes
) {
341 raw_spin_lock(&sbinfo
->stat_lock
);
342 sbinfo
->free_inodes
++;
343 raw_spin_unlock(&sbinfo
->stat_lock
);
348 * shmem_recalc_inode - recalculate the block usage of an inode
349 * @inode: inode to recalc
351 * We have to calculate the free blocks since the mm can drop
352 * undirtied hole pages behind our back.
354 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
355 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
357 * It has to be called with the spinlock held.
359 static void shmem_recalc_inode(struct inode
*inode
)
361 struct shmem_inode_info
*info
= SHMEM_I(inode
);
364 freed
= info
->alloced
- info
->swapped
- inode
->i_mapping
->nrpages
;
366 info
->alloced
-= freed
;
367 inode
->i_blocks
-= freed
* BLOCKS_PER_PAGE
;
368 shmem_inode_unacct_blocks(inode
, freed
);
372 bool shmem_charge(struct inode
*inode
, long pages
)
374 struct shmem_inode_info
*info
= SHMEM_I(inode
);
377 if (!shmem_inode_acct_block(inode
, pages
))
380 /* nrpages adjustment first, then shmem_recalc_inode() when balanced */
381 inode
->i_mapping
->nrpages
+= pages
;
383 spin_lock_irqsave(&info
->lock
, flags
);
384 info
->alloced
+= pages
;
385 inode
->i_blocks
+= pages
* BLOCKS_PER_PAGE
;
386 shmem_recalc_inode(inode
);
387 spin_unlock_irqrestore(&info
->lock
, flags
);
392 void shmem_uncharge(struct inode
*inode
, long pages
)
394 struct shmem_inode_info
*info
= SHMEM_I(inode
);
397 /* nrpages adjustment done by __delete_from_page_cache() or caller */
399 spin_lock_irqsave(&info
->lock
, flags
);
400 info
->alloced
-= pages
;
401 inode
->i_blocks
-= pages
* BLOCKS_PER_PAGE
;
402 shmem_recalc_inode(inode
);
403 spin_unlock_irqrestore(&info
->lock
, flags
);
405 shmem_inode_unacct_blocks(inode
, pages
);
409 * Replace item expected in xarray by a new item, while holding xa_lock.
411 static int shmem_replace_entry(struct address_space
*mapping
,
412 pgoff_t index
, void *expected
, void *replacement
)
414 XA_STATE(xas
, &mapping
->i_pages
, index
);
417 VM_BUG_ON(!expected
);
418 VM_BUG_ON(!replacement
);
419 item
= xas_load(&xas
);
420 if (item
!= expected
)
422 xas_store(&xas
, replacement
);
427 * Sometimes, before we decide whether to proceed or to fail, we must check
428 * that an entry was not already brought back from swap by a racing thread.
430 * Checking page is not enough: by the time a SwapCache page is locked, it
431 * might be reused, and again be SwapCache, using the same swap as before.
433 static bool shmem_confirm_swap(struct address_space
*mapping
,
434 pgoff_t index
, swp_entry_t swap
)
436 return xa_load(&mapping
->i_pages
, index
) == swp_to_radix_entry(swap
);
440 * Definitions for "huge tmpfs": tmpfs mounted with the huge= option
443 * disables huge pages for the mount;
445 * enables huge pages for the mount;
446 * SHMEM_HUGE_WITHIN_SIZE:
447 * only allocate huge pages if the page will be fully within i_size,
448 * also respect fadvise()/madvise() hints;
450 * only allocate huge pages if requested with fadvise()/madvise();
453 #define SHMEM_HUGE_NEVER 0
454 #define SHMEM_HUGE_ALWAYS 1
455 #define SHMEM_HUGE_WITHIN_SIZE 2
456 #define SHMEM_HUGE_ADVISE 3
460 * Only can be set via /sys/kernel/mm/transparent_hugepage/shmem_enabled:
463 * disables huge on shm_mnt and all mounts, for emergency use;
465 * enables huge on shm_mnt and all mounts, w/o needing option, for testing;
468 #define SHMEM_HUGE_DENY (-1)
469 #define SHMEM_HUGE_FORCE (-2)
471 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
472 /* ifdef here to avoid bloating shmem.o when not necessary */
474 static int shmem_huge __read_mostly
= SHMEM_HUGE_NEVER
;
476 bool shmem_is_huge(struct vm_area_struct
*vma
,
477 struct inode
*inode
, pgoff_t index
)
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;
558 int removed
= 0, split
= 0;
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
);
577 /* Check if there's anything to gain */
578 if (round_up(inode
->i_size
, PAGE_SIZE
) ==
579 round_up(inode
->i_size
, HPAGE_PMD_SIZE
)) {
580 list_move(&info
->shrinklist
, &to_remove
);
585 list_move(&info
->shrinklist
, &list
);
590 spin_unlock(&sbinfo
->shrinklist_lock
);
592 list_for_each_safe(pos
, next
, &to_remove
) {
593 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
594 inode
= &info
->vfs_inode
;
595 list_del_init(&info
->shrinklist
);
599 list_for_each_safe(pos
, next
, &list
) {
602 info
= list_entry(pos
, struct shmem_inode_info
, shrinklist
);
603 inode
= &info
->vfs_inode
;
605 if (nr_to_split
&& split
>= nr_to_split
)
608 page
= find_get_page(inode
->i_mapping
,
609 (inode
->i_size
& HPAGE_PMD_MASK
) >> PAGE_SHIFT
);
613 /* No huge page at the end of the file: nothing to split */
614 if (!PageTransHuge(page
)) {
620 * Leave the inode on the list if we failed to lock
621 * the page at this time.
623 * Waiting for the lock may lead to deadlock in the
626 if (!trylock_page(page
)) {
631 ret
= split_huge_page(page
);
635 /* If split failed leave the inode on the list */
641 list_del_init(&info
->shrinklist
);
647 spin_lock(&sbinfo
->shrinklist_lock
);
648 list_splice_tail(&list
, &sbinfo
->shrinklist
);
649 sbinfo
->shrinklist_len
-= removed
;
650 spin_unlock(&sbinfo
->shrinklist_lock
);
655 static long shmem_unused_huge_scan(struct super_block
*sb
,
656 struct shrink_control
*sc
)
658 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
660 if (!READ_ONCE(sbinfo
->shrinklist_len
))
663 return shmem_unused_huge_shrink(sbinfo
, sc
, 0);
666 static long shmem_unused_huge_count(struct super_block
*sb
,
667 struct shrink_control
*sc
)
669 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
670 return READ_ONCE(sbinfo
->shrinklist_len
);
672 #else /* !CONFIG_TRANSPARENT_HUGEPAGE */
674 #define shmem_huge SHMEM_HUGE_DENY
676 bool shmem_is_huge(struct vm_area_struct
*vma
,
677 struct inode
*inode
, pgoff_t index
)
682 static unsigned long shmem_unused_huge_shrink(struct shmem_sb_info
*sbinfo
,
683 struct shrink_control
*sc
, unsigned long nr_to_split
)
687 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
690 * Like add_to_page_cache_locked, but error if expected item has gone.
692 static int shmem_add_to_page_cache(struct page
*page
,
693 struct address_space
*mapping
,
694 pgoff_t index
, void *expected
, gfp_t gfp
,
695 struct mm_struct
*charge_mm
)
697 XA_STATE_ORDER(xas
, &mapping
->i_pages
, index
, compound_order(page
));
699 unsigned long nr
= compound_nr(page
);
702 VM_BUG_ON_PAGE(PageTail(page
), page
);
703 VM_BUG_ON_PAGE(index
!= round_down(index
, nr
), page
);
704 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
705 VM_BUG_ON_PAGE(!PageSwapBacked(page
), page
);
706 VM_BUG_ON(expected
&& PageTransHuge(page
));
708 page_ref_add(page
, nr
);
709 page
->mapping
= mapping
;
712 if (!PageSwapCache(page
)) {
713 error
= mem_cgroup_charge(page
, charge_mm
, gfp
);
715 if (PageTransHuge(page
)) {
716 count_vm_event(THP_FILE_FALLBACK
);
717 count_vm_event(THP_FILE_FALLBACK_CHARGE
);
722 cgroup_throttle_swaprate(page
, gfp
);
727 entry
= xas_find_conflict(&xas
);
728 if (entry
!= expected
)
729 xas_set_err(&xas
, -EEXIST
);
730 xas_create_range(&xas
);
734 xas_store(&xas
, page
);
739 if (PageTransHuge(page
)) {
740 count_vm_event(THP_FILE_ALLOC
);
741 __mod_lruvec_page_state(page
, NR_SHMEM_THPS
, nr
);
743 mapping
->nrpages
+= nr
;
744 __mod_lruvec_page_state(page
, NR_FILE_PAGES
, nr
);
745 __mod_lruvec_page_state(page
, NR_SHMEM
, nr
);
747 xas_unlock_irq(&xas
);
748 } while (xas_nomem(&xas
, gfp
));
750 if (xas_error(&xas
)) {
751 error
= xas_error(&xas
);
757 page
->mapping
= NULL
;
758 page_ref_sub(page
, nr
);
763 * Like delete_from_page_cache, but substitutes swap for page.
765 static void shmem_delete_from_page_cache(struct page
*page
, void *radswap
)
767 struct address_space
*mapping
= page
->mapping
;
770 VM_BUG_ON_PAGE(PageCompound(page
), page
);
772 xa_lock_irq(&mapping
->i_pages
);
773 error
= shmem_replace_entry(mapping
, page
->index
, page
, radswap
);
774 page
->mapping
= NULL
;
776 __dec_lruvec_page_state(page
, NR_FILE_PAGES
);
777 __dec_lruvec_page_state(page
, NR_SHMEM
);
778 xa_unlock_irq(&mapping
->i_pages
);
784 * Remove swap entry from page cache, free the swap and its page cache.
786 static int shmem_free_swap(struct address_space
*mapping
,
787 pgoff_t index
, void *radswap
)
791 old
= xa_cmpxchg_irq(&mapping
->i_pages
, index
, radswap
, NULL
, 0);
794 free_swap_and_cache(radix_to_swp_entry(radswap
));
799 * Determine (in bytes) how many of the shmem object's pages mapped by the
800 * given offsets are swapped out.
802 * This is safe to call without i_rwsem or the i_pages lock thanks to RCU,
803 * as long as the inode doesn't go away and racy results are not a problem.
805 unsigned long shmem_partial_swap_usage(struct address_space
*mapping
,
806 pgoff_t start
, pgoff_t end
)
808 XA_STATE(xas
, &mapping
->i_pages
, start
);
810 unsigned long swapped
= 0;
813 xas_for_each(&xas
, page
, end
- 1) {
814 if (xas_retry(&xas
, page
))
816 if (xa_is_value(page
))
819 if (need_resched()) {
827 return swapped
<< PAGE_SHIFT
;
831 * Determine (in bytes) how many of the shmem object's pages mapped by the
832 * given vma is swapped out.
834 * This is safe to call without i_rwsem or the i_pages lock thanks to RCU,
835 * as long as the inode doesn't go away and racy results are not a problem.
837 unsigned long shmem_swap_usage(struct vm_area_struct
*vma
)
839 struct inode
*inode
= file_inode(vma
->vm_file
);
840 struct shmem_inode_info
*info
= SHMEM_I(inode
);
841 struct address_space
*mapping
= inode
->i_mapping
;
842 unsigned long swapped
;
844 /* Be careful as we don't hold info->lock */
845 swapped
= READ_ONCE(info
->swapped
);
848 * The easier cases are when the shmem object has nothing in swap, or
849 * the vma maps it whole. Then we can simply use the stats that we
855 if (!vma
->vm_pgoff
&& vma
->vm_end
- vma
->vm_start
>= inode
->i_size
)
856 return swapped
<< PAGE_SHIFT
;
858 /* Here comes the more involved part */
859 return shmem_partial_swap_usage(mapping
,
860 linear_page_index(vma
, vma
->vm_start
),
861 linear_page_index(vma
, vma
->vm_end
));
865 * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
867 void shmem_unlock_mapping(struct address_space
*mapping
)
874 * Minor point, but we might as well stop if someone else SHM_LOCKs it.
876 while (!mapping_unevictable(mapping
)) {
877 if (!pagevec_lookup(&pvec
, mapping
, &index
))
879 check_move_unevictable_pages(&pvec
);
880 pagevec_release(&pvec
);
886 * Check whether a hole-punch or truncation needs to split a huge page,
887 * returning true if no split was required, or the split has been successful.
889 * Eviction (or truncation to 0 size) should never need to split a huge page;
890 * but in rare cases might do so, if shmem_undo_range() failed to trylock on
891 * head, and then succeeded to trylock on tail.
893 * A split can only succeed when there are no additional references on the
894 * huge page: so the split below relies upon find_get_entries() having stopped
895 * when it found a subpage of the huge page, without getting further references.
897 static bool shmem_punch_compound(struct page
*page
, pgoff_t start
, pgoff_t end
)
899 if (!PageTransCompound(page
))
902 /* Just proceed to delete a huge page wholly within the range punched */
903 if (PageHead(page
) &&
904 page
->index
>= start
&& page
->index
+ HPAGE_PMD_NR
<= end
)
907 /* Try to split huge page, so we can truly punch the hole or truncate */
908 return split_huge_page(page
) >= 0;
912 * Remove range of pages and swap entries from page cache, and free them.
913 * If !unfalloc, truncate or punch hole; if unfalloc, undo failed fallocate.
915 static void shmem_undo_range(struct inode
*inode
, loff_t lstart
, loff_t lend
,
918 struct address_space
*mapping
= inode
->i_mapping
;
919 struct shmem_inode_info
*info
= SHMEM_I(inode
);
920 pgoff_t start
= (lstart
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
921 pgoff_t end
= (lend
+ 1) >> PAGE_SHIFT
;
922 unsigned int partial_start
= lstart
& (PAGE_SIZE
- 1);
923 unsigned int partial_end
= (lend
+ 1) & (PAGE_SIZE
- 1);
925 pgoff_t indices
[PAGEVEC_SIZE
];
926 long nr_swaps_freed
= 0;
931 end
= -1; /* unsigned, so actually very big */
933 if (info
->fallocend
> start
&& info
->fallocend
<= end
&& !unfalloc
)
934 info
->fallocend
= start
;
938 while (index
< end
&& find_lock_entries(mapping
, index
, end
- 1,
940 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
941 struct page
*page
= pvec
.pages
[i
];
945 if (xa_is_value(page
)) {
948 nr_swaps_freed
+= !shmem_free_swap(mapping
,
952 index
+= thp_nr_pages(page
) - 1;
954 if (!unfalloc
|| !PageUptodate(page
))
955 truncate_inode_page(mapping
, page
);
958 pagevec_remove_exceptionals(&pvec
);
959 pagevec_release(&pvec
);
965 struct page
*page
= NULL
;
966 shmem_getpage(inode
, start
- 1, &page
, SGP_READ
);
968 unsigned int top
= PAGE_SIZE
;
973 zero_user_segment(page
, partial_start
, top
);
974 set_page_dirty(page
);
980 struct page
*page
= NULL
;
981 shmem_getpage(inode
, end
, &page
, SGP_READ
);
983 zero_user_segment(page
, 0, partial_end
);
984 set_page_dirty(page
);
993 while (index
< end
) {
996 if (!find_get_entries(mapping
, index
, end
- 1, &pvec
,
998 /* If all gone or hole-punch or unfalloc, we're done */
999 if (index
== start
|| end
!= -1)
1001 /* But if truncating, restart to make sure all gone */
1005 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
1006 struct page
*page
= pvec
.pages
[i
];
1009 if (xa_is_value(page
)) {
1012 if (shmem_free_swap(mapping
, index
, page
)) {
1013 /* Swap was replaced by page: retry */
1023 if (!unfalloc
|| !PageUptodate(page
)) {
1024 if (page_mapping(page
) != mapping
) {
1025 /* Page was replaced by swap: retry */
1030 VM_BUG_ON_PAGE(PageWriteback(page
), page
);
1031 if (shmem_punch_compound(page
, start
, end
))
1032 truncate_inode_page(mapping
, page
);
1033 else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
)) {
1034 /* Wipe the page and don't get stuck */
1035 clear_highpage(page
);
1036 flush_dcache_page(page
);
1037 set_page_dirty(page
);
1039 round_up(start
, HPAGE_PMD_NR
))
1045 pagevec_remove_exceptionals(&pvec
);
1046 pagevec_release(&pvec
);
1050 spin_lock_irq(&info
->lock
);
1051 info
->swapped
-= nr_swaps_freed
;
1052 shmem_recalc_inode(inode
);
1053 spin_unlock_irq(&info
->lock
);
1056 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
1058 shmem_undo_range(inode
, lstart
, lend
, false);
1059 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
1061 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
1063 static int shmem_getattr(struct user_namespace
*mnt_userns
,
1064 const struct path
*path
, struct kstat
*stat
,
1065 u32 request_mask
, unsigned int query_flags
)
1067 struct inode
*inode
= path
->dentry
->d_inode
;
1068 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1070 if (info
->alloced
- info
->swapped
!= inode
->i_mapping
->nrpages
) {
1071 spin_lock_irq(&info
->lock
);
1072 shmem_recalc_inode(inode
);
1073 spin_unlock_irq(&info
->lock
);
1075 generic_fillattr(&init_user_ns
, inode
, stat
);
1077 if (shmem_is_huge(NULL
, inode
, 0))
1078 stat
->blksize
= HPAGE_PMD_SIZE
;
1083 static int shmem_setattr(struct user_namespace
*mnt_userns
,
1084 struct dentry
*dentry
, struct iattr
*attr
)
1086 struct inode
*inode
= d_inode(dentry
);
1087 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1090 error
= setattr_prepare(&init_user_ns
, dentry
, attr
);
1094 if (S_ISREG(inode
->i_mode
) && (attr
->ia_valid
& ATTR_SIZE
)) {
1095 loff_t oldsize
= inode
->i_size
;
1096 loff_t newsize
= attr
->ia_size
;
1098 /* protected by i_rwsem */
1099 if ((newsize
< oldsize
&& (info
->seals
& F_SEAL_SHRINK
)) ||
1100 (newsize
> oldsize
&& (info
->seals
& F_SEAL_GROW
)))
1103 if (newsize
!= oldsize
) {
1104 error
= shmem_reacct_size(SHMEM_I(inode
)->flags
,
1108 i_size_write(inode
, newsize
);
1109 inode
->i_ctime
= inode
->i_mtime
= current_time(inode
);
1111 if (newsize
<= oldsize
) {
1112 loff_t holebegin
= round_up(newsize
, PAGE_SIZE
);
1113 if (oldsize
> holebegin
)
1114 unmap_mapping_range(inode
->i_mapping
,
1117 shmem_truncate_range(inode
,
1118 newsize
, (loff_t
)-1);
1119 /* unmap again to remove racily COWed private pages */
1120 if (oldsize
> holebegin
)
1121 unmap_mapping_range(inode
->i_mapping
,
1126 setattr_copy(&init_user_ns
, inode
, attr
);
1127 if (attr
->ia_valid
& ATTR_MODE
)
1128 error
= posix_acl_chmod(&init_user_ns
, inode
, inode
->i_mode
);
1132 static void shmem_evict_inode(struct inode
*inode
)
1134 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1135 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
1137 if (shmem_mapping(inode
->i_mapping
)) {
1138 shmem_unacct_size(info
->flags
, inode
->i_size
);
1140 shmem_truncate_range(inode
, 0, (loff_t
)-1);
1141 if (!list_empty(&info
->shrinklist
)) {
1142 spin_lock(&sbinfo
->shrinklist_lock
);
1143 if (!list_empty(&info
->shrinklist
)) {
1144 list_del_init(&info
->shrinklist
);
1145 sbinfo
->shrinklist_len
--;
1147 spin_unlock(&sbinfo
->shrinklist_lock
);
1149 while (!list_empty(&info
->swaplist
)) {
1150 /* Wait while shmem_unuse() is scanning this inode... */
1151 wait_var_event(&info
->stop_eviction
,
1152 !atomic_read(&info
->stop_eviction
));
1153 mutex_lock(&shmem_swaplist_mutex
);
1154 /* ...but beware of the race if we peeked too early */
1155 if (!atomic_read(&info
->stop_eviction
))
1156 list_del_init(&info
->swaplist
);
1157 mutex_unlock(&shmem_swaplist_mutex
);
1161 simple_xattrs_free(&info
->xattrs
);
1162 WARN_ON(inode
->i_blocks
);
1163 shmem_free_inode(inode
->i_sb
);
1167 static int shmem_find_swap_entries(struct address_space
*mapping
,
1168 pgoff_t start
, unsigned int nr_entries
,
1169 struct page
**entries
, pgoff_t
*indices
,
1170 unsigned int type
, bool frontswap
)
1172 XA_STATE(xas
, &mapping
->i_pages
, start
);
1175 unsigned int ret
= 0;
1181 xas_for_each(&xas
, page
, ULONG_MAX
) {
1182 if (xas_retry(&xas
, page
))
1185 if (!xa_is_value(page
))
1188 entry
= radix_to_swp_entry(page
);
1189 if (swp_type(entry
) != type
)
1192 !frontswap_test(swap_info
[type
], swp_offset(entry
)))
1195 indices
[ret
] = xas
.xa_index
;
1196 entries
[ret
] = page
;
1198 if (need_resched()) {
1202 if (++ret
== nr_entries
)
1211 * Move the swapped pages for an inode to page cache. Returns the count
1212 * of pages swapped in, or the error in case of failure.
1214 static int shmem_unuse_swap_entries(struct inode
*inode
, struct pagevec pvec
,
1220 struct address_space
*mapping
= inode
->i_mapping
;
1222 for (i
= 0; i
< pvec
.nr
; i
++) {
1223 struct page
*page
= pvec
.pages
[i
];
1225 if (!xa_is_value(page
))
1227 error
= shmem_swapin_page(inode
, indices
[i
],
1229 mapping_gfp_mask(mapping
),
1236 if (error
== -ENOMEM
)
1240 return error
? error
: ret
;
1244 * If swap found in inode, free it and move page from swapcache to filecache.
1246 static int shmem_unuse_inode(struct inode
*inode
, unsigned int type
,
1247 bool frontswap
, unsigned long *fs_pages_to_unuse
)
1249 struct address_space
*mapping
= inode
->i_mapping
;
1251 struct pagevec pvec
;
1252 pgoff_t indices
[PAGEVEC_SIZE
];
1253 bool frontswap_partial
= (frontswap
&& *fs_pages_to_unuse
> 0);
1256 pagevec_init(&pvec
);
1258 unsigned int nr_entries
= PAGEVEC_SIZE
;
1260 if (frontswap_partial
&& *fs_pages_to_unuse
< PAGEVEC_SIZE
)
1261 nr_entries
= *fs_pages_to_unuse
;
1263 pvec
.nr
= shmem_find_swap_entries(mapping
, start
, nr_entries
,
1264 pvec
.pages
, indices
,
1271 ret
= shmem_unuse_swap_entries(inode
, pvec
, indices
);
1275 if (frontswap_partial
) {
1276 *fs_pages_to_unuse
-= ret
;
1277 if (*fs_pages_to_unuse
== 0) {
1278 ret
= FRONTSWAP_PAGES_UNUSED
;
1283 start
= indices
[pvec
.nr
- 1];
1290 * Read all the shared memory data that resides in the swap
1291 * device 'type' back into memory, so the swap device can be
1294 int shmem_unuse(unsigned int type
, bool frontswap
,
1295 unsigned long *fs_pages_to_unuse
)
1297 struct shmem_inode_info
*info
, *next
;
1300 if (list_empty(&shmem_swaplist
))
1303 mutex_lock(&shmem_swaplist_mutex
);
1304 list_for_each_entry_safe(info
, next
, &shmem_swaplist
, swaplist
) {
1305 if (!info
->swapped
) {
1306 list_del_init(&info
->swaplist
);
1310 * Drop the swaplist mutex while searching the inode for swap;
1311 * but before doing so, make sure shmem_evict_inode() will not
1312 * remove placeholder inode from swaplist, nor let it be freed
1313 * (igrab() would protect from unlink, but not from unmount).
1315 atomic_inc(&info
->stop_eviction
);
1316 mutex_unlock(&shmem_swaplist_mutex
);
1318 error
= shmem_unuse_inode(&info
->vfs_inode
, type
, frontswap
,
1322 mutex_lock(&shmem_swaplist_mutex
);
1323 next
= list_next_entry(info
, swaplist
);
1325 list_del_init(&info
->swaplist
);
1326 if (atomic_dec_and_test(&info
->stop_eviction
))
1327 wake_up_var(&info
->stop_eviction
);
1331 mutex_unlock(&shmem_swaplist_mutex
);
1337 * Move the page from the page cache to the swap cache.
1339 static int shmem_writepage(struct page
*page
, struct writeback_control
*wbc
)
1341 struct shmem_inode_info
*info
;
1342 struct address_space
*mapping
;
1343 struct inode
*inode
;
1348 * If /sys/kernel/mm/transparent_hugepage/shmem_enabled is "always" or
1349 * "force", drivers/gpu/drm/i915/gem/i915_gem_shmem.c gets huge pages,
1350 * and its shmem_writeback() needs them to be split when swapping.
1352 if (PageTransCompound(page
)) {
1353 /* Ensure the subpages are still dirty */
1355 if (split_huge_page(page
) < 0)
1357 ClearPageDirty(page
);
1360 BUG_ON(!PageLocked(page
));
1361 mapping
= page
->mapping
;
1362 index
= page
->index
;
1363 inode
= mapping
->host
;
1364 info
= SHMEM_I(inode
);
1365 if (info
->flags
& VM_LOCKED
)
1367 if (!total_swap_pages
)
1371 * Our capabilities prevent regular writeback or sync from ever calling
1372 * shmem_writepage; but a stacking filesystem might use ->writepage of
1373 * its underlying filesystem, in which case tmpfs should write out to
1374 * swap only in response to memory pressure, and not for the writeback
1377 if (!wbc
->for_reclaim
) {
1378 WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
1383 * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC
1384 * value into swapfile.c, the only way we can correctly account for a
1385 * fallocated page arriving here is now to initialize it and write it.
1387 * That's okay for a page already fallocated earlier, but if we have
1388 * not yet completed the fallocation, then (a) we want to keep track
1389 * of this page in case we have to undo it, and (b) it may not be a
1390 * good idea to continue anyway, once we're pushing into swap. So
1391 * reactivate the page, and let shmem_fallocate() quit when too many.
1393 if (!PageUptodate(page
)) {
1394 if (inode
->i_private
) {
1395 struct shmem_falloc
*shmem_falloc
;
1396 spin_lock(&inode
->i_lock
);
1397 shmem_falloc
= inode
->i_private
;
1399 !shmem_falloc
->waitq
&&
1400 index
>= shmem_falloc
->start
&&
1401 index
< shmem_falloc
->next
)
1402 shmem_falloc
->nr_unswapped
++;
1404 shmem_falloc
= NULL
;
1405 spin_unlock(&inode
->i_lock
);
1409 clear_highpage(page
);
1410 flush_dcache_page(page
);
1411 SetPageUptodate(page
);
1414 swap
= get_swap_page(page
);
1419 * Add inode to shmem_unuse()'s list of swapped-out inodes,
1420 * if it's not already there. Do it now before the page is
1421 * moved to swap cache, when its pagelock no longer protects
1422 * the inode from eviction. But don't unlock the mutex until
1423 * we've incremented swapped, because shmem_unuse_inode() will
1424 * prune a !swapped inode from the swaplist under this mutex.
1426 mutex_lock(&shmem_swaplist_mutex
);
1427 if (list_empty(&info
->swaplist
))
1428 list_add(&info
->swaplist
, &shmem_swaplist
);
1430 if (add_to_swap_cache(page
, swap
,
1431 __GFP_HIGH
| __GFP_NOMEMALLOC
| __GFP_NOWARN
,
1433 spin_lock_irq(&info
->lock
);
1434 shmem_recalc_inode(inode
);
1436 spin_unlock_irq(&info
->lock
);
1438 swap_shmem_alloc(swap
);
1439 shmem_delete_from_page_cache(page
, swp_to_radix_entry(swap
));
1441 mutex_unlock(&shmem_swaplist_mutex
);
1442 BUG_ON(page_mapped(page
));
1443 swap_writepage(page
, wbc
);
1447 mutex_unlock(&shmem_swaplist_mutex
);
1448 put_swap_page(page
, swap
);
1450 set_page_dirty(page
);
1451 if (wbc
->for_reclaim
)
1452 return AOP_WRITEPAGE_ACTIVATE
; /* Return with page locked */
1457 #if defined(CONFIG_NUMA) && defined(CONFIG_TMPFS)
1458 static void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1462 if (!mpol
|| mpol
->mode
== MPOL_DEFAULT
)
1463 return; /* show nothing */
1465 mpol_to_str(buffer
, sizeof(buffer
), mpol
);
1467 seq_printf(seq
, ",mpol=%s", buffer
);
1470 static struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1472 struct mempolicy
*mpol
= NULL
;
1474 raw_spin_lock(&sbinfo
->stat_lock
); /* prevent replace/use races */
1475 mpol
= sbinfo
->mpol
;
1477 raw_spin_unlock(&sbinfo
->stat_lock
);
1481 #else /* !CONFIG_NUMA || !CONFIG_TMPFS */
1482 static inline void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
1485 static inline struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
1489 #endif /* CONFIG_NUMA && CONFIG_TMPFS */
1491 #define vm_policy vm_private_data
1494 static void shmem_pseudo_vma_init(struct vm_area_struct
*vma
,
1495 struct shmem_inode_info
*info
, pgoff_t index
)
1497 /* Create a pseudo vma that just contains the policy */
1498 vma_init(vma
, NULL
);
1499 /* Bias interleave by inode number to distribute better across nodes */
1500 vma
->vm_pgoff
= index
+ info
->vfs_inode
.i_ino
;
1501 vma
->vm_policy
= mpol_shared_policy_lookup(&info
->policy
, index
);
1504 static void shmem_pseudo_vma_destroy(struct vm_area_struct
*vma
)
1506 /* Drop reference taken by mpol_shared_policy_lookup() */
1507 mpol_cond_put(vma
->vm_policy
);
1510 static struct page
*shmem_swapin(swp_entry_t swap
, gfp_t gfp
,
1511 struct shmem_inode_info
*info
, pgoff_t index
)
1513 struct vm_area_struct pvma
;
1515 struct vm_fault vmf
= {
1519 shmem_pseudo_vma_init(&pvma
, info
, index
);
1520 page
= swap_cluster_readahead(swap
, gfp
, &vmf
);
1521 shmem_pseudo_vma_destroy(&pvma
);
1527 * Make sure huge_gfp is always more limited than limit_gfp.
1528 * Some of the flags set permissions, while others set limitations.
1530 static gfp_t
limit_gfp_mask(gfp_t huge_gfp
, gfp_t limit_gfp
)
1532 gfp_t allowflags
= __GFP_IO
| __GFP_FS
| __GFP_RECLAIM
;
1533 gfp_t denyflags
= __GFP_NOWARN
| __GFP_NORETRY
;
1534 gfp_t zoneflags
= limit_gfp
& GFP_ZONEMASK
;
1535 gfp_t result
= huge_gfp
& ~(allowflags
| GFP_ZONEMASK
);
1537 /* Allow allocations only from the originally specified zones. */
1538 result
|= zoneflags
;
1541 * Minimize the result gfp by taking the union with the deny flags,
1542 * and the intersection of the allow flags.
1544 result
|= (limit_gfp
& denyflags
);
1545 result
|= (huge_gfp
& limit_gfp
) & allowflags
;
1550 static struct page
*shmem_alloc_hugepage(gfp_t gfp
,
1551 struct shmem_inode_info
*info
, pgoff_t index
)
1553 struct vm_area_struct pvma
;
1554 struct address_space
*mapping
= info
->vfs_inode
.i_mapping
;
1558 hindex
= round_down(index
, HPAGE_PMD_NR
);
1559 if (xa_find(&mapping
->i_pages
, &hindex
, hindex
+ HPAGE_PMD_NR
- 1,
1563 shmem_pseudo_vma_init(&pvma
, info
, hindex
);
1564 page
= alloc_pages_vma(gfp
, HPAGE_PMD_ORDER
, &pvma
, 0, numa_node_id(),
1566 shmem_pseudo_vma_destroy(&pvma
);
1568 prep_transhuge_page(page
);
1570 count_vm_event(THP_FILE_FALLBACK
);
1574 static struct page
*shmem_alloc_page(gfp_t gfp
,
1575 struct shmem_inode_info
*info
, pgoff_t index
)
1577 struct vm_area_struct pvma
;
1580 shmem_pseudo_vma_init(&pvma
, info
, index
);
1581 page
= alloc_page_vma(gfp
, &pvma
, 0);
1582 shmem_pseudo_vma_destroy(&pvma
);
1587 static struct page
*shmem_alloc_and_acct_page(gfp_t gfp
,
1588 struct inode
*inode
,
1589 pgoff_t index
, bool huge
)
1591 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1596 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
))
1598 nr
= huge
? HPAGE_PMD_NR
: 1;
1600 if (!shmem_inode_acct_block(inode
, nr
))
1604 page
= shmem_alloc_hugepage(gfp
, info
, index
);
1606 page
= shmem_alloc_page(gfp
, info
, index
);
1608 __SetPageLocked(page
);
1609 __SetPageSwapBacked(page
);
1614 shmem_inode_unacct_blocks(inode
, nr
);
1616 return ERR_PTR(err
);
1620 * When a page is moved from swapcache to shmem filecache (either by the
1621 * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
1622 * shmem_unuse_inode()), it may have been read in earlier from swap, in
1623 * ignorance of the mapping it belongs to. If that mapping has special
1624 * constraints (like the gma500 GEM driver, which requires RAM below 4GB),
1625 * we may need to copy to a suitable page before moving to filecache.
1627 * In a future release, this may well be extended to respect cpuset and
1628 * NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
1629 * but for now it is a simple matter of zone.
1631 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
)
1633 return page_zonenum(page
) > gfp_zone(gfp
);
1636 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
1637 struct shmem_inode_info
*info
, pgoff_t index
)
1639 struct page
*oldpage
, *newpage
;
1640 struct address_space
*swap_mapping
;
1646 entry
.val
= page_private(oldpage
);
1647 swap_index
= swp_offset(entry
);
1648 swap_mapping
= page_mapping(oldpage
);
1651 * We have arrived here because our zones are constrained, so don't
1652 * limit chance of success by further cpuset and node constraints.
1654 gfp
&= ~GFP_CONSTRAINT_MASK
;
1655 newpage
= shmem_alloc_page(gfp
, info
, index
);
1660 copy_highpage(newpage
, oldpage
);
1661 flush_dcache_page(newpage
);
1663 __SetPageLocked(newpage
);
1664 __SetPageSwapBacked(newpage
);
1665 SetPageUptodate(newpage
);
1666 set_page_private(newpage
, entry
.val
);
1667 SetPageSwapCache(newpage
);
1670 * Our caller will very soon move newpage out of swapcache, but it's
1671 * a nice clean interface for us to replace oldpage by newpage there.
1673 xa_lock_irq(&swap_mapping
->i_pages
);
1674 error
= shmem_replace_entry(swap_mapping
, swap_index
, oldpage
, newpage
);
1676 mem_cgroup_migrate(oldpage
, newpage
);
1677 __inc_lruvec_page_state(newpage
, NR_FILE_PAGES
);
1678 __dec_lruvec_page_state(oldpage
, NR_FILE_PAGES
);
1680 xa_unlock_irq(&swap_mapping
->i_pages
);
1682 if (unlikely(error
)) {
1684 * Is this possible? I think not, now that our callers check
1685 * both PageSwapCache and page_private after getting page lock;
1686 * but be defensive. Reverse old to newpage for clear and free.
1690 lru_cache_add(newpage
);
1694 ClearPageSwapCache(oldpage
);
1695 set_page_private(oldpage
, 0);
1697 unlock_page(oldpage
);
1704 * Swap in the page pointed to by *pagep.
1705 * Caller has to make sure that *pagep contains a valid swapped page.
1706 * Returns 0 and the page in pagep if success. On failure, returns the
1707 * error code and NULL in *pagep.
1709 static int shmem_swapin_page(struct inode
*inode
, pgoff_t index
,
1710 struct page
**pagep
, enum sgp_type sgp
,
1711 gfp_t gfp
, struct vm_area_struct
*vma
,
1712 vm_fault_t
*fault_type
)
1714 struct address_space
*mapping
= inode
->i_mapping
;
1715 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1716 struct mm_struct
*charge_mm
= vma
? vma
->vm_mm
: NULL
;
1721 VM_BUG_ON(!*pagep
|| !xa_is_value(*pagep
));
1722 swap
= radix_to_swp_entry(*pagep
);
1725 /* Look it up and read it in.. */
1726 page
= lookup_swap_cache(swap
, NULL
, 0);
1728 /* Or update major stats only when swapin succeeds?? */
1730 *fault_type
|= VM_FAULT_MAJOR
;
1731 count_vm_event(PGMAJFAULT
);
1732 count_memcg_event_mm(charge_mm
, PGMAJFAULT
);
1734 /* Here we actually start the io */
1735 page
= shmem_swapin(swap
, gfp
, info
, index
);
1742 /* We have to do this with page locked to prevent races */
1744 if (!PageSwapCache(page
) || page_private(page
) != swap
.val
||
1745 !shmem_confirm_swap(mapping
, index
, swap
)) {
1749 if (!PageUptodate(page
)) {
1753 wait_on_page_writeback(page
);
1756 * Some architectures may have to restore extra metadata to the
1757 * physical page after reading from swap.
1759 arch_swap_restore(swap
, page
);
1761 if (shmem_should_replace_page(page
, gfp
)) {
1762 error
= shmem_replace_page(&page
, gfp
, info
, index
);
1767 error
= shmem_add_to_page_cache(page
, mapping
, index
,
1768 swp_to_radix_entry(swap
), gfp
,
1773 spin_lock_irq(&info
->lock
);
1775 shmem_recalc_inode(inode
);
1776 spin_unlock_irq(&info
->lock
);
1778 if (sgp
== SGP_WRITE
)
1779 mark_page_accessed(page
);
1781 delete_from_swap_cache(page
);
1782 set_page_dirty(page
);
1788 if (!shmem_confirm_swap(mapping
, index
, swap
))
1800 * shmem_getpage_gfp - find page in cache, or get from swap, or allocate
1802 * If we allocate a new one we do not mark it dirty. That's up to the
1803 * vm. If we swap it in we mark it dirty since we also free the swap
1804 * entry since a page cannot live in both the swap and page cache.
1806 * vma, vmf, and fault_type are only supplied by shmem_fault:
1807 * otherwise they are NULL.
1809 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
1810 struct page
**pagep
, enum sgp_type sgp
, gfp_t gfp
,
1811 struct vm_area_struct
*vma
, struct vm_fault
*vmf
,
1812 vm_fault_t
*fault_type
)
1814 struct address_space
*mapping
= inode
->i_mapping
;
1815 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1816 struct shmem_sb_info
*sbinfo
;
1817 struct mm_struct
*charge_mm
;
1819 pgoff_t hindex
= index
;
1825 if (index
> (MAX_LFS_FILESIZE
>> PAGE_SHIFT
))
1828 if (sgp
<= SGP_CACHE
&&
1829 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1833 sbinfo
= SHMEM_SB(inode
->i_sb
);
1834 charge_mm
= vma
? vma
->vm_mm
: NULL
;
1836 page
= pagecache_get_page(mapping
, index
,
1837 FGP_ENTRY
| FGP_HEAD
| FGP_LOCK
, 0);
1839 if (page
&& vma
&& userfaultfd_minor(vma
)) {
1840 if (!xa_is_value(page
)) {
1844 *fault_type
= handle_userfault(vmf
, VM_UFFD_MINOR
);
1848 if (xa_is_value(page
)) {
1849 error
= shmem_swapin_page(inode
, index
, &page
,
1850 sgp
, gfp
, vma
, fault_type
);
1851 if (error
== -EEXIST
)
1859 hindex
= page
->index
;
1860 if (sgp
== SGP_WRITE
)
1861 mark_page_accessed(page
);
1862 if (PageUptodate(page
))
1864 /* fallocated page */
1865 if (sgp
!= SGP_READ
)
1872 * SGP_READ: succeed on hole, with NULL page, letting caller zero.
1873 * SGP_NOALLOC: fail on hole, with NULL page, letting caller fail.
1876 if (sgp
== SGP_READ
)
1878 if (sgp
== SGP_NOALLOC
)
1882 * Fast cache lookup and swap lookup did not find it: allocate.
1885 if (vma
&& userfaultfd_missing(vma
)) {
1886 *fault_type
= handle_userfault(vmf
, VM_UFFD_MISSING
);
1890 /* Never use a huge page for shmem_symlink() */
1891 if (S_ISLNK(inode
->i_mode
))
1893 if (!shmem_is_huge(vma
, inode
, index
))
1896 huge_gfp
= vma_thp_gfp_mask(vma
);
1897 huge_gfp
= limit_gfp_mask(huge_gfp
, gfp
);
1898 page
= shmem_alloc_and_acct_page(huge_gfp
, inode
, index
, true);
1901 page
= shmem_alloc_and_acct_page(gfp
, inode
,
1907 error
= PTR_ERR(page
);
1909 if (error
!= -ENOSPC
)
1912 * Try to reclaim some space by splitting a huge page
1913 * beyond i_size on the filesystem.
1918 ret
= shmem_unused_huge_shrink(sbinfo
, NULL
, 1);
1919 if (ret
== SHRINK_STOP
)
1927 if (PageTransHuge(page
))
1928 hindex
= round_down(index
, HPAGE_PMD_NR
);
1932 if (sgp
== SGP_WRITE
)
1933 __SetPageReferenced(page
);
1935 error
= shmem_add_to_page_cache(page
, mapping
, hindex
,
1936 NULL
, gfp
& GFP_RECLAIM_MASK
,
1940 lru_cache_add(page
);
1942 spin_lock_irq(&info
->lock
);
1943 info
->alloced
+= compound_nr(page
);
1944 inode
->i_blocks
+= BLOCKS_PER_PAGE
<< compound_order(page
);
1945 shmem_recalc_inode(inode
);
1946 spin_unlock_irq(&info
->lock
);
1949 if (PageTransHuge(page
) &&
1950 DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
) <
1951 hindex
+ HPAGE_PMD_NR
- 1) {
1953 * Part of the huge page is beyond i_size: subject
1954 * to shrink under memory pressure.
1956 spin_lock(&sbinfo
->shrinklist_lock
);
1958 * _careful to defend against unlocked access to
1959 * ->shrink_list in shmem_unused_huge_shrink()
1961 if (list_empty_careful(&info
->shrinklist
)) {
1962 list_add_tail(&info
->shrinklist
,
1963 &sbinfo
->shrinklist
);
1964 sbinfo
->shrinklist_len
++;
1966 spin_unlock(&sbinfo
->shrinklist_lock
);
1970 * Let SGP_FALLOC use the SGP_WRITE optimization on a new page.
1972 if (sgp
== SGP_FALLOC
)
1976 * Let SGP_WRITE caller clear ends if write does not fill page;
1977 * but SGP_FALLOC on a page fallocated earlier must initialize
1978 * it now, lest undo on failure cancel our earlier guarantee.
1980 if (sgp
!= SGP_WRITE
&& !PageUptodate(page
)) {
1983 for (i
= 0; i
< compound_nr(page
); i
++) {
1984 clear_highpage(page
+ i
);
1985 flush_dcache_page(page
+ i
);
1987 SetPageUptodate(page
);
1990 /* Perhaps the file has been truncated since we checked */
1991 if (sgp
<= SGP_CACHE
&&
1992 ((loff_t
)index
<< PAGE_SHIFT
) >= i_size_read(inode
)) {
1994 ClearPageDirty(page
);
1995 delete_from_page_cache(page
);
1996 spin_lock_irq(&info
->lock
);
1997 shmem_recalc_inode(inode
);
1998 spin_unlock_irq(&info
->lock
);
2004 *pagep
= page
+ index
- hindex
;
2011 shmem_inode_unacct_blocks(inode
, compound_nr(page
));
2013 if (PageTransHuge(page
)) {
2023 if (error
== -ENOSPC
&& !once
++) {
2024 spin_lock_irq(&info
->lock
);
2025 shmem_recalc_inode(inode
);
2026 spin_unlock_irq(&info
->lock
);
2029 if (error
== -EEXIST
)
2035 * This is like autoremove_wake_function, but it removes the wait queue
2036 * entry unconditionally - even if something else had already woken the
2039 static int synchronous_wake_function(wait_queue_entry_t
*wait
, unsigned mode
, int sync
, void *key
)
2041 int ret
= default_wake_function(wait
, mode
, sync
, key
);
2042 list_del_init(&wait
->entry
);
2046 static vm_fault_t
shmem_fault(struct vm_fault
*vmf
)
2048 struct vm_area_struct
*vma
= vmf
->vma
;
2049 struct inode
*inode
= file_inode(vma
->vm_file
);
2050 gfp_t gfp
= mapping_gfp_mask(inode
->i_mapping
);
2052 vm_fault_t ret
= VM_FAULT_LOCKED
;
2055 * Trinity finds that probing a hole which tmpfs is punching can
2056 * prevent the hole-punch from ever completing: which in turn
2057 * locks writers out with its hold on i_rwsem. So refrain from
2058 * faulting pages into the hole while it's being punched. Although
2059 * shmem_undo_range() does remove the additions, it may be unable to
2060 * keep up, as each new page needs its own unmap_mapping_range() call,
2061 * and the i_mmap tree grows ever slower to scan if new vmas are added.
2063 * It does not matter if we sometimes reach this check just before the
2064 * hole-punch begins, so that one fault then races with the punch:
2065 * we just need to make racing faults a rare case.
2067 * The implementation below would be much simpler if we just used a
2068 * standard mutex or completion: but we cannot take i_rwsem in fault,
2069 * and bloating every shmem inode for this unlikely case would be sad.
2071 if (unlikely(inode
->i_private
)) {
2072 struct shmem_falloc
*shmem_falloc
;
2074 spin_lock(&inode
->i_lock
);
2075 shmem_falloc
= inode
->i_private
;
2077 shmem_falloc
->waitq
&&
2078 vmf
->pgoff
>= shmem_falloc
->start
&&
2079 vmf
->pgoff
< shmem_falloc
->next
) {
2081 wait_queue_head_t
*shmem_falloc_waitq
;
2082 DEFINE_WAIT_FUNC(shmem_fault_wait
, synchronous_wake_function
);
2084 ret
= VM_FAULT_NOPAGE
;
2085 fpin
= maybe_unlock_mmap_for_io(vmf
, NULL
);
2087 ret
= VM_FAULT_RETRY
;
2089 shmem_falloc_waitq
= shmem_falloc
->waitq
;
2090 prepare_to_wait(shmem_falloc_waitq
, &shmem_fault_wait
,
2091 TASK_UNINTERRUPTIBLE
);
2092 spin_unlock(&inode
->i_lock
);
2096 * shmem_falloc_waitq points into the shmem_fallocate()
2097 * stack of the hole-punching task: shmem_falloc_waitq
2098 * is usually invalid by the time we reach here, but
2099 * finish_wait() does not dereference it in that case;
2100 * though i_lock needed lest racing with wake_up_all().
2102 spin_lock(&inode
->i_lock
);
2103 finish_wait(shmem_falloc_waitq
, &shmem_fault_wait
);
2104 spin_unlock(&inode
->i_lock
);
2110 spin_unlock(&inode
->i_lock
);
2113 err
= shmem_getpage_gfp(inode
, vmf
->pgoff
, &vmf
->page
, SGP_CACHE
,
2114 gfp
, vma
, vmf
, &ret
);
2116 return vmf_error(err
);
2120 unsigned long shmem_get_unmapped_area(struct file
*file
,
2121 unsigned long uaddr
, unsigned long len
,
2122 unsigned long pgoff
, unsigned long flags
)
2124 unsigned long (*get_area
)(struct file
*,
2125 unsigned long, unsigned long, unsigned long, unsigned long);
2127 unsigned long offset
;
2128 unsigned long inflated_len
;
2129 unsigned long inflated_addr
;
2130 unsigned long inflated_offset
;
2132 if (len
> TASK_SIZE
)
2135 get_area
= current
->mm
->get_unmapped_area
;
2136 addr
= get_area(file
, uaddr
, len
, pgoff
, flags
);
2138 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
))
2140 if (IS_ERR_VALUE(addr
))
2142 if (addr
& ~PAGE_MASK
)
2144 if (addr
> TASK_SIZE
- len
)
2147 if (shmem_huge
== SHMEM_HUGE_DENY
)
2149 if (len
< HPAGE_PMD_SIZE
)
2151 if (flags
& MAP_FIXED
)
2154 * Our priority is to support MAP_SHARED mapped hugely;
2155 * and support MAP_PRIVATE mapped hugely too, until it is COWed.
2156 * But if caller specified an address hint and we allocated area there
2157 * successfully, respect that as before.
2162 if (shmem_huge
!= SHMEM_HUGE_FORCE
) {
2163 struct super_block
*sb
;
2166 VM_BUG_ON(file
->f_op
!= &shmem_file_operations
);
2167 sb
= file_inode(file
)->i_sb
;
2170 * Called directly from mm/mmap.c, or drivers/char/mem.c
2171 * for "/dev/zero", to create a shared anonymous object.
2173 if (IS_ERR(shm_mnt
))
2175 sb
= shm_mnt
->mnt_sb
;
2177 if (SHMEM_SB(sb
)->huge
== SHMEM_HUGE_NEVER
)
2181 offset
= (pgoff
<< PAGE_SHIFT
) & (HPAGE_PMD_SIZE
-1);
2182 if (offset
&& offset
+ len
< 2 * HPAGE_PMD_SIZE
)
2184 if ((addr
& (HPAGE_PMD_SIZE
-1)) == offset
)
2187 inflated_len
= len
+ HPAGE_PMD_SIZE
- PAGE_SIZE
;
2188 if (inflated_len
> TASK_SIZE
)
2190 if (inflated_len
< len
)
2193 inflated_addr
= get_area(NULL
, uaddr
, inflated_len
, 0, flags
);
2194 if (IS_ERR_VALUE(inflated_addr
))
2196 if (inflated_addr
& ~PAGE_MASK
)
2199 inflated_offset
= inflated_addr
& (HPAGE_PMD_SIZE
-1);
2200 inflated_addr
+= offset
- inflated_offset
;
2201 if (inflated_offset
> offset
)
2202 inflated_addr
+= HPAGE_PMD_SIZE
;
2204 if (inflated_addr
> TASK_SIZE
- len
)
2206 return inflated_addr
;
2210 static int shmem_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*mpol
)
2212 struct inode
*inode
= file_inode(vma
->vm_file
);
2213 return mpol_set_shared_policy(&SHMEM_I(inode
)->policy
, vma
, mpol
);
2216 static struct mempolicy
*shmem_get_policy(struct vm_area_struct
*vma
,
2219 struct inode
*inode
= file_inode(vma
->vm_file
);
2222 index
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2223 return mpol_shared_policy_lookup(&SHMEM_I(inode
)->policy
, index
);
2227 int shmem_lock(struct file
*file
, int lock
, struct ucounts
*ucounts
)
2229 struct inode
*inode
= file_inode(file
);
2230 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2231 int retval
= -ENOMEM
;
2234 * What serializes the accesses to info->flags?
2235 * ipc_lock_object() when called from shmctl_do_lock(),
2236 * no serialization needed when called from shm_destroy().
2238 if (lock
&& !(info
->flags
& VM_LOCKED
)) {
2239 if (!user_shm_lock(inode
->i_size
, ucounts
))
2241 info
->flags
|= VM_LOCKED
;
2242 mapping_set_unevictable(file
->f_mapping
);
2244 if (!lock
&& (info
->flags
& VM_LOCKED
) && ucounts
) {
2245 user_shm_unlock(inode
->i_size
, ucounts
);
2246 info
->flags
&= ~VM_LOCKED
;
2247 mapping_clear_unevictable(file
->f_mapping
);
2255 static int shmem_mmap(struct file
*file
, struct vm_area_struct
*vma
)
2257 struct shmem_inode_info
*info
= SHMEM_I(file_inode(file
));
2260 ret
= seal_check_future_write(info
->seals
, vma
);
2264 /* arm64 - allow memory tagging on RAM-based files */
2265 vma
->vm_flags
|= VM_MTE_ALLOWED
;
2267 file_accessed(file
);
2268 vma
->vm_ops
= &shmem_vm_ops
;
2269 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
2270 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
2271 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
2272 khugepaged_enter(vma
, vma
->vm_flags
);
2277 static struct inode
*shmem_get_inode(struct super_block
*sb
, const struct inode
*dir
,
2278 umode_t mode
, dev_t dev
, unsigned long flags
)
2280 struct inode
*inode
;
2281 struct shmem_inode_info
*info
;
2282 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
2285 if (shmem_reserve_inode(sb
, &ino
))
2288 inode
= new_inode(sb
);
2291 inode_init_owner(&init_user_ns
, inode
, dir
, mode
);
2292 inode
->i_blocks
= 0;
2293 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= current_time(inode
);
2294 inode
->i_generation
= prandom_u32();
2295 info
= SHMEM_I(inode
);
2296 memset(info
, 0, (char *)inode
- (char *)info
);
2297 spin_lock_init(&info
->lock
);
2298 atomic_set(&info
->stop_eviction
, 0);
2299 info
->seals
= F_SEAL_SEAL
;
2300 info
->flags
= flags
& VM_NORESERVE
;
2301 INIT_LIST_HEAD(&info
->shrinklist
);
2302 INIT_LIST_HEAD(&info
->swaplist
);
2303 simple_xattrs_init(&info
->xattrs
);
2304 cache_no_acl(inode
);
2306 switch (mode
& S_IFMT
) {
2308 inode
->i_op
= &shmem_special_inode_operations
;
2309 init_special_inode(inode
, mode
, dev
);
2312 inode
->i_mapping
->a_ops
= &shmem_aops
;
2313 inode
->i_op
= &shmem_inode_operations
;
2314 inode
->i_fop
= &shmem_file_operations
;
2315 mpol_shared_policy_init(&info
->policy
,
2316 shmem_get_sbmpol(sbinfo
));
2320 /* Some things misbehave if size == 0 on a directory */
2321 inode
->i_size
= 2 * BOGO_DIRENT_SIZE
;
2322 inode
->i_op
= &shmem_dir_inode_operations
;
2323 inode
->i_fop
= &simple_dir_operations
;
2327 * Must not load anything in the rbtree,
2328 * mpol_free_shared_policy will not be called.
2330 mpol_shared_policy_init(&info
->policy
, NULL
);
2334 lockdep_annotate_inode_mutex_key(inode
);
2336 shmem_free_inode(sb
);
2340 #ifdef CONFIG_USERFAULTFD
2341 int shmem_mfill_atomic_pte(struct mm_struct
*dst_mm
,
2343 struct vm_area_struct
*dst_vma
,
2344 unsigned long dst_addr
,
2345 unsigned long src_addr
,
2347 struct page
**pagep
)
2349 struct inode
*inode
= file_inode(dst_vma
->vm_file
);
2350 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2351 struct address_space
*mapping
= inode
->i_mapping
;
2352 gfp_t gfp
= mapping_gfp_mask(mapping
);
2353 pgoff_t pgoff
= linear_page_index(dst_vma
, dst_addr
);
2359 if (!shmem_inode_acct_block(inode
, 1)) {
2361 * We may have got a page, returned -ENOENT triggering a retry,
2362 * and now we find ourselves with -ENOMEM. Release the page, to
2363 * avoid a BUG_ON in our caller.
2365 if (unlikely(*pagep
)) {
2374 page
= shmem_alloc_page(gfp
, info
, pgoff
);
2376 goto out_unacct_blocks
;
2378 if (!zeropage
) { /* COPY */
2379 page_kaddr
= kmap_atomic(page
);
2380 ret
= copy_from_user(page_kaddr
,
2381 (const void __user
*)src_addr
,
2383 kunmap_atomic(page_kaddr
);
2385 /* fallback to copy_from_user outside mmap_lock */
2386 if (unlikely(ret
)) {
2389 /* don't free the page */
2390 goto out_unacct_blocks
;
2392 } else { /* ZEROPAGE */
2393 clear_highpage(page
);
2400 VM_BUG_ON(PageLocked(page
));
2401 VM_BUG_ON(PageSwapBacked(page
));
2402 __SetPageLocked(page
);
2403 __SetPageSwapBacked(page
);
2404 __SetPageUptodate(page
);
2407 max_off
= DIV_ROUND_UP(i_size_read(inode
), PAGE_SIZE
);
2408 if (unlikely(pgoff
>= max_off
))
2411 ret
= shmem_add_to_page_cache(page
, mapping
, pgoff
, NULL
,
2412 gfp
& GFP_RECLAIM_MASK
, dst_mm
);
2416 ret
= mfill_atomic_install_pte(dst_mm
, dst_pmd
, dst_vma
, dst_addr
,
2419 goto out_delete_from_cache
;
2421 spin_lock_irq(&info
->lock
);
2423 inode
->i_blocks
+= BLOCKS_PER_PAGE
;
2424 shmem_recalc_inode(inode
);
2425 spin_unlock_irq(&info
->lock
);
2430 out_delete_from_cache
:
2431 delete_from_page_cache(page
);
2436 shmem_inode_unacct_blocks(inode
, 1);
2439 #endif /* CONFIG_USERFAULTFD */
2442 static const struct inode_operations shmem_symlink_inode_operations
;
2443 static const struct inode_operations shmem_short_symlink_operations
;
2445 #ifdef CONFIG_TMPFS_XATTR
2446 static int shmem_initxattrs(struct inode
*, const struct xattr
*, void *);
2448 #define shmem_initxattrs NULL
2452 shmem_write_begin(struct file
*file
, struct address_space
*mapping
,
2453 loff_t pos
, unsigned len
, unsigned flags
,
2454 struct page
**pagep
, void **fsdata
)
2456 struct inode
*inode
= mapping
->host
;
2457 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2458 pgoff_t index
= pos
>> PAGE_SHIFT
;
2460 /* i_rwsem is held by caller */
2461 if (unlikely(info
->seals
& (F_SEAL_GROW
|
2462 F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))) {
2463 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
))
2465 if ((info
->seals
& F_SEAL_GROW
) && pos
+ len
> inode
->i_size
)
2469 return shmem_getpage(inode
, index
, pagep
, SGP_WRITE
);
2473 shmem_write_end(struct file
*file
, struct address_space
*mapping
,
2474 loff_t pos
, unsigned len
, unsigned copied
,
2475 struct page
*page
, void *fsdata
)
2477 struct inode
*inode
= mapping
->host
;
2479 if (pos
+ copied
> inode
->i_size
)
2480 i_size_write(inode
, pos
+ copied
);
2482 if (!PageUptodate(page
)) {
2483 struct page
*head
= compound_head(page
);
2484 if (PageTransCompound(page
)) {
2487 for (i
= 0; i
< HPAGE_PMD_NR
; i
++) {
2488 if (head
+ i
== page
)
2490 clear_highpage(head
+ i
);
2491 flush_dcache_page(head
+ i
);
2494 if (copied
< PAGE_SIZE
) {
2495 unsigned from
= pos
& (PAGE_SIZE
- 1);
2496 zero_user_segments(page
, 0, from
,
2497 from
+ copied
, PAGE_SIZE
);
2499 SetPageUptodate(head
);
2501 set_page_dirty(page
);
2508 static ssize_t
shmem_file_read_iter(struct kiocb
*iocb
, struct iov_iter
*to
)
2510 struct file
*file
= iocb
->ki_filp
;
2511 struct inode
*inode
= file_inode(file
);
2512 struct address_space
*mapping
= inode
->i_mapping
;
2514 unsigned long offset
;
2515 enum sgp_type sgp
= SGP_READ
;
2518 loff_t
*ppos
= &iocb
->ki_pos
;
2521 * Might this read be for a stacking filesystem? Then when reading
2522 * holes of a sparse file, we actually need to allocate those pages,
2523 * and even mark them dirty, so it cannot exceed the max_blocks limit.
2525 if (!iter_is_iovec(to
))
2528 index
= *ppos
>> PAGE_SHIFT
;
2529 offset
= *ppos
& ~PAGE_MASK
;
2532 struct page
*page
= NULL
;
2534 unsigned long nr
, ret
;
2535 loff_t i_size
= i_size_read(inode
);
2537 end_index
= i_size
>> PAGE_SHIFT
;
2538 if (index
> end_index
)
2540 if (index
== end_index
) {
2541 nr
= i_size
& ~PAGE_MASK
;
2546 error
= shmem_getpage(inode
, index
, &page
, sgp
);
2548 if (error
== -EINVAL
)
2553 if (sgp
== SGP_CACHE
)
2554 set_page_dirty(page
);
2559 * We must evaluate after, since reads (unlike writes)
2560 * are called without i_rwsem protection against truncate
2563 i_size
= i_size_read(inode
);
2564 end_index
= i_size
>> PAGE_SHIFT
;
2565 if (index
== end_index
) {
2566 nr
= i_size
& ~PAGE_MASK
;
2577 * If users can be writing to this page using arbitrary
2578 * virtual addresses, take care about potential aliasing
2579 * before reading the page on the kernel side.
2581 if (mapping_writably_mapped(mapping
))
2582 flush_dcache_page(page
);
2584 * Mark the page accessed if we read the beginning.
2587 mark_page_accessed(page
);
2589 page
= ZERO_PAGE(0);
2594 * Ok, we have the page, and it's up-to-date, so
2595 * now we can copy it to user space...
2597 ret
= copy_page_to_iter(page
, offset
, nr
, to
);
2600 index
+= offset
>> PAGE_SHIFT
;
2601 offset
&= ~PAGE_MASK
;
2604 if (!iov_iter_count(to
))
2613 *ppos
= ((loff_t
) index
<< PAGE_SHIFT
) + offset
;
2614 file_accessed(file
);
2615 return retval
? retval
: error
;
2618 static loff_t
shmem_file_llseek(struct file
*file
, loff_t offset
, int whence
)
2620 struct address_space
*mapping
= file
->f_mapping
;
2621 struct inode
*inode
= mapping
->host
;
2623 if (whence
!= SEEK_DATA
&& whence
!= SEEK_HOLE
)
2624 return generic_file_llseek_size(file
, offset
, whence
,
2625 MAX_LFS_FILESIZE
, i_size_read(inode
));
2630 /* We're holding i_rwsem so we can access i_size directly */
2631 offset
= mapping_seek_hole_data(mapping
, offset
, inode
->i_size
, whence
);
2633 offset
= vfs_setpos(file
, offset
, MAX_LFS_FILESIZE
);
2634 inode_unlock(inode
);
2638 static long shmem_fallocate(struct file
*file
, int mode
, loff_t offset
,
2641 struct inode
*inode
= file_inode(file
);
2642 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
2643 struct shmem_inode_info
*info
= SHMEM_I(inode
);
2644 struct shmem_falloc shmem_falloc
;
2645 pgoff_t start
, index
, end
, undo_fallocend
;
2648 if (mode
& ~(FALLOC_FL_KEEP_SIZE
| FALLOC_FL_PUNCH_HOLE
))
2653 if (mode
& FALLOC_FL_PUNCH_HOLE
) {
2654 struct address_space
*mapping
= file
->f_mapping
;
2655 loff_t unmap_start
= round_up(offset
, PAGE_SIZE
);
2656 loff_t unmap_end
= round_down(offset
+ len
, PAGE_SIZE
) - 1;
2657 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(shmem_falloc_waitq
);
2659 /* protected by i_rwsem */
2660 if (info
->seals
& (F_SEAL_WRITE
| F_SEAL_FUTURE_WRITE
)) {
2665 shmem_falloc
.waitq
= &shmem_falloc_waitq
;
2666 shmem_falloc
.start
= (u64
)unmap_start
>> PAGE_SHIFT
;
2667 shmem_falloc
.next
= (unmap_end
+ 1) >> PAGE_SHIFT
;
2668 spin_lock(&inode
->i_lock
);
2669 inode
->i_private
= &shmem_falloc
;
2670 spin_unlock(&inode
->i_lock
);
2672 if ((u64
)unmap_end
> (u64
)unmap_start
)
2673 unmap_mapping_range(mapping
, unmap_start
,
2674 1 + unmap_end
- unmap_start
, 0);
2675 shmem_truncate_range(inode
, offset
, offset
+ len
- 1);
2676 /* No need to unmap again: hole-punching leaves COWed pages */
2678 spin_lock(&inode
->i_lock
);
2679 inode
->i_private
= NULL
;
2680 wake_up_all(&shmem_falloc_waitq
);
2681 WARN_ON_ONCE(!list_empty(&shmem_falloc_waitq
.head
));
2682 spin_unlock(&inode
->i_lock
);
2687 /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */
2688 error
= inode_newsize_ok(inode
, offset
+ len
);
2692 if ((info
->seals
& F_SEAL_GROW
) && offset
+ len
> inode
->i_size
) {
2697 start
= offset
>> PAGE_SHIFT
;
2698 end
= (offset
+ len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2699 /* Try to avoid a swapstorm if len is impossible to satisfy */
2700 if (sbinfo
->max_blocks
&& end
- start
> sbinfo
->max_blocks
) {
2705 shmem_falloc
.waitq
= NULL
;
2706 shmem_falloc
.start
= start
;
2707 shmem_falloc
.next
= start
;
2708 shmem_falloc
.nr_falloced
= 0;
2709 shmem_falloc
.nr_unswapped
= 0;
2710 spin_lock(&inode
->i_lock
);
2711 inode
->i_private
= &shmem_falloc
;
2712 spin_unlock(&inode
->i_lock
);
2715 * info->fallocend is only relevant when huge pages might be
2716 * involved: to prevent split_huge_page() freeing fallocated
2717 * pages when FALLOC_FL_KEEP_SIZE committed beyond i_size.
2719 undo_fallocend
= info
->fallocend
;
2720 if (info
->fallocend
< end
)
2721 info
->fallocend
= end
;
2723 for (index
= start
; index
< end
; ) {
2727 * Good, the fallocate(2) manpage permits EINTR: we may have
2728 * been interrupted because we are using up too much memory.
2730 if (signal_pending(current
))
2732 else if (shmem_falloc
.nr_unswapped
> shmem_falloc
.nr_falloced
)
2735 error
= shmem_getpage(inode
, index
, &page
, SGP_FALLOC
);
2737 info
->fallocend
= undo_fallocend
;
2738 /* Remove the !PageUptodate pages we added */
2739 if (index
> start
) {
2740 shmem_undo_range(inode
,
2741 (loff_t
)start
<< PAGE_SHIFT
,
2742 ((loff_t
)index
<< PAGE_SHIFT
) - 1, true);
2749 * Here is a more important optimization than it appears:
2750 * a second SGP_FALLOC on the same huge page will clear it,
2751 * making it PageUptodate and un-undoable if we fail later.
2753 if (PageTransCompound(page
)) {
2754 index
= round_up(index
, HPAGE_PMD_NR
);
2755 /* Beware 32-bit wraparound */
2761 * Inform shmem_writepage() how far we have reached.
2762 * No need for lock or barrier: we have the page lock.
2764 if (!PageUptodate(page
))
2765 shmem_falloc
.nr_falloced
+= index
- shmem_falloc
.next
;
2766 shmem_falloc
.next
= index
;
2769 * If !PageUptodate, leave it that way so that freeable pages
2770 * can be recognized if we need to rollback on error later.
2771 * But set_page_dirty so that memory pressure will swap rather
2772 * than free the pages we are allocating (and SGP_CACHE pages
2773 * might still be clean: we now need to mark those dirty too).
2775 set_page_dirty(page
);
2781 if (!(mode
& FALLOC_FL_KEEP_SIZE
) && offset
+ len
> inode
->i_size
)
2782 i_size_write(inode
, offset
+ len
);
2783 inode
->i_ctime
= current_time(inode
);
2785 spin_lock(&inode
->i_lock
);
2786 inode
->i_private
= NULL
;
2787 spin_unlock(&inode
->i_lock
);
2789 inode_unlock(inode
);
2793 static int shmem_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
2795 struct shmem_sb_info
*sbinfo
= SHMEM_SB(dentry
->d_sb
);
2797 buf
->f_type
= TMPFS_MAGIC
;
2798 buf
->f_bsize
= PAGE_SIZE
;
2799 buf
->f_namelen
= NAME_MAX
;
2800 if (sbinfo
->max_blocks
) {
2801 buf
->f_blocks
= sbinfo
->max_blocks
;
2803 buf
->f_bfree
= sbinfo
->max_blocks
-
2804 percpu_counter_sum(&sbinfo
->used_blocks
);
2806 if (sbinfo
->max_inodes
) {
2807 buf
->f_files
= sbinfo
->max_inodes
;
2808 buf
->f_ffree
= sbinfo
->free_inodes
;
2810 /* else leave those fields 0 like simple_statfs */
2812 buf
->f_fsid
= uuid_to_fsid(dentry
->d_sb
->s_uuid
.b
);
2818 * File creation. Allocate an inode, and we're done..
2821 shmem_mknod(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2822 struct dentry
*dentry
, umode_t mode
, dev_t dev
)
2824 struct inode
*inode
;
2825 int error
= -ENOSPC
;
2827 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, dev
, VM_NORESERVE
);
2829 error
= simple_acl_create(dir
, inode
);
2832 error
= security_inode_init_security(inode
, dir
,
2834 shmem_initxattrs
, NULL
);
2835 if (error
&& error
!= -EOPNOTSUPP
)
2839 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2840 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
2841 d_instantiate(dentry
, inode
);
2842 dget(dentry
); /* Extra count - pin the dentry in core */
2851 shmem_tmpfile(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2852 struct dentry
*dentry
, umode_t mode
)
2854 struct inode
*inode
;
2855 int error
= -ENOSPC
;
2857 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, 0, VM_NORESERVE
);
2859 error
= security_inode_init_security(inode
, dir
,
2861 shmem_initxattrs
, NULL
);
2862 if (error
&& error
!= -EOPNOTSUPP
)
2864 error
= simple_acl_create(dir
, inode
);
2867 d_tmpfile(dentry
, inode
);
2875 static int shmem_mkdir(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2876 struct dentry
*dentry
, umode_t mode
)
2880 if ((error
= shmem_mknod(&init_user_ns
, dir
, dentry
,
2881 mode
| S_IFDIR
, 0)))
2887 static int shmem_create(struct user_namespace
*mnt_userns
, struct inode
*dir
,
2888 struct dentry
*dentry
, umode_t mode
, bool excl
)
2890 return shmem_mknod(&init_user_ns
, dir
, dentry
, mode
| S_IFREG
, 0);
2896 static int shmem_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*dentry
)
2898 struct inode
*inode
= d_inode(old_dentry
);
2902 * No ordinary (disk based) filesystem counts links as inodes;
2903 * but each new link needs a new dentry, pinning lowmem, and
2904 * tmpfs dentries cannot be pruned until they are unlinked.
2905 * But if an O_TMPFILE file is linked into the tmpfs, the
2906 * first link must skip that, to get the accounting right.
2908 if (inode
->i_nlink
) {
2909 ret
= shmem_reserve_inode(inode
->i_sb
, NULL
);
2914 dir
->i_size
+= BOGO_DIRENT_SIZE
;
2915 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2917 ihold(inode
); /* New dentry reference */
2918 dget(dentry
); /* Extra pinning count for the created dentry */
2919 d_instantiate(dentry
, inode
);
2924 static int shmem_unlink(struct inode
*dir
, struct dentry
*dentry
)
2926 struct inode
*inode
= d_inode(dentry
);
2928 if (inode
->i_nlink
> 1 && !S_ISDIR(inode
->i_mode
))
2929 shmem_free_inode(inode
->i_sb
);
2931 dir
->i_size
-= BOGO_DIRENT_SIZE
;
2932 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= current_time(inode
);
2934 dput(dentry
); /* Undo the count from "create" - this does all the work */
2938 static int shmem_rmdir(struct inode
*dir
, struct dentry
*dentry
)
2940 if (!simple_empty(dentry
))
2943 drop_nlink(d_inode(dentry
));
2945 return shmem_unlink(dir
, dentry
);
2948 static int shmem_exchange(struct inode
*old_dir
, struct dentry
*old_dentry
, struct inode
*new_dir
, struct dentry
*new_dentry
)
2950 bool old_is_dir
= d_is_dir(old_dentry
);
2951 bool new_is_dir
= d_is_dir(new_dentry
);
2953 if (old_dir
!= new_dir
&& old_is_dir
!= new_is_dir
) {
2955 drop_nlink(old_dir
);
2958 drop_nlink(new_dir
);
2962 old_dir
->i_ctime
= old_dir
->i_mtime
=
2963 new_dir
->i_ctime
= new_dir
->i_mtime
=
2964 d_inode(old_dentry
)->i_ctime
=
2965 d_inode(new_dentry
)->i_ctime
= current_time(old_dir
);
2970 static int shmem_whiteout(struct user_namespace
*mnt_userns
,
2971 struct inode
*old_dir
, struct dentry
*old_dentry
)
2973 struct dentry
*whiteout
;
2976 whiteout
= d_alloc(old_dentry
->d_parent
, &old_dentry
->d_name
);
2980 error
= shmem_mknod(&init_user_ns
, old_dir
, whiteout
,
2981 S_IFCHR
| WHITEOUT_MODE
, WHITEOUT_DEV
);
2987 * Cheat and hash the whiteout while the old dentry is still in
2988 * place, instead of playing games with FS_RENAME_DOES_D_MOVE.
2990 * d_lookup() will consistently find one of them at this point,
2991 * not sure which one, but that isn't even important.
2998 * The VFS layer already does all the dentry stuff for rename,
2999 * we just have to decrement the usage count for the target if
3000 * it exists so that the VFS layer correctly free's it when it
3003 static int shmem_rename2(struct user_namespace
*mnt_userns
,
3004 struct inode
*old_dir
, struct dentry
*old_dentry
,
3005 struct inode
*new_dir
, struct dentry
*new_dentry
,
3008 struct inode
*inode
= d_inode(old_dentry
);
3009 int they_are_dirs
= S_ISDIR(inode
->i_mode
);
3011 if (flags
& ~(RENAME_NOREPLACE
| RENAME_EXCHANGE
| RENAME_WHITEOUT
))
3014 if (flags
& RENAME_EXCHANGE
)
3015 return shmem_exchange(old_dir
, old_dentry
, new_dir
, new_dentry
);
3017 if (!simple_empty(new_dentry
))
3020 if (flags
& RENAME_WHITEOUT
) {
3023 error
= shmem_whiteout(&init_user_ns
, old_dir
, old_dentry
);
3028 if (d_really_is_positive(new_dentry
)) {
3029 (void) shmem_unlink(new_dir
, new_dentry
);
3030 if (they_are_dirs
) {
3031 drop_nlink(d_inode(new_dentry
));
3032 drop_nlink(old_dir
);
3034 } else if (they_are_dirs
) {
3035 drop_nlink(old_dir
);
3039 old_dir
->i_size
-= BOGO_DIRENT_SIZE
;
3040 new_dir
->i_size
+= BOGO_DIRENT_SIZE
;
3041 old_dir
->i_ctime
= old_dir
->i_mtime
=
3042 new_dir
->i_ctime
= new_dir
->i_mtime
=
3043 inode
->i_ctime
= current_time(old_dir
);
3047 static int shmem_symlink(struct user_namespace
*mnt_userns
, struct inode
*dir
,
3048 struct dentry
*dentry
, const char *symname
)
3052 struct inode
*inode
;
3055 len
= strlen(symname
) + 1;
3056 if (len
> PAGE_SIZE
)
3057 return -ENAMETOOLONG
;
3059 inode
= shmem_get_inode(dir
->i_sb
, dir
, S_IFLNK
| 0777, 0,
3064 error
= security_inode_init_security(inode
, dir
, &dentry
->d_name
,
3065 shmem_initxattrs
, NULL
);
3066 if (error
&& error
!= -EOPNOTSUPP
) {
3071 inode
->i_size
= len
-1;
3072 if (len
<= SHORT_SYMLINK_LEN
) {
3073 inode
->i_link
= kmemdup(symname
, len
, GFP_KERNEL
);
3074 if (!inode
->i_link
) {
3078 inode
->i_op
= &shmem_short_symlink_operations
;
3080 inode_nohighmem(inode
);
3081 error
= shmem_getpage(inode
, 0, &page
, SGP_WRITE
);
3086 inode
->i_mapping
->a_ops
= &shmem_aops
;
3087 inode
->i_op
= &shmem_symlink_inode_operations
;
3088 memcpy(page_address(page
), symname
, len
);
3089 SetPageUptodate(page
);
3090 set_page_dirty(page
);
3094 dir
->i_size
+= BOGO_DIRENT_SIZE
;
3095 dir
->i_ctime
= dir
->i_mtime
= current_time(dir
);
3096 d_instantiate(dentry
, inode
);
3101 static void shmem_put_link(void *arg
)
3103 mark_page_accessed(arg
);
3107 static const char *shmem_get_link(struct dentry
*dentry
,
3108 struct inode
*inode
,
3109 struct delayed_call
*done
)
3111 struct page
*page
= NULL
;
3114 page
= find_get_page(inode
->i_mapping
, 0);
3116 return ERR_PTR(-ECHILD
);
3117 if (!PageUptodate(page
)) {
3119 return ERR_PTR(-ECHILD
);
3122 error
= shmem_getpage(inode
, 0, &page
, SGP_READ
);
3124 return ERR_PTR(error
);
3127 set_delayed_call(done
, shmem_put_link
, page
);
3128 return page_address(page
);
3131 #ifdef CONFIG_TMPFS_XATTR
3133 * Superblocks without xattr inode operations may get some security.* xattr
3134 * support from the LSM "for free". As soon as we have any other xattrs
3135 * like ACLs, we also need to implement the security.* handlers at
3136 * filesystem level, though.
3140 * Callback for security_inode_init_security() for acquiring xattrs.
3142 static int shmem_initxattrs(struct inode
*inode
,
3143 const struct xattr
*xattr_array
,
3146 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3147 const struct xattr
*xattr
;
3148 struct simple_xattr
*new_xattr
;
3151 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
3152 new_xattr
= simple_xattr_alloc(xattr
->value
, xattr
->value_len
);
3156 len
= strlen(xattr
->name
) + 1;
3157 new_xattr
->name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+ len
,
3159 if (!new_xattr
->name
) {
3164 memcpy(new_xattr
->name
, XATTR_SECURITY_PREFIX
,
3165 XATTR_SECURITY_PREFIX_LEN
);
3166 memcpy(new_xattr
->name
+ XATTR_SECURITY_PREFIX_LEN
,
3169 simple_xattr_list_add(&info
->xattrs
, new_xattr
);
3175 static int shmem_xattr_handler_get(const struct xattr_handler
*handler
,
3176 struct dentry
*unused
, struct inode
*inode
,
3177 const char *name
, void *buffer
, size_t size
)
3179 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3181 name
= xattr_full_name(handler
, name
);
3182 return simple_xattr_get(&info
->xattrs
, name
, buffer
, size
);
3185 static int shmem_xattr_handler_set(const struct xattr_handler
*handler
,
3186 struct user_namespace
*mnt_userns
,
3187 struct dentry
*unused
, struct inode
*inode
,
3188 const char *name
, const void *value
,
3189 size_t size
, int flags
)
3191 struct shmem_inode_info
*info
= SHMEM_I(inode
);
3193 name
= xattr_full_name(handler
, name
);
3194 return simple_xattr_set(&info
->xattrs
, name
, value
, size
, flags
, NULL
);
3197 static const struct xattr_handler shmem_security_xattr_handler
= {
3198 .prefix
= XATTR_SECURITY_PREFIX
,
3199 .get
= shmem_xattr_handler_get
,
3200 .set
= shmem_xattr_handler_set
,
3203 static const struct xattr_handler shmem_trusted_xattr_handler
= {
3204 .prefix
= XATTR_TRUSTED_PREFIX
,
3205 .get
= shmem_xattr_handler_get
,
3206 .set
= shmem_xattr_handler_set
,
3209 static const struct xattr_handler
*shmem_xattr_handlers
[] = {
3210 #ifdef CONFIG_TMPFS_POSIX_ACL
3211 &posix_acl_access_xattr_handler
,
3212 &posix_acl_default_xattr_handler
,
3214 &shmem_security_xattr_handler
,
3215 &shmem_trusted_xattr_handler
,
3219 static ssize_t
shmem_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
3221 struct shmem_inode_info
*info
= SHMEM_I(d_inode(dentry
));
3222 return simple_xattr_list(d_inode(dentry
), &info
->xattrs
, buffer
, size
);
3224 #endif /* CONFIG_TMPFS_XATTR */
3226 static const struct inode_operations shmem_short_symlink_operations
= {
3227 .get_link
= simple_get_link
,
3228 #ifdef CONFIG_TMPFS_XATTR
3229 .listxattr
= shmem_listxattr
,
3233 static const struct inode_operations shmem_symlink_inode_operations
= {
3234 .get_link
= shmem_get_link
,
3235 #ifdef CONFIG_TMPFS_XATTR
3236 .listxattr
= shmem_listxattr
,
3240 static struct dentry
*shmem_get_parent(struct dentry
*child
)
3242 return ERR_PTR(-ESTALE
);
3245 static int shmem_match(struct inode
*ino
, void *vfh
)
3249 inum
= (inum
<< 32) | fh
[1];
3250 return ino
->i_ino
== inum
&& fh
[0] == ino
->i_generation
;
3253 /* Find any alias of inode, but prefer a hashed alias */
3254 static struct dentry
*shmem_find_alias(struct inode
*inode
)
3256 struct dentry
*alias
= d_find_alias(inode
);
3258 return alias
?: d_find_any_alias(inode
);
3262 static struct dentry
*shmem_fh_to_dentry(struct super_block
*sb
,
3263 struct fid
*fid
, int fh_len
, int fh_type
)
3265 struct inode
*inode
;
3266 struct dentry
*dentry
= NULL
;
3273 inum
= (inum
<< 32) | fid
->raw
[1];
3275 inode
= ilookup5(sb
, (unsigned long)(inum
+ fid
->raw
[0]),
3276 shmem_match
, fid
->raw
);
3278 dentry
= shmem_find_alias(inode
);
3285 static int shmem_encode_fh(struct inode
*inode
, __u32
*fh
, int *len
,
3286 struct inode
*parent
)
3290 return FILEID_INVALID
;
3293 if (inode_unhashed(inode
)) {
3294 /* Unfortunately insert_inode_hash is not idempotent,
3295 * so as we hash inodes here rather than at creation
3296 * time, we need a lock to ensure we only try
3299 static DEFINE_SPINLOCK(lock
);
3301 if (inode_unhashed(inode
))
3302 __insert_inode_hash(inode
,
3303 inode
->i_ino
+ inode
->i_generation
);
3307 fh
[0] = inode
->i_generation
;
3308 fh
[1] = inode
->i_ino
;
3309 fh
[2] = ((__u64
)inode
->i_ino
) >> 32;
3315 static const struct export_operations shmem_export_ops
= {
3316 .get_parent
= shmem_get_parent
,
3317 .encode_fh
= shmem_encode_fh
,
3318 .fh_to_dentry
= shmem_fh_to_dentry
,
3334 static const struct constant_table shmem_param_enums_huge
[] = {
3335 {"never", SHMEM_HUGE_NEVER
},
3336 {"always", SHMEM_HUGE_ALWAYS
},
3337 {"within_size", SHMEM_HUGE_WITHIN_SIZE
},
3338 {"advise", SHMEM_HUGE_ADVISE
},
3342 const struct fs_parameter_spec shmem_fs_parameters
[] = {
3343 fsparam_u32 ("gid", Opt_gid
),
3344 fsparam_enum ("huge", Opt_huge
, shmem_param_enums_huge
),
3345 fsparam_u32oct("mode", Opt_mode
),
3346 fsparam_string("mpol", Opt_mpol
),
3347 fsparam_string("nr_blocks", Opt_nr_blocks
),
3348 fsparam_string("nr_inodes", Opt_nr_inodes
),
3349 fsparam_string("size", Opt_size
),
3350 fsparam_u32 ("uid", Opt_uid
),
3351 fsparam_flag ("inode32", Opt_inode32
),
3352 fsparam_flag ("inode64", Opt_inode64
),
3356 static int shmem_parse_one(struct fs_context
*fc
, struct fs_parameter
*param
)
3358 struct shmem_options
*ctx
= fc
->fs_private
;
3359 struct fs_parse_result result
;
3360 unsigned long long size
;
3364 opt
= fs_parse(fc
, shmem_fs_parameters
, param
, &result
);
3370 size
= memparse(param
->string
, &rest
);
3372 size
<<= PAGE_SHIFT
;
3373 size
*= totalram_pages();
3379 ctx
->blocks
= DIV_ROUND_UP(size
, PAGE_SIZE
);
3380 ctx
->seen
|= SHMEM_SEEN_BLOCKS
;
3383 ctx
->blocks
= memparse(param
->string
, &rest
);
3386 ctx
->seen
|= SHMEM_SEEN_BLOCKS
;
3389 ctx
->inodes
= memparse(param
->string
, &rest
);
3392 ctx
->seen
|= SHMEM_SEEN_INODES
;
3395 ctx
->mode
= result
.uint_32
& 07777;
3398 ctx
->uid
= make_kuid(current_user_ns(), result
.uint_32
);
3399 if (!uid_valid(ctx
->uid
))
3403 ctx
->gid
= make_kgid(current_user_ns(), result
.uint_32
);
3404 if (!gid_valid(ctx
->gid
))
3408 ctx
->huge
= result
.uint_32
;
3409 if (ctx
->huge
!= SHMEM_HUGE_NEVER
&&
3410 !(IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
3411 has_transparent_hugepage()))
3412 goto unsupported_parameter
;
3413 ctx
->seen
|= SHMEM_SEEN_HUGE
;
3416 if (IS_ENABLED(CONFIG_NUMA
)) {
3417 mpol_put(ctx
->mpol
);
3419 if (mpol_parse_str(param
->string
, &ctx
->mpol
))
3423 goto unsupported_parameter
;
3425 ctx
->full_inums
= false;
3426 ctx
->seen
|= SHMEM_SEEN_INUMS
;
3429 if (sizeof(ino_t
) < 8) {
3431 "Cannot use inode64 with <64bit inums in kernel\n");
3433 ctx
->full_inums
= true;
3434 ctx
->seen
|= SHMEM_SEEN_INUMS
;
3439 unsupported_parameter
:
3440 return invalfc(fc
, "Unsupported parameter '%s'", param
->key
);
3442 return invalfc(fc
, "Bad value for '%s'", param
->key
);
3445 static int shmem_parse_options(struct fs_context
*fc
, void *data
)
3447 char *options
= data
;
3450 int err
= security_sb_eat_lsm_opts(options
, &fc
->security
);
3455 while (options
!= NULL
) {
3456 char *this_char
= options
;
3459 * NUL-terminate this option: unfortunately,
3460 * mount options form a comma-separated list,
3461 * but mpol's nodelist may also contain commas.
3463 options
= strchr(options
, ',');
3464 if (options
== NULL
)
3467 if (!isdigit(*options
)) {
3473 char *value
= strchr(this_char
, '=');
3479 len
= strlen(value
);
3481 err
= vfs_parse_fs_string(fc
, this_char
, value
, len
);
3490 * Reconfigure a shmem filesystem.
3492 * Note that we disallow change from limited->unlimited blocks/inodes while any
3493 * are in use; but we must separately disallow unlimited->limited, because in
3494 * that case we have no record of how much is already in use.
3496 static int shmem_reconfigure(struct fs_context
*fc
)
3498 struct shmem_options
*ctx
= fc
->fs_private
;
3499 struct shmem_sb_info
*sbinfo
= SHMEM_SB(fc
->root
->d_sb
);
3500 unsigned long inodes
;
3501 struct mempolicy
*mpol
= NULL
;
3504 raw_spin_lock(&sbinfo
->stat_lock
);
3505 inodes
= sbinfo
->max_inodes
- sbinfo
->free_inodes
;
3506 if ((ctx
->seen
& SHMEM_SEEN_BLOCKS
) && ctx
->blocks
) {
3507 if (!sbinfo
->max_blocks
) {
3508 err
= "Cannot retroactively limit size";
3511 if (percpu_counter_compare(&sbinfo
->used_blocks
,
3513 err
= "Too small a size for current use";
3517 if ((ctx
->seen
& SHMEM_SEEN_INODES
) && ctx
->inodes
) {
3518 if (!sbinfo
->max_inodes
) {
3519 err
= "Cannot retroactively limit inodes";
3522 if (ctx
->inodes
< inodes
) {
3523 err
= "Too few inodes for current use";
3528 if ((ctx
->seen
& SHMEM_SEEN_INUMS
) && !ctx
->full_inums
&&
3529 sbinfo
->next_ino
> UINT_MAX
) {
3530 err
= "Current inum too high to switch to 32-bit inums";
3534 if (ctx
->seen
& SHMEM_SEEN_HUGE
)
3535 sbinfo
->huge
= ctx
->huge
;
3536 if (ctx
->seen
& SHMEM_SEEN_INUMS
)
3537 sbinfo
->full_inums
= ctx
->full_inums
;
3538 if (ctx
->seen
& SHMEM_SEEN_BLOCKS
)
3539 sbinfo
->max_blocks
= ctx
->blocks
;
3540 if (ctx
->seen
& SHMEM_SEEN_INODES
) {
3541 sbinfo
->max_inodes
= ctx
->inodes
;
3542 sbinfo
->free_inodes
= ctx
->inodes
- inodes
;
3546 * Preserve previous mempolicy unless mpol remount option was specified.
3549 mpol
= sbinfo
->mpol
;
3550 sbinfo
->mpol
= ctx
->mpol
; /* transfers initial ref */
3553 raw_spin_unlock(&sbinfo
->stat_lock
);
3557 raw_spin_unlock(&sbinfo
->stat_lock
);
3558 return invalfc(fc
, "%s", err
);
3561 static int shmem_show_options(struct seq_file
*seq
, struct dentry
*root
)
3563 struct shmem_sb_info
*sbinfo
= SHMEM_SB(root
->d_sb
);
3565 if (sbinfo
->max_blocks
!= shmem_default_max_blocks())
3566 seq_printf(seq
, ",size=%luk",
3567 sbinfo
->max_blocks
<< (PAGE_SHIFT
- 10));
3568 if (sbinfo
->max_inodes
!= shmem_default_max_inodes())
3569 seq_printf(seq
, ",nr_inodes=%lu", sbinfo
->max_inodes
);
3570 if (sbinfo
->mode
!= (0777 | S_ISVTX
))
3571 seq_printf(seq
, ",mode=%03ho", sbinfo
->mode
);
3572 if (!uid_eq(sbinfo
->uid
, GLOBAL_ROOT_UID
))
3573 seq_printf(seq
, ",uid=%u",
3574 from_kuid_munged(&init_user_ns
, sbinfo
->uid
));
3575 if (!gid_eq(sbinfo
->gid
, GLOBAL_ROOT_GID
))
3576 seq_printf(seq
, ",gid=%u",
3577 from_kgid_munged(&init_user_ns
, sbinfo
->gid
));
3580 * Showing inode{64,32} might be useful even if it's the system default,
3581 * since then people don't have to resort to checking both here and
3582 * /proc/config.gz to confirm 64-bit inums were successfully applied
3583 * (which may not even exist if IKCONFIG_PROC isn't enabled).
3585 * We hide it when inode64 isn't the default and we are using 32-bit
3586 * inodes, since that probably just means the feature isn't even under
3591 * +-----------------+-----------------+
3592 * | TMPFS_INODE64=y | TMPFS_INODE64=n |
3593 * +------------------+-----------------+-----------------+
3594 * | full_inums=true | show | show |
3595 * | full_inums=false | show | hide |
3596 * +------------------+-----------------+-----------------+
3599 if (IS_ENABLED(CONFIG_TMPFS_INODE64
) || sbinfo
->full_inums
)
3600 seq_printf(seq
, ",inode%d", (sbinfo
->full_inums
? 64 : 32));
3601 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3602 /* Rightly or wrongly, show huge mount option unmasked by shmem_huge */
3604 seq_printf(seq
, ",huge=%s", shmem_format_huge(sbinfo
->huge
));
3606 shmem_show_mpol(seq
, sbinfo
->mpol
);
3610 #endif /* CONFIG_TMPFS */
3612 static void shmem_put_super(struct super_block
*sb
)
3614 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
3616 free_percpu(sbinfo
->ino_batch
);
3617 percpu_counter_destroy(&sbinfo
->used_blocks
);
3618 mpol_put(sbinfo
->mpol
);
3620 sb
->s_fs_info
= NULL
;
3623 static int shmem_fill_super(struct super_block
*sb
, struct fs_context
*fc
)
3625 struct shmem_options
*ctx
= fc
->fs_private
;
3626 struct inode
*inode
;
3627 struct shmem_sb_info
*sbinfo
;
3629 /* Round up to L1_CACHE_BYTES to resist false sharing */
3630 sbinfo
= kzalloc(max((int)sizeof(struct shmem_sb_info
),
3631 L1_CACHE_BYTES
), GFP_KERNEL
);
3635 sb
->s_fs_info
= sbinfo
;
3639 * Per default we only allow half of the physical ram per
3640 * tmpfs instance, limiting inodes to one per page of lowmem;
3641 * but the internal instance is left unlimited.
3643 if (!(sb
->s_flags
& SB_KERNMOUNT
)) {
3644 if (!(ctx
->seen
& SHMEM_SEEN_BLOCKS
))
3645 ctx
->blocks
= shmem_default_max_blocks();
3646 if (!(ctx
->seen
& SHMEM_SEEN_INODES
))
3647 ctx
->inodes
= shmem_default_max_inodes();
3648 if (!(ctx
->seen
& SHMEM_SEEN_INUMS
))
3649 ctx
->full_inums
= IS_ENABLED(CONFIG_TMPFS_INODE64
);
3651 sb
->s_flags
|= SB_NOUSER
;
3653 sb
->s_export_op
= &shmem_export_ops
;
3654 sb
->s_flags
|= SB_NOSEC
;
3656 sb
->s_flags
|= SB_NOUSER
;
3658 sbinfo
->max_blocks
= ctx
->blocks
;
3659 sbinfo
->free_inodes
= sbinfo
->max_inodes
= ctx
->inodes
;
3660 if (sb
->s_flags
& SB_KERNMOUNT
) {
3661 sbinfo
->ino_batch
= alloc_percpu(ino_t
);
3662 if (!sbinfo
->ino_batch
)
3665 sbinfo
->uid
= ctx
->uid
;
3666 sbinfo
->gid
= ctx
->gid
;
3667 sbinfo
->full_inums
= ctx
->full_inums
;
3668 sbinfo
->mode
= ctx
->mode
;
3669 sbinfo
->huge
= ctx
->huge
;
3670 sbinfo
->mpol
= ctx
->mpol
;
3673 raw_spin_lock_init(&sbinfo
->stat_lock
);
3674 if (percpu_counter_init(&sbinfo
->used_blocks
, 0, GFP_KERNEL
))
3676 spin_lock_init(&sbinfo
->shrinklist_lock
);
3677 INIT_LIST_HEAD(&sbinfo
->shrinklist
);
3679 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
3680 sb
->s_blocksize
= PAGE_SIZE
;
3681 sb
->s_blocksize_bits
= PAGE_SHIFT
;
3682 sb
->s_magic
= TMPFS_MAGIC
;
3683 sb
->s_op
= &shmem_ops
;
3684 sb
->s_time_gran
= 1;
3685 #ifdef CONFIG_TMPFS_XATTR
3686 sb
->s_xattr
= shmem_xattr_handlers
;
3688 #ifdef CONFIG_TMPFS_POSIX_ACL
3689 sb
->s_flags
|= SB_POSIXACL
;
3691 uuid_gen(&sb
->s_uuid
);
3693 inode
= shmem_get_inode(sb
, NULL
, S_IFDIR
| sbinfo
->mode
, 0, VM_NORESERVE
);
3696 inode
->i_uid
= sbinfo
->uid
;
3697 inode
->i_gid
= sbinfo
->gid
;
3698 sb
->s_root
= d_make_root(inode
);
3704 shmem_put_super(sb
);
3708 static int shmem_get_tree(struct fs_context
*fc
)
3710 return get_tree_nodev(fc
, shmem_fill_super
);
3713 static void shmem_free_fc(struct fs_context
*fc
)
3715 struct shmem_options
*ctx
= fc
->fs_private
;
3718 mpol_put(ctx
->mpol
);
3723 static const struct fs_context_operations shmem_fs_context_ops
= {
3724 .free
= shmem_free_fc
,
3725 .get_tree
= shmem_get_tree
,
3727 .parse_monolithic
= shmem_parse_options
,
3728 .parse_param
= shmem_parse_one
,
3729 .reconfigure
= shmem_reconfigure
,
3733 static struct kmem_cache
*shmem_inode_cachep
;
3735 static struct inode
*shmem_alloc_inode(struct super_block
*sb
)
3737 struct shmem_inode_info
*info
;
3738 info
= kmem_cache_alloc(shmem_inode_cachep
, GFP_KERNEL
);
3741 return &info
->vfs_inode
;
3744 static void shmem_free_in_core_inode(struct inode
*inode
)
3746 if (S_ISLNK(inode
->i_mode
))
3747 kfree(inode
->i_link
);
3748 kmem_cache_free(shmem_inode_cachep
, SHMEM_I(inode
));
3751 static void shmem_destroy_inode(struct inode
*inode
)
3753 if (S_ISREG(inode
->i_mode
))
3754 mpol_free_shared_policy(&SHMEM_I(inode
)->policy
);
3757 static void shmem_init_inode(void *foo
)
3759 struct shmem_inode_info
*info
= foo
;
3760 inode_init_once(&info
->vfs_inode
);
3763 static void shmem_init_inodecache(void)
3765 shmem_inode_cachep
= kmem_cache_create("shmem_inode_cache",
3766 sizeof(struct shmem_inode_info
),
3767 0, SLAB_PANIC
|SLAB_ACCOUNT
, shmem_init_inode
);
3770 static void shmem_destroy_inodecache(void)
3772 kmem_cache_destroy(shmem_inode_cachep
);
3775 const struct address_space_operations shmem_aops
= {
3776 .writepage
= shmem_writepage
,
3777 .set_page_dirty
= __set_page_dirty_no_writeback
,
3779 .write_begin
= shmem_write_begin
,
3780 .write_end
= shmem_write_end
,
3782 #ifdef CONFIG_MIGRATION
3783 .migratepage
= migrate_page
,
3785 .error_remove_page
= generic_error_remove_page
,
3787 EXPORT_SYMBOL(shmem_aops
);
3789 static const struct file_operations shmem_file_operations
= {
3791 .get_unmapped_area
= shmem_get_unmapped_area
,
3793 .llseek
= shmem_file_llseek
,
3794 .read_iter
= shmem_file_read_iter
,
3795 .write_iter
= generic_file_write_iter
,
3796 .fsync
= noop_fsync
,
3797 .splice_read
= generic_file_splice_read
,
3798 .splice_write
= iter_file_splice_write
,
3799 .fallocate
= shmem_fallocate
,
3803 static const struct inode_operations shmem_inode_operations
= {
3804 .getattr
= shmem_getattr
,
3805 .setattr
= shmem_setattr
,
3806 #ifdef CONFIG_TMPFS_XATTR
3807 .listxattr
= shmem_listxattr
,
3808 .set_acl
= simple_set_acl
,
3812 static const struct inode_operations shmem_dir_inode_operations
= {
3814 .create
= shmem_create
,
3815 .lookup
= simple_lookup
,
3817 .unlink
= shmem_unlink
,
3818 .symlink
= shmem_symlink
,
3819 .mkdir
= shmem_mkdir
,
3820 .rmdir
= shmem_rmdir
,
3821 .mknod
= shmem_mknod
,
3822 .rename
= shmem_rename2
,
3823 .tmpfile
= shmem_tmpfile
,
3825 #ifdef CONFIG_TMPFS_XATTR
3826 .listxattr
= shmem_listxattr
,
3828 #ifdef CONFIG_TMPFS_POSIX_ACL
3829 .setattr
= shmem_setattr
,
3830 .set_acl
= simple_set_acl
,
3834 static const struct inode_operations shmem_special_inode_operations
= {
3835 #ifdef CONFIG_TMPFS_XATTR
3836 .listxattr
= shmem_listxattr
,
3838 #ifdef CONFIG_TMPFS_POSIX_ACL
3839 .setattr
= shmem_setattr
,
3840 .set_acl
= simple_set_acl
,
3844 static const struct super_operations shmem_ops
= {
3845 .alloc_inode
= shmem_alloc_inode
,
3846 .free_inode
= shmem_free_in_core_inode
,
3847 .destroy_inode
= shmem_destroy_inode
,
3849 .statfs
= shmem_statfs
,
3850 .show_options
= shmem_show_options
,
3852 .evict_inode
= shmem_evict_inode
,
3853 .drop_inode
= generic_delete_inode
,
3854 .put_super
= shmem_put_super
,
3855 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3856 .nr_cached_objects
= shmem_unused_huge_count
,
3857 .free_cached_objects
= shmem_unused_huge_scan
,
3861 static const struct vm_operations_struct shmem_vm_ops
= {
3862 .fault
= shmem_fault
,
3863 .map_pages
= filemap_map_pages
,
3865 .set_policy
= shmem_set_policy
,
3866 .get_policy
= shmem_get_policy
,
3870 int shmem_init_fs_context(struct fs_context
*fc
)
3872 struct shmem_options
*ctx
;
3874 ctx
= kzalloc(sizeof(struct shmem_options
), GFP_KERNEL
);
3878 ctx
->mode
= 0777 | S_ISVTX
;
3879 ctx
->uid
= current_fsuid();
3880 ctx
->gid
= current_fsgid();
3882 fc
->fs_private
= ctx
;
3883 fc
->ops
= &shmem_fs_context_ops
;
3887 static struct file_system_type shmem_fs_type
= {
3888 .owner
= THIS_MODULE
,
3890 .init_fs_context
= shmem_init_fs_context
,
3892 .parameters
= shmem_fs_parameters
,
3894 .kill_sb
= kill_litter_super
,
3895 .fs_flags
= FS_USERNS_MOUNT
| FS_THP_SUPPORT
,
3898 int __init
shmem_init(void)
3902 shmem_init_inodecache();
3904 error
= register_filesystem(&shmem_fs_type
);
3906 pr_err("Could not register tmpfs\n");
3910 shm_mnt
= kern_mount(&shmem_fs_type
);
3911 if (IS_ERR(shm_mnt
)) {
3912 error
= PTR_ERR(shm_mnt
);
3913 pr_err("Could not kern_mount tmpfs\n");
3917 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3918 if (has_transparent_hugepage() && shmem_huge
> SHMEM_HUGE_DENY
)
3919 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3921 shmem_huge
= SHMEM_HUGE_NEVER
; /* just in case it was patched */
3926 unregister_filesystem(&shmem_fs_type
);
3928 shmem_destroy_inodecache();
3929 shm_mnt
= ERR_PTR(error
);
3933 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && defined(CONFIG_SYSFS)
3934 static ssize_t
shmem_enabled_show(struct kobject
*kobj
,
3935 struct kobj_attribute
*attr
, char *buf
)
3937 static const int values
[] = {
3939 SHMEM_HUGE_WITHIN_SIZE
,
3948 for (i
= 0; i
< ARRAY_SIZE(values
); i
++) {
3949 len
+= sysfs_emit_at(buf
, len
,
3950 shmem_huge
== values
[i
] ? "%s[%s]" : "%s%s",
3952 shmem_format_huge(values
[i
]));
3955 len
+= sysfs_emit_at(buf
, len
, "\n");
3960 static ssize_t
shmem_enabled_store(struct kobject
*kobj
,
3961 struct kobj_attribute
*attr
, const char *buf
, size_t count
)
3966 if (count
+ 1 > sizeof(tmp
))
3968 memcpy(tmp
, buf
, count
);
3970 if (count
&& tmp
[count
- 1] == '\n')
3971 tmp
[count
- 1] = '\0';
3973 huge
= shmem_parse_huge(tmp
);
3974 if (huge
== -EINVAL
)
3976 if (!has_transparent_hugepage() &&
3977 huge
!= SHMEM_HUGE_NEVER
&& huge
!= SHMEM_HUGE_DENY
)
3981 if (shmem_huge
> SHMEM_HUGE_DENY
)
3982 SHMEM_SB(shm_mnt
->mnt_sb
)->huge
= shmem_huge
;
3986 struct kobj_attribute shmem_enabled_attr
=
3987 __ATTR(shmem_enabled
, 0644, shmem_enabled_show
, shmem_enabled_store
);
3988 #endif /* CONFIG_TRANSPARENT_HUGEPAGE && CONFIG_SYSFS */
3990 #else /* !CONFIG_SHMEM */
3993 * tiny-shmem: simple shmemfs and tmpfs using ramfs code
3995 * This is intended for small system where the benefits of the full
3996 * shmem code (swap-backed and resource-limited) are outweighed by
3997 * their complexity. On systems without swap this code should be
3998 * effectively equivalent, but much lighter weight.
4001 static struct file_system_type shmem_fs_type
= {
4003 .init_fs_context
= ramfs_init_fs_context
,
4004 .parameters
= ramfs_fs_parameters
,
4005 .kill_sb
= kill_litter_super
,
4006 .fs_flags
= FS_USERNS_MOUNT
,
4009 int __init
shmem_init(void)
4011 BUG_ON(register_filesystem(&shmem_fs_type
) != 0);
4013 shm_mnt
= kern_mount(&shmem_fs_type
);
4014 BUG_ON(IS_ERR(shm_mnt
));
4019 int shmem_unuse(unsigned int type
, bool frontswap
,
4020 unsigned long *fs_pages_to_unuse
)
4025 int shmem_lock(struct file
*file
, int lock
, struct ucounts
*ucounts
)
4030 void shmem_unlock_mapping(struct address_space
*mapping
)
4035 unsigned long shmem_get_unmapped_area(struct file
*file
,
4036 unsigned long addr
, unsigned long len
,
4037 unsigned long pgoff
, unsigned long flags
)
4039 return current
->mm
->get_unmapped_area(file
, addr
, len
, pgoff
, flags
);
4043 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
4045 truncate_inode_pages_range(inode
->i_mapping
, lstart
, lend
);
4047 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
4049 #define shmem_vm_ops generic_file_vm_ops
4050 #define shmem_file_operations ramfs_file_operations
4051 #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
4052 #define shmem_acct_size(flags, size) 0
4053 #define shmem_unacct_size(flags, size) do {} while (0)
4055 #endif /* CONFIG_SHMEM */
4059 static struct file
*__shmem_file_setup(struct vfsmount
*mnt
, const char *name
, loff_t size
,
4060 unsigned long flags
, unsigned int i_flags
)
4062 struct inode
*inode
;
4066 return ERR_CAST(mnt
);
4068 if (size
< 0 || size
> MAX_LFS_FILESIZE
)
4069 return ERR_PTR(-EINVAL
);
4071 if (shmem_acct_size(flags
, size
))
4072 return ERR_PTR(-ENOMEM
);
4074 inode
= shmem_get_inode(mnt
->mnt_sb
, NULL
, S_IFREG
| S_IRWXUGO
, 0,
4076 if (unlikely(!inode
)) {
4077 shmem_unacct_size(flags
, size
);
4078 return ERR_PTR(-ENOSPC
);
4080 inode
->i_flags
|= i_flags
;
4081 inode
->i_size
= size
;
4082 clear_nlink(inode
); /* It is unlinked */
4083 res
= ERR_PTR(ramfs_nommu_expand_for_mapping(inode
, size
));
4085 res
= alloc_file_pseudo(inode
, mnt
, name
, O_RDWR
,
4086 &shmem_file_operations
);
4093 * shmem_kernel_file_setup - get an unlinked file living in tmpfs which must be
4094 * kernel internal. There will be NO LSM permission checks against the
4095 * underlying inode. So users of this interface must do LSM checks at a
4096 * higher layer. The users are the big_key and shm implementations. LSM
4097 * checks are provided at the key or shm level rather than the inode.
4098 * @name: name for dentry (to be seen in /proc/<pid>/maps
4099 * @size: size to be set for the file
4100 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4102 struct file
*shmem_kernel_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4104 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, S_PRIVATE
);
4108 * shmem_file_setup - get an unlinked file living in tmpfs
4109 * @name: name for dentry (to be seen in /proc/<pid>/maps
4110 * @size: size to be set for the file
4111 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4113 struct file
*shmem_file_setup(const char *name
, loff_t size
, unsigned long flags
)
4115 return __shmem_file_setup(shm_mnt
, name
, size
, flags
, 0);
4117 EXPORT_SYMBOL_GPL(shmem_file_setup
);
4120 * shmem_file_setup_with_mnt - get an unlinked file living in tmpfs
4121 * @mnt: the tmpfs mount where the file will be created
4122 * @name: name for dentry (to be seen in /proc/<pid>/maps
4123 * @size: size to be set for the file
4124 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
4126 struct file
*shmem_file_setup_with_mnt(struct vfsmount
*mnt
, const char *name
,
4127 loff_t size
, unsigned long flags
)
4129 return __shmem_file_setup(mnt
, name
, size
, flags
, 0);
4131 EXPORT_SYMBOL_GPL(shmem_file_setup_with_mnt
);
4134 * shmem_zero_setup - setup a shared anonymous mapping
4135 * @vma: the vma to be mmapped is prepared by do_mmap
4137 int shmem_zero_setup(struct vm_area_struct
*vma
)
4140 loff_t size
= vma
->vm_end
- vma
->vm_start
;
4143 * Cloning a new file under mmap_lock leads to a lock ordering conflict
4144 * between XFS directory reading and selinux: since this file is only
4145 * accessible to the user through its mapping, use S_PRIVATE flag to
4146 * bypass file security, in the same way as shmem_kernel_file_setup().
4148 file
= shmem_kernel_file_setup("dev/zero", size
, vma
->vm_flags
);
4150 return PTR_ERR(file
);
4154 vma
->vm_file
= file
;
4155 vma
->vm_ops
= &shmem_vm_ops
;
4157 if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE
) &&
4158 ((vma
->vm_start
+ ~HPAGE_PMD_MASK
) & HPAGE_PMD_MASK
) <
4159 (vma
->vm_end
& HPAGE_PMD_MASK
)) {
4160 khugepaged_enter(vma
, vma
->vm_flags
);
4167 * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
4168 * @mapping: the page's address_space
4169 * @index: the page index
4170 * @gfp: the page allocator flags to use if allocating
4172 * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
4173 * with any new page allocations done using the specified allocation flags.
4174 * But read_cache_page_gfp() uses the ->readpage() method: which does not
4175 * suit tmpfs, since it may have pages in swapcache, and needs to find those
4176 * for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
4178 * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
4179 * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
4181 struct page
*shmem_read_mapping_page_gfp(struct address_space
*mapping
,
4182 pgoff_t index
, gfp_t gfp
)
4185 struct inode
*inode
= mapping
->host
;
4189 BUG_ON(!shmem_mapping(mapping
));
4190 error
= shmem_getpage_gfp(inode
, index
, &page
, SGP_CACHE
,
4191 gfp
, NULL
, NULL
, NULL
);
4193 page
= ERR_PTR(error
);
4199 * The tiny !SHMEM case uses ramfs without swap
4201 return read_cache_page_gfp(mapping
, index
, gfp
);
4204 EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp
);