2 * Resizable virtual memory filesystem for Linux.
4 * Copyright (C) 2000 Linus Torvalds.
6 * 2000-2001 Christoph Rohland
9 * Copyright (C) 2002-2005 Hugh Dickins.
10 * Copyright (C) 2002-2005 VERITAS Software Corporation.
11 * Copyright (C) 2004 Andi Kleen, SuSE Labs
13 * Extended attribute support for tmpfs:
14 * Copyright (c) 2004, Luke Kenneth Casson Leighton <lkcl@lkcl.net>
15 * Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
17 * This file is released under the GPL.
21 * This virtual memory filesystem is heavily based on the ramfs. It
22 * extends ramfs by the ability to use swap and honor resource limits
23 * which makes it a completely usable filesystem.
26 #include <linux/module.h>
27 #include <linux/init.h>
29 #include <linux/xattr.h>
30 #include <linux/exportfs.h>
31 #include <linux/generic_acl.h>
33 #include <linux/mman.h>
34 #include <linux/file.h>
35 #include <linux/swap.h>
36 #include <linux/pagemap.h>
37 #include <linux/string.h>
38 #include <linux/slab.h>
39 #include <linux/backing-dev.h>
40 #include <linux/shmem_fs.h>
41 #include <linux/mount.h>
42 #include <linux/writeback.h>
43 #include <linux/vfs.h>
44 #include <linux/blkdev.h>
45 #include <linux/security.h>
46 #include <linux/swapops.h>
47 #include <linux/mempolicy.h>
48 #include <linux/namei.h>
49 #include <linux/ctype.h>
50 #include <linux/migrate.h>
51 #include <linux/highmem.h>
52 #include <linux/seq_file.h>
53 #include <linux/magic.h>
54 #include <linux/ima.h>
56 #include <asm/uaccess.h>
57 #include <asm/div64.h>
58 #include <asm/pgtable.h>
60 #define ENTRIES_PER_PAGE (PAGE_CACHE_SIZE/sizeof(unsigned long))
61 #define ENTRIES_PER_PAGEPAGE (ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
62 #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
64 #define SHMEM_MAX_INDEX (SHMEM_NR_DIRECT + (ENTRIES_PER_PAGEPAGE/2) * (ENTRIES_PER_PAGE+1))
65 #define SHMEM_MAX_BYTES ((unsigned long long)SHMEM_MAX_INDEX << PAGE_CACHE_SHIFT)
67 #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
69 /* info->flags needs VM_flags to handle pagein/truncate races efficiently */
70 #define SHMEM_PAGEIN VM_READ
71 #define SHMEM_TRUNCATE VM_WRITE
73 /* Definition to limit shmem_truncate's steps between cond_rescheds */
74 #define LATENCY_LIMIT 64
76 /* Pretend that each entry is of this size in directory's i_size */
77 #define BOGO_DIRENT_SIZE 20
79 /* Flag allocation requirements to shmem_getpage and shmem_swp_alloc */
81 SGP_READ, /* don't exceed i_size, don't allocate page */
82 SGP_CACHE, /* don't exceed i_size, may allocate page */
83 SGP_DIRTY, /* like SGP_CACHE, but set new page dirty */
84 SGP_WRITE, /* may exceed i_size, may allocate page */
88 static unsigned long shmem_default_max_blocks(void)
90 return totalram_pages / 2;
93 static unsigned long shmem_default_max_inodes(void)
95 return min(totalram_pages - totalhigh_pages, totalram_pages / 2);
99 static int shmem_getpage(struct inode *inode, unsigned long idx,
100 struct page **pagep, enum sgp_type sgp, int *type);
102 static inline struct page *shmem_dir_alloc(gfp_t gfp_mask)
105 * The above definition of ENTRIES_PER_PAGE, and the use of
106 * BLOCKS_PER_PAGE on indirect pages, assume PAGE_CACHE_SIZE:
107 * might be reconsidered if it ever diverges from PAGE_SIZE.
109 * Mobility flags are masked out as swap vectors cannot move
111 return alloc_pages((gfp_mask & ~GFP_MOVABLE_MASK) | __GFP_ZERO,
112 PAGE_CACHE_SHIFT-PAGE_SHIFT);
115 static inline void shmem_dir_free(struct page *page)
117 __free_pages(page, PAGE_CACHE_SHIFT-PAGE_SHIFT);
120 static struct page **shmem_dir_map(struct page *page)
122 return (struct page **)kmap_atomic(page, KM_USER0);
125 static inline void shmem_dir_unmap(struct page **dir)
127 kunmap_atomic(dir, KM_USER0);
130 static swp_entry_t *shmem_swp_map(struct page *page)
132 return (swp_entry_t *)kmap_atomic(page, KM_USER1);
135 static inline void shmem_swp_balance_unmap(void)
138 * When passing a pointer to an i_direct entry, to code which
139 * also handles indirect entries and so will shmem_swp_unmap,
140 * we must arrange for the preempt count to remain in balance.
141 * What kmap_atomic of a lowmem page does depends on config
142 * and architecture, so pretend to kmap_atomic some lowmem page.
144 (void) kmap_atomic(ZERO_PAGE(0), KM_USER1);
147 static inline void shmem_swp_unmap(swp_entry_t *entry)
149 kunmap_atomic(entry, KM_USER1);
152 static inline struct shmem_sb_info *SHMEM_SB(struct super_block *sb)
154 return sb->s_fs_info;
158 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
159 * for shared memory and for shared anonymous (/dev/zero) mappings
160 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
161 * consistent with the pre-accounting of private mappings ...
163 static inline int shmem_acct_size(unsigned long flags, loff_t size)
165 return (flags & VM_ACCOUNT) ?
166 security_vm_enough_memory_kern(VM_ACCT(size)) : 0;
169 static inline void shmem_unacct_size(unsigned long flags, loff_t size)
171 if (flags & VM_ACCOUNT)
172 vm_unacct_memory(VM_ACCT(size));
176 * ... whereas tmpfs objects are accounted incrementally as
177 * pages are allocated, in order to allow huge sparse files.
178 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
179 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
181 static inline int shmem_acct_block(unsigned long flags)
183 return (flags & VM_ACCOUNT) ?
184 0 : security_vm_enough_memory_kern(VM_ACCT(PAGE_CACHE_SIZE));
187 static inline void shmem_unacct_blocks(unsigned long flags, long pages)
189 if (!(flags & VM_ACCOUNT))
190 vm_unacct_memory(pages * VM_ACCT(PAGE_CACHE_SIZE));
193 static const struct super_operations shmem_ops;
194 static const struct address_space_operations shmem_aops;
195 static const struct file_operations shmem_file_operations;
196 static const struct inode_operations shmem_inode_operations;
197 static const struct inode_operations shmem_dir_inode_operations;
198 static const struct inode_operations shmem_special_inode_operations;
199 static struct vm_operations_struct shmem_vm_ops;
201 static struct backing_dev_info shmem_backing_dev_info __read_mostly = {
202 .ra_pages = 0, /* No readahead */
203 .capabilities = BDI_CAP_NO_ACCT_AND_WRITEBACK | BDI_CAP_SWAP_BACKED,
204 .unplug_io_fn = default_unplug_io_fn,
207 static LIST_HEAD(shmem_swaplist);
208 static DEFINE_MUTEX(shmem_swaplist_mutex);
210 static void shmem_free_blocks(struct inode *inode, long pages)
212 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
213 if (sbinfo->max_blocks) {
214 spin_lock(&sbinfo->stat_lock);
215 sbinfo->free_blocks += pages;
216 inode->i_blocks -= pages*BLOCKS_PER_PAGE;
217 spin_unlock(&sbinfo->stat_lock);
221 static int shmem_reserve_inode(struct super_block *sb)
223 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
224 if (sbinfo->max_inodes) {
225 spin_lock(&sbinfo->stat_lock);
226 if (!sbinfo->free_inodes) {
227 spin_unlock(&sbinfo->stat_lock);
230 sbinfo->free_inodes--;
231 spin_unlock(&sbinfo->stat_lock);
236 static void shmem_free_inode(struct super_block *sb)
238 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
239 if (sbinfo->max_inodes) {
240 spin_lock(&sbinfo->stat_lock);
241 sbinfo->free_inodes++;
242 spin_unlock(&sbinfo->stat_lock);
247 * shmem_recalc_inode - recalculate the size of an inode
248 * @inode: inode to recalc
250 * We have to calculate the free blocks since the mm can drop
251 * undirtied hole pages behind our back.
253 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
254 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
256 * It has to be called with the spinlock held.
258 static void shmem_recalc_inode(struct inode *inode)
260 struct shmem_inode_info *info = SHMEM_I(inode);
263 freed = info->alloced - info->swapped - inode->i_mapping->nrpages;
265 info->alloced -= freed;
266 shmem_unacct_blocks(info->flags, freed);
267 shmem_free_blocks(inode, freed);
272 * shmem_swp_entry - find the swap vector position in the info structure
273 * @info: info structure for the inode
274 * @index: index of the page to find
275 * @page: optional page to add to the structure. Has to be preset to
278 * If there is no space allocated yet it will return NULL when
279 * page is NULL, else it will use the page for the needed block,
280 * setting it to NULL on return to indicate that it has been used.
282 * The swap vector is organized the following way:
284 * There are SHMEM_NR_DIRECT entries directly stored in the
285 * shmem_inode_info structure. So small files do not need an addional
288 * For pages with index > SHMEM_NR_DIRECT there is the pointer
289 * i_indirect which points to a page which holds in the first half
290 * doubly indirect blocks, in the second half triple indirect blocks:
292 * For an artificial ENTRIES_PER_PAGE = 4 this would lead to the
293 * following layout (for SHMEM_NR_DIRECT == 16):
295 * i_indirect -> dir --> 16-19
308 static swp_entry_t *shmem_swp_entry(struct shmem_inode_info *info, unsigned long index, struct page **page)
310 unsigned long offset;
314 if (index < SHMEM_NR_DIRECT) {
315 shmem_swp_balance_unmap();
316 return info->i_direct+index;
318 if (!info->i_indirect) {
320 info->i_indirect = *page;
323 return NULL; /* need another page */
326 index -= SHMEM_NR_DIRECT;
327 offset = index % ENTRIES_PER_PAGE;
328 index /= ENTRIES_PER_PAGE;
329 dir = shmem_dir_map(info->i_indirect);
331 if (index >= ENTRIES_PER_PAGE/2) {
332 index -= ENTRIES_PER_PAGE/2;
333 dir += ENTRIES_PER_PAGE/2 + index/ENTRIES_PER_PAGE;
334 index %= ENTRIES_PER_PAGE;
341 shmem_dir_unmap(dir);
342 return NULL; /* need another page */
344 shmem_dir_unmap(dir);
345 dir = shmem_dir_map(subdir);
351 if (!page || !(subdir = *page)) {
352 shmem_dir_unmap(dir);
353 return NULL; /* need a page */
358 shmem_dir_unmap(dir);
359 return shmem_swp_map(subdir) + offset;
362 static void shmem_swp_set(struct shmem_inode_info *info, swp_entry_t *entry, unsigned long value)
364 long incdec = value? 1: -1;
367 info->swapped += incdec;
368 if ((unsigned long)(entry - info->i_direct) >= SHMEM_NR_DIRECT) {
369 struct page *page = kmap_atomic_to_page(entry);
370 set_page_private(page, page_private(page) + incdec);
375 * shmem_swp_alloc - get the position of the swap entry for the page.
376 * @info: info structure for the inode
377 * @index: index of the page to find
378 * @sgp: check and recheck i_size? skip allocation?
380 * If the entry does not exist, allocate it.
382 static swp_entry_t *shmem_swp_alloc(struct shmem_inode_info *info, unsigned long index, enum sgp_type sgp)
384 struct inode *inode = &info->vfs_inode;
385 struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb);
386 struct page *page = NULL;
389 if (sgp != SGP_WRITE &&
390 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode))
391 return ERR_PTR(-EINVAL);
393 while (!(entry = shmem_swp_entry(info, index, &page))) {
395 return shmem_swp_map(ZERO_PAGE(0));
397 * Test free_blocks against 1 not 0, since we have 1 data
398 * page (and perhaps indirect index pages) yet to allocate:
399 * a waste to allocate index if we cannot allocate data.
401 if (sbinfo->max_blocks) {
402 spin_lock(&sbinfo->stat_lock);
403 if (sbinfo->free_blocks <= 1) {
404 spin_unlock(&sbinfo->stat_lock);
405 return ERR_PTR(-ENOSPC);
407 sbinfo->free_blocks--;
408 inode->i_blocks += BLOCKS_PER_PAGE;
409 spin_unlock(&sbinfo->stat_lock);
412 spin_unlock(&info->lock);
413 page = shmem_dir_alloc(mapping_gfp_mask(inode->i_mapping));
415 set_page_private(page, 0);
416 spin_lock(&info->lock);
419 shmem_free_blocks(inode, 1);
420 return ERR_PTR(-ENOMEM);
422 if (sgp != SGP_WRITE &&
423 ((loff_t) index << PAGE_CACHE_SHIFT) >= i_size_read(inode)) {
424 entry = ERR_PTR(-EINVAL);
427 if (info->next_index <= index)
428 info->next_index = index + 1;
431 /* another task gave its page, or truncated the file */
432 shmem_free_blocks(inode, 1);
433 shmem_dir_free(page);
435 if (info->next_index <= index && !IS_ERR(entry))
436 info->next_index = index + 1;
441 * shmem_free_swp - free some swap entries in a directory
442 * @dir: pointer to the directory
443 * @edir: pointer after last entry of the directory
444 * @punch_lock: pointer to spinlock when needed for the holepunch case
446 static int shmem_free_swp(swp_entry_t *dir, swp_entry_t *edir,
447 spinlock_t *punch_lock)
449 spinlock_t *punch_unlock = NULL;
453 for (ptr = dir; ptr < edir; ptr++) {
455 if (unlikely(punch_lock)) {
456 punch_unlock = punch_lock;
458 spin_lock(punch_unlock);
462 free_swap_and_cache(*ptr);
463 *ptr = (swp_entry_t){0};
468 spin_unlock(punch_unlock);
472 static int shmem_map_and_free_swp(struct page *subdir, int offset,
473 int limit, struct page ***dir, spinlock_t *punch_lock)
478 ptr = shmem_swp_map(subdir);
479 for (; offset < limit; offset += LATENCY_LIMIT) {
480 int size = limit - offset;
481 if (size > LATENCY_LIMIT)
482 size = LATENCY_LIMIT;
483 freed += shmem_free_swp(ptr+offset, ptr+offset+size,
485 if (need_resched()) {
486 shmem_swp_unmap(ptr);
488 shmem_dir_unmap(*dir);
492 ptr = shmem_swp_map(subdir);
495 shmem_swp_unmap(ptr);
499 static void shmem_free_pages(struct list_head *next)
505 page = container_of(next, struct page, lru);
507 shmem_dir_free(page);
509 if (freed >= LATENCY_LIMIT) {
516 static void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end)
518 struct shmem_inode_info *info = SHMEM_I(inode);
523 unsigned long diroff;
529 LIST_HEAD(pages_to_free);
530 long nr_pages_to_free = 0;
531 long nr_swaps_freed = 0;
535 spinlock_t *needs_lock;
536 spinlock_t *punch_lock;
537 unsigned long upper_limit;
539 inode->i_ctime = inode->i_mtime = CURRENT_TIME;
540 idx = (start + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
541 if (idx >= info->next_index)
544 spin_lock(&info->lock);
545 info->flags |= SHMEM_TRUNCATE;
546 if (likely(end == (loff_t) -1)) {
547 limit = info->next_index;
548 upper_limit = SHMEM_MAX_INDEX;
549 info->next_index = idx;
553 if (end + 1 >= inode->i_size) { /* we may free a little more */
554 limit = (inode->i_size + PAGE_CACHE_SIZE - 1) >>
556 upper_limit = SHMEM_MAX_INDEX;
558 limit = (end + 1) >> PAGE_CACHE_SHIFT;
561 needs_lock = &info->lock;
565 topdir = info->i_indirect;
566 if (topdir && idx <= SHMEM_NR_DIRECT && !punch_hole) {
567 info->i_indirect = NULL;
569 list_add(&topdir->lru, &pages_to_free);
571 spin_unlock(&info->lock);
573 if (info->swapped && idx < SHMEM_NR_DIRECT) {
574 ptr = info->i_direct;
576 if (size > SHMEM_NR_DIRECT)
577 size = SHMEM_NR_DIRECT;
578 nr_swaps_freed = shmem_free_swp(ptr+idx, ptr+size, needs_lock);
582 * If there are no indirect blocks or we are punching a hole
583 * below indirect blocks, nothing to be done.
585 if (!topdir || limit <= SHMEM_NR_DIRECT)
589 * The truncation case has already dropped info->lock, and we're safe
590 * because i_size and next_index have already been lowered, preventing
591 * access beyond. But in the punch_hole case, we still need to take
592 * the lock when updating the swap directory, because there might be
593 * racing accesses by shmem_getpage(SGP_CACHE), shmem_unuse_inode or
594 * shmem_writepage. However, whenever we find we can remove a whole
595 * directory page (not at the misaligned start or end of the range),
596 * we first NULLify its pointer in the level above, and then have no
597 * need to take the lock when updating its contents: needs_lock and
598 * punch_lock (either pointing to info->lock or NULL) manage this.
601 upper_limit -= SHMEM_NR_DIRECT;
602 limit -= SHMEM_NR_DIRECT;
603 idx = (idx > SHMEM_NR_DIRECT)? (idx - SHMEM_NR_DIRECT): 0;
604 offset = idx % ENTRIES_PER_PAGE;
607 dir = shmem_dir_map(topdir);
608 stage = ENTRIES_PER_PAGEPAGE/2;
609 if (idx < ENTRIES_PER_PAGEPAGE/2) {
611 diroff = idx/ENTRIES_PER_PAGE;
613 dir += ENTRIES_PER_PAGE/2;
614 dir += (idx - ENTRIES_PER_PAGEPAGE/2)/ENTRIES_PER_PAGEPAGE;
616 stage += ENTRIES_PER_PAGEPAGE;
619 diroff = ((idx - ENTRIES_PER_PAGEPAGE/2) %
620 ENTRIES_PER_PAGEPAGE) / ENTRIES_PER_PAGE;
621 if (!diroff && !offset && upper_limit >= stage) {
623 spin_lock(needs_lock);
625 spin_unlock(needs_lock);
630 list_add(&middir->lru, &pages_to_free);
632 shmem_dir_unmap(dir);
633 dir = shmem_dir_map(middir);
641 for (; idx < limit; idx += ENTRIES_PER_PAGE, diroff++) {
642 if (unlikely(idx == stage)) {
643 shmem_dir_unmap(dir);
644 dir = shmem_dir_map(topdir) +
645 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
648 idx += ENTRIES_PER_PAGEPAGE;
652 stage = idx + ENTRIES_PER_PAGEPAGE;
655 needs_lock = &info->lock;
656 if (upper_limit >= stage) {
658 spin_lock(needs_lock);
660 spin_unlock(needs_lock);
665 list_add(&middir->lru, &pages_to_free);
667 shmem_dir_unmap(dir);
669 dir = shmem_dir_map(middir);
672 punch_lock = needs_lock;
673 subdir = dir[diroff];
674 if (subdir && !offset && upper_limit-idx >= ENTRIES_PER_PAGE) {
676 spin_lock(needs_lock);
678 spin_unlock(needs_lock);
683 list_add(&subdir->lru, &pages_to_free);
685 if (subdir && page_private(subdir) /* has swap entries */) {
687 if (size > ENTRIES_PER_PAGE)
688 size = ENTRIES_PER_PAGE;
689 freed = shmem_map_and_free_swp(subdir,
690 offset, size, &dir, punch_lock);
692 dir = shmem_dir_map(middir);
693 nr_swaps_freed += freed;
694 if (offset || punch_lock) {
695 spin_lock(&info->lock);
696 set_page_private(subdir,
697 page_private(subdir) - freed);
698 spin_unlock(&info->lock);
700 BUG_ON(page_private(subdir) != freed);
705 shmem_dir_unmap(dir);
707 if (inode->i_mapping->nrpages && (info->flags & SHMEM_PAGEIN)) {
709 * Call truncate_inode_pages again: racing shmem_unuse_inode
710 * may have swizzled a page in from swap since vmtruncate or
711 * generic_delete_inode did it, before we lowered next_index.
712 * Also, though shmem_getpage checks i_size before adding to
713 * cache, no recheck after: so fix the narrow window there too.
715 * Recalling truncate_inode_pages_range and unmap_mapping_range
716 * every time for punch_hole (which never got a chance to clear
717 * SHMEM_PAGEIN at the start of vmtruncate_range) is expensive,
718 * yet hardly ever necessary: try to optimize them out later.
720 truncate_inode_pages_range(inode->i_mapping, start, end);
722 unmap_mapping_range(inode->i_mapping, start,
726 spin_lock(&info->lock);
727 info->flags &= ~SHMEM_TRUNCATE;
728 info->swapped -= nr_swaps_freed;
729 if (nr_pages_to_free)
730 shmem_free_blocks(inode, nr_pages_to_free);
731 shmem_recalc_inode(inode);
732 spin_unlock(&info->lock);
735 * Empty swap vector directory pages to be freed?
737 if (!list_empty(&pages_to_free)) {
738 pages_to_free.prev->next = NULL;
739 shmem_free_pages(pages_to_free.next);
743 static void shmem_truncate(struct inode *inode)
745 shmem_truncate_range(inode, inode->i_size, (loff_t)-1);
748 static int shmem_notify_change(struct dentry *dentry, struct iattr *attr)
750 struct inode *inode = dentry->d_inode;
751 struct page *page = NULL;
754 if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) {
755 if (attr->ia_size < inode->i_size) {
757 * If truncating down to a partial page, then
758 * if that page is already allocated, hold it
759 * in memory until the truncation is over, so
760 * truncate_partial_page cannnot miss it were
761 * it assigned to swap.
763 if (attr->ia_size & (PAGE_CACHE_SIZE-1)) {
764 (void) shmem_getpage(inode,
765 attr->ia_size>>PAGE_CACHE_SHIFT,
766 &page, SGP_READ, NULL);
771 * Reset SHMEM_PAGEIN flag so that shmem_truncate can
772 * detect if any pages might have been added to cache
773 * after truncate_inode_pages. But we needn't bother
774 * if it's being fully truncated to zero-length: the
775 * nrpages check is efficient enough in that case.
778 struct shmem_inode_info *info = SHMEM_I(inode);
779 spin_lock(&info->lock);
780 info->flags &= ~SHMEM_PAGEIN;
781 spin_unlock(&info->lock);
786 error = inode_change_ok(inode, attr);
788 error = inode_setattr(inode, attr);
789 #ifdef CONFIG_TMPFS_POSIX_ACL
790 if (!error && (attr->ia_valid & ATTR_MODE))
791 error = generic_acl_chmod(inode, &shmem_acl_ops);
794 page_cache_release(page);
798 static void shmem_delete_inode(struct inode *inode)
800 struct shmem_inode_info *info = SHMEM_I(inode);
802 if (inode->i_op->truncate == shmem_truncate) {
803 truncate_inode_pages(inode->i_mapping, 0);
804 shmem_unacct_size(info->flags, inode->i_size);
806 shmem_truncate(inode);
807 if (!list_empty(&info->swaplist)) {
808 mutex_lock(&shmem_swaplist_mutex);
809 list_del_init(&info->swaplist);
810 mutex_unlock(&shmem_swaplist_mutex);
813 BUG_ON(inode->i_blocks);
814 shmem_free_inode(inode->i_sb);
818 static inline int shmem_find_swp(swp_entry_t entry, swp_entry_t *dir, swp_entry_t *edir)
822 for (ptr = dir; ptr < edir; ptr++) {
823 if (ptr->val == entry.val)
829 static int shmem_unuse_inode(struct shmem_inode_info *info, swp_entry_t entry, struct page *page)
843 ptr = info->i_direct;
844 spin_lock(&info->lock);
845 if (!info->swapped) {
846 list_del_init(&info->swaplist);
849 limit = info->next_index;
851 if (size > SHMEM_NR_DIRECT)
852 size = SHMEM_NR_DIRECT;
853 offset = shmem_find_swp(entry, ptr, ptr+size);
856 if (!info->i_indirect)
859 dir = shmem_dir_map(info->i_indirect);
860 stage = SHMEM_NR_DIRECT + ENTRIES_PER_PAGEPAGE/2;
862 for (idx = SHMEM_NR_DIRECT; idx < limit; idx += ENTRIES_PER_PAGE, dir++) {
863 if (unlikely(idx == stage)) {
864 shmem_dir_unmap(dir-1);
865 if (cond_resched_lock(&info->lock)) {
866 /* check it has not been truncated */
867 if (limit > info->next_index) {
868 limit = info->next_index;
873 dir = shmem_dir_map(info->i_indirect) +
874 ENTRIES_PER_PAGE/2 + idx/ENTRIES_PER_PAGEPAGE;
877 idx += ENTRIES_PER_PAGEPAGE;
881 stage = idx + ENTRIES_PER_PAGEPAGE;
883 shmem_dir_unmap(dir);
884 dir = shmem_dir_map(subdir);
887 if (subdir && page_private(subdir)) {
888 ptr = shmem_swp_map(subdir);
890 if (size > ENTRIES_PER_PAGE)
891 size = ENTRIES_PER_PAGE;
892 offset = shmem_find_swp(entry, ptr, ptr+size);
893 shmem_swp_unmap(ptr);
895 shmem_dir_unmap(dir);
901 shmem_dir_unmap(dir-1);
903 spin_unlock(&info->lock);
907 inode = igrab(&info->vfs_inode);
908 spin_unlock(&info->lock);
911 * Move _head_ to start search for next from here.
912 * But be careful: shmem_delete_inode checks list_empty without taking
913 * mutex, and there's an instant in list_move_tail when info->swaplist
914 * would appear empty, if it were the only one on shmem_swaplist. We
915 * could avoid doing it if inode NULL; or use this minor optimization.
917 if (shmem_swaplist.next != &info->swaplist)
918 list_move_tail(&shmem_swaplist, &info->swaplist);
919 mutex_unlock(&shmem_swaplist_mutex);
924 /* Precharge page using GFP_KERNEL while we can wait */
925 error = mem_cgroup_cache_charge(page, current->mm, GFP_KERNEL);
928 error = radix_tree_preload(GFP_KERNEL);
930 mem_cgroup_uncharge_cache_page(page);
935 spin_lock(&info->lock);
936 ptr = shmem_swp_entry(info, idx, NULL);
937 if (ptr && ptr->val == entry.val) {
938 error = add_to_page_cache_locked(page, inode->i_mapping,
940 /* does mem_cgroup_uncharge_cache_page on error */
941 } else /* we must compensate for our precharge above */
942 mem_cgroup_uncharge_cache_page(page);
944 if (error == -EEXIST) {
945 struct page *filepage = find_get_page(inode->i_mapping, idx);
949 * There might be a more uptodate page coming down
950 * from a stacked writepage: forget our swappage if so.
952 if (PageUptodate(filepage))
954 page_cache_release(filepage);
958 delete_from_swap_cache(page);
959 set_page_dirty(page);
960 info->flags |= SHMEM_PAGEIN;
961 shmem_swp_set(info, ptr, 0);
963 error = 1; /* not an error, but entry was found */
966 shmem_swp_unmap(ptr);
967 spin_unlock(&info->lock);
968 radix_tree_preload_end();
971 page_cache_release(page);
972 iput(inode); /* allows for NULL */
977 * shmem_unuse() search for an eventually swapped out shmem page.
979 int shmem_unuse(swp_entry_t entry, struct page *page)
981 struct list_head *p, *next;
982 struct shmem_inode_info *info;
985 mutex_lock(&shmem_swaplist_mutex);
986 list_for_each_safe(p, next, &shmem_swaplist) {
987 info = list_entry(p, struct shmem_inode_info, swaplist);
988 found = shmem_unuse_inode(info, entry, page);
993 mutex_unlock(&shmem_swaplist_mutex);
994 out: return found; /* 0 or 1 or -ENOMEM */
998 * Move the page from the page cache to the swap cache.
1000 static int shmem_writepage(struct page *page, struct writeback_control *wbc)
1002 struct shmem_inode_info *info;
1003 swp_entry_t *entry, swap;
1004 struct address_space *mapping;
1005 unsigned long index;
1006 struct inode *inode;
1008 BUG_ON(!PageLocked(page));
1009 mapping = page->mapping;
1010 index = page->index;
1011 inode = mapping->host;
1012 info = SHMEM_I(inode);
1013 if (info->flags & VM_LOCKED)
1015 if (!total_swap_pages)
1019 * shmem_backing_dev_info's capabilities prevent regular writeback or
1020 * sync from ever calling shmem_writepage; but a stacking filesystem
1021 * may use the ->writepage of its underlying filesystem, in which case
1022 * tmpfs should write out to swap only in response to memory pressure,
1023 * and not for pdflush or sync. However, in those cases, we do still
1024 * want to check if there's a redundant swappage to be discarded.
1026 if (wbc->for_reclaim)
1027 swap = get_swap_page();
1031 spin_lock(&info->lock);
1032 if (index >= info->next_index) {
1033 BUG_ON(!(info->flags & SHMEM_TRUNCATE));
1036 entry = shmem_swp_entry(info, index, NULL);
1039 * The more uptodate page coming down from a stacked
1040 * writepage should replace our old swappage.
1042 free_swap_and_cache(*entry);
1043 shmem_swp_set(info, entry, 0);
1045 shmem_recalc_inode(inode);
1047 if (swap.val && add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
1048 remove_from_page_cache(page);
1049 shmem_swp_set(info, entry, swap.val);
1050 shmem_swp_unmap(entry);
1051 if (list_empty(&info->swaplist))
1052 inode = igrab(inode);
1055 spin_unlock(&info->lock);
1056 swap_duplicate(swap);
1057 BUG_ON(page_mapped(page));
1058 page_cache_release(page); /* pagecache ref */
1059 set_page_dirty(page);
1062 mutex_lock(&shmem_swaplist_mutex);
1063 /* move instead of add in case we're racing */
1064 list_move_tail(&info->swaplist, &shmem_swaplist);
1065 mutex_unlock(&shmem_swaplist_mutex);
1071 shmem_swp_unmap(entry);
1073 spin_unlock(&info->lock);
1076 set_page_dirty(page);
1077 if (wbc->for_reclaim)
1078 return AOP_WRITEPAGE_ACTIVATE; /* Return with page locked */
1085 static void shmem_show_mpol(struct seq_file *seq, struct mempolicy *mpol)
1089 if (!mpol || mpol->mode == MPOL_DEFAULT)
1090 return; /* show nothing */
1092 mpol_to_str(buffer, sizeof(buffer), mpol, 1);
1094 seq_printf(seq, ",mpol=%s", buffer);
1097 static struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1099 struct mempolicy *mpol = NULL;
1101 spin_lock(&sbinfo->stat_lock); /* prevent replace/use races */
1102 mpol = sbinfo->mpol;
1104 spin_unlock(&sbinfo->stat_lock);
1108 #endif /* CONFIG_TMPFS */
1110 static struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
1111 struct shmem_inode_info *info, unsigned long idx)
1113 struct mempolicy mpol, *spol;
1114 struct vm_area_struct pvma;
1117 spol = mpol_cond_copy(&mpol,
1118 mpol_shared_policy_lookup(&info->policy, idx));
1120 /* Create a pseudo vma that just contains the policy */
1122 pvma.vm_pgoff = idx;
1124 pvma.vm_policy = spol;
1125 page = swapin_readahead(entry, gfp, &pvma, 0);
1129 static struct page *shmem_alloc_page(gfp_t gfp,
1130 struct shmem_inode_info *info, unsigned long idx)
1132 struct vm_area_struct pvma;
1134 /* Create a pseudo vma that just contains the policy */
1136 pvma.vm_pgoff = idx;
1138 pvma.vm_policy = mpol_shared_policy_lookup(&info->policy, idx);
1141 * alloc_page_vma() will drop the shared policy reference
1143 return alloc_page_vma(gfp, &pvma, 0);
1145 #else /* !CONFIG_NUMA */
1147 static inline void shmem_show_mpol(struct seq_file *seq, struct mempolicy *p)
1150 #endif /* CONFIG_TMPFS */
1152 static inline struct page *shmem_swapin(swp_entry_t entry, gfp_t gfp,
1153 struct shmem_inode_info *info, unsigned long idx)
1155 return swapin_readahead(entry, gfp, NULL, 0);
1158 static inline struct page *shmem_alloc_page(gfp_t gfp,
1159 struct shmem_inode_info *info, unsigned long idx)
1161 return alloc_page(gfp);
1163 #endif /* CONFIG_NUMA */
1165 #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
1166 static inline struct mempolicy *shmem_get_sbmpol(struct shmem_sb_info *sbinfo)
1173 * shmem_getpage - either get the page from swap or allocate a new one
1175 * If we allocate a new one we do not mark it dirty. That's up to the
1176 * vm. If we swap it in we mark it dirty since we also free the swap
1177 * entry since a page cannot live in both the swap and page cache
1179 static int shmem_getpage(struct inode *inode, unsigned long idx,
1180 struct page **pagep, enum sgp_type sgp, int *type)
1182 struct address_space *mapping = inode->i_mapping;
1183 struct shmem_inode_info *info = SHMEM_I(inode);
1184 struct shmem_sb_info *sbinfo;
1185 struct page *filepage = *pagep;
1186 struct page *swappage;
1192 if (idx >= SHMEM_MAX_INDEX)
1199 * Normally, filepage is NULL on entry, and either found
1200 * uptodate immediately, or allocated and zeroed, or read
1201 * in under swappage, which is then assigned to filepage.
1202 * But shmem_readpage (required for splice) passes in a locked
1203 * filepage, which may be found not uptodate by other callers
1204 * too, and may need to be copied from the swappage read in.
1208 filepage = find_lock_page(mapping, idx);
1209 if (filepage && PageUptodate(filepage))
1212 gfp = mapping_gfp_mask(mapping);
1215 * Try to preload while we can wait, to not make a habit of
1216 * draining atomic reserves; but don't latch on to this cpu.
1218 error = radix_tree_preload(gfp & ~__GFP_HIGHMEM);
1221 radix_tree_preload_end();
1224 spin_lock(&info->lock);
1225 shmem_recalc_inode(inode);
1226 entry = shmem_swp_alloc(info, idx, sgp);
1227 if (IS_ERR(entry)) {
1228 spin_unlock(&info->lock);
1229 error = PTR_ERR(entry);
1235 /* Look it up and read it in.. */
1236 swappage = lookup_swap_cache(swap);
1238 shmem_swp_unmap(entry);
1239 /* here we actually do the io */
1240 if (type && !(*type & VM_FAULT_MAJOR)) {
1241 __count_vm_event(PGMAJFAULT);
1242 *type |= VM_FAULT_MAJOR;
1244 spin_unlock(&info->lock);
1245 swappage = shmem_swapin(swap, gfp, info, idx);
1247 spin_lock(&info->lock);
1248 entry = shmem_swp_alloc(info, idx, sgp);
1250 error = PTR_ERR(entry);
1252 if (entry->val == swap.val)
1254 shmem_swp_unmap(entry);
1256 spin_unlock(&info->lock);
1261 wait_on_page_locked(swappage);
1262 page_cache_release(swappage);
1266 /* We have to do this with page locked to prevent races */
1267 if (!trylock_page(swappage)) {
1268 shmem_swp_unmap(entry);
1269 spin_unlock(&info->lock);
1270 wait_on_page_locked(swappage);
1271 page_cache_release(swappage);
1274 if (PageWriteback(swappage)) {
1275 shmem_swp_unmap(entry);
1276 spin_unlock(&info->lock);
1277 wait_on_page_writeback(swappage);
1278 unlock_page(swappage);
1279 page_cache_release(swappage);
1282 if (!PageUptodate(swappage)) {
1283 shmem_swp_unmap(entry);
1284 spin_unlock(&info->lock);
1285 unlock_page(swappage);
1286 page_cache_release(swappage);
1292 shmem_swp_set(info, entry, 0);
1293 shmem_swp_unmap(entry);
1294 delete_from_swap_cache(swappage);
1295 spin_unlock(&info->lock);
1296 copy_highpage(filepage, swappage);
1297 unlock_page(swappage);
1298 page_cache_release(swappage);
1299 flush_dcache_page(filepage);
1300 SetPageUptodate(filepage);
1301 set_page_dirty(filepage);
1303 } else if (!(error = add_to_page_cache_locked(swappage, mapping,
1304 idx, GFP_NOWAIT))) {
1305 info->flags |= SHMEM_PAGEIN;
1306 shmem_swp_set(info, entry, 0);
1307 shmem_swp_unmap(entry);
1308 delete_from_swap_cache(swappage);
1309 spin_unlock(&info->lock);
1310 filepage = swappage;
1311 set_page_dirty(filepage);
1314 shmem_swp_unmap(entry);
1315 spin_unlock(&info->lock);
1316 unlock_page(swappage);
1317 page_cache_release(swappage);
1318 if (error == -ENOMEM) {
1319 /* allow reclaim from this memory cgroup */
1320 error = mem_cgroup_shrink_usage(current->mm,
1327 } else if (sgp == SGP_READ && !filepage) {
1328 shmem_swp_unmap(entry);
1329 filepage = find_get_page(mapping, idx);
1331 (!PageUptodate(filepage) || !trylock_page(filepage))) {
1332 spin_unlock(&info->lock);
1333 wait_on_page_locked(filepage);
1334 page_cache_release(filepage);
1338 spin_unlock(&info->lock);
1340 shmem_swp_unmap(entry);
1341 sbinfo = SHMEM_SB(inode->i_sb);
1342 if (sbinfo->max_blocks) {
1343 spin_lock(&sbinfo->stat_lock);
1344 if (sbinfo->free_blocks == 0 ||
1345 shmem_acct_block(info->flags)) {
1346 spin_unlock(&sbinfo->stat_lock);
1347 spin_unlock(&info->lock);
1351 sbinfo->free_blocks--;
1352 inode->i_blocks += BLOCKS_PER_PAGE;
1353 spin_unlock(&sbinfo->stat_lock);
1354 } else if (shmem_acct_block(info->flags)) {
1355 spin_unlock(&info->lock);
1363 spin_unlock(&info->lock);
1364 filepage = shmem_alloc_page(gfp, info, idx);
1366 shmem_unacct_blocks(info->flags, 1);
1367 shmem_free_blocks(inode, 1);
1371 SetPageSwapBacked(filepage);
1373 /* Precharge page while we can wait, compensate after */
1374 error = mem_cgroup_cache_charge(filepage, current->mm,
1375 gfp & ~__GFP_HIGHMEM);
1377 page_cache_release(filepage);
1378 shmem_unacct_blocks(info->flags, 1);
1379 shmem_free_blocks(inode, 1);
1384 spin_lock(&info->lock);
1385 entry = shmem_swp_alloc(info, idx, sgp);
1387 error = PTR_ERR(entry);
1390 shmem_swp_unmap(entry);
1392 ret = error || swap.val;
1394 mem_cgroup_uncharge_cache_page(filepage);
1396 ret = add_to_page_cache_lru(filepage, mapping,
1399 * At add_to_page_cache_lru() failure, uncharge will
1400 * be done automatically.
1403 spin_unlock(&info->lock);
1404 page_cache_release(filepage);
1405 shmem_unacct_blocks(info->flags, 1);
1406 shmem_free_blocks(inode, 1);
1412 info->flags |= SHMEM_PAGEIN;
1416 spin_unlock(&info->lock);
1417 clear_highpage(filepage);
1418 flush_dcache_page(filepage);
1419 SetPageUptodate(filepage);
1420 if (sgp == SGP_DIRTY)
1421 set_page_dirty(filepage);
1428 if (*pagep != filepage) {
1429 unlock_page(filepage);
1430 page_cache_release(filepage);
1435 static int shmem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1437 struct inode *inode = vma->vm_file->f_path.dentry->d_inode;
1441 if (((loff_t)vmf->pgoff << PAGE_CACHE_SHIFT) >= i_size_read(inode))
1442 return VM_FAULT_SIGBUS;
1444 error = shmem_getpage(inode, vmf->pgoff, &vmf->page, SGP_CACHE, &ret);
1446 return ((error == -ENOMEM) ? VM_FAULT_OOM : VM_FAULT_SIGBUS);
1448 mark_page_accessed(vmf->page);
1449 return ret | VM_FAULT_LOCKED;
1453 static int shmem_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
1455 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
1456 return mpol_set_shared_policy(&SHMEM_I(i)->policy, vma, new);
1459 static struct mempolicy *shmem_get_policy(struct vm_area_struct *vma,
1462 struct inode *i = vma->vm_file->f_path.dentry->d_inode;
1465 idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
1466 return mpol_shared_policy_lookup(&SHMEM_I(i)->policy, idx);
1470 int shmem_lock(struct file *file, int lock, struct user_struct *user)
1472 struct inode *inode = file->f_path.dentry->d_inode;
1473 struct shmem_inode_info *info = SHMEM_I(inode);
1474 int retval = -ENOMEM;
1476 spin_lock(&info->lock);
1477 if (lock && !(info->flags & VM_LOCKED)) {
1478 if (!user_shm_lock(inode->i_size, user))
1480 info->flags |= VM_LOCKED;
1481 mapping_set_unevictable(file->f_mapping);
1483 if (!lock && (info->flags & VM_LOCKED) && user) {
1484 user_shm_unlock(inode->i_size, user);
1485 info->flags &= ~VM_LOCKED;
1486 mapping_clear_unevictable(file->f_mapping);
1487 scan_mapping_unevictable_pages(file->f_mapping);
1492 spin_unlock(&info->lock);
1496 static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
1498 file_accessed(file);
1499 vma->vm_ops = &shmem_vm_ops;
1500 vma->vm_flags |= VM_CAN_NONLINEAR;
1504 static struct inode *
1505 shmem_get_inode(struct super_block *sb, int mode, dev_t dev)
1507 struct inode *inode;
1508 struct shmem_inode_info *info;
1509 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
1511 if (shmem_reserve_inode(sb))
1514 inode = new_inode(sb);
1516 inode->i_mode = mode;
1517 inode->i_uid = current_fsuid();
1518 inode->i_gid = current_fsgid();
1519 inode->i_blocks = 0;
1520 inode->i_mapping->backing_dev_info = &shmem_backing_dev_info;
1521 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
1522 inode->i_generation = get_seconds();
1523 info = SHMEM_I(inode);
1524 memset(info, 0, (char *)inode - (char *)info);
1525 spin_lock_init(&info->lock);
1526 INIT_LIST_HEAD(&info->swaplist);
1528 switch (mode & S_IFMT) {
1530 inode->i_op = &shmem_special_inode_operations;
1531 init_special_inode(inode, mode, dev);
1534 inode->i_mapping->a_ops = &shmem_aops;
1535 inode->i_op = &shmem_inode_operations;
1536 inode->i_fop = &shmem_file_operations;
1537 mpol_shared_policy_init(&info->policy,
1538 shmem_get_sbmpol(sbinfo));
1542 /* Some things misbehave if size == 0 on a directory */
1543 inode->i_size = 2 * BOGO_DIRENT_SIZE;
1544 inode->i_op = &shmem_dir_inode_operations;
1545 inode->i_fop = &simple_dir_operations;
1549 * Must not load anything in the rbtree,
1550 * mpol_free_shared_policy will not be called.
1552 mpol_shared_policy_init(&info->policy, NULL);
1556 shmem_free_inode(sb);
1561 static const struct inode_operations shmem_symlink_inode_operations;
1562 static const struct inode_operations shmem_symlink_inline_operations;
1565 * Normally tmpfs avoids the use of shmem_readpage and shmem_write_begin;
1566 * but providing them allows a tmpfs file to be used for splice, sendfile, and
1567 * below the loop driver, in the generic fashion that many filesystems support.
1569 static int shmem_readpage(struct file *file, struct page *page)
1571 struct inode *inode = page->mapping->host;
1572 int error = shmem_getpage(inode, page->index, &page, SGP_CACHE, NULL);
1578 shmem_write_begin(struct file *file, struct address_space *mapping,
1579 loff_t pos, unsigned len, unsigned flags,
1580 struct page **pagep, void **fsdata)
1582 struct inode *inode = mapping->host;
1583 pgoff_t index = pos >> PAGE_CACHE_SHIFT;
1585 return shmem_getpage(inode, index, pagep, SGP_WRITE, NULL);
1589 shmem_write_end(struct file *file, struct address_space *mapping,
1590 loff_t pos, unsigned len, unsigned copied,
1591 struct page *page, void *fsdata)
1593 struct inode *inode = mapping->host;
1595 if (pos + copied > inode->i_size)
1596 i_size_write(inode, pos + copied);
1599 set_page_dirty(page);
1600 page_cache_release(page);
1605 static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc, read_actor_t actor)
1607 struct inode *inode = filp->f_path.dentry->d_inode;
1608 struct address_space *mapping = inode->i_mapping;
1609 unsigned long index, offset;
1610 enum sgp_type sgp = SGP_READ;
1613 * Might this read be for a stacking filesystem? Then when reading
1614 * holes of a sparse file, we actually need to allocate those pages,
1615 * and even mark them dirty, so it cannot exceed the max_blocks limit.
1617 if (segment_eq(get_fs(), KERNEL_DS))
1620 index = *ppos >> PAGE_CACHE_SHIFT;
1621 offset = *ppos & ~PAGE_CACHE_MASK;
1624 struct page *page = NULL;
1625 unsigned long end_index, nr, ret;
1626 loff_t i_size = i_size_read(inode);
1628 end_index = i_size >> PAGE_CACHE_SHIFT;
1629 if (index > end_index)
1631 if (index == end_index) {
1632 nr = i_size & ~PAGE_CACHE_MASK;
1637 desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
1639 if (desc->error == -EINVAL)
1647 * We must evaluate after, since reads (unlike writes)
1648 * are called without i_mutex protection against truncate
1650 nr = PAGE_CACHE_SIZE;
1651 i_size = i_size_read(inode);
1652 end_index = i_size >> PAGE_CACHE_SHIFT;
1653 if (index == end_index) {
1654 nr = i_size & ~PAGE_CACHE_MASK;
1657 page_cache_release(page);
1665 * If users can be writing to this page using arbitrary
1666 * virtual addresses, take care about potential aliasing
1667 * before reading the page on the kernel side.
1669 if (mapping_writably_mapped(mapping))
1670 flush_dcache_page(page);
1672 * Mark the page accessed if we read the beginning.
1675 mark_page_accessed(page);
1677 page = ZERO_PAGE(0);
1678 page_cache_get(page);
1682 * Ok, we have the page, and it's up-to-date, so
1683 * now we can copy it to user space...
1685 * The actor routine returns how many bytes were actually used..
1686 * NOTE! This may not be the same as how much of a user buffer
1687 * we filled up (we may be padding etc), so we can only update
1688 * "pos" here (the actor routine has to update the user buffer
1689 * pointers and the remaining count).
1691 ret = actor(desc, page, offset, nr);
1693 index += offset >> PAGE_CACHE_SHIFT;
1694 offset &= ~PAGE_CACHE_MASK;
1696 page_cache_release(page);
1697 if (ret != nr || !desc->count)
1703 *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
1704 file_accessed(filp);
1707 static ssize_t shmem_file_aio_read(struct kiocb *iocb,
1708 const struct iovec *iov, unsigned long nr_segs, loff_t pos)
1710 struct file *filp = iocb->ki_filp;
1714 loff_t *ppos = &iocb->ki_pos;
1716 retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
1720 for (seg = 0; seg < nr_segs; seg++) {
1721 read_descriptor_t desc;
1724 desc.arg.buf = iov[seg].iov_base;
1725 desc.count = iov[seg].iov_len;
1726 if (desc.count == 0)
1729 do_shmem_file_read(filp, ppos, &desc, file_read_actor);
1730 retval += desc.written;
1732 retval = retval ?: desc.error;
1741 static int shmem_statfs(struct dentry *dentry, struct kstatfs *buf)
1743 struct shmem_sb_info *sbinfo = SHMEM_SB(dentry->d_sb);
1745 buf->f_type = TMPFS_MAGIC;
1746 buf->f_bsize = PAGE_CACHE_SIZE;
1747 buf->f_namelen = NAME_MAX;
1748 spin_lock(&sbinfo->stat_lock);
1749 if (sbinfo->max_blocks) {
1750 buf->f_blocks = sbinfo->max_blocks;
1751 buf->f_bavail = buf->f_bfree = sbinfo->free_blocks;
1753 if (sbinfo->max_inodes) {
1754 buf->f_files = sbinfo->max_inodes;
1755 buf->f_ffree = sbinfo->free_inodes;
1757 /* else leave those fields 0 like simple_statfs */
1758 spin_unlock(&sbinfo->stat_lock);
1763 * File creation. Allocate an inode, and we're done..
1766 shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
1768 struct inode *inode = shmem_get_inode(dir->i_sb, mode, dev);
1769 int error = -ENOSPC;
1772 error = security_inode_init_security(inode, dir, NULL, NULL,
1775 if (error != -EOPNOTSUPP) {
1780 error = shmem_acl_init(inode, dir);
1785 if (dir->i_mode & S_ISGID) {
1786 inode->i_gid = dir->i_gid;
1788 inode->i_mode |= S_ISGID;
1790 dir->i_size += BOGO_DIRENT_SIZE;
1791 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1792 d_instantiate(dentry, inode);
1793 dget(dentry); /* Extra count - pin the dentry in core */
1798 static int shmem_mkdir(struct inode *dir, struct dentry *dentry, int mode)
1802 if ((error = shmem_mknod(dir, dentry, mode | S_IFDIR, 0)))
1808 static int shmem_create(struct inode *dir, struct dentry *dentry, int mode,
1809 struct nameidata *nd)
1811 return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
1817 static int shmem_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
1819 struct inode *inode = old_dentry->d_inode;
1823 * No ordinary (disk based) filesystem counts links as inodes;
1824 * but each new link needs a new dentry, pinning lowmem, and
1825 * tmpfs dentries cannot be pruned until they are unlinked.
1827 ret = shmem_reserve_inode(inode->i_sb);
1831 dir->i_size += BOGO_DIRENT_SIZE;
1832 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1834 atomic_inc(&inode->i_count); /* New dentry reference */
1835 dget(dentry); /* Extra pinning count for the created dentry */
1836 d_instantiate(dentry, inode);
1841 static int shmem_unlink(struct inode *dir, struct dentry *dentry)
1843 struct inode *inode = dentry->d_inode;
1845 if (inode->i_nlink > 1 && !S_ISDIR(inode->i_mode))
1846 shmem_free_inode(inode->i_sb);
1848 dir->i_size -= BOGO_DIRENT_SIZE;
1849 inode->i_ctime = dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1851 dput(dentry); /* Undo the count from "create" - this does all the work */
1855 static int shmem_rmdir(struct inode *dir, struct dentry *dentry)
1857 if (!simple_empty(dentry))
1860 drop_nlink(dentry->d_inode);
1862 return shmem_unlink(dir, dentry);
1866 * The VFS layer already does all the dentry stuff for rename,
1867 * we just have to decrement the usage count for the target if
1868 * it exists so that the VFS layer correctly free's it when it
1871 static int shmem_rename(struct inode *old_dir, struct dentry *old_dentry, struct inode *new_dir, struct dentry *new_dentry)
1873 struct inode *inode = old_dentry->d_inode;
1874 int they_are_dirs = S_ISDIR(inode->i_mode);
1876 if (!simple_empty(new_dentry))
1879 if (new_dentry->d_inode) {
1880 (void) shmem_unlink(new_dir, new_dentry);
1882 drop_nlink(old_dir);
1883 } else if (they_are_dirs) {
1884 drop_nlink(old_dir);
1888 old_dir->i_size -= BOGO_DIRENT_SIZE;
1889 new_dir->i_size += BOGO_DIRENT_SIZE;
1890 old_dir->i_ctime = old_dir->i_mtime =
1891 new_dir->i_ctime = new_dir->i_mtime =
1892 inode->i_ctime = CURRENT_TIME;
1896 static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
1900 struct inode *inode;
1901 struct page *page = NULL;
1903 struct shmem_inode_info *info;
1905 len = strlen(symname) + 1;
1906 if (len > PAGE_CACHE_SIZE)
1907 return -ENAMETOOLONG;
1909 inode = shmem_get_inode(dir->i_sb, S_IFLNK|S_IRWXUGO, 0);
1913 error = security_inode_init_security(inode, dir, NULL, NULL,
1916 if (error != -EOPNOTSUPP) {
1923 info = SHMEM_I(inode);
1924 inode->i_size = len-1;
1925 if (len <= (char *)inode - (char *)info) {
1927 memcpy(info, symname, len);
1928 inode->i_op = &shmem_symlink_inline_operations;
1930 error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL);
1936 inode->i_mapping->a_ops = &shmem_aops;
1937 inode->i_op = &shmem_symlink_inode_operations;
1938 kaddr = kmap_atomic(page, KM_USER0);
1939 memcpy(kaddr, symname, len);
1940 kunmap_atomic(kaddr, KM_USER0);
1941 set_page_dirty(page);
1942 page_cache_release(page);
1944 if (dir->i_mode & S_ISGID)
1945 inode->i_gid = dir->i_gid;
1946 dir->i_size += BOGO_DIRENT_SIZE;
1947 dir->i_ctime = dir->i_mtime = CURRENT_TIME;
1948 d_instantiate(dentry, inode);
1953 static void *shmem_follow_link_inline(struct dentry *dentry, struct nameidata *nd)
1955 nd_set_link(nd, (char *)SHMEM_I(dentry->d_inode));
1959 static void *shmem_follow_link(struct dentry *dentry, struct nameidata *nd)
1961 struct page *page = NULL;
1962 int res = shmem_getpage(dentry->d_inode, 0, &page, SGP_READ, NULL);
1963 nd_set_link(nd, res ? ERR_PTR(res) : kmap(page));
1969 static void shmem_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)
1971 if (!IS_ERR(nd_get_link(nd))) {
1972 struct page *page = cookie;
1974 mark_page_accessed(page);
1975 page_cache_release(page);
1979 static const struct inode_operations shmem_symlink_inline_operations = {
1980 .readlink = generic_readlink,
1981 .follow_link = shmem_follow_link_inline,
1984 static const struct inode_operations shmem_symlink_inode_operations = {
1985 .truncate = shmem_truncate,
1986 .readlink = generic_readlink,
1987 .follow_link = shmem_follow_link,
1988 .put_link = shmem_put_link,
1991 #ifdef CONFIG_TMPFS_POSIX_ACL
1993 * Superblocks without xattr inode operations will get security.* xattr
1994 * support from the VFS "for free". As soon as we have any other xattrs
1995 * like ACLs, we also need to implement the security.* handlers at
1996 * filesystem level, though.
1999 static size_t shmem_xattr_security_list(struct inode *inode, char *list,
2000 size_t list_len, const char *name,
2003 return security_inode_listsecurity(inode, list, list_len);
2006 static int shmem_xattr_security_get(struct inode *inode, const char *name,
2007 void *buffer, size_t size)
2009 if (strcmp(name, "") == 0)
2011 return xattr_getsecurity(inode, name, buffer, size);
2014 static int shmem_xattr_security_set(struct inode *inode, const char *name,
2015 const void *value, size_t size, int flags)
2017 if (strcmp(name, "") == 0)
2019 return security_inode_setsecurity(inode, name, value, size, flags);
2022 static struct xattr_handler shmem_xattr_security_handler = {
2023 .prefix = XATTR_SECURITY_PREFIX,
2024 .list = shmem_xattr_security_list,
2025 .get = shmem_xattr_security_get,
2026 .set = shmem_xattr_security_set,
2029 static struct xattr_handler *shmem_xattr_handlers[] = {
2030 &shmem_xattr_acl_access_handler,
2031 &shmem_xattr_acl_default_handler,
2032 &shmem_xattr_security_handler,
2037 static struct dentry *shmem_get_parent(struct dentry *child)
2039 return ERR_PTR(-ESTALE);
2042 static int shmem_match(struct inode *ino, void *vfh)
2046 inum = (inum << 32) | fh[1];
2047 return ino->i_ino == inum && fh[0] == ino->i_generation;
2050 static struct dentry *shmem_fh_to_dentry(struct super_block *sb,
2051 struct fid *fid, int fh_len, int fh_type)
2053 struct inode *inode;
2054 struct dentry *dentry = NULL;
2055 u64 inum = fid->raw[2];
2056 inum = (inum << 32) | fid->raw[1];
2061 inode = ilookup5(sb, (unsigned long)(inum + fid->raw[0]),
2062 shmem_match, fid->raw);
2064 dentry = d_find_alias(inode);
2071 static int shmem_encode_fh(struct dentry *dentry, __u32 *fh, int *len,
2074 struct inode *inode = dentry->d_inode;
2079 if (hlist_unhashed(&inode->i_hash)) {
2080 /* Unfortunately insert_inode_hash is not idempotent,
2081 * so as we hash inodes here rather than at creation
2082 * time, we need a lock to ensure we only try
2085 static DEFINE_SPINLOCK(lock);
2087 if (hlist_unhashed(&inode->i_hash))
2088 __insert_inode_hash(inode,
2089 inode->i_ino + inode->i_generation);
2093 fh[0] = inode->i_generation;
2094 fh[1] = inode->i_ino;
2095 fh[2] = ((__u64)inode->i_ino) >> 32;
2101 static const struct export_operations shmem_export_ops = {
2102 .get_parent = shmem_get_parent,
2103 .encode_fh = shmem_encode_fh,
2104 .fh_to_dentry = shmem_fh_to_dentry,
2107 static int shmem_parse_options(char *options, struct shmem_sb_info *sbinfo,
2110 char *this_char, *value, *rest;
2112 while (options != NULL) {
2113 this_char = options;
2116 * NUL-terminate this option: unfortunately,
2117 * mount options form a comma-separated list,
2118 * but mpol's nodelist may also contain commas.
2120 options = strchr(options, ',');
2121 if (options == NULL)
2124 if (!isdigit(*options)) {
2131 if ((value = strchr(this_char,'=')) != NULL) {
2135 "tmpfs: No value for mount option '%s'\n",
2140 if (!strcmp(this_char,"size")) {
2141 unsigned long long size;
2142 size = memparse(value,&rest);
2144 size <<= PAGE_SHIFT;
2145 size *= totalram_pages;
2151 sbinfo->max_blocks =
2152 DIV_ROUND_UP(size, PAGE_CACHE_SIZE);
2153 } else if (!strcmp(this_char,"nr_blocks")) {
2154 sbinfo->max_blocks = memparse(value, &rest);
2157 } else if (!strcmp(this_char,"nr_inodes")) {
2158 sbinfo->max_inodes = memparse(value, &rest);
2161 } else if (!strcmp(this_char,"mode")) {
2164 sbinfo->mode = simple_strtoul(value, &rest, 8) & 07777;
2167 } else if (!strcmp(this_char,"uid")) {
2170 sbinfo->uid = simple_strtoul(value, &rest, 0);
2173 } else if (!strcmp(this_char,"gid")) {
2176 sbinfo->gid = simple_strtoul(value, &rest, 0);
2179 } else if (!strcmp(this_char,"mpol")) {
2180 if (mpol_parse_str(value, &sbinfo->mpol, 1))
2183 printk(KERN_ERR "tmpfs: Bad mount option %s\n",
2191 printk(KERN_ERR "tmpfs: Bad value '%s' for mount option '%s'\n",
2197 static int shmem_remount_fs(struct super_block *sb, int *flags, char *data)
2199 struct shmem_sb_info *sbinfo = SHMEM_SB(sb);
2200 struct shmem_sb_info config = *sbinfo;
2201 unsigned long blocks;
2202 unsigned long inodes;
2203 int error = -EINVAL;
2205 if (shmem_parse_options(data, &config, true))
2208 spin_lock(&sbinfo->stat_lock);
2209 blocks = sbinfo->max_blocks - sbinfo->free_blocks;
2210 inodes = sbinfo->max_inodes - sbinfo->free_inodes;
2211 if (config.max_blocks < blocks)
2213 if (config.max_inodes < inodes)
2216 * Those tests also disallow limited->unlimited while any are in
2217 * use, so i_blocks will always be zero when max_blocks is zero;
2218 * but we must separately disallow unlimited->limited, because
2219 * in that case we have no record of how much is already in use.
2221 if (config.max_blocks && !sbinfo->max_blocks)
2223 if (config.max_inodes && !sbinfo->max_inodes)
2227 sbinfo->max_blocks = config.max_blocks;
2228 sbinfo->free_blocks = config.max_blocks - blocks;
2229 sbinfo->max_inodes = config.max_inodes;
2230 sbinfo->free_inodes = config.max_inodes - inodes;
2232 mpol_put(sbinfo->mpol);
2233 sbinfo->mpol = config.mpol; /* transfers initial ref */
2235 spin_unlock(&sbinfo->stat_lock);
2239 static int shmem_show_options(struct seq_file *seq, struct vfsmount *vfs)
2241 struct shmem_sb_info *sbinfo = SHMEM_SB(vfs->mnt_sb);
2243 if (sbinfo->max_blocks != shmem_default_max_blocks())
2244 seq_printf(seq, ",size=%luk",
2245 sbinfo->max_blocks << (PAGE_CACHE_SHIFT - 10));
2246 if (sbinfo->max_inodes != shmem_default_max_inodes())
2247 seq_printf(seq, ",nr_inodes=%lu", sbinfo->max_inodes);
2248 if (sbinfo->mode != (S_IRWXUGO | S_ISVTX))
2249 seq_printf(seq, ",mode=%03o", sbinfo->mode);
2250 if (sbinfo->uid != 0)
2251 seq_printf(seq, ",uid=%u", sbinfo->uid);
2252 if (sbinfo->gid != 0)
2253 seq_printf(seq, ",gid=%u", sbinfo->gid);
2254 shmem_show_mpol(seq, sbinfo->mpol);
2257 #endif /* CONFIG_TMPFS */
2259 static void shmem_put_super(struct super_block *sb)
2261 kfree(sb->s_fs_info);
2262 sb->s_fs_info = NULL;
2265 static int shmem_fill_super(struct super_block *sb,
2266 void *data, int silent)
2268 struct inode *inode;
2269 struct dentry *root;
2270 struct shmem_sb_info *sbinfo;
2273 /* Round up to L1_CACHE_BYTES to resist false sharing */
2274 sbinfo = kmalloc(max((int)sizeof(struct shmem_sb_info),
2275 L1_CACHE_BYTES), GFP_KERNEL);
2279 sbinfo->max_blocks = 0;
2280 sbinfo->max_inodes = 0;
2281 sbinfo->mode = S_IRWXUGO | S_ISVTX;
2282 sbinfo->uid = current_fsuid();
2283 sbinfo->gid = current_fsgid();
2284 sbinfo->mpol = NULL;
2285 sb->s_fs_info = sbinfo;
2289 * Per default we only allow half of the physical ram per
2290 * tmpfs instance, limiting inodes to one per page of lowmem;
2291 * but the internal instance is left unlimited.
2293 if (!(sb->s_flags & MS_NOUSER)) {
2294 sbinfo->max_blocks = shmem_default_max_blocks();
2295 sbinfo->max_inodes = shmem_default_max_inodes();
2296 if (shmem_parse_options(data, sbinfo, false)) {
2301 sb->s_export_op = &shmem_export_ops;
2303 sb->s_flags |= MS_NOUSER;
2306 spin_lock_init(&sbinfo->stat_lock);
2307 sbinfo->free_blocks = sbinfo->max_blocks;
2308 sbinfo->free_inodes = sbinfo->max_inodes;
2310 sb->s_maxbytes = SHMEM_MAX_BYTES;
2311 sb->s_blocksize = PAGE_CACHE_SIZE;
2312 sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
2313 sb->s_magic = TMPFS_MAGIC;
2314 sb->s_op = &shmem_ops;
2315 sb->s_time_gran = 1;
2316 #ifdef CONFIG_TMPFS_POSIX_ACL
2317 sb->s_xattr = shmem_xattr_handlers;
2318 sb->s_flags |= MS_POSIXACL;
2321 inode = shmem_get_inode(sb, S_IFDIR | sbinfo->mode, 0);
2324 inode->i_uid = sbinfo->uid;
2325 inode->i_gid = sbinfo->gid;
2326 root = d_alloc_root(inode);
2335 shmem_put_super(sb);
2339 static struct kmem_cache *shmem_inode_cachep;
2341 static struct inode *shmem_alloc_inode(struct super_block *sb)
2343 struct shmem_inode_info *p;
2344 p = (struct shmem_inode_info *)kmem_cache_alloc(shmem_inode_cachep, GFP_KERNEL);
2347 return &p->vfs_inode;
2350 static void shmem_destroy_inode(struct inode *inode)
2352 if ((inode->i_mode & S_IFMT) == S_IFREG) {
2353 /* only struct inode is valid if it's an inline symlink */
2354 mpol_free_shared_policy(&SHMEM_I(inode)->policy);
2356 shmem_acl_destroy_inode(inode);
2357 kmem_cache_free(shmem_inode_cachep, SHMEM_I(inode));
2360 static void init_once(void *foo)
2362 struct shmem_inode_info *p = (struct shmem_inode_info *) foo;
2364 inode_init_once(&p->vfs_inode);
2365 #ifdef CONFIG_TMPFS_POSIX_ACL
2367 p->i_default_acl = NULL;
2371 static int init_inodecache(void)
2373 shmem_inode_cachep = kmem_cache_create("shmem_inode_cache",
2374 sizeof(struct shmem_inode_info),
2375 0, SLAB_PANIC, init_once);
2379 static void destroy_inodecache(void)
2381 kmem_cache_destroy(shmem_inode_cachep);
2384 static const struct address_space_operations shmem_aops = {
2385 .writepage = shmem_writepage,
2386 .set_page_dirty = __set_page_dirty_no_writeback,
2388 .readpage = shmem_readpage,
2389 .write_begin = shmem_write_begin,
2390 .write_end = shmem_write_end,
2392 .migratepage = migrate_page,
2395 static const struct file_operations shmem_file_operations = {
2398 .llseek = generic_file_llseek,
2399 .read = do_sync_read,
2400 .write = do_sync_write,
2401 .aio_read = shmem_file_aio_read,
2402 .aio_write = generic_file_aio_write,
2403 .fsync = simple_sync_file,
2404 .splice_read = generic_file_splice_read,
2405 .splice_write = generic_file_splice_write,
2409 static const struct inode_operations shmem_inode_operations = {
2410 .truncate = shmem_truncate,
2411 .setattr = shmem_notify_change,
2412 .truncate_range = shmem_truncate_range,
2413 #ifdef CONFIG_TMPFS_POSIX_ACL
2414 .setxattr = generic_setxattr,
2415 .getxattr = generic_getxattr,
2416 .listxattr = generic_listxattr,
2417 .removexattr = generic_removexattr,
2418 .permission = shmem_permission,
2423 static const struct inode_operations shmem_dir_inode_operations = {
2425 .create = shmem_create,
2426 .lookup = simple_lookup,
2428 .unlink = shmem_unlink,
2429 .symlink = shmem_symlink,
2430 .mkdir = shmem_mkdir,
2431 .rmdir = shmem_rmdir,
2432 .mknod = shmem_mknod,
2433 .rename = shmem_rename,
2435 #ifdef CONFIG_TMPFS_POSIX_ACL
2436 .setattr = shmem_notify_change,
2437 .setxattr = generic_setxattr,
2438 .getxattr = generic_getxattr,
2439 .listxattr = generic_listxattr,
2440 .removexattr = generic_removexattr,
2441 .permission = shmem_permission,
2445 static const struct inode_operations shmem_special_inode_operations = {
2446 #ifdef CONFIG_TMPFS_POSIX_ACL
2447 .setattr = shmem_notify_change,
2448 .setxattr = generic_setxattr,
2449 .getxattr = generic_getxattr,
2450 .listxattr = generic_listxattr,
2451 .removexattr = generic_removexattr,
2452 .permission = shmem_permission,
2456 static const struct super_operations shmem_ops = {
2457 .alloc_inode = shmem_alloc_inode,
2458 .destroy_inode = shmem_destroy_inode,
2460 .statfs = shmem_statfs,
2461 .remount_fs = shmem_remount_fs,
2462 .show_options = shmem_show_options,
2464 .delete_inode = shmem_delete_inode,
2465 .drop_inode = generic_delete_inode,
2466 .put_super = shmem_put_super,
2469 static struct vm_operations_struct shmem_vm_ops = {
2470 .fault = shmem_fault,
2472 .set_policy = shmem_set_policy,
2473 .get_policy = shmem_get_policy,
2478 static int shmem_get_sb(struct file_system_type *fs_type,
2479 int flags, const char *dev_name, void *data, struct vfsmount *mnt)
2481 return get_sb_nodev(fs_type, flags, data, shmem_fill_super, mnt);
2484 static struct file_system_type tmpfs_fs_type = {
2485 .owner = THIS_MODULE,
2487 .get_sb = shmem_get_sb,
2488 .kill_sb = kill_litter_super,
2490 static struct vfsmount *shm_mnt;
2492 static int __init init_tmpfs(void)
2496 error = bdi_init(&shmem_backing_dev_info);
2500 error = init_inodecache();
2504 error = register_filesystem(&tmpfs_fs_type);
2506 printk(KERN_ERR "Could not register tmpfs\n");
2510 shm_mnt = vfs_kern_mount(&tmpfs_fs_type, MS_NOUSER,
2511 tmpfs_fs_type.name, NULL);
2512 if (IS_ERR(shm_mnt)) {
2513 error = PTR_ERR(shm_mnt);
2514 printk(KERN_ERR "Could not kern_mount tmpfs\n");
2520 unregister_filesystem(&tmpfs_fs_type);
2522 destroy_inodecache();
2524 bdi_destroy(&shmem_backing_dev_info);
2526 shm_mnt = ERR_PTR(error);
2529 module_init(init_tmpfs)
2532 * shmem_file_setup - get an unlinked file living in tmpfs
2533 * @name: name for dentry (to be seen in /proc/<pid>/maps
2534 * @size: size to be set for the file
2537 struct file *shmem_file_setup(char *name, loff_t size, unsigned long flags)
2541 struct inode *inode;
2542 struct dentry *dentry, *root;
2545 if (IS_ERR(shm_mnt))
2546 return (void *)shm_mnt;
2548 if (size < 0 || size > SHMEM_MAX_BYTES)
2549 return ERR_PTR(-EINVAL);
2551 if (shmem_acct_size(flags, size))
2552 return ERR_PTR(-ENOMEM);
2556 this.len = strlen(name);
2557 this.hash = 0; /* will go */
2558 root = shm_mnt->mnt_root;
2559 dentry = d_alloc(root, &this);
2564 file = get_empty_filp();
2569 inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
2573 SHMEM_I(inode)->flags = flags & VM_ACCOUNT;
2574 d_instantiate(dentry, inode);
2575 inode->i_size = size;
2576 inode->i_nlink = 0; /* It is unlinked */
2577 init_file(file, shm_mnt, dentry, FMODE_WRITE | FMODE_READ,
2578 &shmem_file_operations);
2586 shmem_unacct_size(flags, size);
2587 return ERR_PTR(error);
2589 EXPORT_SYMBOL_GPL(shmem_file_setup);
2592 * shmem_zero_setup - setup a shared anonymous mapping
2593 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2595 int shmem_zero_setup(struct vm_area_struct *vma)
2598 loff_t size = vma->vm_end - vma->vm_start;
2600 file = shmem_file_setup("dev/zero", size, vma->vm_flags);
2602 return PTR_ERR(file);
2604 ima_shm_check(file);
2607 vma->vm_file = file;
2608 vma->vm_ops = &shmem_vm_ops;