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/pagemap.h>
29 #include <linux/file.h>
31 #include <linux/export.h>
32 #include <linux/swap.h>
34 static struct vfsmount
*shm_mnt
;
38 * This virtual memory filesystem is heavily based on the ramfs. It
39 * extends ramfs by the ability to use swap and honor resource limits
40 * which makes it a completely usable filesystem.
43 #include <linux/xattr.h>
44 #include <linux/exportfs.h>
45 #include <linux/posix_acl.h>
46 #include <linux/generic_acl.h>
47 #include <linux/mman.h>
48 #include <linux/string.h>
49 #include <linux/slab.h>
50 #include <linux/backing-dev.h>
51 #include <linux/shmem_fs.h>
52 #include <linux/writeback.h>
53 #include <linux/blkdev.h>
54 #include <linux/pagevec.h>
55 #include <linux/percpu_counter.h>
56 #include <linux/falloc.h>
57 #include <linux/splice.h>
58 #include <linux/security.h>
59 #include <linux/swapops.h>
60 #include <linux/mempolicy.h>
61 #include <linux/namei.h>
62 #include <linux/ctype.h>
63 #include <linux/migrate.h>
64 #include <linux/highmem.h>
65 #include <linux/seq_file.h>
66 #include <linux/magic.h>
68 #include <asm/uaccess.h>
69 #include <asm/pgtable.h>
71 #define BLOCKS_PER_PAGE (PAGE_CACHE_SIZE/512)
72 #define VM_ACCT(size) (PAGE_CACHE_ALIGN(size) >> PAGE_SHIFT)
74 /* Pretend that each entry is of this size in directory's i_size */
75 #define BOGO_DIRENT_SIZE 20
77 /* Symlink up to this size is kmalloc'ed instead of using a swappable page */
78 #define SHORT_SYMLINK_LEN 128
81 struct list_head list
; /* anchored by shmem_inode_info->xattr_list */
82 char *name
; /* xattr name */
87 /* Flag allocation requirements to shmem_getpage */
89 SGP_READ
, /* don't exceed i_size, don't allocate page */
90 SGP_CACHE
, /* don't exceed i_size, may allocate page */
91 SGP_DIRTY
, /* like SGP_CACHE, but set new page dirty */
92 SGP_WRITE
, /* may exceed i_size, may allocate page */
96 static unsigned long shmem_default_max_blocks(void)
98 return totalram_pages
/ 2;
101 static unsigned long shmem_default_max_inodes(void)
103 return min(totalram_pages
- totalhigh_pages
, totalram_pages
/ 2);
107 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
);
108 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
109 struct shmem_inode_info
*info
, pgoff_t index
);
110 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
111 struct page
**pagep
, enum sgp_type sgp
, gfp_t gfp
, int *fault_type
);
113 static inline int shmem_getpage(struct inode
*inode
, pgoff_t index
,
114 struct page
**pagep
, enum sgp_type sgp
, int *fault_type
)
116 return shmem_getpage_gfp(inode
, index
, pagep
, sgp
,
117 mapping_gfp_mask(inode
->i_mapping
), fault_type
);
120 static inline struct shmem_sb_info
*SHMEM_SB(struct super_block
*sb
)
122 return sb
->s_fs_info
;
126 * shmem_file_setup pre-accounts the whole fixed size of a VM object,
127 * for shared memory and for shared anonymous (/dev/zero) mappings
128 * (unless MAP_NORESERVE and sysctl_overcommit_memory <= 1),
129 * consistent with the pre-accounting of private mappings ...
131 static inline int shmem_acct_size(unsigned long flags
, loff_t size
)
133 return (flags
& VM_NORESERVE
) ?
134 0 : security_vm_enough_memory_mm(current
->mm
, VM_ACCT(size
));
137 static inline void shmem_unacct_size(unsigned long flags
, loff_t size
)
139 if (!(flags
& VM_NORESERVE
))
140 vm_unacct_memory(VM_ACCT(size
));
144 * ... whereas tmpfs objects are accounted incrementally as
145 * pages are allocated, in order to allow huge sparse files.
146 * shmem_getpage reports shmem_acct_block failure as -ENOSPC not -ENOMEM,
147 * so that a failure on a sparse tmpfs mapping will give SIGBUS not OOM.
149 static inline int shmem_acct_block(unsigned long flags
)
151 return (flags
& VM_NORESERVE
) ?
152 security_vm_enough_memory_mm(current
->mm
, VM_ACCT(PAGE_CACHE_SIZE
)) : 0;
155 static inline void shmem_unacct_blocks(unsigned long flags
, long pages
)
157 if (flags
& VM_NORESERVE
)
158 vm_unacct_memory(pages
* VM_ACCT(PAGE_CACHE_SIZE
));
161 static const struct super_operations shmem_ops
;
162 static const struct address_space_operations shmem_aops
;
163 static const struct file_operations shmem_file_operations
;
164 static const struct inode_operations shmem_inode_operations
;
165 static const struct inode_operations shmem_dir_inode_operations
;
166 static const struct inode_operations shmem_special_inode_operations
;
167 static const struct vm_operations_struct shmem_vm_ops
;
169 static struct backing_dev_info shmem_backing_dev_info __read_mostly
= {
170 .ra_pages
= 0, /* No readahead */
171 .capabilities
= BDI_CAP_NO_ACCT_AND_WRITEBACK
| BDI_CAP_SWAP_BACKED
,
174 static LIST_HEAD(shmem_swaplist
);
175 static DEFINE_MUTEX(shmem_swaplist_mutex
);
177 static int shmem_reserve_inode(struct super_block
*sb
)
179 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
180 if (sbinfo
->max_inodes
) {
181 spin_lock(&sbinfo
->stat_lock
);
182 if (!sbinfo
->free_inodes
) {
183 spin_unlock(&sbinfo
->stat_lock
);
186 sbinfo
->free_inodes
--;
187 spin_unlock(&sbinfo
->stat_lock
);
192 static void shmem_free_inode(struct super_block
*sb
)
194 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
195 if (sbinfo
->max_inodes
) {
196 spin_lock(&sbinfo
->stat_lock
);
197 sbinfo
->free_inodes
++;
198 spin_unlock(&sbinfo
->stat_lock
);
203 * shmem_recalc_inode - recalculate the block usage of an inode
204 * @inode: inode to recalc
206 * We have to calculate the free blocks since the mm can drop
207 * undirtied hole pages behind our back.
209 * But normally info->alloced == inode->i_mapping->nrpages + info->swapped
210 * So mm freed is info->alloced - (inode->i_mapping->nrpages + info->swapped)
212 * It has to be called with the spinlock held.
214 static void shmem_recalc_inode(struct inode
*inode
)
216 struct shmem_inode_info
*info
= SHMEM_I(inode
);
219 freed
= info
->alloced
- info
->swapped
- inode
->i_mapping
->nrpages
;
221 struct shmem_sb_info
*sbinfo
= SHMEM_SB(inode
->i_sb
);
222 if (sbinfo
->max_blocks
)
223 percpu_counter_add(&sbinfo
->used_blocks
, -freed
);
224 info
->alloced
-= freed
;
225 inode
->i_blocks
-= freed
* BLOCKS_PER_PAGE
;
226 shmem_unacct_blocks(info
->flags
, freed
);
231 * Replace item expected in radix tree by a new item, while holding tree lock.
233 static int shmem_radix_tree_replace(struct address_space
*mapping
,
234 pgoff_t index
, void *expected
, void *replacement
)
239 VM_BUG_ON(!expected
);
240 pslot
= radix_tree_lookup_slot(&mapping
->page_tree
, index
);
242 item
= radix_tree_deref_slot_protected(pslot
,
243 &mapping
->tree_lock
);
244 if (item
!= expected
)
247 radix_tree_replace_slot(pslot
, replacement
);
249 radix_tree_delete(&mapping
->page_tree
, index
);
254 * Like add_to_page_cache_locked, but error if expected item has gone.
256 static int shmem_add_to_page_cache(struct page
*page
,
257 struct address_space
*mapping
,
258 pgoff_t index
, gfp_t gfp
, void *expected
)
262 VM_BUG_ON(!PageLocked(page
));
263 VM_BUG_ON(!PageSwapBacked(page
));
266 error
= radix_tree_preload(gfp
& GFP_RECLAIM_MASK
);
268 page_cache_get(page
);
269 page
->mapping
= mapping
;
272 spin_lock_irq(&mapping
->tree_lock
);
274 error
= radix_tree_insert(&mapping
->page_tree
,
277 error
= shmem_radix_tree_replace(mapping
, index
,
281 __inc_zone_page_state(page
, NR_FILE_PAGES
);
282 __inc_zone_page_state(page
, NR_SHMEM
);
283 spin_unlock_irq(&mapping
->tree_lock
);
285 page
->mapping
= NULL
;
286 spin_unlock_irq(&mapping
->tree_lock
);
287 page_cache_release(page
);
290 radix_tree_preload_end();
293 mem_cgroup_uncharge_cache_page(page
);
298 * Like delete_from_page_cache, but substitutes swap for page.
300 static void shmem_delete_from_page_cache(struct page
*page
, void *radswap
)
302 struct address_space
*mapping
= page
->mapping
;
305 spin_lock_irq(&mapping
->tree_lock
);
306 error
= shmem_radix_tree_replace(mapping
, page
->index
, page
, radswap
);
307 page
->mapping
= NULL
;
309 __dec_zone_page_state(page
, NR_FILE_PAGES
);
310 __dec_zone_page_state(page
, NR_SHMEM
);
311 spin_unlock_irq(&mapping
->tree_lock
);
312 page_cache_release(page
);
317 * Like find_get_pages, but collecting swap entries as well as pages.
319 static unsigned shmem_find_get_pages_and_swap(struct address_space
*mapping
,
320 pgoff_t start
, unsigned int nr_pages
,
321 struct page
**pages
, pgoff_t
*indices
)
325 unsigned int nr_found
;
329 nr_found
= radix_tree_gang_lookup_slot(&mapping
->page_tree
,
330 (void ***)pages
, indices
, start
, nr_pages
);
332 for (i
= 0; i
< nr_found
; i
++) {
335 page
= radix_tree_deref_slot((void **)pages
[i
]);
338 if (radix_tree_exception(page
)) {
339 if (radix_tree_deref_retry(page
))
342 * Otherwise, we must be storing a swap entry
343 * here as an exceptional entry: so return it
344 * without attempting to raise page count.
348 if (!page_cache_get_speculative(page
))
351 /* Has the page moved? */
352 if (unlikely(page
!= *((void **)pages
[i
]))) {
353 page_cache_release(page
);
357 indices
[ret
] = indices
[i
];
361 if (unlikely(!ret
&& nr_found
))
368 * Remove swap entry from radix tree, free the swap and its page cache.
370 static int shmem_free_swap(struct address_space
*mapping
,
371 pgoff_t index
, void *radswap
)
375 spin_lock_irq(&mapping
->tree_lock
);
376 error
= shmem_radix_tree_replace(mapping
, index
, radswap
, NULL
);
377 spin_unlock_irq(&mapping
->tree_lock
);
379 free_swap_and_cache(radix_to_swp_entry(radswap
));
384 * Pagevec may contain swap entries, so shuffle up pages before releasing.
386 static void shmem_deswap_pagevec(struct pagevec
*pvec
)
390 for (i
= 0, j
= 0; i
< pagevec_count(pvec
); i
++) {
391 struct page
*page
= pvec
->pages
[i
];
392 if (!radix_tree_exceptional_entry(page
))
393 pvec
->pages
[j
++] = page
;
399 * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists.
401 void shmem_unlock_mapping(struct address_space
*mapping
)
404 pgoff_t indices
[PAGEVEC_SIZE
];
407 pagevec_init(&pvec
, 0);
409 * Minor point, but we might as well stop if someone else SHM_LOCKs it.
411 while (!mapping_unevictable(mapping
)) {
413 * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it
414 * has finished, if it hits a row of PAGEVEC_SIZE swap entries.
416 pvec
.nr
= shmem_find_get_pages_and_swap(mapping
, index
,
417 PAGEVEC_SIZE
, pvec
.pages
, indices
);
420 index
= indices
[pvec
.nr
- 1] + 1;
421 shmem_deswap_pagevec(&pvec
);
422 check_move_unevictable_pages(pvec
.pages
, pvec
.nr
);
423 pagevec_release(&pvec
);
429 * Remove range of pages and swap entries from radix tree, and free them.
431 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
433 struct address_space
*mapping
= inode
->i_mapping
;
434 struct shmem_inode_info
*info
= SHMEM_I(inode
);
435 pgoff_t start
= (lstart
+ PAGE_CACHE_SIZE
- 1) >> PAGE_CACHE_SHIFT
;
436 pgoff_t end
= (lend
+ 1) >> PAGE_CACHE_SHIFT
;
437 unsigned int partial_start
= lstart
& (PAGE_CACHE_SIZE
- 1);
438 unsigned int partial_end
= (lend
+ 1) & (PAGE_CACHE_SIZE
- 1);
440 pgoff_t indices
[PAGEVEC_SIZE
];
441 long nr_swaps_freed
= 0;
446 end
= -1; /* unsigned, so actually very big */
448 pagevec_init(&pvec
, 0);
450 while (index
< end
) {
451 pvec
.nr
= shmem_find_get_pages_and_swap(mapping
, index
,
452 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
),
453 pvec
.pages
, indices
);
456 mem_cgroup_uncharge_start();
457 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
458 struct page
*page
= pvec
.pages
[i
];
464 if (radix_tree_exceptional_entry(page
)) {
465 nr_swaps_freed
+= !shmem_free_swap(mapping
,
470 if (!trylock_page(page
))
472 if (page
->mapping
== mapping
) {
473 VM_BUG_ON(PageWriteback(page
));
474 truncate_inode_page(mapping
, page
);
478 shmem_deswap_pagevec(&pvec
);
479 pagevec_release(&pvec
);
480 mem_cgroup_uncharge_end();
486 struct page
*page
= NULL
;
487 shmem_getpage(inode
, start
- 1, &page
, SGP_READ
, NULL
);
489 unsigned int top
= PAGE_CACHE_SIZE
;
494 zero_user_segment(page
, partial_start
, top
);
495 set_page_dirty(page
);
497 page_cache_release(page
);
501 struct page
*page
= NULL
;
502 shmem_getpage(inode
, end
, &page
, SGP_READ
, NULL
);
504 zero_user_segment(page
, 0, partial_end
);
505 set_page_dirty(page
);
507 page_cache_release(page
);
516 pvec
.nr
= shmem_find_get_pages_and_swap(mapping
, index
,
517 min(end
- index
, (pgoff_t
)PAGEVEC_SIZE
),
518 pvec
.pages
, indices
);
525 if (index
== start
&& indices
[0] >= end
) {
526 shmem_deswap_pagevec(&pvec
);
527 pagevec_release(&pvec
);
530 mem_cgroup_uncharge_start();
531 for (i
= 0; i
< pagevec_count(&pvec
); i
++) {
532 struct page
*page
= pvec
.pages
[i
];
538 if (radix_tree_exceptional_entry(page
)) {
539 nr_swaps_freed
+= !shmem_free_swap(mapping
,
545 if (page
->mapping
== mapping
) {
546 VM_BUG_ON(PageWriteback(page
));
547 truncate_inode_page(mapping
, page
);
551 shmem_deswap_pagevec(&pvec
);
552 pagevec_release(&pvec
);
553 mem_cgroup_uncharge_end();
557 spin_lock(&info
->lock
);
558 info
->swapped
-= nr_swaps_freed
;
559 shmem_recalc_inode(inode
);
560 spin_unlock(&info
->lock
);
562 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
564 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
566 static int shmem_setattr(struct dentry
*dentry
, struct iattr
*attr
)
568 struct inode
*inode
= dentry
->d_inode
;
571 error
= inode_change_ok(inode
, attr
);
575 if (S_ISREG(inode
->i_mode
) && (attr
->ia_valid
& ATTR_SIZE
)) {
576 loff_t oldsize
= inode
->i_size
;
577 loff_t newsize
= attr
->ia_size
;
579 if (newsize
!= oldsize
) {
580 i_size_write(inode
, newsize
);
581 inode
->i_ctime
= inode
->i_mtime
= CURRENT_TIME
;
583 if (newsize
< oldsize
) {
584 loff_t holebegin
= round_up(newsize
, PAGE_SIZE
);
585 unmap_mapping_range(inode
->i_mapping
, holebegin
, 0, 1);
586 shmem_truncate_range(inode
, newsize
, (loff_t
)-1);
587 /* unmap again to remove racily COWed private pages */
588 unmap_mapping_range(inode
->i_mapping
, holebegin
, 0, 1);
592 setattr_copy(inode
, attr
);
593 #ifdef CONFIG_TMPFS_POSIX_ACL
594 if (attr
->ia_valid
& ATTR_MODE
)
595 error
= generic_acl_chmod(inode
);
600 static void shmem_evict_inode(struct inode
*inode
)
602 struct shmem_inode_info
*info
= SHMEM_I(inode
);
603 struct shmem_xattr
*xattr
, *nxattr
;
605 if (inode
->i_mapping
->a_ops
== &shmem_aops
) {
606 shmem_unacct_size(info
->flags
, inode
->i_size
);
608 shmem_truncate_range(inode
, 0, (loff_t
)-1);
609 if (!list_empty(&info
->swaplist
)) {
610 mutex_lock(&shmem_swaplist_mutex
);
611 list_del_init(&info
->swaplist
);
612 mutex_unlock(&shmem_swaplist_mutex
);
615 kfree(info
->symlink
);
617 list_for_each_entry_safe(xattr
, nxattr
, &info
->xattr_list
, list
) {
621 BUG_ON(inode
->i_blocks
);
622 shmem_free_inode(inode
->i_sb
);
627 * If swap found in inode, free it and move page from swapcache to filecache.
629 static int shmem_unuse_inode(struct shmem_inode_info
*info
,
630 swp_entry_t swap
, struct page
**pagep
)
632 struct address_space
*mapping
= info
->vfs_inode
.i_mapping
;
638 radswap
= swp_to_radix_entry(swap
);
639 index
= radix_tree_locate_item(&mapping
->page_tree
, radswap
);
644 * Move _head_ to start search for next from here.
645 * But be careful: shmem_evict_inode checks list_empty without taking
646 * mutex, and there's an instant in list_move_tail when info->swaplist
647 * would appear empty, if it were the only one on shmem_swaplist.
649 if (shmem_swaplist
.next
!= &info
->swaplist
)
650 list_move_tail(&shmem_swaplist
, &info
->swaplist
);
652 gfp
= mapping_gfp_mask(mapping
);
653 if (shmem_should_replace_page(*pagep
, gfp
)) {
654 mutex_unlock(&shmem_swaplist_mutex
);
655 error
= shmem_replace_page(pagep
, gfp
, info
, index
);
656 mutex_lock(&shmem_swaplist_mutex
);
658 * We needed to drop mutex to make that restrictive page
659 * allocation; but the inode might already be freed by now,
660 * and we cannot refer to inode or mapping or info to check.
661 * However, we do hold page lock on the PageSwapCache page,
662 * so can check if that still has our reference remaining.
664 if (!page_swapcount(*pagep
))
669 * We rely on shmem_swaplist_mutex, not only to protect the swaplist,
670 * but also to hold up shmem_evict_inode(): so inode cannot be freed
671 * beneath us (pagelock doesn't help until the page is in pagecache).
674 error
= shmem_add_to_page_cache(*pagep
, mapping
, index
,
675 GFP_NOWAIT
, radswap
);
676 if (error
!= -ENOMEM
) {
678 * Truncation and eviction use free_swap_and_cache(), which
679 * only does trylock page: if we raced, best clean up here.
681 delete_from_swap_cache(*pagep
);
682 set_page_dirty(*pagep
);
684 spin_lock(&info
->lock
);
686 spin_unlock(&info
->lock
);
689 error
= 1; /* not an error, but entry was found */
695 * Search through swapped inodes to find and replace swap by page.
697 int shmem_unuse(swp_entry_t swap
, struct page
*page
)
699 struct list_head
*this, *next
;
700 struct shmem_inode_info
*info
;
705 * There's a faint possibility that swap page was replaced before
706 * caller locked it: it will come back later with the right page.
708 if (unlikely(!PageSwapCache(page
)))
712 * Charge page using GFP_KERNEL while we can wait, before taking
713 * the shmem_swaplist_mutex which might hold up shmem_writepage().
714 * Charged back to the user (not to caller) when swap account is used.
716 error
= mem_cgroup_cache_charge(page
, current
->mm
, GFP_KERNEL
);
719 /* No radix_tree_preload: swap entry keeps a place for page in tree */
721 mutex_lock(&shmem_swaplist_mutex
);
722 list_for_each_safe(this, next
, &shmem_swaplist
) {
723 info
= list_entry(this, struct shmem_inode_info
, swaplist
);
725 found
= shmem_unuse_inode(info
, swap
, &page
);
727 list_del_init(&info
->swaplist
);
732 mutex_unlock(&shmem_swaplist_mutex
);
738 page_cache_release(page
);
743 * Move the page from the page cache to the swap cache.
745 static int shmem_writepage(struct page
*page
, struct writeback_control
*wbc
)
747 struct shmem_inode_info
*info
;
748 struct address_space
*mapping
;
753 BUG_ON(!PageLocked(page
));
754 mapping
= page
->mapping
;
756 inode
= mapping
->host
;
757 info
= SHMEM_I(inode
);
758 if (info
->flags
& VM_LOCKED
)
760 if (!total_swap_pages
)
764 * shmem_backing_dev_info's capabilities prevent regular writeback or
765 * sync from ever calling shmem_writepage; but a stacking filesystem
766 * might use ->writepage of its underlying filesystem, in which case
767 * tmpfs should write out to swap only in response to memory pressure,
768 * and not for the writeback threads or sync.
770 if (!wbc
->for_reclaim
) {
771 WARN_ON_ONCE(1); /* Still happens? Tell us about it! */
774 swap
= get_swap_page();
779 * Add inode to shmem_unuse()'s list of swapped-out inodes,
780 * if it's not already there. Do it now before the page is
781 * moved to swap cache, when its pagelock no longer protects
782 * the inode from eviction. But don't unlock the mutex until
783 * we've incremented swapped, because shmem_unuse_inode() will
784 * prune a !swapped inode from the swaplist under this mutex.
786 mutex_lock(&shmem_swaplist_mutex
);
787 if (list_empty(&info
->swaplist
))
788 list_add_tail(&info
->swaplist
, &shmem_swaplist
);
790 if (add_to_swap_cache(page
, swap
, GFP_ATOMIC
) == 0) {
791 swap_shmem_alloc(swap
);
792 shmem_delete_from_page_cache(page
, swp_to_radix_entry(swap
));
794 spin_lock(&info
->lock
);
796 shmem_recalc_inode(inode
);
797 spin_unlock(&info
->lock
);
799 mutex_unlock(&shmem_swaplist_mutex
);
800 BUG_ON(page_mapped(page
));
801 swap_writepage(page
, wbc
);
805 mutex_unlock(&shmem_swaplist_mutex
);
806 swapcache_free(swap
, NULL
);
808 set_page_dirty(page
);
809 if (wbc
->for_reclaim
)
810 return AOP_WRITEPAGE_ACTIVATE
; /* Return with page locked */
817 static void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
821 if (!mpol
|| mpol
->mode
== MPOL_DEFAULT
)
822 return; /* show nothing */
824 mpol_to_str(buffer
, sizeof(buffer
), mpol
, 1);
826 seq_printf(seq
, ",mpol=%s", buffer
);
829 static struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
831 struct mempolicy
*mpol
= NULL
;
833 spin_lock(&sbinfo
->stat_lock
); /* prevent replace/use races */
836 spin_unlock(&sbinfo
->stat_lock
);
840 #endif /* CONFIG_TMPFS */
842 static struct page
*shmem_swapin(swp_entry_t swap
, gfp_t gfp
,
843 struct shmem_inode_info
*info
, pgoff_t index
)
845 struct mempolicy mpol
, *spol
;
846 struct vm_area_struct pvma
;
848 spol
= mpol_cond_copy(&mpol
,
849 mpol_shared_policy_lookup(&info
->policy
, index
));
851 /* Create a pseudo vma that just contains the policy */
853 pvma
.vm_pgoff
= index
;
855 pvma
.vm_policy
= spol
;
856 return swapin_readahead(swap
, gfp
, &pvma
, 0);
859 static struct page
*shmem_alloc_page(gfp_t gfp
,
860 struct shmem_inode_info
*info
, pgoff_t index
)
862 struct vm_area_struct pvma
;
864 /* Create a pseudo vma that just contains the policy */
866 pvma
.vm_pgoff
= index
;
868 pvma
.vm_policy
= mpol_shared_policy_lookup(&info
->policy
, index
);
871 * alloc_page_vma() will drop the shared policy reference
873 return alloc_page_vma(gfp
, &pvma
, 0);
875 #else /* !CONFIG_NUMA */
877 static inline void shmem_show_mpol(struct seq_file
*seq
, struct mempolicy
*mpol
)
880 #endif /* CONFIG_TMPFS */
882 static inline struct page
*shmem_swapin(swp_entry_t swap
, gfp_t gfp
,
883 struct shmem_inode_info
*info
, pgoff_t index
)
885 return swapin_readahead(swap
, gfp
, NULL
, 0);
888 static inline struct page
*shmem_alloc_page(gfp_t gfp
,
889 struct shmem_inode_info
*info
, pgoff_t index
)
891 return alloc_page(gfp
);
893 #endif /* CONFIG_NUMA */
895 #if !defined(CONFIG_NUMA) || !defined(CONFIG_TMPFS)
896 static inline struct mempolicy
*shmem_get_sbmpol(struct shmem_sb_info
*sbinfo
)
903 * When a page is moved from swapcache to shmem filecache (either by the
904 * usual swapin of shmem_getpage_gfp(), or by the less common swapoff of
905 * shmem_unuse_inode()), it may have been read in earlier from swap, in
906 * ignorance of the mapping it belongs to. If that mapping has special
907 * constraints (like the gma500 GEM driver, which requires RAM below 4GB),
908 * we may need to copy to a suitable page before moving to filecache.
910 * In a future release, this may well be extended to respect cpuset and
911 * NUMA mempolicy, and applied also to anonymous pages in do_swap_page();
912 * but for now it is a simple matter of zone.
914 static bool shmem_should_replace_page(struct page
*page
, gfp_t gfp
)
916 return page_zonenum(page
) > gfp_zone(gfp
);
919 static int shmem_replace_page(struct page
**pagep
, gfp_t gfp
,
920 struct shmem_inode_info
*info
, pgoff_t index
)
922 struct page
*oldpage
, *newpage
;
923 struct address_space
*swap_mapping
;
928 swap_index
= page_private(oldpage
);
929 swap_mapping
= page_mapping(oldpage
);
932 * We have arrived here because our zones are constrained, so don't
933 * limit chance of success by further cpuset and node constraints.
935 gfp
&= ~GFP_CONSTRAINT_MASK
;
936 newpage
= shmem_alloc_page(gfp
, info
, index
);
939 VM_BUG_ON(shmem_should_replace_page(newpage
, gfp
));
942 page_cache_get(newpage
);
943 copy_highpage(newpage
, oldpage
);
945 VM_BUG_ON(!PageLocked(oldpage
));
946 __set_page_locked(newpage
);
947 VM_BUG_ON(!PageUptodate(oldpage
));
948 SetPageUptodate(newpage
);
949 VM_BUG_ON(!PageSwapBacked(oldpage
));
950 SetPageSwapBacked(newpage
);
951 VM_BUG_ON(!swap_index
);
952 set_page_private(newpage
, swap_index
);
953 VM_BUG_ON(!PageSwapCache(oldpage
));
954 SetPageSwapCache(newpage
);
957 * Our caller will very soon move newpage out of swapcache, but it's
958 * a nice clean interface for us to replace oldpage by newpage there.
960 spin_lock_irq(&swap_mapping
->tree_lock
);
961 error
= shmem_radix_tree_replace(swap_mapping
, swap_index
, oldpage
,
963 __inc_zone_page_state(newpage
, NR_FILE_PAGES
);
964 __dec_zone_page_state(oldpage
, NR_FILE_PAGES
);
965 spin_unlock_irq(&swap_mapping
->tree_lock
);
968 mem_cgroup_replace_page_cache(oldpage
, newpage
);
969 lru_cache_add_anon(newpage
);
971 ClearPageSwapCache(oldpage
);
972 set_page_private(oldpage
, 0);
974 unlock_page(oldpage
);
975 page_cache_release(oldpage
);
976 page_cache_release(oldpage
);
981 * shmem_getpage_gfp - find page in cache, or get from swap, or allocate
983 * If we allocate a new one we do not mark it dirty. That's up to the
984 * vm. If we swap it in we mark it dirty since we also free the swap
985 * entry since a page cannot live in both the swap and page cache
987 static int shmem_getpage_gfp(struct inode
*inode
, pgoff_t index
,
988 struct page
**pagep
, enum sgp_type sgp
, gfp_t gfp
, int *fault_type
)
990 struct address_space
*mapping
= inode
->i_mapping
;
991 struct shmem_inode_info
*info
;
992 struct shmem_sb_info
*sbinfo
;
998 if (index
> (MAX_LFS_FILESIZE
>> PAGE_CACHE_SHIFT
))
1002 page
= find_lock_page(mapping
, index
);
1003 if (radix_tree_exceptional_entry(page
)) {
1004 swap
= radix_to_swp_entry(page
);
1008 if (sgp
!= SGP_WRITE
&&
1009 ((loff_t
)index
<< PAGE_CACHE_SHIFT
) >= i_size_read(inode
)) {
1014 if (page
|| (sgp
== SGP_READ
&& !swap
.val
)) {
1016 * Once we can get the page lock, it must be uptodate:
1017 * if there were an error in reading back from swap,
1018 * the page would not be inserted into the filecache.
1020 BUG_ON(page
&& !PageUptodate(page
));
1026 * Fast cache lookup did not find it:
1027 * bring it back from swap or allocate.
1029 info
= SHMEM_I(inode
);
1030 sbinfo
= SHMEM_SB(inode
->i_sb
);
1033 /* Look it up and read it in.. */
1034 page
= lookup_swap_cache(swap
);
1036 /* here we actually do the io */
1038 *fault_type
|= VM_FAULT_MAJOR
;
1039 page
= shmem_swapin(swap
, gfp
, info
, index
);
1046 /* We have to do this with page locked to prevent races */
1048 if (!PageSwapCache(page
) || page
->mapping
) {
1049 error
= -EEXIST
; /* try again */
1052 if (!PageUptodate(page
)) {
1056 wait_on_page_writeback(page
);
1058 if (shmem_should_replace_page(page
, gfp
)) {
1059 error
= shmem_replace_page(&page
, gfp
, info
, index
);
1064 error
= mem_cgroup_cache_charge(page
, current
->mm
,
1065 gfp
& GFP_RECLAIM_MASK
);
1067 error
= shmem_add_to_page_cache(page
, mapping
, index
,
1068 gfp
, swp_to_radix_entry(swap
));
1072 spin_lock(&info
->lock
);
1074 shmem_recalc_inode(inode
);
1075 spin_unlock(&info
->lock
);
1077 delete_from_swap_cache(page
);
1078 set_page_dirty(page
);
1082 if (shmem_acct_block(info
->flags
)) {
1086 if (sbinfo
->max_blocks
) {
1087 if (percpu_counter_compare(&sbinfo
->used_blocks
,
1088 sbinfo
->max_blocks
) >= 0) {
1092 percpu_counter_inc(&sbinfo
->used_blocks
);
1095 page
= shmem_alloc_page(gfp
, info
, index
);
1101 SetPageSwapBacked(page
);
1102 __set_page_locked(page
);
1103 error
= mem_cgroup_cache_charge(page
, current
->mm
,
1104 gfp
& GFP_RECLAIM_MASK
);
1106 error
= shmem_add_to_page_cache(page
, mapping
, index
,
1110 lru_cache_add_anon(page
);
1112 spin_lock(&info
->lock
);
1114 inode
->i_blocks
+= BLOCKS_PER_PAGE
;
1115 shmem_recalc_inode(inode
);
1116 spin_unlock(&info
->lock
);
1119 * Let SGP_WRITE caller clear ends if write does not fill page
1121 if (sgp
!= SGP_WRITE
) {
1122 clear_highpage(page
);
1123 flush_dcache_page(page
);
1124 SetPageUptodate(page
);
1126 if (sgp
== SGP_DIRTY
)
1127 set_page_dirty(page
);
1130 /* Perhaps the file has been truncated since we checked */
1131 if (sgp
!= SGP_WRITE
&&
1132 ((loff_t
)index
<< PAGE_CACHE_SHIFT
) >= i_size_read(inode
)) {
1143 ClearPageDirty(page
);
1144 delete_from_page_cache(page
);
1145 spin_lock(&info
->lock
);
1147 inode
->i_blocks
-= BLOCKS_PER_PAGE
;
1148 spin_unlock(&info
->lock
);
1150 if (sbinfo
->max_blocks
)
1151 percpu_counter_add(&sbinfo
->used_blocks
, -1);
1153 shmem_unacct_blocks(info
->flags
, 1);
1155 if (swap
.val
&& error
!= -EINVAL
) {
1156 struct page
*test
= find_get_page(mapping
, index
);
1157 if (test
&& !radix_tree_exceptional_entry(test
))
1158 page_cache_release(test
);
1159 /* Have another try if the entry has changed */
1160 if (test
!= swp_to_radix_entry(swap
))
1165 page_cache_release(page
);
1167 if (error
== -ENOSPC
&& !once
++) {
1168 info
= SHMEM_I(inode
);
1169 spin_lock(&info
->lock
);
1170 shmem_recalc_inode(inode
);
1171 spin_unlock(&info
->lock
);
1174 if (error
== -EEXIST
)
1179 static int shmem_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1181 struct inode
*inode
= vma
->vm_file
->f_path
.dentry
->d_inode
;
1183 int ret
= VM_FAULT_LOCKED
;
1185 error
= shmem_getpage(inode
, vmf
->pgoff
, &vmf
->page
, SGP_CACHE
, &ret
);
1187 return ((error
== -ENOMEM
) ? VM_FAULT_OOM
: VM_FAULT_SIGBUS
);
1189 if (ret
& VM_FAULT_MAJOR
) {
1190 count_vm_event(PGMAJFAULT
);
1191 mem_cgroup_count_vm_event(vma
->vm_mm
, PGMAJFAULT
);
1197 static int shmem_set_policy(struct vm_area_struct
*vma
, struct mempolicy
*mpol
)
1199 struct inode
*inode
= vma
->vm_file
->f_path
.dentry
->d_inode
;
1200 return mpol_set_shared_policy(&SHMEM_I(inode
)->policy
, vma
, mpol
);
1203 static struct mempolicy
*shmem_get_policy(struct vm_area_struct
*vma
,
1206 struct inode
*inode
= vma
->vm_file
->f_path
.dentry
->d_inode
;
1209 index
= ((addr
- vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
1210 return mpol_shared_policy_lookup(&SHMEM_I(inode
)->policy
, index
);
1214 int shmem_lock(struct file
*file
, int lock
, struct user_struct
*user
)
1216 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1217 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1218 int retval
= -ENOMEM
;
1220 spin_lock(&info
->lock
);
1221 if (lock
&& !(info
->flags
& VM_LOCKED
)) {
1222 if (!user_shm_lock(inode
->i_size
, user
))
1224 info
->flags
|= VM_LOCKED
;
1225 mapping_set_unevictable(file
->f_mapping
);
1227 if (!lock
&& (info
->flags
& VM_LOCKED
) && user
) {
1228 user_shm_unlock(inode
->i_size
, user
);
1229 info
->flags
&= ~VM_LOCKED
;
1230 mapping_clear_unevictable(file
->f_mapping
);
1235 spin_unlock(&info
->lock
);
1239 static int shmem_mmap(struct file
*file
, struct vm_area_struct
*vma
)
1241 file_accessed(file
);
1242 vma
->vm_ops
= &shmem_vm_ops
;
1243 vma
->vm_flags
|= VM_CAN_NONLINEAR
;
1247 static struct inode
*shmem_get_inode(struct super_block
*sb
, const struct inode
*dir
,
1248 umode_t mode
, dev_t dev
, unsigned long flags
)
1250 struct inode
*inode
;
1251 struct shmem_inode_info
*info
;
1252 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
1254 if (shmem_reserve_inode(sb
))
1257 inode
= new_inode(sb
);
1259 inode
->i_ino
= get_next_ino();
1260 inode_init_owner(inode
, dir
, mode
);
1261 inode
->i_blocks
= 0;
1262 inode
->i_mapping
->backing_dev_info
= &shmem_backing_dev_info
;
1263 inode
->i_atime
= inode
->i_mtime
= inode
->i_ctime
= CURRENT_TIME
;
1264 inode
->i_generation
= get_seconds();
1265 info
= SHMEM_I(inode
);
1266 memset(info
, 0, (char *)inode
- (char *)info
);
1267 spin_lock_init(&info
->lock
);
1268 info
->flags
= flags
& VM_NORESERVE
;
1269 INIT_LIST_HEAD(&info
->swaplist
);
1270 INIT_LIST_HEAD(&info
->xattr_list
);
1271 cache_no_acl(inode
);
1273 switch (mode
& S_IFMT
) {
1275 inode
->i_op
= &shmem_special_inode_operations
;
1276 init_special_inode(inode
, mode
, dev
);
1279 inode
->i_mapping
->a_ops
= &shmem_aops
;
1280 inode
->i_op
= &shmem_inode_operations
;
1281 inode
->i_fop
= &shmem_file_operations
;
1282 mpol_shared_policy_init(&info
->policy
,
1283 shmem_get_sbmpol(sbinfo
));
1287 /* Some things misbehave if size == 0 on a directory */
1288 inode
->i_size
= 2 * BOGO_DIRENT_SIZE
;
1289 inode
->i_op
= &shmem_dir_inode_operations
;
1290 inode
->i_fop
= &simple_dir_operations
;
1294 * Must not load anything in the rbtree,
1295 * mpol_free_shared_policy will not be called.
1297 mpol_shared_policy_init(&info
->policy
, NULL
);
1301 shmem_free_inode(sb
);
1306 static const struct inode_operations shmem_symlink_inode_operations
;
1307 static const struct inode_operations shmem_short_symlink_operations
;
1309 #ifdef CONFIG_TMPFS_XATTR
1310 static int shmem_initxattrs(struct inode
*, const struct xattr
*, void *);
1312 #define shmem_initxattrs NULL
1316 shmem_write_begin(struct file
*file
, struct address_space
*mapping
,
1317 loff_t pos
, unsigned len
, unsigned flags
,
1318 struct page
**pagep
, void **fsdata
)
1320 struct inode
*inode
= mapping
->host
;
1321 pgoff_t index
= pos
>> PAGE_CACHE_SHIFT
;
1322 return shmem_getpage(inode
, index
, pagep
, SGP_WRITE
, NULL
);
1326 shmem_write_end(struct file
*file
, struct address_space
*mapping
,
1327 loff_t pos
, unsigned len
, unsigned copied
,
1328 struct page
*page
, void *fsdata
)
1330 struct inode
*inode
= mapping
->host
;
1332 if (pos
+ copied
> inode
->i_size
)
1333 i_size_write(inode
, pos
+ copied
);
1335 if (!PageUptodate(page
)) {
1336 if (copied
< PAGE_CACHE_SIZE
) {
1337 unsigned from
= pos
& (PAGE_CACHE_SIZE
- 1);
1338 zero_user_segments(page
, 0, from
,
1339 from
+ copied
, PAGE_CACHE_SIZE
);
1341 SetPageUptodate(page
);
1343 set_page_dirty(page
);
1345 page_cache_release(page
);
1350 static void do_shmem_file_read(struct file
*filp
, loff_t
*ppos
, read_descriptor_t
*desc
, read_actor_t actor
)
1352 struct inode
*inode
= filp
->f_path
.dentry
->d_inode
;
1353 struct address_space
*mapping
= inode
->i_mapping
;
1355 unsigned long offset
;
1356 enum sgp_type sgp
= SGP_READ
;
1359 * Might this read be for a stacking filesystem? Then when reading
1360 * holes of a sparse file, we actually need to allocate those pages,
1361 * and even mark them dirty, so it cannot exceed the max_blocks limit.
1363 if (segment_eq(get_fs(), KERNEL_DS
))
1366 index
= *ppos
>> PAGE_CACHE_SHIFT
;
1367 offset
= *ppos
& ~PAGE_CACHE_MASK
;
1370 struct page
*page
= NULL
;
1372 unsigned long nr
, ret
;
1373 loff_t i_size
= i_size_read(inode
);
1375 end_index
= i_size
>> PAGE_CACHE_SHIFT
;
1376 if (index
> end_index
)
1378 if (index
== end_index
) {
1379 nr
= i_size
& ~PAGE_CACHE_MASK
;
1384 desc
->error
= shmem_getpage(inode
, index
, &page
, sgp
, NULL
);
1386 if (desc
->error
== -EINVAL
)
1394 * We must evaluate after, since reads (unlike writes)
1395 * are called without i_mutex protection against truncate
1397 nr
= PAGE_CACHE_SIZE
;
1398 i_size
= i_size_read(inode
);
1399 end_index
= i_size
>> PAGE_CACHE_SHIFT
;
1400 if (index
== end_index
) {
1401 nr
= i_size
& ~PAGE_CACHE_MASK
;
1404 page_cache_release(page
);
1412 * If users can be writing to this page using arbitrary
1413 * virtual addresses, take care about potential aliasing
1414 * before reading the page on the kernel side.
1416 if (mapping_writably_mapped(mapping
))
1417 flush_dcache_page(page
);
1419 * Mark the page accessed if we read the beginning.
1422 mark_page_accessed(page
);
1424 page
= ZERO_PAGE(0);
1425 page_cache_get(page
);
1429 * Ok, we have the page, and it's up-to-date, so
1430 * now we can copy it to user space...
1432 * The actor routine returns how many bytes were actually used..
1433 * NOTE! This may not be the same as how much of a user buffer
1434 * we filled up (we may be padding etc), so we can only update
1435 * "pos" here (the actor routine has to update the user buffer
1436 * pointers and the remaining count).
1438 ret
= actor(desc
, page
, offset
, nr
);
1440 index
+= offset
>> PAGE_CACHE_SHIFT
;
1441 offset
&= ~PAGE_CACHE_MASK
;
1443 page_cache_release(page
);
1444 if (ret
!= nr
|| !desc
->count
)
1450 *ppos
= ((loff_t
) index
<< PAGE_CACHE_SHIFT
) + offset
;
1451 file_accessed(filp
);
1454 static ssize_t
shmem_file_aio_read(struct kiocb
*iocb
,
1455 const struct iovec
*iov
, unsigned long nr_segs
, loff_t pos
)
1457 struct file
*filp
= iocb
->ki_filp
;
1461 loff_t
*ppos
= &iocb
->ki_pos
;
1463 retval
= generic_segment_checks(iov
, &nr_segs
, &count
, VERIFY_WRITE
);
1467 for (seg
= 0; seg
< nr_segs
; seg
++) {
1468 read_descriptor_t desc
;
1471 desc
.arg
.buf
= iov
[seg
].iov_base
;
1472 desc
.count
= iov
[seg
].iov_len
;
1473 if (desc
.count
== 0)
1476 do_shmem_file_read(filp
, ppos
, &desc
, file_read_actor
);
1477 retval
+= desc
.written
;
1479 retval
= retval
?: desc
.error
;
1488 static ssize_t
shmem_file_splice_read(struct file
*in
, loff_t
*ppos
,
1489 struct pipe_inode_info
*pipe
, size_t len
,
1492 struct address_space
*mapping
= in
->f_mapping
;
1493 struct inode
*inode
= mapping
->host
;
1494 unsigned int loff
, nr_pages
, req_pages
;
1495 struct page
*pages
[PIPE_DEF_BUFFERS
];
1496 struct partial_page partial
[PIPE_DEF_BUFFERS
];
1498 pgoff_t index
, end_index
;
1501 struct splice_pipe_desc spd
= {
1505 .ops
= &page_cache_pipe_buf_ops
,
1506 .spd_release
= spd_release_page
,
1509 isize
= i_size_read(inode
);
1510 if (unlikely(*ppos
>= isize
))
1513 left
= isize
- *ppos
;
1514 if (unlikely(left
< len
))
1517 if (splice_grow_spd(pipe
, &spd
))
1520 index
= *ppos
>> PAGE_CACHE_SHIFT
;
1521 loff
= *ppos
& ~PAGE_CACHE_MASK
;
1522 req_pages
= (len
+ loff
+ PAGE_CACHE_SIZE
- 1) >> PAGE_CACHE_SHIFT
;
1523 nr_pages
= min(req_pages
, pipe
->buffers
);
1525 spd
.nr_pages
= find_get_pages_contig(mapping
, index
,
1526 nr_pages
, spd
.pages
);
1527 index
+= spd
.nr_pages
;
1530 while (spd
.nr_pages
< nr_pages
) {
1531 error
= shmem_getpage(inode
, index
, &page
, SGP_CACHE
, NULL
);
1535 spd
.pages
[spd
.nr_pages
++] = page
;
1539 index
= *ppos
>> PAGE_CACHE_SHIFT
;
1540 nr_pages
= spd
.nr_pages
;
1543 for (page_nr
= 0; page_nr
< nr_pages
; page_nr
++) {
1544 unsigned int this_len
;
1549 this_len
= min_t(unsigned long, len
, PAGE_CACHE_SIZE
- loff
);
1550 page
= spd
.pages
[page_nr
];
1552 if (!PageUptodate(page
) || page
->mapping
!= mapping
) {
1553 error
= shmem_getpage(inode
, index
, &page
,
1558 page_cache_release(spd
.pages
[page_nr
]);
1559 spd
.pages
[page_nr
] = page
;
1562 isize
= i_size_read(inode
);
1563 end_index
= (isize
- 1) >> PAGE_CACHE_SHIFT
;
1564 if (unlikely(!isize
|| index
> end_index
))
1567 if (end_index
== index
) {
1570 plen
= ((isize
- 1) & ~PAGE_CACHE_MASK
) + 1;
1574 this_len
= min(this_len
, plen
- loff
);
1578 spd
.partial
[page_nr
].offset
= loff
;
1579 spd
.partial
[page_nr
].len
= this_len
;
1586 while (page_nr
< nr_pages
)
1587 page_cache_release(spd
.pages
[page_nr
++]);
1590 error
= splice_to_pipe(pipe
, &spd
);
1592 splice_shrink_spd(pipe
, &spd
);
1601 static long shmem_fallocate(struct file
*file
, int mode
, loff_t offset
,
1604 struct inode
*inode
= file
->f_path
.dentry
->d_inode
;
1605 int error
= -EOPNOTSUPP
;
1607 mutex_lock(&inode
->i_mutex
);
1609 if (mode
& FALLOC_FL_PUNCH_HOLE
) {
1610 struct address_space
*mapping
= file
->f_mapping
;
1611 loff_t unmap_start
= round_up(offset
, PAGE_SIZE
);
1612 loff_t unmap_end
= round_down(offset
+ len
, PAGE_SIZE
) - 1;
1614 if ((u64
)unmap_end
> (u64
)unmap_start
)
1615 unmap_mapping_range(mapping
, unmap_start
,
1616 1 + unmap_end
- unmap_start
, 0);
1617 shmem_truncate_range(inode
, offset
, offset
+ len
- 1);
1618 /* No need to unmap again: hole-punching leaves COWed pages */
1622 mutex_unlock(&inode
->i_mutex
);
1626 static int shmem_statfs(struct dentry
*dentry
, struct kstatfs
*buf
)
1628 struct shmem_sb_info
*sbinfo
= SHMEM_SB(dentry
->d_sb
);
1630 buf
->f_type
= TMPFS_MAGIC
;
1631 buf
->f_bsize
= PAGE_CACHE_SIZE
;
1632 buf
->f_namelen
= NAME_MAX
;
1633 if (sbinfo
->max_blocks
) {
1634 buf
->f_blocks
= sbinfo
->max_blocks
;
1636 buf
->f_bfree
= sbinfo
->max_blocks
-
1637 percpu_counter_sum(&sbinfo
->used_blocks
);
1639 if (sbinfo
->max_inodes
) {
1640 buf
->f_files
= sbinfo
->max_inodes
;
1641 buf
->f_ffree
= sbinfo
->free_inodes
;
1643 /* else leave those fields 0 like simple_statfs */
1648 * File creation. Allocate an inode, and we're done..
1651 shmem_mknod(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
, dev_t dev
)
1653 struct inode
*inode
;
1654 int error
= -ENOSPC
;
1656 inode
= shmem_get_inode(dir
->i_sb
, dir
, mode
, dev
, VM_NORESERVE
);
1658 error
= security_inode_init_security(inode
, dir
,
1660 shmem_initxattrs
, NULL
);
1662 if (error
!= -EOPNOTSUPP
) {
1667 #ifdef CONFIG_TMPFS_POSIX_ACL
1668 error
= generic_acl_init(inode
, dir
);
1676 dir
->i_size
+= BOGO_DIRENT_SIZE
;
1677 dir
->i_ctime
= dir
->i_mtime
= CURRENT_TIME
;
1678 d_instantiate(dentry
, inode
);
1679 dget(dentry
); /* Extra count - pin the dentry in core */
1684 static int shmem_mkdir(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
)
1688 if ((error
= shmem_mknod(dir
, dentry
, mode
| S_IFDIR
, 0)))
1694 static int shmem_create(struct inode
*dir
, struct dentry
*dentry
, umode_t mode
,
1695 struct nameidata
*nd
)
1697 return shmem_mknod(dir
, dentry
, mode
| S_IFREG
, 0);
1703 static int shmem_link(struct dentry
*old_dentry
, struct inode
*dir
, struct dentry
*dentry
)
1705 struct inode
*inode
= old_dentry
->d_inode
;
1709 * No ordinary (disk based) filesystem counts links as inodes;
1710 * but each new link needs a new dentry, pinning lowmem, and
1711 * tmpfs dentries cannot be pruned until they are unlinked.
1713 ret
= shmem_reserve_inode(inode
->i_sb
);
1717 dir
->i_size
+= BOGO_DIRENT_SIZE
;
1718 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= CURRENT_TIME
;
1720 ihold(inode
); /* New dentry reference */
1721 dget(dentry
); /* Extra pinning count for the created dentry */
1722 d_instantiate(dentry
, inode
);
1727 static int shmem_unlink(struct inode
*dir
, struct dentry
*dentry
)
1729 struct inode
*inode
= dentry
->d_inode
;
1731 if (inode
->i_nlink
> 1 && !S_ISDIR(inode
->i_mode
))
1732 shmem_free_inode(inode
->i_sb
);
1734 dir
->i_size
-= BOGO_DIRENT_SIZE
;
1735 inode
->i_ctime
= dir
->i_ctime
= dir
->i_mtime
= CURRENT_TIME
;
1737 dput(dentry
); /* Undo the count from "create" - this does all the work */
1741 static int shmem_rmdir(struct inode
*dir
, struct dentry
*dentry
)
1743 if (!simple_empty(dentry
))
1746 drop_nlink(dentry
->d_inode
);
1748 return shmem_unlink(dir
, dentry
);
1752 * The VFS layer already does all the dentry stuff for rename,
1753 * we just have to decrement the usage count for the target if
1754 * it exists so that the VFS layer correctly free's it when it
1757 static int shmem_rename(struct inode
*old_dir
, struct dentry
*old_dentry
, struct inode
*new_dir
, struct dentry
*new_dentry
)
1759 struct inode
*inode
= old_dentry
->d_inode
;
1760 int they_are_dirs
= S_ISDIR(inode
->i_mode
);
1762 if (!simple_empty(new_dentry
))
1765 if (new_dentry
->d_inode
) {
1766 (void) shmem_unlink(new_dir
, new_dentry
);
1768 drop_nlink(old_dir
);
1769 } else if (they_are_dirs
) {
1770 drop_nlink(old_dir
);
1774 old_dir
->i_size
-= BOGO_DIRENT_SIZE
;
1775 new_dir
->i_size
+= BOGO_DIRENT_SIZE
;
1776 old_dir
->i_ctime
= old_dir
->i_mtime
=
1777 new_dir
->i_ctime
= new_dir
->i_mtime
=
1778 inode
->i_ctime
= CURRENT_TIME
;
1782 static int shmem_symlink(struct inode
*dir
, struct dentry
*dentry
, const char *symname
)
1786 struct inode
*inode
;
1789 struct shmem_inode_info
*info
;
1791 len
= strlen(symname
) + 1;
1792 if (len
> PAGE_CACHE_SIZE
)
1793 return -ENAMETOOLONG
;
1795 inode
= shmem_get_inode(dir
->i_sb
, dir
, S_IFLNK
|S_IRWXUGO
, 0, VM_NORESERVE
);
1799 error
= security_inode_init_security(inode
, dir
, &dentry
->d_name
,
1800 shmem_initxattrs
, NULL
);
1802 if (error
!= -EOPNOTSUPP
) {
1809 info
= SHMEM_I(inode
);
1810 inode
->i_size
= len
-1;
1811 if (len
<= SHORT_SYMLINK_LEN
) {
1812 info
->symlink
= kmemdup(symname
, len
, GFP_KERNEL
);
1813 if (!info
->symlink
) {
1817 inode
->i_op
= &shmem_short_symlink_operations
;
1819 error
= shmem_getpage(inode
, 0, &page
, SGP_WRITE
, NULL
);
1824 inode
->i_mapping
->a_ops
= &shmem_aops
;
1825 inode
->i_op
= &shmem_symlink_inode_operations
;
1826 kaddr
= kmap_atomic(page
);
1827 memcpy(kaddr
, symname
, len
);
1828 kunmap_atomic(kaddr
);
1829 SetPageUptodate(page
);
1830 set_page_dirty(page
);
1832 page_cache_release(page
);
1834 dir
->i_size
+= BOGO_DIRENT_SIZE
;
1835 dir
->i_ctime
= dir
->i_mtime
= CURRENT_TIME
;
1836 d_instantiate(dentry
, inode
);
1841 static void *shmem_follow_short_symlink(struct dentry
*dentry
, struct nameidata
*nd
)
1843 nd_set_link(nd
, SHMEM_I(dentry
->d_inode
)->symlink
);
1847 static void *shmem_follow_link(struct dentry
*dentry
, struct nameidata
*nd
)
1849 struct page
*page
= NULL
;
1850 int error
= shmem_getpage(dentry
->d_inode
, 0, &page
, SGP_READ
, NULL
);
1851 nd_set_link(nd
, error
? ERR_PTR(error
) : kmap(page
));
1857 static void shmem_put_link(struct dentry
*dentry
, struct nameidata
*nd
, void *cookie
)
1859 if (!IS_ERR(nd_get_link(nd
))) {
1860 struct page
*page
= cookie
;
1862 mark_page_accessed(page
);
1863 page_cache_release(page
);
1867 #ifdef CONFIG_TMPFS_XATTR
1869 * Superblocks without xattr inode operations may get some security.* xattr
1870 * support from the LSM "for free". As soon as we have any other xattrs
1871 * like ACLs, we also need to implement the security.* handlers at
1872 * filesystem level, though.
1876 * Allocate new xattr and copy in the value; but leave the name to callers.
1878 static struct shmem_xattr
*shmem_xattr_alloc(const void *value
, size_t size
)
1880 struct shmem_xattr
*new_xattr
;
1884 len
= sizeof(*new_xattr
) + size
;
1885 if (len
<= sizeof(*new_xattr
))
1888 new_xattr
= kmalloc(len
, GFP_KERNEL
);
1892 new_xattr
->size
= size
;
1893 memcpy(new_xattr
->value
, value
, size
);
1898 * Callback for security_inode_init_security() for acquiring xattrs.
1900 static int shmem_initxattrs(struct inode
*inode
,
1901 const struct xattr
*xattr_array
,
1904 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1905 const struct xattr
*xattr
;
1906 struct shmem_xattr
*new_xattr
;
1909 for (xattr
= xattr_array
; xattr
->name
!= NULL
; xattr
++) {
1910 new_xattr
= shmem_xattr_alloc(xattr
->value
, xattr
->value_len
);
1914 len
= strlen(xattr
->name
) + 1;
1915 new_xattr
->name
= kmalloc(XATTR_SECURITY_PREFIX_LEN
+ len
,
1917 if (!new_xattr
->name
) {
1922 memcpy(new_xattr
->name
, XATTR_SECURITY_PREFIX
,
1923 XATTR_SECURITY_PREFIX_LEN
);
1924 memcpy(new_xattr
->name
+ XATTR_SECURITY_PREFIX_LEN
,
1927 spin_lock(&info
->lock
);
1928 list_add(&new_xattr
->list
, &info
->xattr_list
);
1929 spin_unlock(&info
->lock
);
1935 static int shmem_xattr_get(struct dentry
*dentry
, const char *name
,
1936 void *buffer
, size_t size
)
1938 struct shmem_inode_info
*info
;
1939 struct shmem_xattr
*xattr
;
1942 info
= SHMEM_I(dentry
->d_inode
);
1944 spin_lock(&info
->lock
);
1945 list_for_each_entry(xattr
, &info
->xattr_list
, list
) {
1946 if (strcmp(name
, xattr
->name
))
1951 if (size
< xattr
->size
)
1954 memcpy(buffer
, xattr
->value
, xattr
->size
);
1958 spin_unlock(&info
->lock
);
1962 static int shmem_xattr_set(struct inode
*inode
, const char *name
,
1963 const void *value
, size_t size
, int flags
)
1965 struct shmem_inode_info
*info
= SHMEM_I(inode
);
1966 struct shmem_xattr
*xattr
;
1967 struct shmem_xattr
*new_xattr
= NULL
;
1970 /* value == NULL means remove */
1972 new_xattr
= shmem_xattr_alloc(value
, size
);
1976 new_xattr
->name
= kstrdup(name
, GFP_KERNEL
);
1977 if (!new_xattr
->name
) {
1983 spin_lock(&info
->lock
);
1984 list_for_each_entry(xattr
, &info
->xattr_list
, list
) {
1985 if (!strcmp(name
, xattr
->name
)) {
1986 if (flags
& XATTR_CREATE
) {
1989 } else if (new_xattr
) {
1990 list_replace(&xattr
->list
, &new_xattr
->list
);
1992 list_del(&xattr
->list
);
1997 if (flags
& XATTR_REPLACE
) {
2001 list_add(&new_xattr
->list
, &info
->xattr_list
);
2005 spin_unlock(&info
->lock
);
2012 static const struct xattr_handler
*shmem_xattr_handlers
[] = {
2013 #ifdef CONFIG_TMPFS_POSIX_ACL
2014 &generic_acl_access_handler
,
2015 &generic_acl_default_handler
,
2020 static int shmem_xattr_validate(const char *name
)
2022 struct { const char *prefix
; size_t len
; } arr
[] = {
2023 { XATTR_SECURITY_PREFIX
, XATTR_SECURITY_PREFIX_LEN
},
2024 { XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
}
2028 for (i
= 0; i
< ARRAY_SIZE(arr
); i
++) {
2029 size_t preflen
= arr
[i
].len
;
2030 if (strncmp(name
, arr
[i
].prefix
, preflen
) == 0) {
2039 static ssize_t
shmem_getxattr(struct dentry
*dentry
, const char *name
,
2040 void *buffer
, size_t size
)
2045 * If this is a request for a synthetic attribute in the system.*
2046 * namespace use the generic infrastructure to resolve a handler
2047 * for it via sb->s_xattr.
2049 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
2050 return generic_getxattr(dentry
, name
, buffer
, size
);
2052 err
= shmem_xattr_validate(name
);
2056 return shmem_xattr_get(dentry
, name
, buffer
, size
);
2059 static int shmem_setxattr(struct dentry
*dentry
, const char *name
,
2060 const void *value
, size_t size
, int flags
)
2065 * If this is a request for a synthetic attribute in the system.*
2066 * namespace use the generic infrastructure to resolve a handler
2067 * for it via sb->s_xattr.
2069 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
2070 return generic_setxattr(dentry
, name
, value
, size
, flags
);
2072 err
= shmem_xattr_validate(name
);
2077 value
= ""; /* empty EA, do not remove */
2079 return shmem_xattr_set(dentry
->d_inode
, name
, value
, size
, flags
);
2083 static int shmem_removexattr(struct dentry
*dentry
, const char *name
)
2088 * If this is a request for a synthetic attribute in the system.*
2089 * namespace use the generic infrastructure to resolve a handler
2090 * for it via sb->s_xattr.
2092 if (!strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
2093 return generic_removexattr(dentry
, name
);
2095 err
= shmem_xattr_validate(name
);
2099 return shmem_xattr_set(dentry
->d_inode
, name
, NULL
, 0, XATTR_REPLACE
);
2102 static bool xattr_is_trusted(const char *name
)
2104 return !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
);
2107 static ssize_t
shmem_listxattr(struct dentry
*dentry
, char *buffer
, size_t size
)
2109 bool trusted
= capable(CAP_SYS_ADMIN
);
2110 struct shmem_xattr
*xattr
;
2111 struct shmem_inode_info
*info
;
2114 info
= SHMEM_I(dentry
->d_inode
);
2116 spin_lock(&info
->lock
);
2117 list_for_each_entry(xattr
, &info
->xattr_list
, list
) {
2120 /* skip "trusted." attributes for unprivileged callers */
2121 if (!trusted
&& xattr_is_trusted(xattr
->name
))
2124 len
= strlen(xattr
->name
) + 1;
2131 memcpy(buffer
, xattr
->name
, len
);
2135 spin_unlock(&info
->lock
);
2139 #endif /* CONFIG_TMPFS_XATTR */
2141 static const struct inode_operations shmem_short_symlink_operations
= {
2142 .readlink
= generic_readlink
,
2143 .follow_link
= shmem_follow_short_symlink
,
2144 #ifdef CONFIG_TMPFS_XATTR
2145 .setxattr
= shmem_setxattr
,
2146 .getxattr
= shmem_getxattr
,
2147 .listxattr
= shmem_listxattr
,
2148 .removexattr
= shmem_removexattr
,
2152 static const struct inode_operations shmem_symlink_inode_operations
= {
2153 .readlink
= generic_readlink
,
2154 .follow_link
= shmem_follow_link
,
2155 .put_link
= shmem_put_link
,
2156 #ifdef CONFIG_TMPFS_XATTR
2157 .setxattr
= shmem_setxattr
,
2158 .getxattr
= shmem_getxattr
,
2159 .listxattr
= shmem_listxattr
,
2160 .removexattr
= shmem_removexattr
,
2164 static struct dentry
*shmem_get_parent(struct dentry
*child
)
2166 return ERR_PTR(-ESTALE
);
2169 static int shmem_match(struct inode
*ino
, void *vfh
)
2173 inum
= (inum
<< 32) | fh
[1];
2174 return ino
->i_ino
== inum
&& fh
[0] == ino
->i_generation
;
2177 static struct dentry
*shmem_fh_to_dentry(struct super_block
*sb
,
2178 struct fid
*fid
, int fh_len
, int fh_type
)
2180 struct inode
*inode
;
2181 struct dentry
*dentry
= NULL
;
2182 u64 inum
= fid
->raw
[2];
2183 inum
= (inum
<< 32) | fid
->raw
[1];
2188 inode
= ilookup5(sb
, (unsigned long)(inum
+ fid
->raw
[0]),
2189 shmem_match
, fid
->raw
);
2191 dentry
= d_find_alias(inode
);
2198 static int shmem_encode_fh(struct dentry
*dentry
, __u32
*fh
, int *len
,
2201 struct inode
*inode
= dentry
->d_inode
;
2208 if (inode_unhashed(inode
)) {
2209 /* Unfortunately insert_inode_hash is not idempotent,
2210 * so as we hash inodes here rather than at creation
2211 * time, we need a lock to ensure we only try
2214 static DEFINE_SPINLOCK(lock
);
2216 if (inode_unhashed(inode
))
2217 __insert_inode_hash(inode
,
2218 inode
->i_ino
+ inode
->i_generation
);
2222 fh
[0] = inode
->i_generation
;
2223 fh
[1] = inode
->i_ino
;
2224 fh
[2] = ((__u64
)inode
->i_ino
) >> 32;
2230 static const struct export_operations shmem_export_ops
= {
2231 .get_parent
= shmem_get_parent
,
2232 .encode_fh
= shmem_encode_fh
,
2233 .fh_to_dentry
= shmem_fh_to_dentry
,
2236 static int shmem_parse_options(char *options
, struct shmem_sb_info
*sbinfo
,
2239 char *this_char
, *value
, *rest
;
2243 while (options
!= NULL
) {
2244 this_char
= options
;
2247 * NUL-terminate this option: unfortunately,
2248 * mount options form a comma-separated list,
2249 * but mpol's nodelist may also contain commas.
2251 options
= strchr(options
, ',');
2252 if (options
== NULL
)
2255 if (!isdigit(*options
)) {
2262 if ((value
= strchr(this_char
,'=')) != NULL
) {
2266 "tmpfs: No value for mount option '%s'\n",
2271 if (!strcmp(this_char
,"size")) {
2272 unsigned long long size
;
2273 size
= memparse(value
,&rest
);
2275 size
<<= PAGE_SHIFT
;
2276 size
*= totalram_pages
;
2282 sbinfo
->max_blocks
=
2283 DIV_ROUND_UP(size
, PAGE_CACHE_SIZE
);
2284 } else if (!strcmp(this_char
,"nr_blocks")) {
2285 sbinfo
->max_blocks
= memparse(value
, &rest
);
2288 } else if (!strcmp(this_char
,"nr_inodes")) {
2289 sbinfo
->max_inodes
= memparse(value
, &rest
);
2292 } else if (!strcmp(this_char
,"mode")) {
2295 sbinfo
->mode
= simple_strtoul(value
, &rest
, 8) & 07777;
2298 } else if (!strcmp(this_char
,"uid")) {
2301 uid
= simple_strtoul(value
, &rest
, 0);
2304 sbinfo
->uid
= make_kuid(current_user_ns(), uid
);
2305 if (!uid_valid(sbinfo
->uid
))
2307 } else if (!strcmp(this_char
,"gid")) {
2310 gid
= simple_strtoul(value
, &rest
, 0);
2313 sbinfo
->gid
= make_kgid(current_user_ns(), gid
);
2314 if (!gid_valid(sbinfo
->gid
))
2316 } else if (!strcmp(this_char
,"mpol")) {
2317 if (mpol_parse_str(value
, &sbinfo
->mpol
, 1))
2320 printk(KERN_ERR
"tmpfs: Bad mount option %s\n",
2328 printk(KERN_ERR
"tmpfs: Bad value '%s' for mount option '%s'\n",
2334 static int shmem_remount_fs(struct super_block
*sb
, int *flags
, char *data
)
2336 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
2337 struct shmem_sb_info config
= *sbinfo
;
2338 unsigned long inodes
;
2339 int error
= -EINVAL
;
2341 if (shmem_parse_options(data
, &config
, true))
2344 spin_lock(&sbinfo
->stat_lock
);
2345 inodes
= sbinfo
->max_inodes
- sbinfo
->free_inodes
;
2346 if (percpu_counter_compare(&sbinfo
->used_blocks
, config
.max_blocks
) > 0)
2348 if (config
.max_inodes
< inodes
)
2351 * Those tests disallow limited->unlimited while any are in use;
2352 * but we must separately disallow unlimited->limited, because
2353 * in that case we have no record of how much is already in use.
2355 if (config
.max_blocks
&& !sbinfo
->max_blocks
)
2357 if (config
.max_inodes
&& !sbinfo
->max_inodes
)
2361 sbinfo
->max_blocks
= config
.max_blocks
;
2362 sbinfo
->max_inodes
= config
.max_inodes
;
2363 sbinfo
->free_inodes
= config
.max_inodes
- inodes
;
2365 mpol_put(sbinfo
->mpol
);
2366 sbinfo
->mpol
= config
.mpol
; /* transfers initial ref */
2368 spin_unlock(&sbinfo
->stat_lock
);
2372 static int shmem_show_options(struct seq_file
*seq
, struct dentry
*root
)
2374 struct shmem_sb_info
*sbinfo
= SHMEM_SB(root
->d_sb
);
2376 if (sbinfo
->max_blocks
!= shmem_default_max_blocks())
2377 seq_printf(seq
, ",size=%luk",
2378 sbinfo
->max_blocks
<< (PAGE_CACHE_SHIFT
- 10));
2379 if (sbinfo
->max_inodes
!= shmem_default_max_inodes())
2380 seq_printf(seq
, ",nr_inodes=%lu", sbinfo
->max_inodes
);
2381 if (sbinfo
->mode
!= (S_IRWXUGO
| S_ISVTX
))
2382 seq_printf(seq
, ",mode=%03ho", sbinfo
->mode
);
2383 if (!uid_eq(sbinfo
->uid
, GLOBAL_ROOT_UID
))
2384 seq_printf(seq
, ",uid=%u",
2385 from_kuid_munged(&init_user_ns
, sbinfo
->uid
));
2386 if (!gid_eq(sbinfo
->gid
, GLOBAL_ROOT_GID
))
2387 seq_printf(seq
, ",gid=%u",
2388 from_kgid_munged(&init_user_ns
, sbinfo
->gid
));
2389 shmem_show_mpol(seq
, sbinfo
->mpol
);
2392 #endif /* CONFIG_TMPFS */
2394 static void shmem_put_super(struct super_block
*sb
)
2396 struct shmem_sb_info
*sbinfo
= SHMEM_SB(sb
);
2398 percpu_counter_destroy(&sbinfo
->used_blocks
);
2400 sb
->s_fs_info
= NULL
;
2403 int shmem_fill_super(struct super_block
*sb
, void *data
, int silent
)
2405 struct inode
*inode
;
2406 struct shmem_sb_info
*sbinfo
;
2409 /* Round up to L1_CACHE_BYTES to resist false sharing */
2410 sbinfo
= kzalloc(max((int)sizeof(struct shmem_sb_info
),
2411 L1_CACHE_BYTES
), GFP_KERNEL
);
2415 sbinfo
->mode
= S_IRWXUGO
| S_ISVTX
;
2416 sbinfo
->uid
= current_fsuid();
2417 sbinfo
->gid
= current_fsgid();
2418 sb
->s_fs_info
= sbinfo
;
2422 * Per default we only allow half of the physical ram per
2423 * tmpfs instance, limiting inodes to one per page of lowmem;
2424 * but the internal instance is left unlimited.
2426 if (!(sb
->s_flags
& MS_NOUSER
)) {
2427 sbinfo
->max_blocks
= shmem_default_max_blocks();
2428 sbinfo
->max_inodes
= shmem_default_max_inodes();
2429 if (shmem_parse_options(data
, sbinfo
, false)) {
2434 sb
->s_export_op
= &shmem_export_ops
;
2435 sb
->s_flags
|= MS_NOSEC
;
2437 sb
->s_flags
|= MS_NOUSER
;
2440 spin_lock_init(&sbinfo
->stat_lock
);
2441 if (percpu_counter_init(&sbinfo
->used_blocks
, 0))
2443 sbinfo
->free_inodes
= sbinfo
->max_inodes
;
2445 sb
->s_maxbytes
= MAX_LFS_FILESIZE
;
2446 sb
->s_blocksize
= PAGE_CACHE_SIZE
;
2447 sb
->s_blocksize_bits
= PAGE_CACHE_SHIFT
;
2448 sb
->s_magic
= TMPFS_MAGIC
;
2449 sb
->s_op
= &shmem_ops
;
2450 sb
->s_time_gran
= 1;
2451 #ifdef CONFIG_TMPFS_XATTR
2452 sb
->s_xattr
= shmem_xattr_handlers
;
2454 #ifdef CONFIG_TMPFS_POSIX_ACL
2455 sb
->s_flags
|= MS_POSIXACL
;
2458 inode
= shmem_get_inode(sb
, NULL
, S_IFDIR
| sbinfo
->mode
, 0, VM_NORESERVE
);
2461 inode
->i_uid
= sbinfo
->uid
;
2462 inode
->i_gid
= sbinfo
->gid
;
2463 sb
->s_root
= d_make_root(inode
);
2469 shmem_put_super(sb
);
2473 static struct kmem_cache
*shmem_inode_cachep
;
2475 static struct inode
*shmem_alloc_inode(struct super_block
*sb
)
2477 struct shmem_inode_info
*info
;
2478 info
= kmem_cache_alloc(shmem_inode_cachep
, GFP_KERNEL
);
2481 return &info
->vfs_inode
;
2484 static void shmem_destroy_callback(struct rcu_head
*head
)
2486 struct inode
*inode
= container_of(head
, struct inode
, i_rcu
);
2487 kmem_cache_free(shmem_inode_cachep
, SHMEM_I(inode
));
2490 static void shmem_destroy_inode(struct inode
*inode
)
2492 if (S_ISREG(inode
->i_mode
))
2493 mpol_free_shared_policy(&SHMEM_I(inode
)->policy
);
2494 call_rcu(&inode
->i_rcu
, shmem_destroy_callback
);
2497 static void shmem_init_inode(void *foo
)
2499 struct shmem_inode_info
*info
= foo
;
2500 inode_init_once(&info
->vfs_inode
);
2503 static int shmem_init_inodecache(void)
2505 shmem_inode_cachep
= kmem_cache_create("shmem_inode_cache",
2506 sizeof(struct shmem_inode_info
),
2507 0, SLAB_PANIC
, shmem_init_inode
);
2511 static void shmem_destroy_inodecache(void)
2513 kmem_cache_destroy(shmem_inode_cachep
);
2516 static const struct address_space_operations shmem_aops
= {
2517 .writepage
= shmem_writepage
,
2518 .set_page_dirty
= __set_page_dirty_no_writeback
,
2520 .write_begin
= shmem_write_begin
,
2521 .write_end
= shmem_write_end
,
2523 .migratepage
= migrate_page
,
2524 .error_remove_page
= generic_error_remove_page
,
2527 static const struct file_operations shmem_file_operations
= {
2530 .llseek
= generic_file_llseek
,
2531 .read
= do_sync_read
,
2532 .write
= do_sync_write
,
2533 .aio_read
= shmem_file_aio_read
,
2534 .aio_write
= generic_file_aio_write
,
2535 .fsync
= noop_fsync
,
2536 .splice_read
= shmem_file_splice_read
,
2537 .splice_write
= generic_file_splice_write
,
2538 .fallocate
= shmem_fallocate
,
2542 static const struct inode_operations shmem_inode_operations
= {
2543 .setattr
= shmem_setattr
,
2544 #ifdef CONFIG_TMPFS_XATTR
2545 .setxattr
= shmem_setxattr
,
2546 .getxattr
= shmem_getxattr
,
2547 .listxattr
= shmem_listxattr
,
2548 .removexattr
= shmem_removexattr
,
2552 static const struct inode_operations shmem_dir_inode_operations
= {
2554 .create
= shmem_create
,
2555 .lookup
= simple_lookup
,
2557 .unlink
= shmem_unlink
,
2558 .symlink
= shmem_symlink
,
2559 .mkdir
= shmem_mkdir
,
2560 .rmdir
= shmem_rmdir
,
2561 .mknod
= shmem_mknod
,
2562 .rename
= shmem_rename
,
2564 #ifdef CONFIG_TMPFS_XATTR
2565 .setxattr
= shmem_setxattr
,
2566 .getxattr
= shmem_getxattr
,
2567 .listxattr
= shmem_listxattr
,
2568 .removexattr
= shmem_removexattr
,
2570 #ifdef CONFIG_TMPFS_POSIX_ACL
2571 .setattr
= shmem_setattr
,
2575 static const struct inode_operations shmem_special_inode_operations
= {
2576 #ifdef CONFIG_TMPFS_XATTR
2577 .setxattr
= shmem_setxattr
,
2578 .getxattr
= shmem_getxattr
,
2579 .listxattr
= shmem_listxattr
,
2580 .removexattr
= shmem_removexattr
,
2582 #ifdef CONFIG_TMPFS_POSIX_ACL
2583 .setattr
= shmem_setattr
,
2587 static const struct super_operations shmem_ops
= {
2588 .alloc_inode
= shmem_alloc_inode
,
2589 .destroy_inode
= shmem_destroy_inode
,
2591 .statfs
= shmem_statfs
,
2592 .remount_fs
= shmem_remount_fs
,
2593 .show_options
= shmem_show_options
,
2595 .evict_inode
= shmem_evict_inode
,
2596 .drop_inode
= generic_delete_inode
,
2597 .put_super
= shmem_put_super
,
2600 static const struct vm_operations_struct shmem_vm_ops
= {
2601 .fault
= shmem_fault
,
2603 .set_policy
= shmem_set_policy
,
2604 .get_policy
= shmem_get_policy
,
2608 static struct dentry
*shmem_mount(struct file_system_type
*fs_type
,
2609 int flags
, const char *dev_name
, void *data
)
2611 return mount_nodev(fs_type
, flags
, data
, shmem_fill_super
);
2614 static struct file_system_type shmem_fs_type
= {
2615 .owner
= THIS_MODULE
,
2617 .mount
= shmem_mount
,
2618 .kill_sb
= kill_litter_super
,
2621 int __init
shmem_init(void)
2625 error
= bdi_init(&shmem_backing_dev_info
);
2629 error
= shmem_init_inodecache();
2633 error
= register_filesystem(&shmem_fs_type
);
2635 printk(KERN_ERR
"Could not register tmpfs\n");
2639 shm_mnt
= vfs_kern_mount(&shmem_fs_type
, MS_NOUSER
,
2640 shmem_fs_type
.name
, NULL
);
2641 if (IS_ERR(shm_mnt
)) {
2642 error
= PTR_ERR(shm_mnt
);
2643 printk(KERN_ERR
"Could not kern_mount tmpfs\n");
2649 unregister_filesystem(&shmem_fs_type
);
2651 shmem_destroy_inodecache();
2653 bdi_destroy(&shmem_backing_dev_info
);
2655 shm_mnt
= ERR_PTR(error
);
2659 #else /* !CONFIG_SHMEM */
2662 * tiny-shmem: simple shmemfs and tmpfs using ramfs code
2664 * This is intended for small system where the benefits of the full
2665 * shmem code (swap-backed and resource-limited) are outweighed by
2666 * their complexity. On systems without swap this code should be
2667 * effectively equivalent, but much lighter weight.
2670 #include <linux/ramfs.h>
2672 static struct file_system_type shmem_fs_type
= {
2674 .mount
= ramfs_mount
,
2675 .kill_sb
= kill_litter_super
,
2678 int __init
shmem_init(void)
2680 BUG_ON(register_filesystem(&shmem_fs_type
) != 0);
2682 shm_mnt
= kern_mount(&shmem_fs_type
);
2683 BUG_ON(IS_ERR(shm_mnt
));
2688 int shmem_unuse(swp_entry_t swap
, struct page
*page
)
2693 int shmem_lock(struct file
*file
, int lock
, struct user_struct
*user
)
2698 void shmem_unlock_mapping(struct address_space
*mapping
)
2702 void shmem_truncate_range(struct inode
*inode
, loff_t lstart
, loff_t lend
)
2704 truncate_inode_pages_range(inode
->i_mapping
, lstart
, lend
);
2706 EXPORT_SYMBOL_GPL(shmem_truncate_range
);
2708 #define shmem_vm_ops generic_file_vm_ops
2709 #define shmem_file_operations ramfs_file_operations
2710 #define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
2711 #define shmem_acct_size(flags, size) 0
2712 #define shmem_unacct_size(flags, size) do {} while (0)
2714 #endif /* CONFIG_SHMEM */
2719 * shmem_file_setup - get an unlinked file living in tmpfs
2720 * @name: name for dentry (to be seen in /proc/<pid>/maps
2721 * @size: size to be set for the file
2722 * @flags: VM_NORESERVE suppresses pre-accounting of the entire object size
2724 struct file
*shmem_file_setup(const char *name
, loff_t size
, unsigned long flags
)
2728 struct inode
*inode
;
2730 struct dentry
*root
;
2733 if (IS_ERR(shm_mnt
))
2734 return (void *)shm_mnt
;
2736 if (size
< 0 || size
> MAX_LFS_FILESIZE
)
2737 return ERR_PTR(-EINVAL
);
2739 if (shmem_acct_size(flags
, size
))
2740 return ERR_PTR(-ENOMEM
);
2744 this.len
= strlen(name
);
2745 this.hash
= 0; /* will go */
2746 root
= shm_mnt
->mnt_root
;
2747 path
.dentry
= d_alloc(root
, &this);
2750 path
.mnt
= mntget(shm_mnt
);
2753 inode
= shmem_get_inode(root
->d_sb
, NULL
, S_IFREG
| S_IRWXUGO
, 0, flags
);
2757 d_instantiate(path
.dentry
, inode
);
2758 inode
->i_size
= size
;
2759 clear_nlink(inode
); /* It is unlinked */
2761 error
= ramfs_nommu_expand_for_mapping(inode
, size
);
2767 file
= alloc_file(&path
, FMODE_WRITE
| FMODE_READ
,
2768 &shmem_file_operations
);
2777 shmem_unacct_size(flags
, size
);
2778 return ERR_PTR(error
);
2780 EXPORT_SYMBOL_GPL(shmem_file_setup
);
2783 * shmem_zero_setup - setup a shared anonymous mapping
2784 * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
2786 int shmem_zero_setup(struct vm_area_struct
*vma
)
2789 loff_t size
= vma
->vm_end
- vma
->vm_start
;
2791 file
= shmem_file_setup("dev/zero", size
, vma
->vm_flags
);
2793 return PTR_ERR(file
);
2797 vma
->vm_file
= file
;
2798 vma
->vm_ops
= &shmem_vm_ops
;
2799 vma
->vm_flags
|= VM_CAN_NONLINEAR
;
2804 * shmem_read_mapping_page_gfp - read into page cache, using specified page allocation flags.
2805 * @mapping: the page's address_space
2806 * @index: the page index
2807 * @gfp: the page allocator flags to use if allocating
2809 * This behaves as a tmpfs "read_cache_page_gfp(mapping, index, gfp)",
2810 * with any new page allocations done using the specified allocation flags.
2811 * But read_cache_page_gfp() uses the ->readpage() method: which does not
2812 * suit tmpfs, since it may have pages in swapcache, and needs to find those
2813 * for itself; although drivers/gpu/drm i915 and ttm rely upon this support.
2815 * i915_gem_object_get_pages_gtt() mixes __GFP_NORETRY | __GFP_NOWARN in
2816 * with the mapping_gfp_mask(), to avoid OOMing the machine unnecessarily.
2818 struct page
*shmem_read_mapping_page_gfp(struct address_space
*mapping
,
2819 pgoff_t index
, gfp_t gfp
)
2822 struct inode
*inode
= mapping
->host
;
2826 BUG_ON(mapping
->a_ops
!= &shmem_aops
);
2827 error
= shmem_getpage_gfp(inode
, index
, &page
, SGP_CACHE
, gfp
, NULL
);
2829 page
= ERR_PTR(error
);
2835 * The tiny !SHMEM case uses ramfs without swap
2837 return read_cache_page_gfp(mapping
, index
, gfp
);
2840 EXPORT_SYMBOL_GPL(shmem_read_mapping_page_gfp
);