]>
git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - mm/fadvise.c
4 * Copyright (C) 2002, Linus Torvalds
6 * 11Jan2003 akpm@digeo.com
10 #include <linux/kernel.h>
11 #include <linux/file.h>
14 #include <linux/pagemap.h>
15 #include <linux/backing-dev.h>
16 #include <linux/pagevec.h>
17 #include <linux/fadvise.h>
18 #include <linux/writeback.h>
19 #include <linux/syscalls.h>
21 #include <asm/unistd.h>
24 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
25 * deactivate the pages and clear PG_Referenced.
27 asmlinkage
long sys_fadvise64_64(int fd
, loff_t offset
, loff_t len
, int advice
)
29 struct file
*file
= fget(fd
);
30 struct address_space
*mapping
;
31 struct backing_dev_info
*bdi
;
32 loff_t endbyte
; /* inclusive */
35 unsigned long nrpages
;
41 if (S_ISFIFO(file
->f_path
.dentry
->d_inode
->i_mode
)) {
46 mapping
= file
->f_mapping
;
47 if (!mapping
|| len
< 0) {
52 if (mapping
->a_ops
->get_xip_page
) {
54 case POSIX_FADV_NORMAL
:
55 case POSIX_FADV_RANDOM
:
56 case POSIX_FADV_SEQUENTIAL
:
57 case POSIX_FADV_WILLNEED
:
58 case POSIX_FADV_NOREUSE
:
59 case POSIX_FADV_DONTNEED
:
60 /* no bad return value, but ignore advice */
68 /* Careful about overflows. Len == 0 means "as much as possible" */
69 endbyte
= offset
+ len
;
70 if (!len
|| endbyte
< len
)
73 endbyte
--; /* inclusive */
75 bdi
= mapping
->backing_dev_info
;
78 case POSIX_FADV_NORMAL
:
79 file
->f_ra
.ra_pages
= bdi
->ra_pages
;
81 case POSIX_FADV_RANDOM
:
82 file
->f_ra
.ra_pages
= 0;
84 case POSIX_FADV_SEQUENTIAL
:
85 file
->f_ra
.ra_pages
= bdi
->ra_pages
* 2;
87 case POSIX_FADV_WILLNEED
:
88 if (!mapping
->a_ops
->readpage
) {
93 /* First and last PARTIAL page! */
94 start_index
= offset
>> PAGE_CACHE_SHIFT
;
95 end_index
= endbyte
>> PAGE_CACHE_SHIFT
;
97 /* Careful about overflow on the "+1" */
98 nrpages
= end_index
- start_index
+ 1;
102 ret
= force_page_cache_readahead(mapping
, file
,
104 max_sane_readahead(nrpages
));
108 case POSIX_FADV_NOREUSE
:
110 case POSIX_FADV_DONTNEED
:
111 if (!bdi_write_congested(mapping
->backing_dev_info
))
112 filemap_flush(mapping
);
114 /* First and last FULL page! */
115 start_index
= (offset
+(PAGE_CACHE_SIZE
-1)) >> PAGE_CACHE_SHIFT
;
116 end_index
= (endbyte
>> PAGE_CACHE_SHIFT
);
118 if (end_index
>= start_index
)
119 invalidate_mapping_pages(mapping
, start_index
,
130 #ifdef __ARCH_WANT_SYS_FADVISE64
132 asmlinkage
long sys_fadvise64(int fd
, loff_t offset
, size_t len
, int advice
)
134 return sys_fadvise64_64(fd
, offset
, len
, advice
);