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>
20 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
21 * deactivate the pages and clear PG_Referenced.
23 long sys_fadvise64(int fd
, loff_t offset
, size_t len
, int advice
)
25 struct file
*file
= fget(fd
);
27 struct address_space
*mapping
;
28 struct backing_dev_info
*bdi
;
34 inode
= file
->f_dentry
->d_inode
;
35 mapping
= inode
->i_mapping
;
41 bdi
= mapping
->backing_dev_info
;
44 case POSIX_FADV_NORMAL
:
45 file
->f_ra
.ra_pages
= bdi
->ra_pages
;
47 case POSIX_FADV_RANDOM
:
48 file
->f_ra
.ra_pages
= 0;
50 case POSIX_FADV_SEQUENTIAL
:
51 file
->f_ra
.ra_pages
= bdi
->ra_pages
* 2;
53 case POSIX_FADV_WILLNEED
:
54 case POSIX_FADV_NOREUSE
:
55 if (!mapping
->a_ops
->readpage
) {
59 ret
= do_page_cache_readahead(mapping
, file
,
60 offset
>> PAGE_CACHE_SHIFT
,
61 max_sane_readahead(len
>> PAGE_CACHE_SHIFT
));
65 case POSIX_FADV_DONTNEED
:
66 if (!bdi_write_congested(mapping
->backing_dev_info
))
67 filemap_flush(mapping
);
68 invalidate_mapping_pages(mapping
, offset
>> PAGE_CACHE_SHIFT
,
69 (len
>> PAGE_CACHE_SHIFT
) + 1);