blob: 168c78a121bb0f67835dabcae5e3f4edb74e8e7d [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/fadvise.c
3 *
4 * Copyright (C) 2002, Linus Torvalds
5 *
6 * 11Jan2003 akpm@digeo.com
7 * Initial version.
8 */
9
10#include <linux/kernel.h>
11#include <linux/file.h>
12#include <linux/fs.h>
13#include <linux/mm.h>
14#include <linux/pagemap.h>
15#include <linux/backing-dev.h>
16#include <linux/pagevec.h>
17#include <linux/fadvise.h>
Andrew Mortonebcf28e2006-03-24 03:18:04 -080018#include <linux/writeback.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/syscalls.h>
20
21#include <asm/unistd.h>
22
23/*
24 * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could
25 * deactivate the pages and clear PG_Referenced.
26 */
27asmlinkage long sys_fadvise64_64(int fd, loff_t offset, loff_t len, int advice)
28{
29 struct file *file = fget(fd);
30 struct address_space *mapping;
31 struct backing_dev_info *bdi;
Andrew Mortonebcf28e2006-03-24 03:18:04 -080032 loff_t endbyte; /* inclusive */
Linus Torvalds1da177e2005-04-16 15:20:36 -070033 pgoff_t start_index;
34 pgoff_t end_index;
35 unsigned long nrpages;
36 int ret = 0;
37
38 if (!file)
39 return -EBADF;
40
Valentine Barshak87ba81d2006-01-08 01:03:44 -080041 if (S_ISFIFO(file->f_dentry->d_inode->i_mode)) {
42 ret = -ESPIPE;
43 goto out;
44 }
45
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 mapping = file->f_mapping;
47 if (!mapping || len < 0) {
48 ret = -EINVAL;
49 goto out;
50 }
51
Carsten Ottefe77ba62005-06-23 22:05:29 -070052 if (mapping->a_ops->get_xip_page)
53 /* no bad return value, but ignore advice */
54 goto out;
55
Linus Torvalds1da177e2005-04-16 15:20:36 -070056 /* Careful about overflows. Len == 0 means "as much as possible" */
57 endbyte = offset + len;
58 if (!len || endbyte < len)
59 endbyte = -1;
Andrew Mortonebcf28e2006-03-24 03:18:04 -080060 else
61 endbyte--; /* inclusive */
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
63 bdi = mapping->backing_dev_info;
64
65 switch (advice) {
66 case POSIX_FADV_NORMAL:
67 file->f_ra.ra_pages = bdi->ra_pages;
68 break;
69 case POSIX_FADV_RANDOM:
70 file->f_ra.ra_pages = 0;
71 break;
72 case POSIX_FADV_SEQUENTIAL:
73 file->f_ra.ra_pages = bdi->ra_pages * 2;
74 break;
75 case POSIX_FADV_WILLNEED:
Linus Torvalds1da177e2005-04-16 15:20:36 -070076 if (!mapping->a_ops->readpage) {
77 ret = -EINVAL;
78 break;
79 }
80
81 /* First and last PARTIAL page! */
82 start_index = offset >> PAGE_CACHE_SHIFT;
Andrew Mortonebcf28e2006-03-24 03:18:04 -080083 end_index = endbyte >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
85 /* Careful about overflow on the "+1" */
86 nrpages = end_index - start_index + 1;
87 if (!nrpages)
88 nrpages = ~0UL;
89
90 ret = force_page_cache_readahead(mapping, file,
91 start_index,
92 max_sane_readahead(nrpages));
93 if (ret > 0)
94 ret = 0;
95 break;
Andrew Morton60c371b2006-08-05 12:14:25 -070096 case POSIX_FADV_NOREUSE:
97 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 case POSIX_FADV_DONTNEED:
99 if (!bdi_write_congested(mapping->backing_dev_info))
100 filemap_flush(mapping);
101
102 /* First and last FULL page! */
Andrew Mortonebcf28e2006-03-24 03:18:04 -0800103 start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104 end_index = (endbyte >> PAGE_CACHE_SHIFT);
105
Andrew Mortonebcf28e2006-03-24 03:18:04 -0800106 if (end_index >= start_index)
107 invalidate_mapping_pages(mapping, start_index,
108 end_index);
109 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 default:
111 ret = -EINVAL;
112 }
113out:
114 fput(file);
115 return ret;
116}
117
118#ifdef __ARCH_WANT_SYS_FADVISE64
119
120asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
121{
122 return sys_fadvise64_64(fd, offset, len, advice);
123}
124
125#endif