blob: a1da969bd9803cf334c3c5c1e9746e96eba1f377 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * mm/fadvise.c
3 *
4 * Copyright (C) 2002, Linus Torvalds
5 *
Francois Camie1f8e872008-10-15 22:01:59 -07006 * 11Jan2003 Andrew Morton
Linus Torvalds1da177e2005-04-16 15:20:36 -07007 * 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
Josef "Jeff" Sipekd3ac7f82006-12-08 02:36:44 -080041 if (S_ISFIFO(file->f_path.dentry->d_inode->i_mode)) {
Valentine Barshak87ba81d2006-01-08 01:03:44 -080042 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
Nick Piggin70688e42008-04-28 02:13:02 -070052 if (mapping->a_ops->get_xip_mem) {
Masatake YAMATOb5beb1c2008-02-04 22:29:31 -080053 switch (advice) {
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 */
61 break;
62 default:
63 ret = -EINVAL;
64 }
Carsten Ottefe77ba62005-06-23 22:05:29 -070065 goto out;
Masatake YAMATOb5beb1c2008-02-04 22:29:31 -080066 }
Carsten Ottefe77ba62005-06-23 22:05:29 -070067
Linus Torvalds1da177e2005-04-16 15:20:36 -070068 /* Careful about overflows. Len == 0 means "as much as possible" */
69 endbyte = offset + len;
70 if (!len || endbyte < len)
71 endbyte = -1;
Andrew Mortonebcf28e2006-03-24 03:18:04 -080072 else
73 endbyte--; /* inclusive */
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
75 bdi = mapping->backing_dev_info;
76
77 switch (advice) {
78 case POSIX_FADV_NORMAL:
79 file->f_ra.ra_pages = bdi->ra_pages;
80 break;
81 case POSIX_FADV_RANDOM:
82 file->f_ra.ra_pages = 0;
83 break;
84 case POSIX_FADV_SEQUENTIAL:
85 file->f_ra.ra_pages = bdi->ra_pages * 2;
86 break;
87 case POSIX_FADV_WILLNEED:
Linus Torvalds1da177e2005-04-16 15:20:36 -070088 if (!mapping->a_ops->readpage) {
89 ret = -EINVAL;
90 break;
91 }
92
93 /* First and last PARTIAL page! */
94 start_index = offset >> PAGE_CACHE_SHIFT;
Andrew Mortonebcf28e2006-03-24 03:18:04 -080095 end_index = endbyte >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096
97 /* Careful about overflow on the "+1" */
98 nrpages = end_index - start_index + 1;
99 if (!nrpages)
100 nrpages = ~0UL;
101
102 ret = force_page_cache_readahead(mapping, file,
103 start_index,
104 max_sane_readahead(nrpages));
105 if (ret > 0)
106 ret = 0;
107 break;
Andrew Morton60c371b2006-08-05 12:14:25 -0700108 case POSIX_FADV_NOREUSE:
109 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 case POSIX_FADV_DONTNEED:
111 if (!bdi_write_congested(mapping->backing_dev_info))
112 filemap_flush(mapping);
113
114 /* First and last FULL page! */
Andrew Mortonebcf28e2006-03-24 03:18:04 -0800115 start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 end_index = (endbyte >> PAGE_CACHE_SHIFT);
117
Andrew Mortonebcf28e2006-03-24 03:18:04 -0800118 if (end_index >= start_index)
119 invalidate_mapping_pages(mapping, start_index,
120 end_index);
121 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 default:
123 ret = -EINVAL;
124 }
125out:
126 fput(file);
127 return ret;
128}
129
130#ifdef __ARCH_WANT_SYS_FADVISE64
131
132asmlinkage long sys_fadvise64(int fd, loff_t offset, size_t len, int advice)
133{
134 return sys_fadvise64_64(fd, offset, len, advice);
135}
136
137#endif