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1 | /* | |
2 | * mm/fadvise.c | |
3 | * | |
4 | * Copyright (C) 2002, Linus Torvalds | |
5 | * | |
6 | * 11Jan2003 Andrew Morton | |
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> | |
18 | #include <linux/writeback.h> | |
19 | #include <linux/syscalls.h> | |
20 | #include <linux/swap.h> | |
21 | ||
22 | #include <asm/unistd.h> | |
23 | ||
24 | /* | |
25 | * POSIX_FADV_WILLNEED could set PG_Referenced, and POSIX_FADV_NOREUSE could | |
26 | * deactivate the pages and clear PG_Referenced. | |
27 | */ | |
28 | SYSCALL_DEFINE4(fadvise64_64, int, fd, loff_t, offset, loff_t, len, int, advice) | |
29 | { | |
30 | struct fd f = fdget(fd); | |
31 | struct address_space *mapping; | |
32 | struct backing_dev_info *bdi; | |
33 | loff_t endbyte; /* inclusive */ | |
34 | pgoff_t start_index; | |
35 | pgoff_t end_index; | |
36 | unsigned long nrpages; | |
37 | int ret = 0; | |
38 | ||
39 | if (!f.file) | |
40 | return -EBADF; | |
41 | ||
42 | if (S_ISFIFO(file_inode(f.file)->i_mode)) { | |
43 | ret = -ESPIPE; | |
44 | goto out; | |
45 | } | |
46 | ||
47 | mapping = f.file->f_mapping; | |
48 | if (!mapping || len < 0) { | |
49 | ret = -EINVAL; | |
50 | goto out; | |
51 | } | |
52 | ||
53 | if (mapping->a_ops->get_xip_mem) { | |
54 | switch (advice) { | |
55 | case POSIX_FADV_NORMAL: | |
56 | case POSIX_FADV_RANDOM: | |
57 | case POSIX_FADV_SEQUENTIAL: | |
58 | case POSIX_FADV_WILLNEED: | |
59 | case POSIX_FADV_NOREUSE: | |
60 | case POSIX_FADV_DONTNEED: | |
61 | /* no bad return value, but ignore advice */ | |
62 | break; | |
63 | default: | |
64 | ret = -EINVAL; | |
65 | } | |
66 | goto out; | |
67 | } | |
68 | ||
69 | /* Careful about overflows. Len == 0 means "as much as possible" */ | |
70 | endbyte = offset + len; | |
71 | if (!len || endbyte < len) | |
72 | endbyte = -1; | |
73 | else | |
74 | endbyte--; /* inclusive */ | |
75 | ||
76 | bdi = mapping->backing_dev_info; | |
77 | ||
78 | switch (advice) { | |
79 | case POSIX_FADV_NORMAL: | |
80 | f.file->f_ra.ra_pages = bdi->ra_pages; | |
81 | spin_lock(&f.file->f_lock); | |
82 | f.file->f_mode &= ~FMODE_RANDOM; | |
83 | spin_unlock(&f.file->f_lock); | |
84 | break; | |
85 | case POSIX_FADV_RANDOM: | |
86 | spin_lock(&f.file->f_lock); | |
87 | f.file->f_mode |= FMODE_RANDOM; | |
88 | spin_unlock(&f.file->f_lock); | |
89 | break; | |
90 | case POSIX_FADV_SEQUENTIAL: | |
91 | f.file->f_ra.ra_pages = bdi->ra_pages * 2; | |
92 | spin_lock(&f.file->f_lock); | |
93 | f.file->f_mode &= ~FMODE_RANDOM; | |
94 | spin_unlock(&f.file->f_lock); | |
95 | break; | |
96 | case POSIX_FADV_WILLNEED: | |
97 | /* First and last PARTIAL page! */ | |
98 | start_index = offset >> PAGE_CACHE_SHIFT; | |
99 | end_index = endbyte >> PAGE_CACHE_SHIFT; | |
100 | ||
101 | /* Careful about overflow on the "+1" */ | |
102 | nrpages = end_index - start_index + 1; | |
103 | if (!nrpages) | |
104 | nrpages = ~0UL; | |
105 | ||
106 | /* | |
107 | * Ignore return value because fadvise() shall return | |
108 | * success even if filesystem can't retrieve a hint, | |
109 | */ | |
110 | force_page_cache_readahead(mapping, f.file, start_index, | |
111 | nrpages); | |
112 | break; | |
113 | case POSIX_FADV_NOREUSE: | |
114 | break; | |
115 | case POSIX_FADV_DONTNEED: | |
116 | if (!bdi_write_congested(mapping->backing_dev_info)) | |
117 | __filemap_fdatawrite_range(mapping, offset, endbyte, | |
118 | WB_SYNC_NONE); | |
119 | ||
120 | /* First and last FULL page! */ | |
121 | start_index = (offset+(PAGE_CACHE_SIZE-1)) >> PAGE_CACHE_SHIFT; | |
122 | end_index = (endbyte >> PAGE_CACHE_SHIFT); | |
123 | ||
124 | if (end_index >= start_index) { | |
125 | unsigned long count = invalidate_mapping_pages(mapping, | |
126 | start_index, end_index); | |
127 | ||
128 | /* | |
129 | * If fewer pages were invalidated than expected then | |
130 | * it is possible that some of the pages were on | |
131 | * a per-cpu pagevec for a remote CPU. Drain all | |
132 | * pagevecs and try again. | |
133 | */ | |
134 | if (count < (end_index - start_index + 1)) { | |
135 | lru_add_drain_all(); | |
136 | invalidate_mapping_pages(mapping, start_index, | |
137 | end_index); | |
138 | } | |
139 | } | |
140 | break; | |
141 | default: | |
142 | ret = -EINVAL; | |
143 | } | |
144 | out: | |
145 | fdput(f); | |
146 | return ret; | |
147 | } | |
148 | ||
149 | #ifdef __ARCH_WANT_SYS_FADVISE64 | |
150 | ||
151 | SYSCALL_DEFINE4(fadvise64, int, fd, loff_t, offset, size_t, len, int, advice) | |
152 | { | |
153 | return sys_fadvise64_64(fd, offset, len, advice); | |
154 | } | |
155 | ||
156 | #endif |