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-rw-r--r--fs/Makefile2
-rw-r--r--fs/sync.c164
2 files changed, 165 insertions, 1 deletions
diff --git a/fs/Makefile b/fs/Makefile
index f3a4f7077175..83bf478e786b 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -10,7 +10,7 @@ obj-y := open.o read_write.o file_table.o buffer.o bio.o super.o \
10 ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \ 10 ioctl.o readdir.o select.o fifo.o locks.o dcache.o inode.o \
11 attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \ 11 attr.o bad_inode.o file.o filesystems.o namespace.o aio.o \
12 seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \ 12 seq_file.o xattr.o libfs.o fs-writeback.o mpage.o direct-io.o \
13 ioprio.o pnode.o drop_caches.o splice.o 13 ioprio.o pnode.o drop_caches.o splice.o sync.o
14 14
15obj-$(CONFIG_INOTIFY) += inotify.o 15obj-$(CONFIG_INOTIFY) += inotify.o
16obj-$(CONFIG_EPOLL) += eventpoll.o 16obj-$(CONFIG_EPOLL) += eventpoll.o
diff --git a/fs/sync.c b/fs/sync.c
new file mode 100644
index 000000000000..8616006d2094
--- /dev/null
+++ b/fs/sync.c
@@ -0,0 +1,164 @@
1/*
2 * High-level sync()-related operations
3 */
4
5#include <linux/kernel.h>
6#include <linux/file.h>
7#include <linux/fs.h>
8#include <linux/module.h>
9#include <linux/writeback.h>
10#include <linux/syscalls.h>
11#include <linux/linkage.h>
12#include <linux/pagemap.h>
13
14#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
15 SYNC_FILE_RANGE_WAIT_AFTER)
16
17/*
18 * sys_sync_file_range() permits finely controlled syncing over a segment of
19 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
20 * zero then sys_sync_file_range() will operate from offset out to EOF.
21 *
22 * The flag bits are:
23 *
24 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
25 * before performing the write.
26 *
27 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
28 * range which are not presently under writeback.
29 *
30 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
31 * after performing the write.
32 *
33 * Useful combinations of the flag bits are:
34 *
35 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
36 * in the range which were dirty on entry to sys_sync_file_range() are placed
37 * under writeout. This is a start-write-for-data-integrity operation.
38 *
39 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
40 * are not presently under writeout. This is an asynchronous flush-to-disk
41 * operation. Not suitable for data integrity operations.
42 *
43 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
44 * completion of writeout of all pages in the range. This will be used after an
45 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
46 * for that operation to complete and to return the result.
47 *
48 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
49 * a traditional sync() operation. This is a write-for-data-integrity operation
50 * which will ensure that all pages in the range which were dirty on entry to
51 * sys_sync_file_range() are committed to disk.
52 *
53 *
54 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
55 * I/O errors or ENOSPC conditions and will return those to the caller, after
56 * clearing the EIO and ENOSPC flags in the address_space.
57 *
58 * It should be noted that none of these operations write out the file's
59 * metadata. So unless the application is strictly performing overwrites of
60 * already-instantiated disk blocks, there are no guarantees here that the data
61 * will be available after a crash.
62 */
63asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
64 int flags)
65{
66 int ret;
67 struct file *file;
68 loff_t endbyte; /* inclusive */
69 int fput_needed;
70 umode_t i_mode;
71
72 ret = -EINVAL;
73 if (flags & ~VALID_FLAGS)
74 goto out;
75
76 endbyte = offset + nbytes;
77
78 if ((s64)offset < 0)
79 goto out;
80 if ((s64)endbyte < 0)
81 goto out;
82 if (endbyte < offset)
83 goto out;
84
85 if (sizeof(pgoff_t) == 4) {
86 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
87 /*
88 * The range starts outside a 32 bit machine's
89 * pagecache addressing capabilities. Let it "succeed"
90 */
91 ret = 0;
92 goto out;
93 }
94 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
95 /*
96 * Out to EOF
97 */
98 nbytes = 0;
99 }
100 }
101
102 if (nbytes == 0)
103 endbyte = -1;
104 else
105 endbyte--; /* inclusive */
106
107 ret = -EBADF;
108 file = fget_light(fd, &fput_needed);
109 if (!file)
110 goto out;
111
112 i_mode = file->f_dentry->d_inode->i_mode;
113 ret = -ESPIPE;
114 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
115 !S_ISLNK(i_mode))
116 goto out_put;
117
118 ret = do_sync_file_range(file, offset, endbyte, flags);
119out_put:
120 fput_light(file, fput_needed);
121out:
122 return ret;
123}
124
125/*
126 * `endbyte' is inclusive
127 */
128int do_sync_file_range(struct file *file, loff_t offset, loff_t endbyte,
129 int flags)
130{
131 int ret;
132 struct address_space *mapping;
133
134 mapping = file->f_mapping;
135 if (!mapping) {
136 ret = -EINVAL;
137 goto out;
138 }
139
140 ret = 0;
141 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
142 ret = wait_on_page_writeback_range(mapping,
143 offset >> PAGE_CACHE_SHIFT,
144 endbyte >> PAGE_CACHE_SHIFT);
145 if (ret < 0)
146 goto out;
147 }
148
149 if (flags & SYNC_FILE_RANGE_WRITE) {
150 ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
151 WB_SYNC_NONE);
152 if (ret < 0)
153 goto out;
154 }
155
156 if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
157 ret = wait_on_page_writeback_range(mapping,
158 offset >> PAGE_CACHE_SHIFT,
159 endbyte >> PAGE_CACHE_SHIFT);
160 }
161out:
162 return ret;
163}
164EXPORT_SYMBOL_GPL(do_sync_file_range);
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-22 15:15:21 -0500