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[mirror_ubuntu-bionic-kernel.git] / fs / sync.c
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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>
914e2637 9#include <linux/sched.h>
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10#include <linux/writeback.h>
11#include <linux/syscalls.h>
12#include <linux/linkage.h>
13#include <linux/pagemap.h>
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14#include <linux/quotaops.h>
15#include <linux/buffer_head.h>
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16
17#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
18 SYNC_FILE_RANGE_WAIT_AFTER)
19
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20/*
21 * sync everything. Start out by waking pdflush, because that writes back
22 * all queues in parallel.
23 */
24static void do_sync(unsigned long wait)
25{
26 wakeup_pdflush(0);
27 sync_inodes(0); /* All mappings, inodes and their blockdevs */
28 DQUOT_SYNC(NULL);
29 sync_supers(); /* Write the superblocks */
30 sync_filesystems(0); /* Start syncing the filesystems */
31 sync_filesystems(wait); /* Waitingly sync the filesystems */
32 sync_inodes(wait); /* Mappings, inodes and blockdevs, again. */
33 if (!wait)
34 printk("Emergency Sync complete\n");
35 if (unlikely(laptop_mode))
36 laptop_sync_completion();
37}
38
39asmlinkage long sys_sync(void)
40{
41 do_sync(1);
42 return 0;
43}
44
45void emergency_sync(void)
46{
47 pdflush_operation(do_sync, 0);
48}
49
50/*
51 * Generic function to fsync a file.
52 *
53 * filp may be NULL if called via the msync of a vma.
54 */
55int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
56{
57 struct inode * inode = dentry->d_inode;
58 struct super_block * sb;
59 int ret, err;
60
61 /* sync the inode to buffers */
62 ret = write_inode_now(inode, 0);
63
64 /* sync the superblock to buffers */
65 sb = inode->i_sb;
66 lock_super(sb);
762873c2 67 if (sb->s_dirt && sb->s_op->write_super)
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68 sb->s_op->write_super(sb);
69 unlock_super(sb);
70
71 /* .. finally sync the buffers to disk */
72 err = sync_blockdev(sb->s_bdev);
73 if (!ret)
74 ret = err;
75 return ret;
76}
77
78long do_fsync(struct file *file, int datasync)
79{
80 int ret;
81 int err;
82 struct address_space *mapping = file->f_mapping;
83
84 if (!file->f_op || !file->f_op->fsync) {
85 /* Why? We can still call filemap_fdatawrite */
86 ret = -EINVAL;
87 goto out;
88 }
89
90 ret = filemap_fdatawrite(mapping);
91
92 /*
93 * We need to protect against concurrent writers, which could cause
94 * livelocks in fsync_buffers_list().
95 */
96 mutex_lock(&mapping->host->i_mutex);
0f7fc9e4 97 err = file->f_op->fsync(file, file->f_path.dentry, datasync);
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98 if (!ret)
99 ret = err;
100 mutex_unlock(&mapping->host->i_mutex);
101 err = filemap_fdatawait(mapping);
102 if (!ret)
103 ret = err;
104out:
105 return ret;
106}
107
108static long __do_fsync(unsigned int fd, int datasync)
109{
110 struct file *file;
111 int ret = -EBADF;
112
113 file = fget(fd);
114 if (file) {
115 ret = do_fsync(file, datasync);
116 fput(file);
117 }
118 return ret;
119}
120
121asmlinkage long sys_fsync(unsigned int fd)
122{
123 return __do_fsync(fd, 0);
124}
125
126asmlinkage long sys_fdatasync(unsigned int fd)
127{
128 return __do_fsync(fd, 1);
129}
130
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131/*
132 * sys_sync_file_range() permits finely controlled syncing over a segment of
133 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
134 * zero then sys_sync_file_range() will operate from offset out to EOF.
135 *
136 * The flag bits are:
137 *
138 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
139 * before performing the write.
140 *
141 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
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142 * range which are not presently under writeback. Note that this may block for
143 * significant periods due to exhaustion of disk request structures.
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144 *
145 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
146 * after performing the write.
147 *
148 * Useful combinations of the flag bits are:
149 *
150 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
151 * in the range which were dirty on entry to sys_sync_file_range() are placed
152 * under writeout. This is a start-write-for-data-integrity operation.
153 *
154 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
155 * are not presently under writeout. This is an asynchronous flush-to-disk
156 * operation. Not suitable for data integrity operations.
157 *
158 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
159 * completion of writeout of all pages in the range. This will be used after an
160 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
161 * for that operation to complete and to return the result.
162 *
163 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
164 * a traditional sync() operation. This is a write-for-data-integrity operation
165 * which will ensure that all pages in the range which were dirty on entry to
166 * sys_sync_file_range() are committed to disk.
167 *
168 *
169 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
170 * I/O errors or ENOSPC conditions and will return those to the caller, after
171 * clearing the EIO and ENOSPC flags in the address_space.
172 *
173 * It should be noted that none of these operations write out the file's
174 * metadata. So unless the application is strictly performing overwrites of
175 * already-instantiated disk blocks, there are no guarantees here that the data
176 * will be available after a crash.
177 */
178asmlinkage long sys_sync_file_range(int fd, loff_t offset, loff_t nbytes,
5246d050 179 unsigned int flags)
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180{
181 int ret;
182 struct file *file;
183 loff_t endbyte; /* inclusive */
184 int fput_needed;
185 umode_t i_mode;
186
187 ret = -EINVAL;
188 if (flags & ~VALID_FLAGS)
189 goto out;
190
191 endbyte = offset + nbytes;
192
193 if ((s64)offset < 0)
194 goto out;
195 if ((s64)endbyte < 0)
196 goto out;
197 if (endbyte < offset)
198 goto out;
199
200 if (sizeof(pgoff_t) == 4) {
201 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
202 /*
203 * The range starts outside a 32 bit machine's
204 * pagecache addressing capabilities. Let it "succeed"
205 */
206 ret = 0;
207 goto out;
208 }
209 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
210 /*
211 * Out to EOF
212 */
213 nbytes = 0;
214 }
215 }
216
217 if (nbytes == 0)
111ebb6e 218 endbyte = LLONG_MAX;
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219 else
220 endbyte--; /* inclusive */
221
222 ret = -EBADF;
223 file = fget_light(fd, &fput_needed);
224 if (!file)
225 goto out;
226
0f7fc9e4 227 i_mode = file->f_path.dentry->d_inode->i_mode;
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228 ret = -ESPIPE;
229 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
230 !S_ISLNK(i_mode))
231 goto out_put;
232
ef51c976 233 ret = do_sync_mapping_range(file->f_mapping, offset, endbyte, flags);
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234out_put:
235 fput_light(file, fput_needed);
236out:
237 return ret;
238}
239
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240/* It would be nice if people remember that not all the world's an i386
241 when they introduce new system calls */
242asmlinkage long sys_sync_file_range2(int fd, unsigned int flags,
243 loff_t offset, loff_t nbytes)
244{
245 return sys_sync_file_range(fd, offset, nbytes, flags);
246}
247
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248/*
249 * `endbyte' is inclusive
250 */
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251int do_sync_mapping_range(struct address_space *mapping, loff_t offset,
252 loff_t endbyte, unsigned int flags)
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253{
254 int ret;
f79e2abb 255
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256 if (!mapping) {
257 ret = -EINVAL;
258 goto out;
259 }
260
261 ret = 0;
262 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
263 ret = wait_on_page_writeback_range(mapping,
264 offset >> PAGE_CACHE_SHIFT,
265 endbyte >> PAGE_CACHE_SHIFT);
266 if (ret < 0)
267 goto out;
268 }
269
270 if (flags & SYNC_FILE_RANGE_WRITE) {
271 ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
272 WB_SYNC_NONE);
273 if (ret < 0)
274 goto out;
275 }
276
277 if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
278 ret = wait_on_page_writeback_range(mapping,
279 offset >> PAGE_CACHE_SHIFT,
280 endbyte >> PAGE_CACHE_SHIFT);
281 }
282out:
283 return ret;
284}
5b04aa3a 285EXPORT_SYMBOL_GPL(do_sync_mapping_range);