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Commit | Line | Data |
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f79e2abb AM |
1 | /* |
2 | * High-level sync()-related operations | |
3 | */ | |
4 | ||
5 | #include <linux/kernel.h> | |
6 | #include <linux/file.h> | |
7 | #include <linux/fs.h> | |
5a0e3ad6 | 8 | #include <linux/slab.h> |
630d9c47 | 9 | #include <linux/export.h> |
b7ed78f5 | 10 | #include <linux/namei.h> |
914e2637 | 11 | #include <linux/sched.h> |
f79e2abb AM |
12 | #include <linux/writeback.h> |
13 | #include <linux/syscalls.h> | |
14 | #include <linux/linkage.h> | |
15 | #include <linux/pagemap.h> | |
cf9a2ae8 | 16 | #include <linux/quotaops.h> |
5129a469 | 17 | #include <linux/backing-dev.h> |
5a3e5cb8 | 18 | #include "internal.h" |
f79e2abb AM |
19 | |
20 | #define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \ | |
21 | SYNC_FILE_RANGE_WAIT_AFTER) | |
22 | ||
c15c54f5 | 23 | /* |
d8a8559c JA |
24 | * Do the filesystem syncing work. For simple filesystems |
25 | * writeback_inodes_sb(sb) just dirties buffers with inodes so we have to | |
26 | * submit IO for these buffers via __sync_blockdev(). This also speeds up the | |
27 | * wait == 1 case since in that case write_inode() functions do | |
28 | * sync_dirty_buffer() and thus effectively write one block at a time. | |
c15c54f5 | 29 | */ |
0dc83bd3 | 30 | static int __sync_filesystem(struct super_block *sb, int wait) |
c15c54f5 | 31 | { |
5fb324ad | 32 | if (wait) |
0dc83bd3 | 33 | sync_inodes_sb(sb); |
5fb324ad | 34 | else |
0e175a18 | 35 | writeback_inodes_sb(sb, WB_REASON_SYNC); |
5fb324ad | 36 | |
c15c54f5 JK |
37 | if (sb->s_op->sync_fs) |
38 | sb->s_op->sync_fs(sb, wait); | |
39 | return __sync_blockdev(sb->s_bdev, wait); | |
40 | } | |
41 | ||
42 | /* | |
43 | * Write out and wait upon all dirty data associated with this | |
44 | * superblock. Filesystem data as well as the underlying block | |
45 | * device. Takes the superblock lock. | |
46 | */ | |
60b0680f | 47 | int sync_filesystem(struct super_block *sb) |
c15c54f5 JK |
48 | { |
49 | int ret; | |
50 | ||
5af7926f CH |
51 | /* |
52 | * We need to be protected against the filesystem going from | |
53 | * r/o to r/w or vice versa. | |
54 | */ | |
55 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); | |
56 | ||
57 | /* | |
58 | * No point in syncing out anything if the filesystem is read-only. | |
59 | */ | |
60 | if (sb->s_flags & MS_RDONLY) | |
61 | return 0; | |
62 | ||
0dc83bd3 | 63 | ret = __sync_filesystem(sb, 0); |
c15c54f5 JK |
64 | if (ret < 0) |
65 | return ret; | |
0dc83bd3 | 66 | return __sync_filesystem(sb, 1); |
c15c54f5 | 67 | } |
10096fb1 | 68 | EXPORT_SYMBOL(sync_filesystem); |
c15c54f5 | 69 | |
b3de6531 | 70 | static void sync_inodes_one_sb(struct super_block *sb, void *arg) |
01a05b33 | 71 | { |
95f28604 | 72 | if (!(sb->s_flags & MS_RDONLY)) |
0dc83bd3 | 73 | sync_inodes_sb(sb); |
01a05b33 | 74 | } |
b3de6531 | 75 | |
b3de6531 JK |
76 | static void sync_fs_one_sb(struct super_block *sb, void *arg) |
77 | { | |
78 | if (!(sb->s_flags & MS_RDONLY) && sb->s_op->sync_fs) | |
79 | sb->s_op->sync_fs(sb, *(int *)arg); | |
80 | } | |
81 | ||
d0e91b13 | 82 | static void fdatawrite_one_bdev(struct block_device *bdev, void *arg) |
b3de6531 | 83 | { |
d0e91b13 | 84 | filemap_fdatawrite(bdev->bd_inode->i_mapping); |
a8c7176b JK |
85 | } |
86 | ||
d0e91b13 | 87 | static void fdatawait_one_bdev(struct block_device *bdev, void *arg) |
a8c7176b | 88 | { |
aa750fd7 JN |
89 | /* |
90 | * We keep the error status of individual mapping so that | |
91 | * applications can catch the writeback error using fsync(2). | |
92 | * See filemap_fdatawait_keep_errors() for details. | |
93 | */ | |
94 | filemap_fdatawait_keep_errors(bdev->bd_inode->i_mapping); | |
c15c54f5 JK |
95 | } |
96 | ||
3beab0b4 | 97 | /* |
4ea425b6 JK |
98 | * Sync everything. We start by waking flusher threads so that most of |
99 | * writeback runs on all devices in parallel. Then we sync all inodes reliably | |
100 | * which effectively also waits for all flusher threads to finish doing | |
101 | * writeback. At this point all data is on disk so metadata should be stable | |
102 | * and we tell filesystems to sync their metadata via ->sync_fs() calls. | |
103 | * Finally, we writeout all block devices because some filesystems (e.g. ext2) | |
104 | * just write metadata (such as inodes or bitmaps) to block device page cache | |
105 | * and do not sync it on their own in ->sync_fs(). | |
3beab0b4 | 106 | */ |
5cee5815 | 107 | SYSCALL_DEFINE0(sync) |
cf9a2ae8 | 108 | { |
b3de6531 JK |
109 | int nowait = 0, wait = 1; |
110 | ||
0e175a18 | 111 | wakeup_flusher_threads(0, WB_REASON_SYNC); |
0dc83bd3 | 112 | iterate_supers(sync_inodes_one_sb, NULL); |
4ea425b6 | 113 | iterate_supers(sync_fs_one_sb, &nowait); |
b3de6531 | 114 | iterate_supers(sync_fs_one_sb, &wait); |
d0e91b13 JK |
115 | iterate_bdevs(fdatawrite_one_bdev, NULL); |
116 | iterate_bdevs(fdatawait_one_bdev, NULL); | |
cf9a2ae8 DH |
117 | if (unlikely(laptop_mode)) |
118 | laptop_sync_completion(); | |
cf9a2ae8 DH |
119 | return 0; |
120 | } | |
121 | ||
a2a9537a JA |
122 | static void do_sync_work(struct work_struct *work) |
123 | { | |
b3de6531 JK |
124 | int nowait = 0; |
125 | ||
5cee5815 JK |
126 | /* |
127 | * Sync twice to reduce the possibility we skipped some inodes / pages | |
128 | * because they were temporarily locked | |
129 | */ | |
b3de6531 JK |
130 | iterate_supers(sync_inodes_one_sb, &nowait); |
131 | iterate_supers(sync_fs_one_sb, &nowait); | |
d0e91b13 | 132 | iterate_bdevs(fdatawrite_one_bdev, NULL); |
b3de6531 JK |
133 | iterate_supers(sync_inodes_one_sb, &nowait); |
134 | iterate_supers(sync_fs_one_sb, &nowait); | |
d0e91b13 | 135 | iterate_bdevs(fdatawrite_one_bdev, NULL); |
5cee5815 | 136 | printk("Emergency Sync complete\n"); |
a2a9537a JA |
137 | kfree(work); |
138 | } | |
139 | ||
cf9a2ae8 DH |
140 | void emergency_sync(void) |
141 | { | |
a2a9537a JA |
142 | struct work_struct *work; |
143 | ||
144 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
145 | if (work) { | |
146 | INIT_WORK(work, do_sync_work); | |
147 | schedule_work(work); | |
148 | } | |
cf9a2ae8 DH |
149 | } |
150 | ||
b7ed78f5 SW |
151 | /* |
152 | * sync a single super | |
153 | */ | |
154 | SYSCALL_DEFINE1(syncfs, int, fd) | |
155 | { | |
2903ff01 | 156 | struct fd f = fdget(fd); |
b7ed78f5 SW |
157 | struct super_block *sb; |
158 | int ret; | |
b7ed78f5 | 159 | |
2903ff01 | 160 | if (!f.file) |
b7ed78f5 | 161 | return -EBADF; |
b583043e | 162 | sb = f.file->f_path.dentry->d_sb; |
b7ed78f5 SW |
163 | |
164 | down_read(&sb->s_umount); | |
165 | ret = sync_filesystem(sb); | |
166 | up_read(&sb->s_umount); | |
167 | ||
2903ff01 | 168 | fdput(f); |
b7ed78f5 SW |
169 | return ret; |
170 | } | |
171 | ||
4c728ef5 | 172 | /** |
148f948b | 173 | * vfs_fsync_range - helper to sync a range of data & metadata to disk |
4c728ef5 | 174 | * @file: file to sync |
148f948b JK |
175 | * @start: offset in bytes of the beginning of data range to sync |
176 | * @end: offset in bytes of the end of data range (inclusive) | |
177 | * @datasync: perform only datasync | |
4c728ef5 | 178 | * |
148f948b JK |
179 | * Write back data in range @start..@end and metadata for @file to disk. If |
180 | * @datasync is set only metadata needed to access modified file data is | |
181 | * written. | |
4c728ef5 | 182 | */ |
8018ab05 | 183 | int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync) |
cf9a2ae8 | 184 | { |
0ae45f63 TT |
185 | struct inode *inode = file->f_mapping->host; |
186 | ||
72c2d531 | 187 | if (!file->f_op->fsync) |
02c24a82 | 188 | return -EINVAL; |
0ae45f63 TT |
189 | if (!datasync && (inode->i_state & I_DIRTY_TIME)) { |
190 | spin_lock(&inode->i_lock); | |
191 | inode->i_state &= ~I_DIRTY_TIME; | |
192 | spin_unlock(&inode->i_lock); | |
193 | mark_inode_dirty_sync(inode); | |
194 | } | |
02c24a82 | 195 | return file->f_op->fsync(file, start, end, datasync); |
cf9a2ae8 | 196 | } |
148f948b JK |
197 | EXPORT_SYMBOL(vfs_fsync_range); |
198 | ||
199 | /** | |
200 | * vfs_fsync - perform a fsync or fdatasync on a file | |
201 | * @file: file to sync | |
148f948b JK |
202 | * @datasync: only perform a fdatasync operation |
203 | * | |
204 | * Write back data and metadata for @file to disk. If @datasync is | |
205 | * set only metadata needed to access modified file data is written. | |
148f948b | 206 | */ |
8018ab05 | 207 | int vfs_fsync(struct file *file, int datasync) |
148f948b | 208 | { |
8018ab05 | 209 | return vfs_fsync_range(file, 0, LLONG_MAX, datasync); |
148f948b | 210 | } |
4c728ef5 | 211 | EXPORT_SYMBOL(vfs_fsync); |
cf9a2ae8 | 212 | |
4c728ef5 | 213 | static int do_fsync(unsigned int fd, int datasync) |
cf9a2ae8 | 214 | { |
2903ff01 | 215 | struct fd f = fdget(fd); |
cf9a2ae8 DH |
216 | int ret = -EBADF; |
217 | ||
2903ff01 AV |
218 | if (f.file) { |
219 | ret = vfs_fsync(f.file, datasync); | |
220 | fdput(f); | |
cf9a2ae8 DH |
221 | } |
222 | return ret; | |
223 | } | |
224 | ||
a5f8fa9e | 225 | SYSCALL_DEFINE1(fsync, unsigned int, fd) |
cf9a2ae8 | 226 | { |
4c728ef5 | 227 | return do_fsync(fd, 0); |
cf9a2ae8 DH |
228 | } |
229 | ||
a5f8fa9e | 230 | SYSCALL_DEFINE1(fdatasync, unsigned int, fd) |
cf9a2ae8 | 231 | { |
4c728ef5 | 232 | return do_fsync(fd, 1); |
cf9a2ae8 DH |
233 | } |
234 | ||
f79e2abb AM |
235 | /* |
236 | * sys_sync_file_range() permits finely controlled syncing over a segment of | |
237 | * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is | |
238 | * zero then sys_sync_file_range() will operate from offset out to EOF. | |
239 | * | |
240 | * The flag bits are: | |
241 | * | |
242 | * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range | |
243 | * before performing the write. | |
244 | * | |
245 | * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the | |
cce77081 PM |
246 | * range which are not presently under writeback. Note that this may block for |
247 | * significant periods due to exhaustion of disk request structures. | |
f79e2abb AM |
248 | * |
249 | * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range | |
250 | * after performing the write. | |
251 | * | |
252 | * Useful combinations of the flag bits are: | |
253 | * | |
254 | * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages | |
255 | * in the range which were dirty on entry to sys_sync_file_range() are placed | |
256 | * under writeout. This is a start-write-for-data-integrity operation. | |
257 | * | |
258 | * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which | |
259 | * are not presently under writeout. This is an asynchronous flush-to-disk | |
260 | * operation. Not suitable for data integrity operations. | |
261 | * | |
262 | * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for | |
263 | * completion of writeout of all pages in the range. This will be used after an | |
264 | * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait | |
265 | * for that operation to complete and to return the result. | |
266 | * | |
267 | * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER: | |
268 | * a traditional sync() operation. This is a write-for-data-integrity operation | |
269 | * which will ensure that all pages in the range which were dirty on entry to | |
270 | * sys_sync_file_range() are committed to disk. | |
271 | * | |
272 | * | |
273 | * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any | |
274 | * I/O errors or ENOSPC conditions and will return those to the caller, after | |
275 | * clearing the EIO and ENOSPC flags in the address_space. | |
276 | * | |
277 | * It should be noted that none of these operations write out the file's | |
278 | * metadata. So unless the application is strictly performing overwrites of | |
279 | * already-instantiated disk blocks, there are no guarantees here that the data | |
280 | * will be available after a crash. | |
281 | */ | |
4a0fd5bf AV |
282 | SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes, |
283 | unsigned int, flags) | |
f79e2abb AM |
284 | { |
285 | int ret; | |
2903ff01 | 286 | struct fd f; |
7a0ad10c | 287 | struct address_space *mapping; |
f79e2abb | 288 | loff_t endbyte; /* inclusive */ |
f79e2abb AM |
289 | umode_t i_mode; |
290 | ||
291 | ret = -EINVAL; | |
292 | if (flags & ~VALID_FLAGS) | |
293 | goto out; | |
294 | ||
295 | endbyte = offset + nbytes; | |
296 | ||
297 | if ((s64)offset < 0) | |
298 | goto out; | |
299 | if ((s64)endbyte < 0) | |
300 | goto out; | |
301 | if (endbyte < offset) | |
302 | goto out; | |
303 | ||
304 | if (sizeof(pgoff_t) == 4) { | |
09cbfeaf | 305 | if (offset >= (0x100000000ULL << PAGE_SHIFT)) { |
f79e2abb AM |
306 | /* |
307 | * The range starts outside a 32 bit machine's | |
308 | * pagecache addressing capabilities. Let it "succeed" | |
309 | */ | |
310 | ret = 0; | |
311 | goto out; | |
312 | } | |
09cbfeaf | 313 | if (endbyte >= (0x100000000ULL << PAGE_SHIFT)) { |
f79e2abb AM |
314 | /* |
315 | * Out to EOF | |
316 | */ | |
317 | nbytes = 0; | |
318 | } | |
319 | } | |
320 | ||
321 | if (nbytes == 0) | |
111ebb6e | 322 | endbyte = LLONG_MAX; |
f79e2abb AM |
323 | else |
324 | endbyte--; /* inclusive */ | |
325 | ||
326 | ret = -EBADF; | |
2903ff01 AV |
327 | f = fdget(fd); |
328 | if (!f.file) | |
f79e2abb AM |
329 | goto out; |
330 | ||
496ad9aa | 331 | i_mode = file_inode(f.file)->i_mode; |
f79e2abb AM |
332 | ret = -ESPIPE; |
333 | if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) && | |
334 | !S_ISLNK(i_mode)) | |
335 | goto out_put; | |
336 | ||
2903ff01 | 337 | mapping = f.file->f_mapping; |
7a0ad10c CH |
338 | if (!mapping) { |
339 | ret = -EINVAL; | |
340 | goto out_put; | |
341 | } | |
342 | ||
343 | ret = 0; | |
344 | if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) { | |
345 | ret = filemap_fdatawait_range(mapping, offset, endbyte); | |
346 | if (ret < 0) | |
347 | goto out_put; | |
348 | } | |
349 | ||
350 | if (flags & SYNC_FILE_RANGE_WRITE) { | |
23d01270 JK |
351 | ret = __filemap_fdatawrite_range(mapping, offset, endbyte, |
352 | WB_SYNC_NONE); | |
7a0ad10c CH |
353 | if (ret < 0) |
354 | goto out_put; | |
355 | } | |
356 | ||
357 | if (flags & SYNC_FILE_RANGE_WAIT_AFTER) | |
358 | ret = filemap_fdatawait_range(mapping, offset, endbyte); | |
359 | ||
f79e2abb | 360 | out_put: |
2903ff01 | 361 | fdput(f); |
f79e2abb AM |
362 | out: |
363 | return ret; | |
364 | } | |
365 | ||
edd5cd4a DW |
366 | /* It would be nice if people remember that not all the world's an i386 |
367 | when they introduce new system calls */ | |
4a0fd5bf AV |
368 | SYSCALL_DEFINE4(sync_file_range2, int, fd, unsigned int, flags, |
369 | loff_t, offset, loff_t, nbytes) | |
edd5cd4a DW |
370 | { |
371 | return sys_sync_file_range(fd, offset, nbytes, flags); | |
372 | } |