Commit | Line | Data |
---|---|---|
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> |
f79e2abb | 9 | #include <linux/module.h> |
914e2637 | 10 | #include <linux/sched.h> |
f79e2abb AM |
11 | #include <linux/writeback.h> |
12 | #include <linux/syscalls.h> | |
13 | #include <linux/linkage.h> | |
14 | #include <linux/pagemap.h> | |
cf9a2ae8 DH |
15 | #include <linux/quotaops.h> |
16 | #include <linux/buffer_head.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 | */ |
60b0680f | 30 | static int __sync_filesystem(struct super_block *sb, int wait) |
c15c54f5 | 31 | { |
32a88aa1 JA |
32 | /* |
33 | * This should be safe, as we require bdi backing to actually | |
34 | * write out data in the first place | |
35 | */ | |
5129a469 | 36 | if (!sb->s_bdi || sb->s_bdi == &noop_backing_dev_info) |
32a88aa1 JA |
37 | return 0; |
38 | ||
5fb324ad CH |
39 | if (sb->s_qcop && sb->s_qcop->quota_sync) |
40 | sb->s_qcop->quota_sync(sb, -1, wait); | |
41 | ||
42 | if (wait) | |
d8a8559c | 43 | sync_inodes_sb(sb); |
5fb324ad CH |
44 | else |
45 | writeback_inodes_sb(sb); | |
46 | ||
c15c54f5 JK |
47 | if (sb->s_op->sync_fs) |
48 | sb->s_op->sync_fs(sb, wait); | |
49 | return __sync_blockdev(sb->s_bdev, wait); | |
50 | } | |
51 | ||
52 | /* | |
53 | * Write out and wait upon all dirty data associated with this | |
54 | * superblock. Filesystem data as well as the underlying block | |
55 | * device. Takes the superblock lock. | |
56 | */ | |
60b0680f | 57 | int sync_filesystem(struct super_block *sb) |
c15c54f5 JK |
58 | { |
59 | int ret; | |
60 | ||
5af7926f CH |
61 | /* |
62 | * We need to be protected against the filesystem going from | |
63 | * r/o to r/w or vice versa. | |
64 | */ | |
65 | WARN_ON(!rwsem_is_locked(&sb->s_umount)); | |
66 | ||
67 | /* | |
68 | * No point in syncing out anything if the filesystem is read-only. | |
69 | */ | |
70 | if (sb->s_flags & MS_RDONLY) | |
71 | return 0; | |
72 | ||
60b0680f | 73 | ret = __sync_filesystem(sb, 0); |
c15c54f5 JK |
74 | if (ret < 0) |
75 | return ret; | |
60b0680f | 76 | return __sync_filesystem(sb, 1); |
c15c54f5 | 77 | } |
60b0680f | 78 | EXPORT_SYMBOL_GPL(sync_filesystem); |
c15c54f5 | 79 | |
01a05b33 AV |
80 | static void sync_one_sb(struct super_block *sb, void *arg) |
81 | { | |
82 | if (!(sb->s_flags & MS_RDONLY) && sb->s_bdi) | |
83 | __sync_filesystem(sb, *(int *)arg); | |
84 | } | |
c15c54f5 JK |
85 | /* |
86 | * Sync all the data for all the filesystems (called by sys_sync() and | |
87 | * emergency sync) | |
c15c54f5 JK |
88 | */ |
89 | static void sync_filesystems(int wait) | |
90 | { | |
01a05b33 | 91 | iterate_supers(sync_one_sb, &wait); |
c15c54f5 JK |
92 | } |
93 | ||
3beab0b4 ZY |
94 | /* |
95 | * sync everything. Start out by waking pdflush, because that writes back | |
96 | * all queues in parallel. | |
97 | */ | |
5cee5815 | 98 | SYSCALL_DEFINE0(sync) |
cf9a2ae8 | 99 | { |
03ba3782 | 100 | wakeup_flusher_threads(0); |
5cee5815 JK |
101 | sync_filesystems(0); |
102 | sync_filesystems(1); | |
cf9a2ae8 DH |
103 | if (unlikely(laptop_mode)) |
104 | laptop_sync_completion(); | |
cf9a2ae8 DH |
105 | return 0; |
106 | } | |
107 | ||
a2a9537a JA |
108 | static void do_sync_work(struct work_struct *work) |
109 | { | |
5cee5815 JK |
110 | /* |
111 | * Sync twice to reduce the possibility we skipped some inodes / pages | |
112 | * because they were temporarily locked | |
113 | */ | |
114 | sync_filesystems(0); | |
115 | sync_filesystems(0); | |
116 | printk("Emergency Sync complete\n"); | |
a2a9537a JA |
117 | kfree(work); |
118 | } | |
119 | ||
cf9a2ae8 DH |
120 | void emergency_sync(void) |
121 | { | |
a2a9537a JA |
122 | struct work_struct *work; |
123 | ||
124 | work = kmalloc(sizeof(*work), GFP_ATOMIC); | |
125 | if (work) { | |
126 | INIT_WORK(work, do_sync_work); | |
127 | schedule_work(work); | |
128 | } | |
cf9a2ae8 DH |
129 | } |
130 | ||
131 | /* | |
132 | * Generic function to fsync a file. | |
133 | * | |
134 | * filp may be NULL if called via the msync of a vma. | |
135 | */ | |
136 | int file_fsync(struct file *filp, struct dentry *dentry, int datasync) | |
137 | { | |
138 | struct inode * inode = dentry->d_inode; | |
139 | struct super_block * sb; | |
140 | int ret, err; | |
141 | ||
142 | /* sync the inode to buffers */ | |
143 | ret = write_inode_now(inode, 0); | |
144 | ||
145 | /* sync the superblock to buffers */ | |
146 | sb = inode->i_sb; | |
762873c2 | 147 | if (sb->s_dirt && sb->s_op->write_super) |
cf9a2ae8 | 148 | sb->s_op->write_super(sb); |
cf9a2ae8 DH |
149 | |
150 | /* .. finally sync the buffers to disk */ | |
151 | err = sync_blockdev(sb->s_bdev); | |
152 | if (!ret) | |
153 | ret = err; | |
154 | return ret; | |
155 | } | |
1fe72eaa | 156 | EXPORT_SYMBOL(file_fsync); |
cf9a2ae8 | 157 | |
4c728ef5 | 158 | /** |
148f948b | 159 | * vfs_fsync_range - helper to sync a range of data & metadata to disk |
4c728ef5 CH |
160 | * @file: file to sync |
161 | * @dentry: dentry of @file | |
148f948b JK |
162 | * @start: offset in bytes of the beginning of data range to sync |
163 | * @end: offset in bytes of the end of data range (inclusive) | |
164 | * @datasync: perform only datasync | |
4c728ef5 | 165 | * |
148f948b JK |
166 | * Write back data in range @start..@end and metadata for @file to disk. If |
167 | * @datasync is set only metadata needed to access modified file data is | |
168 | * written. | |
4c728ef5 CH |
169 | * |
170 | * In case this function is called from nfsd @file may be %NULL and | |
171 | * only @dentry is set. This can only happen when the filesystem | |
172 | * implements the export_operations API. | |
173 | */ | |
148f948b JK |
174 | int vfs_fsync_range(struct file *file, struct dentry *dentry, loff_t start, |
175 | loff_t end, int datasync) | |
cf9a2ae8 | 176 | { |
4c728ef5 CH |
177 | const struct file_operations *fop; |
178 | struct address_space *mapping; | |
179 | int err, ret; | |
180 | ||
181 | /* | |
182 | * Get mapping and operations from the file in case we have | |
183 | * as file, or get the default values for them in case we | |
184 | * don't have a struct file available. Damn nfsd.. | |
185 | */ | |
186 | if (file) { | |
187 | mapping = file->f_mapping; | |
188 | fop = file->f_op; | |
189 | } else { | |
190 | mapping = dentry->d_inode->i_mapping; | |
191 | fop = dentry->d_inode->i_fop; | |
192 | } | |
cf9a2ae8 | 193 | |
4c728ef5 | 194 | if (!fop || !fop->fsync) { |
cf9a2ae8 DH |
195 | ret = -EINVAL; |
196 | goto out; | |
197 | } | |
198 | ||
2daea67e | 199 | ret = filemap_write_and_wait_range(mapping, start, end); |
cf9a2ae8 DH |
200 | |
201 | /* | |
202 | * We need to protect against concurrent writers, which could cause | |
203 | * livelocks in fsync_buffers_list(). | |
204 | */ | |
205 | mutex_lock(&mapping->host->i_mutex); | |
4c728ef5 | 206 | err = fop->fsync(file, dentry, datasync); |
cf9a2ae8 DH |
207 | if (!ret) |
208 | ret = err; | |
209 | mutex_unlock(&mapping->host->i_mutex); | |
148f948b | 210 | |
cf9a2ae8 DH |
211 | out: |
212 | return ret; | |
213 | } | |
148f948b JK |
214 | EXPORT_SYMBOL(vfs_fsync_range); |
215 | ||
216 | /** | |
217 | * vfs_fsync - perform a fsync or fdatasync on a file | |
218 | * @file: file to sync | |
219 | * @dentry: dentry of @file | |
220 | * @datasync: only perform a fdatasync operation | |
221 | * | |
222 | * Write back data and metadata for @file to disk. If @datasync is | |
223 | * set only metadata needed to access modified file data is written. | |
224 | * | |
225 | * In case this function is called from nfsd @file may be %NULL and | |
226 | * only @dentry is set. This can only happen when the filesystem | |
227 | * implements the export_operations API. | |
228 | */ | |
229 | int vfs_fsync(struct file *file, struct dentry *dentry, int datasync) | |
230 | { | |
231 | return vfs_fsync_range(file, dentry, 0, LLONG_MAX, datasync); | |
232 | } | |
4c728ef5 | 233 | EXPORT_SYMBOL(vfs_fsync); |
cf9a2ae8 | 234 | |
4c728ef5 | 235 | static int do_fsync(unsigned int fd, int datasync) |
cf9a2ae8 DH |
236 | { |
237 | struct file *file; | |
238 | int ret = -EBADF; | |
239 | ||
240 | file = fget(fd); | |
241 | if (file) { | |
4c728ef5 | 242 | ret = vfs_fsync(file, file->f_path.dentry, datasync); |
cf9a2ae8 DH |
243 | fput(file); |
244 | } | |
245 | return ret; | |
246 | } | |
247 | ||
a5f8fa9e | 248 | SYSCALL_DEFINE1(fsync, unsigned int, fd) |
cf9a2ae8 | 249 | { |
4c728ef5 | 250 | return do_fsync(fd, 0); |
cf9a2ae8 DH |
251 | } |
252 | ||
a5f8fa9e | 253 | SYSCALL_DEFINE1(fdatasync, unsigned int, fd) |
cf9a2ae8 | 254 | { |
4c728ef5 | 255 | return do_fsync(fd, 1); |
cf9a2ae8 DH |
256 | } |
257 | ||
148f948b JK |
258 | /** |
259 | * generic_write_sync - perform syncing after a write if file / inode is sync | |
260 | * @file: file to which the write happened | |
261 | * @pos: offset where the write started | |
262 | * @count: length of the write | |
263 | * | |
264 | * This is just a simple wrapper about our general syncing function. | |
265 | */ | |
266 | int generic_write_sync(struct file *file, loff_t pos, loff_t count) | |
267 | { | |
6b2f3d1f | 268 | if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host)) |
148f948b JK |
269 | return 0; |
270 | return vfs_fsync_range(file, file->f_path.dentry, pos, | |
6b2f3d1f CH |
271 | pos + count - 1, |
272 | (file->f_flags & __O_SYNC) ? 0 : 1); | |
148f948b JK |
273 | } |
274 | EXPORT_SYMBOL(generic_write_sync); | |
275 | ||
f79e2abb AM |
276 | /* |
277 | * sys_sync_file_range() permits finely controlled syncing over a segment of | |
278 | * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is | |
279 | * zero then sys_sync_file_range() will operate from offset out to EOF. | |
280 | * | |
281 | * The flag bits are: | |
282 | * | |
283 | * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range | |
284 | * before performing the write. | |
285 | * | |
286 | * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the | |
cce77081 PM |
287 | * range which are not presently under writeback. Note that this may block for |
288 | * significant periods due to exhaustion of disk request structures. | |
f79e2abb AM |
289 | * |
290 | * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range | |
291 | * after performing the write. | |
292 | * | |
293 | * Useful combinations of the flag bits are: | |
294 | * | |
295 | * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages | |
296 | * in the range which were dirty on entry to sys_sync_file_range() are placed | |
297 | * under writeout. This is a start-write-for-data-integrity operation. | |
298 | * | |
299 | * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which | |
300 | * are not presently under writeout. This is an asynchronous flush-to-disk | |
301 | * operation. Not suitable for data integrity operations. | |
302 | * | |
303 | * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for | |
304 | * completion of writeout of all pages in the range. This will be used after an | |
305 | * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait | |
306 | * for that operation to complete and to return the result. | |
307 | * | |
308 | * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER: | |
309 | * a traditional sync() operation. This is a write-for-data-integrity operation | |
310 | * which will ensure that all pages in the range which were dirty on entry to | |
311 | * sys_sync_file_range() are committed to disk. | |
312 | * | |
313 | * | |
314 | * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any | |
315 | * I/O errors or ENOSPC conditions and will return those to the caller, after | |
316 | * clearing the EIO and ENOSPC flags in the address_space. | |
317 | * | |
318 | * It should be noted that none of these operations write out the file's | |
319 | * metadata. So unless the application is strictly performing overwrites of | |
320 | * already-instantiated disk blocks, there are no guarantees here that the data | |
321 | * will be available after a crash. | |
322 | */ | |
6673e0c3 HC |
323 | SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes, |
324 | unsigned int flags) | |
f79e2abb AM |
325 | { |
326 | int ret; | |
327 | struct file *file; | |
7a0ad10c | 328 | struct address_space *mapping; |
f79e2abb AM |
329 | loff_t endbyte; /* inclusive */ |
330 | int fput_needed; | |
331 | umode_t i_mode; | |
332 | ||
333 | ret = -EINVAL; | |
334 | if (flags & ~VALID_FLAGS) | |
335 | goto out; | |
336 | ||
337 | endbyte = offset + nbytes; | |
338 | ||
339 | if ((s64)offset < 0) | |
340 | goto out; | |
341 | if ((s64)endbyte < 0) | |
342 | goto out; | |
343 | if (endbyte < offset) | |
344 | goto out; | |
345 | ||
346 | if (sizeof(pgoff_t) == 4) { | |
347 | if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) { | |
348 | /* | |
349 | * The range starts outside a 32 bit machine's | |
350 | * pagecache addressing capabilities. Let it "succeed" | |
351 | */ | |
352 | ret = 0; | |
353 | goto out; | |
354 | } | |
355 | if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) { | |
356 | /* | |
357 | * Out to EOF | |
358 | */ | |
359 | nbytes = 0; | |
360 | } | |
361 | } | |
362 | ||
363 | if (nbytes == 0) | |
111ebb6e | 364 | endbyte = LLONG_MAX; |
f79e2abb AM |
365 | else |
366 | endbyte--; /* inclusive */ | |
367 | ||
368 | ret = -EBADF; | |
369 | file = fget_light(fd, &fput_needed); | |
370 | if (!file) | |
371 | goto out; | |
372 | ||
0f7fc9e4 | 373 | i_mode = file->f_path.dentry->d_inode->i_mode; |
f79e2abb AM |
374 | ret = -ESPIPE; |
375 | if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) && | |
376 | !S_ISLNK(i_mode)) | |
377 | goto out_put; | |
378 | ||
7a0ad10c CH |
379 | mapping = file->f_mapping; |
380 | if (!mapping) { | |
381 | ret = -EINVAL; | |
382 | goto out_put; | |
383 | } | |
384 | ||
385 | ret = 0; | |
386 | if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) { | |
387 | ret = filemap_fdatawait_range(mapping, offset, endbyte); | |
388 | if (ret < 0) | |
389 | goto out_put; | |
390 | } | |
391 | ||
392 | if (flags & SYNC_FILE_RANGE_WRITE) { | |
393 | ret = filemap_fdatawrite_range(mapping, offset, endbyte); | |
394 | if (ret < 0) | |
395 | goto out_put; | |
396 | } | |
397 | ||
398 | if (flags & SYNC_FILE_RANGE_WAIT_AFTER) | |
399 | ret = filemap_fdatawait_range(mapping, offset, endbyte); | |
400 | ||
f79e2abb AM |
401 | out_put: |
402 | fput_light(file, fput_needed); | |
403 | out: | |
404 | return ret; | |
405 | } | |
6673e0c3 HC |
406 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
407 | asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes, | |
408 | long flags) | |
409 | { | |
410 | return SYSC_sync_file_range((int) fd, offset, nbytes, | |
411 | (unsigned int) flags); | |
412 | } | |
413 | SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range); | |
414 | #endif | |
f79e2abb | 415 | |
edd5cd4a DW |
416 | /* It would be nice if people remember that not all the world's an i386 |
417 | when they introduce new system calls */ | |
6673e0c3 HC |
418 | SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags, |
419 | loff_t offset, loff_t nbytes) | |
edd5cd4a DW |
420 | { |
421 | return sys_sync_file_range(fd, offset, nbytes, flags); | |
422 | } | |
6673e0c3 HC |
423 | #ifdef CONFIG_HAVE_SYSCALL_WRAPPERS |
424 | asmlinkage long SyS_sync_file_range2(long fd, long flags, | |
425 | loff_t offset, loff_t nbytes) | |
426 | { | |
427 | return SYSC_sync_file_range2((int) fd, (unsigned int) flags, | |
428 | offset, nbytes); | |
429 | } | |
430 | SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2); | |
431 | #endif |