blob: 418727a2a2390f435d68b1fad91dede88dc4c17f [file] [log] [blame]
Andrew Mortonf79e2ab2006-03-31 02:30:42 -08001/*
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>
Al Viro914e2632006-10-18 13:55:46 -04009#include <linux/sched.h>
Andrew Mortonf79e2ab2006-03-31 02:30:42 -080010#include <linux/writeback.h>
11#include <linux/syscalls.h>
12#include <linux/linkage.h>
13#include <linux/pagemap.h>
David Howellscf9a2ae2006-08-29 19:05:54 +010014#include <linux/quotaops.h>
15#include <linux/buffer_head.h>
Jan Kara5a3e5cb2009-04-27 16:43:48 +020016#include "internal.h"
Andrew Mortonf79e2ab2006-03-31 02:30:42 -080017
18#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
19 SYNC_FILE_RANGE_WAIT_AFTER)
20
Jan Karac15c54f2009-04-27 16:43:52 +020021/*
Jens Axboed8a85592009-09-02 12:34:32 +020022 * Do the filesystem syncing work. For simple filesystems
23 * writeback_inodes_sb(sb) just dirties buffers with inodes so we have to
24 * submit IO for these buffers via __sync_blockdev(). This also speeds up the
25 * wait == 1 case since in that case write_inode() functions do
26 * sync_dirty_buffer() and thus effectively write one block at a time.
Jan Karac15c54f2009-04-27 16:43:52 +020027 */
Jan Kara60b06802009-04-27 16:43:53 +020028static int __sync_filesystem(struct super_block *sb, int wait)
Jan Karac15c54f2009-04-27 16:43:52 +020029{
Jens Axboe32a88aa2009-09-16 15:02:33 +020030 /*
31 * This should be safe, as we require bdi backing to actually
32 * write out data in the first place
33 */
34 if (!sb->s_bdi)
35 return 0;
36
Jan Karac3f8a402009-04-27 16:43:55 +020037 /* Avoid doing twice syncing and cache pruning for quota sync */
Jens Axboed8a85592009-09-02 12:34:32 +020038 if (!wait) {
Jan Karac3f8a402009-04-27 16:43:55 +020039 writeout_quota_sb(sb, -1);
Jens Axboed8a85592009-09-02 12:34:32 +020040 writeback_inodes_sb(sb);
41 } else {
Jan Karac3f8a402009-04-27 16:43:55 +020042 sync_quota_sb(sb, -1);
Jens Axboed8a85592009-09-02 12:34:32 +020043 sync_inodes_sb(sb);
44 }
Jan Karac15c54f2009-04-27 16:43:52 +020045 if (sb->s_op->sync_fs)
46 sb->s_op->sync_fs(sb, wait);
47 return __sync_blockdev(sb->s_bdev, wait);
48}
49
50/*
51 * Write out and wait upon all dirty data associated with this
52 * superblock. Filesystem data as well as the underlying block
53 * device. Takes the superblock lock.
54 */
Jan Kara60b06802009-04-27 16:43:53 +020055int sync_filesystem(struct super_block *sb)
Jan Karac15c54f2009-04-27 16:43:52 +020056{
57 int ret;
58
Christoph Hellwig5af79262009-05-05 15:41:25 +020059 /*
60 * We need to be protected against the filesystem going from
61 * r/o to r/w or vice versa.
62 */
63 WARN_ON(!rwsem_is_locked(&sb->s_umount));
64
65 /*
66 * No point in syncing out anything if the filesystem is read-only.
67 */
68 if (sb->s_flags & MS_RDONLY)
69 return 0;
70
Jan Kara60b06802009-04-27 16:43:53 +020071 ret = __sync_filesystem(sb, 0);
Jan Karac15c54f2009-04-27 16:43:52 +020072 if (ret < 0)
73 return ret;
Jan Kara60b06802009-04-27 16:43:53 +020074 return __sync_filesystem(sb, 1);
Jan Karac15c54f2009-04-27 16:43:52 +020075}
Jan Kara60b06802009-04-27 16:43:53 +020076EXPORT_SYMBOL_GPL(sync_filesystem);
Jan Karac15c54f2009-04-27 16:43:52 +020077
78/*
79 * Sync all the data for all the filesystems (called by sys_sync() and
80 * emergency sync)
81 *
82 * This operation is careful to avoid the livelock which could easily happen
83 * if two or more filesystems are being continuously dirtied. s_need_sync
84 * is used only here. We set it against all filesystems and then clear it as
85 * we sync them. So redirtied filesystems are skipped.
86 *
87 * But if process A is currently running sync_filesystems and then process B
88 * calls sync_filesystems as well, process B will set all the s_need_sync
89 * flags again, which will cause process A to resync everything. Fix that with
90 * a local mutex.
91 */
92static void sync_filesystems(int wait)
93{
94 struct super_block *sb;
95 static DEFINE_MUTEX(mutex);
96
97 mutex_lock(&mutex); /* Could be down_interruptible */
98 spin_lock(&sb_lock);
Christoph Hellwig5af79262009-05-05 15:41:25 +020099 list_for_each_entry(sb, &super_blocks, s_list)
Jan Karac15c54f2009-04-27 16:43:52 +0200100 sb->s_need_sync = 1;
Jan Karac15c54f2009-04-27 16:43:52 +0200101
102restart:
103 list_for_each_entry(sb, &super_blocks, s_list) {
104 if (!sb->s_need_sync)
105 continue;
106 sb->s_need_sync = 0;
Jan Karac15c54f2009-04-27 16:43:52 +0200107 sb->s_count++;
108 spin_unlock(&sb_lock);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200109
Jan Karac15c54f2009-04-27 16:43:52 +0200110 down_read(&sb->s_umount);
Jens Axboe32a88aa2009-09-16 15:02:33 +0200111 if (!(sb->s_flags & MS_RDONLY) && sb->s_root && sb->s_bdi)
Jan Kara60b06802009-04-27 16:43:53 +0200112 __sync_filesystem(sb, wait);
Jan Karac15c54f2009-04-27 16:43:52 +0200113 up_read(&sb->s_umount);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200114
Jan Karac15c54f2009-04-27 16:43:52 +0200115 /* restart only when sb is no longer on the list */
116 spin_lock(&sb_lock);
117 if (__put_super_and_need_restart(sb))
118 goto restart;
119 }
120 spin_unlock(&sb_lock);
121 mutex_unlock(&mutex);
122}
123
Zhang, Yanmin3beab0b2009-07-05 12:08:08 -0700124/*
125 * sync everything. Start out by waking pdflush, because that writes back
126 * all queues in parallel.
127 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100128SYSCALL_DEFINE0(sync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100129{
Jens Axboe03ba3782009-09-09 09:08:54 +0200130 wakeup_flusher_threads(0);
Jan Kara5cee5812009-04-27 16:43:51 +0200131 sync_filesystems(0);
132 sync_filesystems(1);
133 if (unlikely(laptop_mode))
134 laptop_sync_completion();
David Howellscf9a2ae2006-08-29 19:05:54 +0100135 return 0;
136}
137
Jens Axboea2a95372009-03-17 09:38:40 +0100138static void do_sync_work(struct work_struct *work)
139{
Jan Kara5cee5812009-04-27 16:43:51 +0200140 /*
141 * Sync twice to reduce the possibility we skipped some inodes / pages
142 * because they were temporarily locked
143 */
144 sync_filesystems(0);
145 sync_filesystems(0);
146 printk("Emergency Sync complete\n");
Jens Axboea2a95372009-03-17 09:38:40 +0100147 kfree(work);
148}
149
David Howellscf9a2ae2006-08-29 19:05:54 +0100150void emergency_sync(void)
151{
Jens Axboea2a95372009-03-17 09:38:40 +0100152 struct work_struct *work;
153
154 work = kmalloc(sizeof(*work), GFP_ATOMIC);
155 if (work) {
156 INIT_WORK(work, do_sync_work);
157 schedule_work(work);
158 }
David Howellscf9a2ae2006-08-29 19:05:54 +0100159}
160
161/*
162 * Generic function to fsync a file.
163 *
164 * filp may be NULL if called via the msync of a vma.
165 */
166int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
167{
168 struct inode * inode = dentry->d_inode;
169 struct super_block * sb;
170 int ret, err;
171
172 /* sync the inode to buffers */
173 ret = write_inode_now(inode, 0);
174
175 /* sync the superblock to buffers */
176 sb = inode->i_sb;
OGAWA Hirofumi762873c2008-04-29 00:59:42 -0700177 if (sb->s_dirt && sb->s_op->write_super)
David Howellscf9a2ae2006-08-29 19:05:54 +0100178 sb->s_op->write_super(sb);
David Howellscf9a2ae2006-08-29 19:05:54 +0100179
180 /* .. finally sync the buffers to disk */
181 err = sync_blockdev(sb->s_bdev);
182 if (!ret)
183 ret = err;
184 return ret;
185}
H Hartley Sweeten1fe72ea2009-09-22 16:43:51 -0700186EXPORT_SYMBOL(file_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100187
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100188/**
Jan Kara148f9482009-08-17 19:52:36 +0200189 * vfs_fsync_range - helper to sync a range of data & metadata to disk
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100190 * @file: file to sync
191 * @dentry: dentry of @file
Jan Kara148f9482009-08-17 19:52:36 +0200192 * @start: offset in bytes of the beginning of data range to sync
193 * @end: offset in bytes of the end of data range (inclusive)
194 * @datasync: perform only datasync
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100195 *
Jan Kara148f9482009-08-17 19:52:36 +0200196 * Write back data in range @start..@end and metadata for @file to disk. If
197 * @datasync is set only metadata needed to access modified file data is
198 * written.
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100199 *
200 * In case this function is called from nfsd @file may be %NULL and
201 * only @dentry is set. This can only happen when the filesystem
202 * implements the export_operations API.
203 */
Jan Kara148f9482009-08-17 19:52:36 +0200204int vfs_fsync_range(struct file *file, struct dentry *dentry, loff_t start,
205 loff_t end, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100206{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100207 const struct file_operations *fop;
208 struct address_space *mapping;
209 int err, ret;
David Howellscf9a2ae2006-08-29 19:05:54 +0100210
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100211 /*
212 * Get mapping and operations from the file in case we have
213 * as file, or get the default values for them in case we
214 * don't have a struct file available. Damn nfsd..
215 */
216 if (file) {
217 mapping = file->f_mapping;
218 fop = file->f_op;
219 } else {
220 mapping = dentry->d_inode->i_mapping;
221 fop = dentry->d_inode->i_fop;
222 }
223
224 if (!fop || !fop->fsync) {
David Howellscf9a2ae2006-08-29 19:05:54 +0100225 ret = -EINVAL;
226 goto out;
227 }
228
Christoph Hellwig2daea672009-09-03 12:39:39 +0200229 ret = filemap_write_and_wait_range(mapping, start, end);
David Howellscf9a2ae2006-08-29 19:05:54 +0100230
231 /*
232 * We need to protect against concurrent writers, which could cause
233 * livelocks in fsync_buffers_list().
234 */
235 mutex_lock(&mapping->host->i_mutex);
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100236 err = fop->fsync(file, dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100237 if (!ret)
238 ret = err;
239 mutex_unlock(&mapping->host->i_mutex);
Jan Kara148f9482009-08-17 19:52:36 +0200240
David Howellscf9a2ae2006-08-29 19:05:54 +0100241out:
242 return ret;
243}
Jan Kara148f9482009-08-17 19:52:36 +0200244EXPORT_SYMBOL(vfs_fsync_range);
245
246/**
247 * vfs_fsync - perform a fsync or fdatasync on a file
248 * @file: file to sync
249 * @dentry: dentry of @file
250 * @datasync: only perform a fdatasync operation
251 *
252 * Write back data and metadata for @file to disk. If @datasync is
253 * set only metadata needed to access modified file data is written.
254 *
255 * In case this function is called from nfsd @file may be %NULL and
256 * only @dentry is set. This can only happen when the filesystem
257 * implements the export_operations API.
258 */
259int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
260{
261 return vfs_fsync_range(file, dentry, 0, LLONG_MAX, datasync);
262}
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100263EXPORT_SYMBOL(vfs_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100264
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100265static int do_fsync(unsigned int fd, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100266{
267 struct file *file;
268 int ret = -EBADF;
269
270 file = fget(fd);
271 if (file) {
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100272 ret = vfs_fsync(file, file->f_path.dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100273 fput(file);
274 }
275 return ret;
276}
277
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100278SYSCALL_DEFINE1(fsync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100279{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100280 return do_fsync(fd, 0);
David Howellscf9a2ae2006-08-29 19:05:54 +0100281}
282
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100283SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100284{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100285 return do_fsync(fd, 1);
David Howellscf9a2ae2006-08-29 19:05:54 +0100286}
287
Jan Kara148f9482009-08-17 19:52:36 +0200288/**
289 * generic_write_sync - perform syncing after a write if file / inode is sync
290 * @file: file to which the write happened
291 * @pos: offset where the write started
292 * @count: length of the write
293 *
294 * This is just a simple wrapper about our general syncing function.
295 */
296int generic_write_sync(struct file *file, loff_t pos, loff_t count)
297{
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100298 if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
Jan Kara148f9482009-08-17 19:52:36 +0200299 return 0;
300 return vfs_fsync_range(file, file->f_path.dentry, pos,
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100301 pos + count - 1,
302 (file->f_flags & __O_SYNC) ? 0 : 1);
Jan Kara148f9482009-08-17 19:52:36 +0200303}
304EXPORT_SYMBOL(generic_write_sync);
305
David Howellscf9a2ae2006-08-29 19:05:54 +0100306/*
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800307 * sys_sync_file_range() permits finely controlled syncing over a segment of
308 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
309 * zero then sys_sync_file_range() will operate from offset out to EOF.
310 *
311 * The flag bits are:
312 *
313 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
314 * before performing the write.
315 *
316 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
Pavel Machekcce77082008-07-23 21:27:36 -0700317 * range which are not presently under writeback. Note that this may block for
318 * significant periods due to exhaustion of disk request structures.
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800319 *
320 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
321 * after performing the write.
322 *
323 * Useful combinations of the flag bits are:
324 *
325 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
326 * in the range which were dirty on entry to sys_sync_file_range() are placed
327 * under writeout. This is a start-write-for-data-integrity operation.
328 *
329 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
330 * are not presently under writeout. This is an asynchronous flush-to-disk
331 * operation. Not suitable for data integrity operations.
332 *
333 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
334 * completion of writeout of all pages in the range. This will be used after an
335 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
336 * for that operation to complete and to return the result.
337 *
338 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
339 * a traditional sync() operation. This is a write-for-data-integrity operation
340 * which will ensure that all pages in the range which were dirty on entry to
341 * sys_sync_file_range() are committed to disk.
342 *
343 *
344 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
345 * I/O errors or ENOSPC conditions and will return those to the caller, after
346 * clearing the EIO and ENOSPC flags in the address_space.
347 *
348 * It should be noted that none of these operations write out the file's
349 * metadata. So unless the application is strictly performing overwrites of
350 * already-instantiated disk blocks, there are no guarantees here that the data
351 * will be available after a crash.
352 */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100353SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
354 unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800355{
356 int ret;
357 struct file *file;
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100358 struct address_space *mapping;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800359 loff_t endbyte; /* inclusive */
360 int fput_needed;
361 umode_t i_mode;
362
363 ret = -EINVAL;
364 if (flags & ~VALID_FLAGS)
365 goto out;
366
367 endbyte = offset + nbytes;
368
369 if ((s64)offset < 0)
370 goto out;
371 if ((s64)endbyte < 0)
372 goto out;
373 if (endbyte < offset)
374 goto out;
375
376 if (sizeof(pgoff_t) == 4) {
377 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
378 /*
379 * The range starts outside a 32 bit machine's
380 * pagecache addressing capabilities. Let it "succeed"
381 */
382 ret = 0;
383 goto out;
384 }
385 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
386 /*
387 * Out to EOF
388 */
389 nbytes = 0;
390 }
391 }
392
393 if (nbytes == 0)
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -0700394 endbyte = LLONG_MAX;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800395 else
396 endbyte--; /* inclusive */
397
398 ret = -EBADF;
399 file = fget_light(fd, &fput_needed);
400 if (!file)
401 goto out;
402
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800403 i_mode = file->f_path.dentry->d_inode->i_mode;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800404 ret = -ESPIPE;
405 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
406 !S_ISLNK(i_mode))
407 goto out_put;
408
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100409 mapping = file->f_mapping;
410 if (!mapping) {
411 ret = -EINVAL;
412 goto out_put;
413 }
414
415 ret = 0;
416 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
417 ret = filemap_fdatawait_range(mapping, offset, endbyte);
418 if (ret < 0)
419 goto out_put;
420 }
421
422 if (flags & SYNC_FILE_RANGE_WRITE) {
423 ret = filemap_fdatawrite_range(mapping, offset, endbyte);
424 if (ret < 0)
425 goto out_put;
426 }
427
428 if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
429 ret = filemap_fdatawait_range(mapping, offset, endbyte);
430
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800431out_put:
432 fput_light(file, fput_needed);
433out:
434 return ret;
435}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100436#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
437asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
438 long flags)
439{
440 return SYSC_sync_file_range((int) fd, offset, nbytes,
441 (unsigned int) flags);
442}
443SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
444#endif
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800445
David Woodhouseedd5cd42007-06-27 14:10:09 -0700446/* It would be nice if people remember that not all the world's an i386
447 when they introduce new system calls */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100448SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
449 loff_t offset, loff_t nbytes)
David Woodhouseedd5cd42007-06-27 14:10:09 -0700450{
451 return sys_sync_file_range(fd, offset, nbytes, flags);
452}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100453#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
454asmlinkage long SyS_sync_file_range2(long fd, long flags,
455 loff_t offset, loff_t nbytes)
456{
457 return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
458 offset, nbytes);
459}
460SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
461#endif