blob: 92b228176f7cb05f4be58aabcae02e6ffb0b832d [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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +09008#include <linux/slab.h>
Andrew Mortonf79e2ab2006-03-31 02:30:42 -08009#include <linux/module.h>
Al Viro914e2632006-10-18 13:55:46 -040010#include <linux/sched.h>
Andrew Mortonf79e2ab2006-03-31 02:30:42 -080011#include <linux/writeback.h>
12#include <linux/syscalls.h>
13#include <linux/linkage.h>
14#include <linux/pagemap.h>
David Howellscf9a2ae2006-08-29 19:05:54 +010015#include <linux/quotaops.h>
16#include <linux/buffer_head.h>
Jörn Engel5129a462010-04-25 08:54:42 +020017#include <linux/backing-dev.h>
Jan Kara5a3e5cb2009-04-27 16:43:48 +020018#include "internal.h"
Andrew Mortonf79e2ab2006-03-31 02:30:42 -080019
20#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
21 SYNC_FILE_RANGE_WAIT_AFTER)
22
Jan Karac15c54f2009-04-27 16:43:52 +020023/*
Jens Axboed8a85592009-09-02 12:34:32 +020024 * 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.
Jan Karac15c54f2009-04-27 16:43:52 +020029 */
Jan Kara60b06802009-04-27 16:43:53 +020030static int __sync_filesystem(struct super_block *sb, int wait)
Jan Karac15c54f2009-04-27 16:43:52 +020031{
Jens Axboe32a88aa2009-09-16 15:02:33 +020032 /*
33 * This should be safe, as we require bdi backing to actually
34 * write out data in the first place
35 */
Jörn Engel5129a462010-04-25 08:54:42 +020036 if (!sb->s_bdi || sb->s_bdi == &noop_backing_dev_info)
Jens Axboe32a88aa2009-09-16 15:02:33 +020037 return 0;
38
Christoph Hellwig5fb324a2010-02-16 03:44:52 -050039 if (sb->s_qcop && sb->s_qcop->quota_sync)
40 sb->s_qcop->quota_sync(sb, -1, wait);
41
42 if (wait)
Jens Axboed8a85592009-09-02 12:34:32 +020043 sync_inodes_sb(sb);
Christoph Hellwig5fb324a2010-02-16 03:44:52 -050044 else
45 writeback_inodes_sb(sb);
46
Jan Karac15c54f2009-04-27 16:43:52 +020047 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 */
Jan Kara60b06802009-04-27 16:43:53 +020057int sync_filesystem(struct super_block *sb)
Jan Karac15c54f2009-04-27 16:43:52 +020058{
59 int ret;
60
Christoph Hellwig5af79262009-05-05 15:41:25 +020061 /*
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
Jan Kara60b06802009-04-27 16:43:53 +020073 ret = __sync_filesystem(sb, 0);
Jan Karac15c54f2009-04-27 16:43:52 +020074 if (ret < 0)
75 return ret;
Jan Kara60b06802009-04-27 16:43:53 +020076 return __sync_filesystem(sb, 1);
Jan Karac15c54f2009-04-27 16:43:52 +020077}
Jan Kara60b06802009-04-27 16:43:53 +020078EXPORT_SYMBOL_GPL(sync_filesystem);
Jan Karac15c54f2009-04-27 16:43:52 +020079
80/*
81 * Sync all the data for all the filesystems (called by sys_sync() and
82 * emergency sync)
83 *
84 * This operation is careful to avoid the livelock which could easily happen
85 * if two or more filesystems are being continuously dirtied. s_need_sync
86 * is used only here. We set it against all filesystems and then clear it as
87 * we sync them. So redirtied filesystems are skipped.
88 *
89 * But if process A is currently running sync_filesystems and then process B
90 * calls sync_filesystems as well, process B will set all the s_need_sync
91 * flags again, which will cause process A to resync everything. Fix that with
92 * a local mutex.
93 */
94static void sync_filesystems(int wait)
95{
96 struct super_block *sb;
97 static DEFINE_MUTEX(mutex);
98
99 mutex_lock(&mutex); /* Could be down_interruptible */
100 spin_lock(&sb_lock);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200101 list_for_each_entry(sb, &super_blocks, s_list)
Jan Karac15c54f2009-04-27 16:43:52 +0200102 sb->s_need_sync = 1;
Jan Karac15c54f2009-04-27 16:43:52 +0200103
104restart:
105 list_for_each_entry(sb, &super_blocks, s_list) {
106 if (!sb->s_need_sync)
107 continue;
108 sb->s_need_sync = 0;
Jan Karac15c54f2009-04-27 16:43:52 +0200109 sb->s_count++;
110 spin_unlock(&sb_lock);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200111
Jan Karac15c54f2009-04-27 16:43:52 +0200112 down_read(&sb->s_umount);
Jens Axboe32a88aa2009-09-16 15:02:33 +0200113 if (!(sb->s_flags & MS_RDONLY) && sb->s_root && sb->s_bdi)
Jan Kara60b06802009-04-27 16:43:53 +0200114 __sync_filesystem(sb, wait);
Jan Karac15c54f2009-04-27 16:43:52 +0200115 up_read(&sb->s_umount);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200116
Jan Karac15c54f2009-04-27 16:43:52 +0200117 /* restart only when sb is no longer on the list */
118 spin_lock(&sb_lock);
119 if (__put_super_and_need_restart(sb))
120 goto restart;
121 }
122 spin_unlock(&sb_lock);
123 mutex_unlock(&mutex);
124}
125
Zhang, Yanmin3beab0b2009-07-05 12:08:08 -0700126/*
127 * sync everything. Start out by waking pdflush, because that writes back
128 * all queues in parallel.
129 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100130SYSCALL_DEFINE0(sync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100131{
Jens Axboe03ba3782009-09-09 09:08:54 +0200132 wakeup_flusher_threads(0);
Jan Kara5cee5812009-04-27 16:43:51 +0200133 sync_filesystems(0);
134 sync_filesystems(1);
135 if (unlikely(laptop_mode))
136 laptop_sync_completion();
David Howellscf9a2ae2006-08-29 19:05:54 +0100137 return 0;
138}
139
Jens Axboea2a95372009-03-17 09:38:40 +0100140static void do_sync_work(struct work_struct *work)
141{
Jan Kara5cee5812009-04-27 16:43:51 +0200142 /*
143 * Sync twice to reduce the possibility we skipped some inodes / pages
144 * because they were temporarily locked
145 */
146 sync_filesystems(0);
147 sync_filesystems(0);
148 printk("Emergency Sync complete\n");
Jens Axboea2a95372009-03-17 09:38:40 +0100149 kfree(work);
150}
151
David Howellscf9a2ae2006-08-29 19:05:54 +0100152void emergency_sync(void)
153{
Jens Axboea2a95372009-03-17 09:38:40 +0100154 struct work_struct *work;
155
156 work = kmalloc(sizeof(*work), GFP_ATOMIC);
157 if (work) {
158 INIT_WORK(work, do_sync_work);
159 schedule_work(work);
160 }
David Howellscf9a2ae2006-08-29 19:05:54 +0100161}
162
163/*
164 * Generic function to fsync a file.
165 *
166 * filp may be NULL if called via the msync of a vma.
167 */
168int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
169{
170 struct inode * inode = dentry->d_inode;
171 struct super_block * sb;
172 int ret, err;
173
174 /* sync the inode to buffers */
175 ret = write_inode_now(inode, 0);
176
177 /* sync the superblock to buffers */
178 sb = inode->i_sb;
OGAWA Hirofumi762873c2008-04-29 00:59:42 -0700179 if (sb->s_dirt && sb->s_op->write_super)
David Howellscf9a2ae2006-08-29 19:05:54 +0100180 sb->s_op->write_super(sb);
David Howellscf9a2ae2006-08-29 19:05:54 +0100181
182 /* .. finally sync the buffers to disk */
183 err = sync_blockdev(sb->s_bdev);
184 if (!ret)
185 ret = err;
186 return ret;
187}
H Hartley Sweeten1fe72ea2009-09-22 16:43:51 -0700188EXPORT_SYMBOL(file_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100189
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100190/**
Jan Kara148f9482009-08-17 19:52:36 +0200191 * vfs_fsync_range - helper to sync a range of data & metadata to disk
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100192 * @file: file to sync
193 * @dentry: dentry of @file
Jan Kara148f9482009-08-17 19:52:36 +0200194 * @start: offset in bytes of the beginning of data range to sync
195 * @end: offset in bytes of the end of data range (inclusive)
196 * @datasync: perform only datasync
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100197 *
Jan Kara148f9482009-08-17 19:52:36 +0200198 * Write back data in range @start..@end and metadata for @file to disk. If
199 * @datasync is set only metadata needed to access modified file data is
200 * written.
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100201 *
202 * In case this function is called from nfsd @file may be %NULL and
203 * only @dentry is set. This can only happen when the filesystem
204 * implements the export_operations API.
205 */
Jan Kara148f9482009-08-17 19:52:36 +0200206int vfs_fsync_range(struct file *file, struct dentry *dentry, loff_t start,
207 loff_t end, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100208{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100209 const struct file_operations *fop;
210 struct address_space *mapping;
211 int err, ret;
David Howellscf9a2ae2006-08-29 19:05:54 +0100212
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100213 /*
214 * Get mapping and operations from the file in case we have
215 * as file, or get the default values for them in case we
216 * don't have a struct file available. Damn nfsd..
217 */
218 if (file) {
219 mapping = file->f_mapping;
220 fop = file->f_op;
221 } else {
222 mapping = dentry->d_inode->i_mapping;
223 fop = dentry->d_inode->i_fop;
224 }
225
226 if (!fop || !fop->fsync) {
David Howellscf9a2ae2006-08-29 19:05:54 +0100227 ret = -EINVAL;
228 goto out;
229 }
230
Christoph Hellwig2daea672009-09-03 12:39:39 +0200231 ret = filemap_write_and_wait_range(mapping, start, end);
David Howellscf9a2ae2006-08-29 19:05:54 +0100232
233 /*
234 * We need to protect against concurrent writers, which could cause
235 * livelocks in fsync_buffers_list().
236 */
237 mutex_lock(&mapping->host->i_mutex);
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100238 err = fop->fsync(file, dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100239 if (!ret)
240 ret = err;
241 mutex_unlock(&mapping->host->i_mutex);
Jan Kara148f9482009-08-17 19:52:36 +0200242
David Howellscf9a2ae2006-08-29 19:05:54 +0100243out:
244 return ret;
245}
Jan Kara148f9482009-08-17 19:52:36 +0200246EXPORT_SYMBOL(vfs_fsync_range);
247
248/**
249 * vfs_fsync - perform a fsync or fdatasync on a file
250 * @file: file to sync
251 * @dentry: dentry of @file
252 * @datasync: only perform a fdatasync operation
253 *
254 * Write back data and metadata for @file to disk. If @datasync is
255 * set only metadata needed to access modified file data is written.
256 *
257 * In case this function is called from nfsd @file may be %NULL and
258 * only @dentry is set. This can only happen when the filesystem
259 * implements the export_operations API.
260 */
261int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
262{
263 return vfs_fsync_range(file, dentry, 0, LLONG_MAX, datasync);
264}
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100265EXPORT_SYMBOL(vfs_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100266
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100267static int do_fsync(unsigned int fd, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100268{
269 struct file *file;
270 int ret = -EBADF;
271
272 file = fget(fd);
273 if (file) {
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100274 ret = vfs_fsync(file, file->f_path.dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100275 fput(file);
276 }
277 return ret;
278}
279
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100280SYSCALL_DEFINE1(fsync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100281{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100282 return do_fsync(fd, 0);
David Howellscf9a2ae2006-08-29 19:05:54 +0100283}
284
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100285SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100286{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100287 return do_fsync(fd, 1);
David Howellscf9a2ae2006-08-29 19:05:54 +0100288}
289
Jan Kara148f9482009-08-17 19:52:36 +0200290/**
291 * generic_write_sync - perform syncing after a write if file / inode is sync
292 * @file: file to which the write happened
293 * @pos: offset where the write started
294 * @count: length of the write
295 *
296 * This is just a simple wrapper about our general syncing function.
297 */
298int generic_write_sync(struct file *file, loff_t pos, loff_t count)
299{
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100300 if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
Jan Kara148f9482009-08-17 19:52:36 +0200301 return 0;
302 return vfs_fsync_range(file, file->f_path.dentry, pos,
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100303 pos + count - 1,
304 (file->f_flags & __O_SYNC) ? 0 : 1);
Jan Kara148f9482009-08-17 19:52:36 +0200305}
306EXPORT_SYMBOL(generic_write_sync);
307
David Howellscf9a2ae2006-08-29 19:05:54 +0100308/*
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800309 * sys_sync_file_range() permits finely controlled syncing over a segment of
310 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
311 * zero then sys_sync_file_range() will operate from offset out to EOF.
312 *
313 * The flag bits are:
314 *
315 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
316 * before performing the write.
317 *
318 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
Pavel Machekcce77082008-07-23 21:27:36 -0700319 * range which are not presently under writeback. Note that this may block for
320 * significant periods due to exhaustion of disk request structures.
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800321 *
322 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
323 * after performing the write.
324 *
325 * Useful combinations of the flag bits are:
326 *
327 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
328 * in the range which were dirty on entry to sys_sync_file_range() are placed
329 * under writeout. This is a start-write-for-data-integrity operation.
330 *
331 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
332 * are not presently under writeout. This is an asynchronous flush-to-disk
333 * operation. Not suitable for data integrity operations.
334 *
335 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
336 * completion of writeout of all pages in the range. This will be used after an
337 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
338 * for that operation to complete and to return the result.
339 *
340 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
341 * a traditional sync() operation. This is a write-for-data-integrity operation
342 * which will ensure that all pages in the range which were dirty on entry to
343 * sys_sync_file_range() are committed to disk.
344 *
345 *
346 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
347 * I/O errors or ENOSPC conditions and will return those to the caller, after
348 * clearing the EIO and ENOSPC flags in the address_space.
349 *
350 * It should be noted that none of these operations write out the file's
351 * metadata. So unless the application is strictly performing overwrites of
352 * already-instantiated disk blocks, there are no guarantees here that the data
353 * will be available after a crash.
354 */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100355SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
356 unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800357{
358 int ret;
359 struct file *file;
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100360 struct address_space *mapping;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800361 loff_t endbyte; /* inclusive */
362 int fput_needed;
363 umode_t i_mode;
364
365 ret = -EINVAL;
366 if (flags & ~VALID_FLAGS)
367 goto out;
368
369 endbyte = offset + nbytes;
370
371 if ((s64)offset < 0)
372 goto out;
373 if ((s64)endbyte < 0)
374 goto out;
375 if (endbyte < offset)
376 goto out;
377
378 if (sizeof(pgoff_t) == 4) {
379 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
380 /*
381 * The range starts outside a 32 bit machine's
382 * pagecache addressing capabilities. Let it "succeed"
383 */
384 ret = 0;
385 goto out;
386 }
387 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
388 /*
389 * Out to EOF
390 */
391 nbytes = 0;
392 }
393 }
394
395 if (nbytes == 0)
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -0700396 endbyte = LLONG_MAX;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800397 else
398 endbyte--; /* inclusive */
399
400 ret = -EBADF;
401 file = fget_light(fd, &fput_needed);
402 if (!file)
403 goto out;
404
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800405 i_mode = file->f_path.dentry->d_inode->i_mode;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800406 ret = -ESPIPE;
407 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
408 !S_ISLNK(i_mode))
409 goto out_put;
410
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100411 mapping = file->f_mapping;
412 if (!mapping) {
413 ret = -EINVAL;
414 goto out_put;
415 }
416
417 ret = 0;
418 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
419 ret = filemap_fdatawait_range(mapping, offset, endbyte);
420 if (ret < 0)
421 goto out_put;
422 }
423
424 if (flags & SYNC_FILE_RANGE_WRITE) {
425 ret = filemap_fdatawrite_range(mapping, offset, endbyte);
426 if (ret < 0)
427 goto out_put;
428 }
429
430 if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
431 ret = filemap_fdatawait_range(mapping, offset, endbyte);
432
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800433out_put:
434 fput_light(file, fput_needed);
435out:
436 return ret;
437}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100438#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
439asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
440 long flags)
441{
442 return SYSC_sync_file_range((int) fd, offset, nbytes,
443 (unsigned int) flags);
444}
445SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
446#endif
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800447
David Woodhouseedd5cd42007-06-27 14:10:09 -0700448/* It would be nice if people remember that not all the world's an i386
449 when they introduce new system calls */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100450SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
451 loff_t offset, loff_t nbytes)
David Woodhouseedd5cd42007-06-27 14:10:09 -0700452{
453 return sys_sync_file_range(fd, offset, nbytes, flags);
454}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100455#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
456asmlinkage long SyS_sync_file_range2(long fd, long flags,
457 loff_t offset, loff_t nbytes)
458{
459 return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
460 offset, nbytes);
461}
462SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
463#endif