blob: 192340930bb477f506eeee2eb132db06a1a6309f [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{
Jan Karac3f8a402009-04-27 16:43:55 +020030 /* Avoid doing twice syncing and cache pruning for quota sync */
Jens Axboed8a85592009-09-02 12:34:32 +020031 if (!wait) {
Jan Karac3f8a402009-04-27 16:43:55 +020032 writeout_quota_sb(sb, -1);
Jens Axboed8a85592009-09-02 12:34:32 +020033 writeback_inodes_sb(sb);
34 } else {
Jan Karac3f8a402009-04-27 16:43:55 +020035 sync_quota_sb(sb, -1);
Jens Axboed8a85592009-09-02 12:34:32 +020036 sync_inodes_sb(sb);
37 }
Jan Karac15c54f2009-04-27 16:43:52 +020038 if (sb->s_op->sync_fs)
39 sb->s_op->sync_fs(sb, wait);
40 return __sync_blockdev(sb->s_bdev, wait);
41}
42
43/*
44 * Write out and wait upon all dirty data associated with this
45 * superblock. Filesystem data as well as the underlying block
46 * device. Takes the superblock lock.
47 */
Jan Kara60b06802009-04-27 16:43:53 +020048int sync_filesystem(struct super_block *sb)
Jan Karac15c54f2009-04-27 16:43:52 +020049{
50 int ret;
51
Christoph Hellwig5af79262009-05-05 15:41:25 +020052 /*
53 * We need to be protected against the filesystem going from
54 * r/o to r/w or vice versa.
55 */
56 WARN_ON(!rwsem_is_locked(&sb->s_umount));
57
58 /*
59 * No point in syncing out anything if the filesystem is read-only.
60 */
61 if (sb->s_flags & MS_RDONLY)
62 return 0;
63
Jan Kara60b06802009-04-27 16:43:53 +020064 ret = __sync_filesystem(sb, 0);
Jan Karac15c54f2009-04-27 16:43:52 +020065 if (ret < 0)
66 return ret;
Jan Kara60b06802009-04-27 16:43:53 +020067 return __sync_filesystem(sb, 1);
Jan Karac15c54f2009-04-27 16:43:52 +020068}
Jan Kara60b06802009-04-27 16:43:53 +020069EXPORT_SYMBOL_GPL(sync_filesystem);
Jan Karac15c54f2009-04-27 16:43:52 +020070
71/*
72 * Sync all the data for all the filesystems (called by sys_sync() and
73 * emergency sync)
74 *
75 * This operation is careful to avoid the livelock which could easily happen
76 * if two or more filesystems are being continuously dirtied. s_need_sync
77 * is used only here. We set it against all filesystems and then clear it as
78 * we sync them. So redirtied filesystems are skipped.
79 *
80 * But if process A is currently running sync_filesystems and then process B
81 * calls sync_filesystems as well, process B will set all the s_need_sync
82 * flags again, which will cause process A to resync everything. Fix that with
83 * a local mutex.
84 */
85static void sync_filesystems(int wait)
86{
87 struct super_block *sb;
88 static DEFINE_MUTEX(mutex);
89
90 mutex_lock(&mutex); /* Could be down_interruptible */
91 spin_lock(&sb_lock);
Christoph Hellwig5af79262009-05-05 15:41:25 +020092 list_for_each_entry(sb, &super_blocks, s_list)
Jan Karac15c54f2009-04-27 16:43:52 +020093 sb->s_need_sync = 1;
Jan Karac15c54f2009-04-27 16:43:52 +020094
95restart:
96 list_for_each_entry(sb, &super_blocks, s_list) {
97 if (!sb->s_need_sync)
98 continue;
99 sb->s_need_sync = 0;
Jan Karac15c54f2009-04-27 16:43:52 +0200100 sb->s_count++;
101 spin_unlock(&sb_lock);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200102
Jan Karac15c54f2009-04-27 16:43:52 +0200103 down_read(&sb->s_umount);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200104 if (!(sb->s_flags & MS_RDONLY) && sb->s_root)
Jan Kara60b06802009-04-27 16:43:53 +0200105 __sync_filesystem(sb, wait);
Jan Karac15c54f2009-04-27 16:43:52 +0200106 up_read(&sb->s_umount);
Christoph Hellwig5af79262009-05-05 15:41:25 +0200107
Jan Karac15c54f2009-04-27 16:43:52 +0200108 /* restart only when sb is no longer on the list */
109 spin_lock(&sb_lock);
110 if (__put_super_and_need_restart(sb))
111 goto restart;
112 }
113 spin_unlock(&sb_lock);
114 mutex_unlock(&mutex);
115}
116
Zhang, Yanmin3beab0b2009-07-05 12:08:08 -0700117/*
118 * sync everything. Start out by waking pdflush, because that writes back
119 * all queues in parallel.
120 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100121SYSCALL_DEFINE0(sync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100122{
Jens Axboe03ba3782009-09-09 09:08:54 +0200123 wakeup_flusher_threads(0);
Jan Kara5cee5812009-04-27 16:43:51 +0200124 sync_filesystems(0);
125 sync_filesystems(1);
126 if (unlikely(laptop_mode))
127 laptop_sync_completion();
David Howellscf9a2ae2006-08-29 19:05:54 +0100128 return 0;
129}
130
Jens Axboea2a95372009-03-17 09:38:40 +0100131static void do_sync_work(struct work_struct *work)
132{
Jan Kara5cee5812009-04-27 16:43:51 +0200133 /*
134 * Sync twice to reduce the possibility we skipped some inodes / pages
135 * because they were temporarily locked
136 */
137 sync_filesystems(0);
138 sync_filesystems(0);
139 printk("Emergency Sync complete\n");
Jens Axboea2a95372009-03-17 09:38:40 +0100140 kfree(work);
141}
142
David Howellscf9a2ae2006-08-29 19:05:54 +0100143void emergency_sync(void)
144{
Jens Axboea2a95372009-03-17 09:38:40 +0100145 struct work_struct *work;
146
147 work = kmalloc(sizeof(*work), GFP_ATOMIC);
148 if (work) {
149 INIT_WORK(work, do_sync_work);
150 schedule_work(work);
151 }
David Howellscf9a2ae2006-08-29 19:05:54 +0100152}
153
154/*
155 * Generic function to fsync a file.
156 *
157 * filp may be NULL if called via the msync of a vma.
158 */
159int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
160{
161 struct inode * inode = dentry->d_inode;
162 struct super_block * sb;
163 int ret, err;
164
165 /* sync the inode to buffers */
166 ret = write_inode_now(inode, 0);
167
168 /* sync the superblock to buffers */
169 sb = inode->i_sb;
OGAWA Hirofumi762873c2008-04-29 00:59:42 -0700170 if (sb->s_dirt && sb->s_op->write_super)
David Howellscf9a2ae2006-08-29 19:05:54 +0100171 sb->s_op->write_super(sb);
David Howellscf9a2ae2006-08-29 19:05:54 +0100172
173 /* .. finally sync the buffers to disk */
174 err = sync_blockdev(sb->s_bdev);
175 if (!ret)
176 ret = err;
177 return ret;
178}
179
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100180/**
Jan Kara148f9482009-08-17 19:52:36 +0200181 * vfs_fsync_range - helper to sync a range of data & metadata to disk
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100182 * @file: file to sync
183 * @dentry: dentry of @file
Jan Kara148f9482009-08-17 19:52:36 +0200184 * @start: offset in bytes of the beginning of data range to sync
185 * @end: offset in bytes of the end of data range (inclusive)
186 * @datasync: perform only datasync
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100187 *
Jan Kara148f9482009-08-17 19:52:36 +0200188 * Write back data in range @start..@end and metadata for @file to disk. If
189 * @datasync is set only metadata needed to access modified file data is
190 * written.
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100191 *
192 * In case this function is called from nfsd @file may be %NULL and
193 * only @dentry is set. This can only happen when the filesystem
194 * implements the export_operations API.
195 */
Jan Kara148f9482009-08-17 19:52:36 +0200196int vfs_fsync_range(struct file *file, struct dentry *dentry, loff_t start,
197 loff_t end, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100198{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100199 const struct file_operations *fop;
200 struct address_space *mapping;
201 int err, ret;
David Howellscf9a2ae2006-08-29 19:05:54 +0100202
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100203 /*
204 * Get mapping and operations from the file in case we have
205 * as file, or get the default values for them in case we
206 * don't have a struct file available. Damn nfsd..
207 */
208 if (file) {
209 mapping = file->f_mapping;
210 fop = file->f_op;
211 } else {
212 mapping = dentry->d_inode->i_mapping;
213 fop = dentry->d_inode->i_fop;
214 }
215
216 if (!fop || !fop->fsync) {
David Howellscf9a2ae2006-08-29 19:05:54 +0100217 ret = -EINVAL;
218 goto out;
219 }
220
Christoph Hellwig2daea672009-09-03 12:39:39 +0200221 ret = filemap_write_and_wait_range(mapping, start, end);
David Howellscf9a2ae2006-08-29 19:05:54 +0100222
223 /*
224 * We need to protect against concurrent writers, which could cause
225 * livelocks in fsync_buffers_list().
226 */
227 mutex_lock(&mapping->host->i_mutex);
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100228 err = fop->fsync(file, dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100229 if (!ret)
230 ret = err;
231 mutex_unlock(&mapping->host->i_mutex);
Jan Kara148f9482009-08-17 19:52:36 +0200232
David Howellscf9a2ae2006-08-29 19:05:54 +0100233out:
234 return ret;
235}
Jan Kara148f9482009-08-17 19:52:36 +0200236EXPORT_SYMBOL(vfs_fsync_range);
237
238/**
239 * vfs_fsync - perform a fsync or fdatasync on a file
240 * @file: file to sync
241 * @dentry: dentry of @file
242 * @datasync: only perform a fdatasync operation
243 *
244 * Write back data and metadata for @file to disk. If @datasync is
245 * set only metadata needed to access modified file data is written.
246 *
247 * In case this function is called from nfsd @file may be %NULL and
248 * only @dentry is set. This can only happen when the filesystem
249 * implements the export_operations API.
250 */
251int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
252{
253 return vfs_fsync_range(file, dentry, 0, LLONG_MAX, datasync);
254}
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100255EXPORT_SYMBOL(vfs_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100256
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100257static int do_fsync(unsigned int fd, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100258{
259 struct file *file;
260 int ret = -EBADF;
261
262 file = fget(fd);
263 if (file) {
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100264 ret = vfs_fsync(file, file->f_path.dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100265 fput(file);
266 }
267 return ret;
268}
269
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100270SYSCALL_DEFINE1(fsync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100271{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100272 return do_fsync(fd, 0);
David Howellscf9a2ae2006-08-29 19:05:54 +0100273}
274
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100275SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100276{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100277 return do_fsync(fd, 1);
David Howellscf9a2ae2006-08-29 19:05:54 +0100278}
279
Jan Kara148f9482009-08-17 19:52:36 +0200280/**
281 * generic_write_sync - perform syncing after a write if file / inode is sync
282 * @file: file to which the write happened
283 * @pos: offset where the write started
284 * @count: length of the write
285 *
286 * This is just a simple wrapper about our general syncing function.
287 */
288int generic_write_sync(struct file *file, loff_t pos, loff_t count)
289{
290 if (!(file->f_flags & O_SYNC) && !IS_SYNC(file->f_mapping->host))
291 return 0;
292 return vfs_fsync_range(file, file->f_path.dentry, pos,
293 pos + count - 1, 1);
294}
295EXPORT_SYMBOL(generic_write_sync);
296
David Howellscf9a2ae2006-08-29 19:05:54 +0100297/*
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800298 * sys_sync_file_range() permits finely controlled syncing over a segment of
299 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
300 * zero then sys_sync_file_range() will operate from offset out to EOF.
301 *
302 * The flag bits are:
303 *
304 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
305 * before performing the write.
306 *
307 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
Pavel Machekcce77082008-07-23 21:27:36 -0700308 * range which are not presently under writeback. Note that this may block for
309 * significant periods due to exhaustion of disk request structures.
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800310 *
311 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
312 * after performing the write.
313 *
314 * Useful combinations of the flag bits are:
315 *
316 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
317 * in the range which were dirty on entry to sys_sync_file_range() are placed
318 * under writeout. This is a start-write-for-data-integrity operation.
319 *
320 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
321 * are not presently under writeout. This is an asynchronous flush-to-disk
322 * operation. Not suitable for data integrity operations.
323 *
324 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
325 * completion of writeout of all pages in the range. This will be used after an
326 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
327 * for that operation to complete and to return the result.
328 *
329 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
330 * a traditional sync() operation. This is a write-for-data-integrity operation
331 * which will ensure that all pages in the range which were dirty on entry to
332 * sys_sync_file_range() are committed to disk.
333 *
334 *
335 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
336 * I/O errors or ENOSPC conditions and will return those to the caller, after
337 * clearing the EIO and ENOSPC flags in the address_space.
338 *
339 * It should be noted that none of these operations write out the file's
340 * metadata. So unless the application is strictly performing overwrites of
341 * already-instantiated disk blocks, there are no guarantees here that the data
342 * will be available after a crash.
343 */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100344SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
345 unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800346{
347 int ret;
348 struct file *file;
349 loff_t endbyte; /* inclusive */
350 int fput_needed;
351 umode_t i_mode;
352
353 ret = -EINVAL;
354 if (flags & ~VALID_FLAGS)
355 goto out;
356
357 endbyte = offset + nbytes;
358
359 if ((s64)offset < 0)
360 goto out;
361 if ((s64)endbyte < 0)
362 goto out;
363 if (endbyte < offset)
364 goto out;
365
366 if (sizeof(pgoff_t) == 4) {
367 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
368 /*
369 * The range starts outside a 32 bit machine's
370 * pagecache addressing capabilities. Let it "succeed"
371 */
372 ret = 0;
373 goto out;
374 }
375 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
376 /*
377 * Out to EOF
378 */
379 nbytes = 0;
380 }
381 }
382
383 if (nbytes == 0)
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -0700384 endbyte = LLONG_MAX;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800385 else
386 endbyte--; /* inclusive */
387
388 ret = -EBADF;
389 file = fget_light(fd, &fput_needed);
390 if (!file)
391 goto out;
392
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800393 i_mode = file->f_path.dentry->d_inode->i_mode;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800394 ret = -ESPIPE;
395 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
396 !S_ISLNK(i_mode))
397 goto out_put;
398
Mark Fashehef51c972007-05-08 00:27:10 -0700399 ret = do_sync_mapping_range(file->f_mapping, offset, endbyte, flags);
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800400out_put:
401 fput_light(file, fput_needed);
402out:
403 return ret;
404}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100405#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
406asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
407 long flags)
408{
409 return SYSC_sync_file_range((int) fd, offset, nbytes,
410 (unsigned int) flags);
411}
412SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
413#endif
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800414
David Woodhouseedd5cd42007-06-27 14:10:09 -0700415/* It would be nice if people remember that not all the world's an i386
416 when they introduce new system calls */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100417SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
418 loff_t offset, loff_t nbytes)
David Woodhouseedd5cd42007-06-27 14:10:09 -0700419{
420 return sys_sync_file_range(fd, offset, nbytes, flags);
421}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100422#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
423asmlinkage long SyS_sync_file_range2(long fd, long flags,
424 loff_t offset, loff_t nbytes)
425{
426 return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
427 offset, nbytes);
428}
429SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
430#endif
David Woodhouseedd5cd42007-06-27 14:10:09 -0700431
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800432/*
433 * `endbyte' is inclusive
434 */
Mark Fasheh5b04aa32007-03-01 11:01:55 -0800435int do_sync_mapping_range(struct address_space *mapping, loff_t offset,
436 loff_t endbyte, unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800437{
438 int ret;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800439
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800440 if (!mapping) {
441 ret = -EINVAL;
442 goto out;
443 }
444
445 ret = 0;
446 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
447 ret = wait_on_page_writeback_range(mapping,
448 offset >> PAGE_CACHE_SHIFT,
449 endbyte >> PAGE_CACHE_SHIFT);
450 if (ret < 0)
451 goto out;
452 }
453
454 if (flags & SYNC_FILE_RANGE_WRITE) {
455 ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
Nick Pigginee53a892009-01-06 14:39:12 -0800456 WB_SYNC_ALL);
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800457 if (ret < 0)
458 goto out;
459 }
460
461 if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
462 ret = wait_on_page_writeback_range(mapping,
463 offset >> PAGE_CACHE_SHIFT,
464 endbyte >> PAGE_CACHE_SHIFT);
465 }
466out:
467 return ret;
468}
Mark Fasheh5b04aa32007-03-01 11:01:55 -0800469EXPORT_SYMBOL_GPL(do_sync_mapping_range);