blob: c9f83f480ec55ec751d41021c73c9b3aa8c0b99a [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
Jens Axboee913fc82010-05-17 12:55:07 +020045 writeback_inodes_sb_locked(sb);
Christoph Hellwig5fb324a2010-02-16 03:44:52 -050046
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
Al Viro01a05b32010-03-23 06:06:58 -040080static 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}
Jan Karac15c54f2009-04-27 16:43:52 +020085/*
86 * Sync all the data for all the filesystems (called by sys_sync() and
87 * emergency sync)
Jan Karac15c54f2009-04-27 16:43:52 +020088 */
89static void sync_filesystems(int wait)
90{
Al Viro01a05b32010-03-23 06:06:58 -040091 iterate_supers(sync_one_sb, &wait);
Jan Karac15c54f2009-04-27 16:43:52 +020092}
93
Zhang, Yanmin3beab0b2009-07-05 12:08:08 -070094/*
95 * sync everything. Start out by waking pdflush, because that writes back
96 * all queues in parallel.
97 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +010098SYSCALL_DEFINE0(sync)
David Howellscf9a2ae2006-08-29 19:05:54 +010099{
Jens Axboe03ba3782009-09-09 09:08:54 +0200100 wakeup_flusher_threads(0);
Jan Kara5cee5812009-04-27 16:43:51 +0200101 sync_filesystems(0);
102 sync_filesystems(1);
103 if (unlikely(laptop_mode))
104 laptop_sync_completion();
David Howellscf9a2ae2006-08-29 19:05:54 +0100105 return 0;
106}
107
Jens Axboea2a95372009-03-17 09:38:40 +0100108static void do_sync_work(struct work_struct *work)
109{
Jan Kara5cee5812009-04-27 16:43:51 +0200110 /*
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");
Jens Axboea2a95372009-03-17 09:38:40 +0100117 kfree(work);
118}
119
David Howellscf9a2ae2006-08-29 19:05:54 +0100120void emergency_sync(void)
121{
Jens Axboea2a95372009-03-17 09:38:40 +0100122 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 }
David Howellscf9a2ae2006-08-29 19:05:54 +0100129}
130
131/*
132 * Generic function to fsync a file.
David Howellscf9a2ae2006-08-29 19:05:54 +0100133 */
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200134int file_fsync(struct file *filp, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100135{
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200136 struct inode *inode = filp->f_mapping->host;
David Howellscf9a2ae2006-08-29 19:05:54 +0100137 struct super_block * sb;
138 int ret, err;
139
140 /* sync the inode to buffers */
141 ret = write_inode_now(inode, 0);
142
143 /* sync the superblock to buffers */
144 sb = inode->i_sb;
OGAWA Hirofumi762873c2008-04-29 00:59:42 -0700145 if (sb->s_dirt && sb->s_op->write_super)
David Howellscf9a2ae2006-08-29 19:05:54 +0100146 sb->s_op->write_super(sb);
David Howellscf9a2ae2006-08-29 19:05:54 +0100147
148 /* .. finally sync the buffers to disk */
149 err = sync_blockdev(sb->s_bdev);
150 if (!ret)
151 ret = err;
152 return ret;
153}
H Hartley Sweeten1fe72ea2009-09-22 16:43:51 -0700154EXPORT_SYMBOL(file_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100155
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100156/**
Jan Kara148f9482009-08-17 19:52:36 +0200157 * vfs_fsync_range - helper to sync a range of data & metadata to disk
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100158 * @file: file to sync
Jan Kara148f9482009-08-17 19:52:36 +0200159 * @start: offset in bytes of the beginning of data range to sync
160 * @end: offset in bytes of the end of data range (inclusive)
161 * @datasync: perform only datasync
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100162 *
Jan Kara148f9482009-08-17 19:52:36 +0200163 * Write back data in range @start..@end and metadata for @file to disk. If
164 * @datasync is set only metadata needed to access modified file data is
165 * written.
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100166 */
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100167int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100168{
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100169 struct address_space *mapping = file->f_mapping;
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100170 int err, ret;
David Howellscf9a2ae2006-08-29 19:05:54 +0100171
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100172 if (!file->f_op || !file->f_op->fsync) {
David Howellscf9a2ae2006-08-29 19:05:54 +0100173 ret = -EINVAL;
174 goto out;
175 }
176
Christoph Hellwig2daea672009-09-03 12:39:39 +0200177 ret = filemap_write_and_wait_range(mapping, start, end);
David Howellscf9a2ae2006-08-29 19:05:54 +0100178
179 /*
180 * We need to protect against concurrent writers, which could cause
181 * livelocks in fsync_buffers_list().
182 */
183 mutex_lock(&mapping->host->i_mutex);
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200184 err = file->f_op->fsync(file, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100185 if (!ret)
186 ret = err;
187 mutex_unlock(&mapping->host->i_mutex);
Jan Kara148f9482009-08-17 19:52:36 +0200188
David Howellscf9a2ae2006-08-29 19:05:54 +0100189out:
190 return ret;
191}
Jan Kara148f9482009-08-17 19:52:36 +0200192EXPORT_SYMBOL(vfs_fsync_range);
193
194/**
195 * vfs_fsync - perform a fsync or fdatasync on a file
196 * @file: file to sync
Jan Kara148f9482009-08-17 19:52:36 +0200197 * @datasync: only perform a fdatasync operation
198 *
199 * Write back data and metadata for @file to disk. If @datasync is
200 * set only metadata needed to access modified file data is written.
Jan Kara148f9482009-08-17 19:52:36 +0200201 */
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100202int vfs_fsync(struct file *file, int datasync)
Jan Kara148f9482009-08-17 19:52:36 +0200203{
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100204 return vfs_fsync_range(file, 0, LLONG_MAX, datasync);
Jan Kara148f9482009-08-17 19:52:36 +0200205}
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100206EXPORT_SYMBOL(vfs_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100207
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100208static int do_fsync(unsigned int fd, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100209{
210 struct file *file;
211 int ret = -EBADF;
212
213 file = fget(fd);
214 if (file) {
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100215 ret = vfs_fsync(file, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100216 fput(file);
217 }
218 return ret;
219}
220
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100221SYSCALL_DEFINE1(fsync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100222{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100223 return do_fsync(fd, 0);
David Howellscf9a2ae2006-08-29 19:05:54 +0100224}
225
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100226SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100227{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100228 return do_fsync(fd, 1);
David Howellscf9a2ae2006-08-29 19:05:54 +0100229}
230
Jan Kara148f9482009-08-17 19:52:36 +0200231/**
232 * generic_write_sync - perform syncing after a write if file / inode is sync
233 * @file: file to which the write happened
234 * @pos: offset where the write started
235 * @count: length of the write
236 *
237 * This is just a simple wrapper about our general syncing function.
238 */
239int generic_write_sync(struct file *file, loff_t pos, loff_t count)
240{
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100241 if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
Jan Kara148f9482009-08-17 19:52:36 +0200242 return 0;
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100243 return vfs_fsync_range(file, pos, pos + count - 1,
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100244 (file->f_flags & __O_SYNC) ? 0 : 1);
Jan Kara148f9482009-08-17 19:52:36 +0200245}
246EXPORT_SYMBOL(generic_write_sync);
247
David Howellscf9a2ae2006-08-29 19:05:54 +0100248/*
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800249 * sys_sync_file_range() permits finely controlled syncing over a segment of
250 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
251 * zero then sys_sync_file_range() will operate from offset out to EOF.
252 *
253 * The flag bits are:
254 *
255 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
256 * before performing the write.
257 *
258 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
Pavel Machekcce77082008-07-23 21:27:36 -0700259 * range which are not presently under writeback. Note that this may block for
260 * significant periods due to exhaustion of disk request structures.
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800261 *
262 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
263 * after performing the write.
264 *
265 * Useful combinations of the flag bits are:
266 *
267 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
268 * in the range which were dirty on entry to sys_sync_file_range() are placed
269 * under writeout. This is a start-write-for-data-integrity operation.
270 *
271 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
272 * are not presently under writeout. This is an asynchronous flush-to-disk
273 * operation. Not suitable for data integrity operations.
274 *
275 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
276 * completion of writeout of all pages in the range. This will be used after an
277 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
278 * for that operation to complete and to return the result.
279 *
280 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
281 * a traditional sync() operation. This is a write-for-data-integrity operation
282 * which will ensure that all pages in the range which were dirty on entry to
283 * sys_sync_file_range() are committed to disk.
284 *
285 *
286 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
287 * I/O errors or ENOSPC conditions and will return those to the caller, after
288 * clearing the EIO and ENOSPC flags in the address_space.
289 *
290 * It should be noted that none of these operations write out the file's
291 * metadata. So unless the application is strictly performing overwrites of
292 * already-instantiated disk blocks, there are no guarantees here that the data
293 * will be available after a crash.
294 */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100295SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
296 unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800297{
298 int ret;
299 struct file *file;
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100300 struct address_space *mapping;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800301 loff_t endbyte; /* inclusive */
302 int fput_needed;
303 umode_t i_mode;
304
305 ret = -EINVAL;
306 if (flags & ~VALID_FLAGS)
307 goto out;
308
309 endbyte = offset + nbytes;
310
311 if ((s64)offset < 0)
312 goto out;
313 if ((s64)endbyte < 0)
314 goto out;
315 if (endbyte < offset)
316 goto out;
317
318 if (sizeof(pgoff_t) == 4) {
319 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
320 /*
321 * The range starts outside a 32 bit machine's
322 * pagecache addressing capabilities. Let it "succeed"
323 */
324 ret = 0;
325 goto out;
326 }
327 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
328 /*
329 * Out to EOF
330 */
331 nbytes = 0;
332 }
333 }
334
335 if (nbytes == 0)
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -0700336 endbyte = LLONG_MAX;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800337 else
338 endbyte--; /* inclusive */
339
340 ret = -EBADF;
341 file = fget_light(fd, &fput_needed);
342 if (!file)
343 goto out;
344
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800345 i_mode = file->f_path.dentry->d_inode->i_mode;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800346 ret = -ESPIPE;
347 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
348 !S_ISLNK(i_mode))
349 goto out_put;
350
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100351 mapping = file->f_mapping;
352 if (!mapping) {
353 ret = -EINVAL;
354 goto out_put;
355 }
356
357 ret = 0;
358 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
359 ret = filemap_fdatawait_range(mapping, offset, endbyte);
360 if (ret < 0)
361 goto out_put;
362 }
363
364 if (flags & SYNC_FILE_RANGE_WRITE) {
365 ret = filemap_fdatawrite_range(mapping, offset, endbyte);
366 if (ret < 0)
367 goto out_put;
368 }
369
370 if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
371 ret = filemap_fdatawait_range(mapping, offset, endbyte);
372
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800373out_put:
374 fput_light(file, fput_needed);
375out:
376 return ret;
377}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100378#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
379asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
380 long flags)
381{
382 return SYSC_sync_file_range((int) fd, offset, nbytes,
383 (unsigned int) flags);
384}
385SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
386#endif
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800387
David Woodhouseedd5cd42007-06-27 14:10:09 -0700388/* It would be nice if people remember that not all the world's an i386
389 when they introduce new system calls */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100390SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
391 loff_t offset, loff_t nbytes)
David Woodhouseedd5cd42007-06-27 14:10:09 -0700392{
393 return sys_sync_file_range(fd, offset, nbytes, flags);
394}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100395#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
396asmlinkage long SyS_sync_file_range2(long fd, long flags,
397 loff_t offset, loff_t nbytes)
398{
399 return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
400 offset, nbytes);
401}
402SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
403#endif