blob: 92ca208777d562e64bfc769dc41a326f7c3da84e [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>
Sage Weilb7ed78f2011-03-10 11:31:30 -080010#include <linux/namei.h>
Al Viro914e2632006-10-18 13:55:46 -040011#include <linux/sched.h>
Andrew Mortonf79e2ab2006-03-31 02:30:42 -080012#include <linux/writeback.h>
13#include <linux/syscalls.h>
14#include <linux/linkage.h>
15#include <linux/pagemap.h>
David Howellscf9a2ae2006-08-29 19:05:54 +010016#include <linux/quotaops.h>
17#include <linux/buffer_head.h>
Jörn Engel5129a462010-04-25 08:54:42 +020018#include <linux/backing-dev.h>
Jan Kara5a3e5cb2009-04-27 16:43:48 +020019#include "internal.h"
Andrew Mortonf79e2ab2006-03-31 02:30:42 -080020
21#define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
22 SYNC_FILE_RANGE_WAIT_AFTER)
23
Jan Karac15c54f2009-04-27 16:43:52 +020024/*
Jens Axboed8a85592009-09-02 12:34:32 +020025 * Do the filesystem syncing work. For simple filesystems
26 * writeback_inodes_sb(sb) just dirties buffers with inodes so we have to
27 * submit IO for these buffers via __sync_blockdev(). This also speeds up the
28 * wait == 1 case since in that case write_inode() functions do
29 * sync_dirty_buffer() and thus effectively write one block at a time.
Jan Karac15c54f2009-04-27 16:43:52 +020030 */
Jan Kara60b06802009-04-27 16:43:53 +020031static int __sync_filesystem(struct super_block *sb, int wait)
Jan Karac15c54f2009-04-27 16:43:52 +020032{
Jens Axboe32a88aa2009-09-16 15:02:33 +020033 /*
34 * This should be safe, as we require bdi backing to actually
35 * write out data in the first place
36 */
Jörn Engel5129a462010-04-25 08:54:42 +020037 if (!sb->s_bdi || sb->s_bdi == &noop_backing_dev_info)
Jens Axboe32a88aa2009-09-16 15:02:33 +020038 return 0;
39
Christoph Hellwig5fb324a2010-02-16 03:44:52 -050040 if (sb->s_qcop && sb->s_qcop->quota_sync)
41 sb->s_qcop->quota_sync(sb, -1, wait);
42
43 if (wait)
Jens Axboed8a85592009-09-02 12:34:32 +020044 sync_inodes_sb(sb);
Christoph Hellwig5fb324a2010-02-16 03:44:52 -050045 else
Jens Axboe0e3c9a22010-06-01 11:08:43 +020046 writeback_inodes_sb(sb);
Christoph Hellwig5fb324a2010-02-16 03:44:52 -050047
Jan Karac15c54f2009-04-27 16:43:52 +020048 if (sb->s_op->sync_fs)
49 sb->s_op->sync_fs(sb, wait);
50 return __sync_blockdev(sb->s_bdev, wait);
51}
52
53/*
54 * Write out and wait upon all dirty data associated with this
55 * superblock. Filesystem data as well as the underlying block
56 * device. Takes the superblock lock.
57 */
Jan Kara60b06802009-04-27 16:43:53 +020058int sync_filesystem(struct super_block *sb)
Jan Karac15c54f2009-04-27 16:43:52 +020059{
60 int ret;
61
Christoph Hellwig5af79262009-05-05 15:41:25 +020062 /*
63 * We need to be protected against the filesystem going from
64 * r/o to r/w or vice versa.
65 */
66 WARN_ON(!rwsem_is_locked(&sb->s_umount));
67
68 /*
69 * No point in syncing out anything if the filesystem is read-only.
70 */
71 if (sb->s_flags & MS_RDONLY)
72 return 0;
73
Jan Kara60b06802009-04-27 16:43:53 +020074 ret = __sync_filesystem(sb, 0);
Jan Karac15c54f2009-04-27 16:43:52 +020075 if (ret < 0)
76 return ret;
Jan Kara60b06802009-04-27 16:43:53 +020077 return __sync_filesystem(sb, 1);
Jan Karac15c54f2009-04-27 16:43:52 +020078}
Jan Kara60b06802009-04-27 16:43:53 +020079EXPORT_SYMBOL_GPL(sync_filesystem);
Jan Karac15c54f2009-04-27 16:43:52 +020080
Al Viro01a05b32010-03-23 06:06:58 -040081static void sync_one_sb(struct super_block *sb, void *arg)
82{
83 if (!(sb->s_flags & MS_RDONLY) && sb->s_bdi)
84 __sync_filesystem(sb, *(int *)arg);
85}
Jan Karac15c54f2009-04-27 16:43:52 +020086/*
87 * Sync all the data for all the filesystems (called by sys_sync() and
88 * emergency sync)
Jan Karac15c54f2009-04-27 16:43:52 +020089 */
90static void sync_filesystems(int wait)
91{
Al Viro01a05b32010-03-23 06:06:58 -040092 iterate_supers(sync_one_sb, &wait);
Jan Karac15c54f2009-04-27 16:43:52 +020093}
94
Zhang, Yanmin3beab0b2009-07-05 12:08:08 -070095/*
96 * sync everything. Start out by waking pdflush, because that writes back
97 * all queues in parallel.
98 */
Heiko Carstensa5f8fa92009-01-14 14:14:11 +010099SYSCALL_DEFINE0(sync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100100{
Jens Axboe03ba3782009-09-09 09:08:54 +0200101 wakeup_flusher_threads(0);
Jan Kara5cee5812009-04-27 16:43:51 +0200102 sync_filesystems(0);
103 sync_filesystems(1);
104 if (unlikely(laptop_mode))
105 laptop_sync_completion();
David Howellscf9a2ae2006-08-29 19:05:54 +0100106 return 0;
107}
108
Jens Axboea2a95372009-03-17 09:38:40 +0100109static void do_sync_work(struct work_struct *work)
110{
Jan Kara5cee5812009-04-27 16:43:51 +0200111 /*
112 * Sync twice to reduce the possibility we skipped some inodes / pages
113 * because they were temporarily locked
114 */
115 sync_filesystems(0);
116 sync_filesystems(0);
117 printk("Emergency Sync complete\n");
Jens Axboea2a95372009-03-17 09:38:40 +0100118 kfree(work);
119}
120
David Howellscf9a2ae2006-08-29 19:05:54 +0100121void emergency_sync(void)
122{
Jens Axboea2a95372009-03-17 09:38:40 +0100123 struct work_struct *work;
124
125 work = kmalloc(sizeof(*work), GFP_ATOMIC);
126 if (work) {
127 INIT_WORK(work, do_sync_work);
128 schedule_work(work);
129 }
David Howellscf9a2ae2006-08-29 19:05:54 +0100130}
131
Sage Weilb7ed78f2011-03-10 11:31:30 -0800132/*
133 * sync a single super
134 */
135SYSCALL_DEFINE1(syncfs, int, fd)
136{
137 struct file *file;
138 struct super_block *sb;
139 int ret;
140 int fput_needed;
141
142 file = fget_light(fd, &fput_needed);
143 if (!file)
144 return -EBADF;
145 sb = file->f_dentry->d_sb;
146
147 down_read(&sb->s_umount);
148 ret = sync_filesystem(sb);
149 up_read(&sb->s_umount);
150
151 fput_light(file, fput_needed);
152 return ret;
153}
154
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100155/**
Jan Kara148f9482009-08-17 19:52:36 +0200156 * vfs_fsync_range - helper to sync a range of data & metadata to disk
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100157 * @file: file to sync
Jan Kara148f9482009-08-17 19:52:36 +0200158 * @start: offset in bytes of the beginning of data range to sync
159 * @end: offset in bytes of the end of data range (inclusive)
160 * @datasync: perform only datasync
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100161 *
Jan Kara148f9482009-08-17 19:52:36 +0200162 * Write back data in range @start..@end and metadata for @file to disk. If
163 * @datasync is set only metadata needed to access modified file data is
164 * written.
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100165 */
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100166int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100167{
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100168 struct address_space *mapping = file->f_mapping;
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100169 int err, ret;
David Howellscf9a2ae2006-08-29 19:05:54 +0100170
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100171 if (!file->f_op || !file->f_op->fsync) {
David Howellscf9a2ae2006-08-29 19:05:54 +0100172 ret = -EINVAL;
173 goto out;
174 }
175
Christoph Hellwig2daea672009-09-03 12:39:39 +0200176 ret = filemap_write_and_wait_range(mapping, start, end);
David Howellscf9a2ae2006-08-29 19:05:54 +0100177
178 /*
179 * We need to protect against concurrent writers, which could cause
180 * livelocks in fsync_buffers_list().
181 */
182 mutex_lock(&mapping->host->i_mutex);
Christoph Hellwig7ea80852010-05-26 17:53:25 +0200183 err = file->f_op->fsync(file, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100184 if (!ret)
185 ret = err;
186 mutex_unlock(&mapping->host->i_mutex);
Jan Kara148f9482009-08-17 19:52:36 +0200187
David Howellscf9a2ae2006-08-29 19:05:54 +0100188out:
189 return ret;
190}
Jan Kara148f9482009-08-17 19:52:36 +0200191EXPORT_SYMBOL(vfs_fsync_range);
192
193/**
194 * vfs_fsync - perform a fsync or fdatasync on a file
195 * @file: file to sync
Jan Kara148f9482009-08-17 19:52:36 +0200196 * @datasync: only perform a fdatasync operation
197 *
198 * Write back data and metadata for @file to disk. If @datasync is
199 * set only metadata needed to access modified file data is written.
Jan Kara148f9482009-08-17 19:52:36 +0200200 */
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100201int vfs_fsync(struct file *file, int datasync)
Jan Kara148f9482009-08-17 19:52:36 +0200202{
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100203 return vfs_fsync_range(file, 0, LLONG_MAX, datasync);
Jan Kara148f9482009-08-17 19:52:36 +0200204}
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100205EXPORT_SYMBOL(vfs_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100206
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100207static int do_fsync(unsigned int fd, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100208{
209 struct file *file;
210 int ret = -EBADF;
211
212 file = fget(fd);
213 if (file) {
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100214 ret = vfs_fsync(file, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100215 fput(file);
216 }
217 return ret;
218}
219
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100220SYSCALL_DEFINE1(fsync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100221{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100222 return do_fsync(fd, 0);
David Howellscf9a2ae2006-08-29 19:05:54 +0100223}
224
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100225SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100226{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100227 return do_fsync(fd, 1);
David Howellscf9a2ae2006-08-29 19:05:54 +0100228}
229
Jan Kara148f9482009-08-17 19:52:36 +0200230/**
231 * generic_write_sync - perform syncing after a write if file / inode is sync
232 * @file: file to which the write happened
233 * @pos: offset where the write started
234 * @count: length of the write
235 *
236 * This is just a simple wrapper about our general syncing function.
237 */
238int generic_write_sync(struct file *file, loff_t pos, loff_t count)
239{
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100240 if (!(file->f_flags & O_DSYNC) && !IS_SYNC(file->f_mapping->host))
Jan Kara148f9482009-08-17 19:52:36 +0200241 return 0;
Christoph Hellwig8018ab02010-03-22 17:32:25 +0100242 return vfs_fsync_range(file, pos, pos + count - 1,
Christoph Hellwig6b2f3d12009-10-27 11:05:28 +0100243 (file->f_flags & __O_SYNC) ? 0 : 1);
Jan Kara148f9482009-08-17 19:52:36 +0200244}
245EXPORT_SYMBOL(generic_write_sync);
246
David Howellscf9a2ae2006-08-29 19:05:54 +0100247/*
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800248 * sys_sync_file_range() permits finely controlled syncing over a segment of
249 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
250 * zero then sys_sync_file_range() will operate from offset out to EOF.
251 *
252 * The flag bits are:
253 *
254 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
255 * before performing the write.
256 *
257 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
Pavel Machekcce77082008-07-23 21:27:36 -0700258 * range which are not presently under writeback. Note that this may block for
259 * significant periods due to exhaustion of disk request structures.
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800260 *
261 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
262 * after performing the write.
263 *
264 * Useful combinations of the flag bits are:
265 *
266 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
267 * in the range which were dirty on entry to sys_sync_file_range() are placed
268 * under writeout. This is a start-write-for-data-integrity operation.
269 *
270 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
271 * are not presently under writeout. This is an asynchronous flush-to-disk
272 * operation. Not suitable for data integrity operations.
273 *
274 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
275 * completion of writeout of all pages in the range. This will be used after an
276 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
277 * for that operation to complete and to return the result.
278 *
279 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
280 * a traditional sync() operation. This is a write-for-data-integrity operation
281 * which will ensure that all pages in the range which were dirty on entry to
282 * sys_sync_file_range() are committed to disk.
283 *
284 *
285 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
286 * I/O errors or ENOSPC conditions and will return those to the caller, after
287 * clearing the EIO and ENOSPC flags in the address_space.
288 *
289 * It should be noted that none of these operations write out the file's
290 * metadata. So unless the application is strictly performing overwrites of
291 * already-instantiated disk blocks, there are no guarantees here that the data
292 * will be available after a crash.
293 */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100294SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
295 unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800296{
297 int ret;
298 struct file *file;
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100299 struct address_space *mapping;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800300 loff_t endbyte; /* inclusive */
301 int fput_needed;
302 umode_t i_mode;
303
304 ret = -EINVAL;
305 if (flags & ~VALID_FLAGS)
306 goto out;
307
308 endbyte = offset + nbytes;
309
310 if ((s64)offset < 0)
311 goto out;
312 if ((s64)endbyte < 0)
313 goto out;
314 if (endbyte < offset)
315 goto out;
316
317 if (sizeof(pgoff_t) == 4) {
318 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
319 /*
320 * The range starts outside a 32 bit machine's
321 * pagecache addressing capabilities. Let it "succeed"
322 */
323 ret = 0;
324 goto out;
325 }
326 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
327 /*
328 * Out to EOF
329 */
330 nbytes = 0;
331 }
332 }
333
334 if (nbytes == 0)
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -0700335 endbyte = LLONG_MAX;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800336 else
337 endbyte--; /* inclusive */
338
339 ret = -EBADF;
340 file = fget_light(fd, &fput_needed);
341 if (!file)
342 goto out;
343
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800344 i_mode = file->f_path.dentry->d_inode->i_mode;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800345 ret = -ESPIPE;
346 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
347 !S_ISLNK(i_mode))
348 goto out_put;
349
Christoph Hellwig7a0ad102009-12-17 14:24:40 +0100350 mapping = file->f_mapping;
351 if (!mapping) {
352 ret = -EINVAL;
353 goto out_put;
354 }
355
356 ret = 0;
357 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
358 ret = filemap_fdatawait_range(mapping, offset, endbyte);
359 if (ret < 0)
360 goto out_put;
361 }
362
363 if (flags & SYNC_FILE_RANGE_WRITE) {
364 ret = filemap_fdatawrite_range(mapping, offset, endbyte);
365 if (ret < 0)
366 goto out_put;
367 }
368
369 if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
370 ret = filemap_fdatawait_range(mapping, offset, endbyte);
371
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800372out_put:
373 fput_light(file, fput_needed);
374out:
375 return ret;
376}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100377#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
378asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
379 long flags)
380{
381 return SYSC_sync_file_range((int) fd, offset, nbytes,
382 (unsigned int) flags);
383}
384SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
385#endif
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800386
David Woodhouseedd5cd42007-06-27 14:10:09 -0700387/* It would be nice if people remember that not all the world's an i386
388 when they introduce new system calls */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100389SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
390 loff_t offset, loff_t nbytes)
David Woodhouseedd5cd42007-06-27 14:10:09 -0700391{
392 return sys_sync_file_range(fd, offset, nbytes, flags);
393}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100394#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
395asmlinkage long SyS_sync_file_range2(long fd, long flags,
396 loff_t offset, loff_t nbytes)
397{
398 return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
399 offset, nbytes);
400}
401SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
402#endif