blob: d5fa7b79982ed153245b6d5367b06cb13aa364c7 [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/*
22 * Do the filesystem syncing work. For simple filesystems sync_inodes_sb(sb, 0)
23 * just dirties buffers with inodes so we have to submit IO for these buffers
24 * via __sync_blockdev(). This also speeds up the wait == 1 case since in that
25 * case write_inode() functions do sync_dirty_buffer() and thus effectively
26 * write one block at a time.
27 */
28static int __fsync_super(struct super_block *sb, int wait)
29{
30 vfs_dq_sync(sb);
31 sync_inodes_sb(sb, wait);
32 lock_super(sb);
33 if (sb->s_dirt && sb->s_op->write_super)
34 sb->s_op->write_super(sb);
35 unlock_super(sb);
36 if (sb->s_op->sync_fs)
37 sb->s_op->sync_fs(sb, wait);
38 return __sync_blockdev(sb->s_bdev, wait);
39}
40
41/*
42 * Write out and wait upon all dirty data associated with this
43 * superblock. Filesystem data as well as the underlying block
44 * device. Takes the superblock lock.
45 */
46int fsync_super(struct super_block *sb)
47{
48 int ret;
49
50 ret = __fsync_super(sb, 0);
51 if (ret < 0)
52 return ret;
53 return __fsync_super(sb, 1);
54}
55EXPORT_SYMBOL_GPL(fsync_super);
56
57/*
58 * Sync all the data for all the filesystems (called by sys_sync() and
59 * emergency sync)
60 *
61 * This operation is careful to avoid the livelock which could easily happen
62 * if two or more filesystems are being continuously dirtied. s_need_sync
63 * is used only here. We set it against all filesystems and then clear it as
64 * we sync them. So redirtied filesystems are skipped.
65 *
66 * But if process A is currently running sync_filesystems and then process B
67 * calls sync_filesystems as well, process B will set all the s_need_sync
68 * flags again, which will cause process A to resync everything. Fix that with
69 * a local mutex.
70 */
71static void sync_filesystems(int wait)
72{
73 struct super_block *sb;
74 static DEFINE_MUTEX(mutex);
75
76 mutex_lock(&mutex); /* Could be down_interruptible */
77 spin_lock(&sb_lock);
78 list_for_each_entry(sb, &super_blocks, s_list) {
79 if (sb->s_flags & MS_RDONLY)
80 continue;
81 sb->s_need_sync = 1;
82 }
83
84restart:
85 list_for_each_entry(sb, &super_blocks, s_list) {
86 if (!sb->s_need_sync)
87 continue;
88 sb->s_need_sync = 0;
89 if (sb->s_flags & MS_RDONLY)
90 continue; /* hm. Was remounted r/o meanwhile */
91 sb->s_count++;
92 spin_unlock(&sb_lock);
93 down_read(&sb->s_umount);
94 if (sb->s_root)
95 __fsync_super(sb, wait);
96 up_read(&sb->s_umount);
97 /* restart only when sb is no longer on the list */
98 spin_lock(&sb_lock);
99 if (__put_super_and_need_restart(sb))
100 goto restart;
101 }
102 spin_unlock(&sb_lock);
103 mutex_unlock(&mutex);
104}
105
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100106SYSCALL_DEFINE0(sync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100107{
Jan Kara5cee5812009-04-27 16:43:51 +0200108 sync_filesystems(0);
109 sync_filesystems(1);
110 if (unlikely(laptop_mode))
111 laptop_sync_completion();
David Howellscf9a2ae2006-08-29 19:05:54 +0100112 return 0;
113}
114
Jens Axboea2a95372009-03-17 09:38:40 +0100115static void do_sync_work(struct work_struct *work)
116{
Jan Kara5cee5812009-04-27 16:43:51 +0200117 /*
118 * Sync twice to reduce the possibility we skipped some inodes / pages
119 * because they were temporarily locked
120 */
121 sync_filesystems(0);
122 sync_filesystems(0);
123 printk("Emergency Sync complete\n");
Jens Axboea2a95372009-03-17 09:38:40 +0100124 kfree(work);
125}
126
David Howellscf9a2ae2006-08-29 19:05:54 +0100127void emergency_sync(void)
128{
Jens Axboea2a95372009-03-17 09:38:40 +0100129 struct work_struct *work;
130
131 work = kmalloc(sizeof(*work), GFP_ATOMIC);
132 if (work) {
133 INIT_WORK(work, do_sync_work);
134 schedule_work(work);
135 }
David Howellscf9a2ae2006-08-29 19:05:54 +0100136}
137
138/*
139 * Generic function to fsync a file.
140 *
141 * filp may be NULL if called via the msync of a vma.
142 */
143int file_fsync(struct file *filp, struct dentry *dentry, int datasync)
144{
145 struct inode * inode = dentry->d_inode;
146 struct super_block * sb;
147 int ret, err;
148
149 /* sync the inode to buffers */
150 ret = write_inode_now(inode, 0);
151
152 /* sync the superblock to buffers */
153 sb = inode->i_sb;
154 lock_super(sb);
OGAWA Hirofumi762873c2008-04-29 00:59:42 -0700155 if (sb->s_dirt && sb->s_op->write_super)
David Howellscf9a2ae2006-08-29 19:05:54 +0100156 sb->s_op->write_super(sb);
157 unlock_super(sb);
158
159 /* .. finally sync the buffers to disk */
160 err = sync_blockdev(sb->s_bdev);
161 if (!ret)
162 ret = err;
163 return ret;
164}
165
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100166/**
167 * vfs_fsync - perform a fsync or fdatasync on a file
168 * @file: file to sync
169 * @dentry: dentry of @file
170 * @data: only perform a fdatasync operation
171 *
172 * Write back data and metadata for @file to disk. If @datasync is
173 * set only metadata needed to access modified file data is written.
174 *
175 * In case this function is called from nfsd @file may be %NULL and
176 * only @dentry is set. This can only happen when the filesystem
177 * implements the export_operations API.
178 */
179int vfs_fsync(struct file *file, struct dentry *dentry, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100180{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100181 const struct file_operations *fop;
182 struct address_space *mapping;
183 int err, ret;
David Howellscf9a2ae2006-08-29 19:05:54 +0100184
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100185 /*
186 * Get mapping and operations from the file in case we have
187 * as file, or get the default values for them in case we
188 * don't have a struct file available. Damn nfsd..
189 */
190 if (file) {
191 mapping = file->f_mapping;
192 fop = file->f_op;
193 } else {
194 mapping = dentry->d_inode->i_mapping;
195 fop = dentry->d_inode->i_fop;
196 }
197
198 if (!fop || !fop->fsync) {
David Howellscf9a2ae2006-08-29 19:05:54 +0100199 ret = -EINVAL;
200 goto out;
201 }
202
203 ret = filemap_fdatawrite(mapping);
204
205 /*
206 * We need to protect against concurrent writers, which could cause
207 * livelocks in fsync_buffers_list().
208 */
209 mutex_lock(&mapping->host->i_mutex);
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100210 err = fop->fsync(file, dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100211 if (!ret)
212 ret = err;
213 mutex_unlock(&mapping->host->i_mutex);
214 err = filemap_fdatawait(mapping);
215 if (!ret)
216 ret = err;
217out:
218 return ret;
219}
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100220EXPORT_SYMBOL(vfs_fsync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100221
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100222static int do_fsync(unsigned int fd, int datasync)
David Howellscf9a2ae2006-08-29 19:05:54 +0100223{
224 struct file *file;
225 int ret = -EBADF;
226
227 file = fget(fd);
228 if (file) {
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100229 ret = vfs_fsync(file, file->f_path.dentry, datasync);
David Howellscf9a2ae2006-08-29 19:05:54 +0100230 fput(file);
231 }
232 return ret;
233}
234
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100235SYSCALL_DEFINE1(fsync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100236{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100237 return do_fsync(fd, 0);
David Howellscf9a2ae2006-08-29 19:05:54 +0100238}
239
Heiko Carstensa5f8fa92009-01-14 14:14:11 +0100240SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
David Howellscf9a2ae2006-08-29 19:05:54 +0100241{
Christoph Hellwig4c728ef2008-12-22 21:11:15 +0100242 return do_fsync(fd, 1);
David Howellscf9a2ae2006-08-29 19:05:54 +0100243}
244
245/*
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800246 * sys_sync_file_range() permits finely controlled syncing over a segment of
247 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
248 * zero then sys_sync_file_range() will operate from offset out to EOF.
249 *
250 * The flag bits are:
251 *
252 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
253 * before performing the write.
254 *
255 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
Pavel Machekcce77082008-07-23 21:27:36 -0700256 * range which are not presently under writeback. Note that this may block for
257 * significant periods due to exhaustion of disk request structures.
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800258 *
259 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
260 * after performing the write.
261 *
262 * Useful combinations of the flag bits are:
263 *
264 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
265 * in the range which were dirty on entry to sys_sync_file_range() are placed
266 * under writeout. This is a start-write-for-data-integrity operation.
267 *
268 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
269 * are not presently under writeout. This is an asynchronous flush-to-disk
270 * operation. Not suitable for data integrity operations.
271 *
272 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
273 * completion of writeout of all pages in the range. This will be used after an
274 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
275 * for that operation to complete and to return the result.
276 *
277 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
278 * a traditional sync() operation. This is a write-for-data-integrity operation
279 * which will ensure that all pages in the range which were dirty on entry to
280 * sys_sync_file_range() are committed to disk.
281 *
282 *
283 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
284 * I/O errors or ENOSPC conditions and will return those to the caller, after
285 * clearing the EIO and ENOSPC flags in the address_space.
286 *
287 * It should be noted that none of these operations write out the file's
288 * metadata. So unless the application is strictly performing overwrites of
289 * already-instantiated disk blocks, there are no guarantees here that the data
290 * will be available after a crash.
291 */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100292SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
293 unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800294{
295 int ret;
296 struct file *file;
297 loff_t endbyte; /* inclusive */
298 int fput_needed;
299 umode_t i_mode;
300
301 ret = -EINVAL;
302 if (flags & ~VALID_FLAGS)
303 goto out;
304
305 endbyte = offset + nbytes;
306
307 if ((s64)offset < 0)
308 goto out;
309 if ((s64)endbyte < 0)
310 goto out;
311 if (endbyte < offset)
312 goto out;
313
314 if (sizeof(pgoff_t) == 4) {
315 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
316 /*
317 * The range starts outside a 32 bit machine's
318 * pagecache addressing capabilities. Let it "succeed"
319 */
320 ret = 0;
321 goto out;
322 }
323 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
324 /*
325 * Out to EOF
326 */
327 nbytes = 0;
328 }
329 }
330
331 if (nbytes == 0)
OGAWA Hirofumi111ebb62006-06-23 02:03:26 -0700332 endbyte = LLONG_MAX;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800333 else
334 endbyte--; /* inclusive */
335
336 ret = -EBADF;
337 file = fget_light(fd, &fput_needed);
338 if (!file)
339 goto out;
340
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800341 i_mode = file->f_path.dentry->d_inode->i_mode;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800342 ret = -ESPIPE;
343 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
344 !S_ISLNK(i_mode))
345 goto out_put;
346
Mark Fashehef51c972007-05-08 00:27:10 -0700347 ret = do_sync_mapping_range(file->f_mapping, offset, endbyte, flags);
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800348out_put:
349 fput_light(file, fput_needed);
350out:
351 return ret;
352}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100353#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
354asmlinkage long SyS_sync_file_range(long fd, loff_t offset, loff_t nbytes,
355 long flags)
356{
357 return SYSC_sync_file_range((int) fd, offset, nbytes,
358 (unsigned int) flags);
359}
360SYSCALL_ALIAS(sys_sync_file_range, SyS_sync_file_range);
361#endif
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800362
David Woodhouseedd5cd42007-06-27 14:10:09 -0700363/* It would be nice if people remember that not all the world's an i386
364 when they introduce new system calls */
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100365SYSCALL_DEFINE(sync_file_range2)(int fd, unsigned int flags,
366 loff_t offset, loff_t nbytes)
David Woodhouseedd5cd42007-06-27 14:10:09 -0700367{
368 return sys_sync_file_range(fd, offset, nbytes, flags);
369}
Heiko Carstens6673e0c2009-01-14 14:14:02 +0100370#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
371asmlinkage long SyS_sync_file_range2(long fd, long flags,
372 loff_t offset, loff_t nbytes)
373{
374 return SYSC_sync_file_range2((int) fd, (unsigned int) flags,
375 offset, nbytes);
376}
377SYSCALL_ALIAS(sys_sync_file_range2, SyS_sync_file_range2);
378#endif
David Woodhouseedd5cd42007-06-27 14:10:09 -0700379
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800380/*
381 * `endbyte' is inclusive
382 */
Mark Fasheh5b04aa32007-03-01 11:01:55 -0800383int do_sync_mapping_range(struct address_space *mapping, loff_t offset,
384 loff_t endbyte, unsigned int flags)
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800385{
386 int ret;
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800387
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800388 if (!mapping) {
389 ret = -EINVAL;
390 goto out;
391 }
392
393 ret = 0;
394 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
395 ret = wait_on_page_writeback_range(mapping,
396 offset >> PAGE_CACHE_SHIFT,
397 endbyte >> PAGE_CACHE_SHIFT);
398 if (ret < 0)
399 goto out;
400 }
401
402 if (flags & SYNC_FILE_RANGE_WRITE) {
403 ret = __filemap_fdatawrite_range(mapping, offset, endbyte,
Nick Pigginee53a892009-01-06 14:39:12 -0800404 WB_SYNC_ALL);
Andrew Mortonf79e2ab2006-03-31 02:30:42 -0800405 if (ret < 0)
406 goto out;
407 }
408
409 if (flags & SYNC_FILE_RANGE_WAIT_AFTER) {
410 ret = wait_on_page_writeback_range(mapping,
411 offset >> PAGE_CACHE_SHIFT,
412 endbyte >> PAGE_CACHE_SHIFT);
413 }
414out:
415 return ret;
416}
Mark Fasheh5b04aa32007-03-01 11:01:55 -0800417EXPORT_SYMBOL_GPL(do_sync_mapping_range);