Linux 3.16-rc2
[linux/fpc-iii.git] / fs / sync.c
blobb28d1dd10e8b70194a604a1fca654237edd817be
1 /*
2 * High-level sync()-related operations
3 */
5 #include <linux/kernel.h>
6 #include <linux/file.h>
7 #include <linux/fs.h>
8 #include <linux/slab.h>
9 #include <linux/export.h>
10 #include <linux/namei.h>
11 #include <linux/sched.h>
12 #include <linux/writeback.h>
13 #include <linux/syscalls.h>
14 #include <linux/linkage.h>
15 #include <linux/pagemap.h>
16 #include <linux/quotaops.h>
17 #include <linux/backing-dev.h>
18 #include "internal.h"
20 #define VALID_FLAGS (SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE| \
21 SYNC_FILE_RANGE_WAIT_AFTER)
24 * 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.
30 static int __sync_filesystem(struct super_block *sb, int wait)
32 if (wait)
33 sync_inodes_sb(sb);
34 else
35 writeback_inodes_sb(sb, WB_REASON_SYNC);
37 if (sb->s_op->sync_fs)
38 sb->s_op->sync_fs(sb, wait);
39 return __sync_blockdev(sb->s_bdev, wait);
43 * Write out and wait upon all dirty data associated with this
44 * superblock. Filesystem data as well as the underlying block
45 * device. Takes the superblock lock.
47 int sync_filesystem(struct super_block *sb)
49 int ret;
52 * We need to be protected against the filesystem going from
53 * r/o to r/w or vice versa.
55 WARN_ON(!rwsem_is_locked(&sb->s_umount));
58 * No point in syncing out anything if the filesystem is read-only.
60 if (sb->s_flags & MS_RDONLY)
61 return 0;
63 ret = __sync_filesystem(sb, 0);
64 if (ret < 0)
65 return ret;
66 return __sync_filesystem(sb, 1);
68 EXPORT_SYMBOL_GPL(sync_filesystem);
70 static void sync_inodes_one_sb(struct super_block *sb, void *arg)
72 if (!(sb->s_flags & MS_RDONLY))
73 sync_inodes_sb(sb);
76 static void sync_fs_one_sb(struct super_block *sb, void *arg)
78 if (!(sb->s_flags & MS_RDONLY) && sb->s_op->sync_fs)
79 sb->s_op->sync_fs(sb, *(int *)arg);
82 static void fdatawrite_one_bdev(struct block_device *bdev, void *arg)
84 filemap_fdatawrite(bdev->bd_inode->i_mapping);
87 static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
89 filemap_fdatawait(bdev->bd_inode->i_mapping);
93 * Sync everything. We start by waking flusher threads so that most of
94 * writeback runs on all devices in parallel. Then we sync all inodes reliably
95 * which effectively also waits for all flusher threads to finish doing
96 * writeback. At this point all data is on disk so metadata should be stable
97 * and we tell filesystems to sync their metadata via ->sync_fs() calls.
98 * Finally, we writeout all block devices because some filesystems (e.g. ext2)
99 * just write metadata (such as inodes or bitmaps) to block device page cache
100 * and do not sync it on their own in ->sync_fs().
102 SYSCALL_DEFINE0(sync)
104 int nowait = 0, wait = 1;
106 wakeup_flusher_threads(0, WB_REASON_SYNC);
107 iterate_supers(sync_inodes_one_sb, NULL);
108 iterate_supers(sync_fs_one_sb, &nowait);
109 iterate_supers(sync_fs_one_sb, &wait);
110 iterate_bdevs(fdatawrite_one_bdev, NULL);
111 iterate_bdevs(fdatawait_one_bdev, NULL);
112 if (unlikely(laptop_mode))
113 laptop_sync_completion();
114 return 0;
117 static void do_sync_work(struct work_struct *work)
119 int nowait = 0;
122 * Sync twice to reduce the possibility we skipped some inodes / pages
123 * because they were temporarily locked
125 iterate_supers(sync_inodes_one_sb, &nowait);
126 iterate_supers(sync_fs_one_sb, &nowait);
127 iterate_bdevs(fdatawrite_one_bdev, NULL);
128 iterate_supers(sync_inodes_one_sb, &nowait);
129 iterate_supers(sync_fs_one_sb, &nowait);
130 iterate_bdevs(fdatawrite_one_bdev, NULL);
131 printk("Emergency Sync complete\n");
132 kfree(work);
135 void emergency_sync(void)
137 struct work_struct *work;
139 work = kmalloc(sizeof(*work), GFP_ATOMIC);
140 if (work) {
141 INIT_WORK(work, do_sync_work);
142 schedule_work(work);
147 * sync a single super
149 SYSCALL_DEFINE1(syncfs, int, fd)
151 struct fd f = fdget(fd);
152 struct super_block *sb;
153 int ret;
155 if (!f.file)
156 return -EBADF;
157 sb = f.file->f_dentry->d_sb;
159 down_read(&sb->s_umount);
160 ret = sync_filesystem(sb);
161 up_read(&sb->s_umount);
163 fdput(f);
164 return ret;
168 * vfs_fsync_range - helper to sync a range of data & metadata to disk
169 * @file: file to sync
170 * @start: offset in bytes of the beginning of data range to sync
171 * @end: offset in bytes of the end of data range (inclusive)
172 * @datasync: perform only datasync
174 * Write back data in range @start..@end and metadata for @file to disk. If
175 * @datasync is set only metadata needed to access modified file data is
176 * written.
178 int vfs_fsync_range(struct file *file, loff_t start, loff_t end, int datasync)
180 if (!file->f_op->fsync)
181 return -EINVAL;
182 return file->f_op->fsync(file, start, end, datasync);
184 EXPORT_SYMBOL(vfs_fsync_range);
187 * vfs_fsync - perform a fsync or fdatasync on a file
188 * @file: file to sync
189 * @datasync: only perform a fdatasync operation
191 * Write back data and metadata for @file to disk. If @datasync is
192 * set only metadata needed to access modified file data is written.
194 int vfs_fsync(struct file *file, int datasync)
196 return vfs_fsync_range(file, 0, LLONG_MAX, datasync);
198 EXPORT_SYMBOL(vfs_fsync);
200 static int do_fsync(unsigned int fd, int datasync)
202 struct fd f = fdget(fd);
203 int ret = -EBADF;
205 if (f.file) {
206 ret = vfs_fsync(f.file, datasync);
207 fdput(f);
209 return ret;
212 SYSCALL_DEFINE1(fsync, unsigned int, fd)
214 return do_fsync(fd, 0);
217 SYSCALL_DEFINE1(fdatasync, unsigned int, fd)
219 return do_fsync(fd, 1);
223 * sys_sync_file_range() permits finely controlled syncing over a segment of
224 * a file in the range offset .. (offset+nbytes-1) inclusive. If nbytes is
225 * zero then sys_sync_file_range() will operate from offset out to EOF.
227 * The flag bits are:
229 * SYNC_FILE_RANGE_WAIT_BEFORE: wait upon writeout of all pages in the range
230 * before performing the write.
232 * SYNC_FILE_RANGE_WRITE: initiate writeout of all those dirty pages in the
233 * range which are not presently under writeback. Note that this may block for
234 * significant periods due to exhaustion of disk request structures.
236 * SYNC_FILE_RANGE_WAIT_AFTER: wait upon writeout of all pages in the range
237 * after performing the write.
239 * Useful combinations of the flag bits are:
241 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE: ensures that all pages
242 * in the range which were dirty on entry to sys_sync_file_range() are placed
243 * under writeout. This is a start-write-for-data-integrity operation.
245 * SYNC_FILE_RANGE_WRITE: start writeout of all dirty pages in the range which
246 * are not presently under writeout. This is an asynchronous flush-to-disk
247 * operation. Not suitable for data integrity operations.
249 * SYNC_FILE_RANGE_WAIT_BEFORE (or SYNC_FILE_RANGE_WAIT_AFTER): wait for
250 * completion of writeout of all pages in the range. This will be used after an
251 * earlier SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE operation to wait
252 * for that operation to complete and to return the result.
254 * SYNC_FILE_RANGE_WAIT_BEFORE|SYNC_FILE_RANGE_WRITE|SYNC_FILE_RANGE_WAIT_AFTER:
255 * a traditional sync() operation. This is a write-for-data-integrity operation
256 * which will ensure that all pages in the range which were dirty on entry to
257 * sys_sync_file_range() are committed to disk.
260 * SYNC_FILE_RANGE_WAIT_BEFORE and SYNC_FILE_RANGE_WAIT_AFTER will detect any
261 * I/O errors or ENOSPC conditions and will return those to the caller, after
262 * clearing the EIO and ENOSPC flags in the address_space.
264 * It should be noted that none of these operations write out the file's
265 * metadata. So unless the application is strictly performing overwrites of
266 * already-instantiated disk blocks, there are no guarantees here that the data
267 * will be available after a crash.
269 SYSCALL_DEFINE4(sync_file_range, int, fd, loff_t, offset, loff_t, nbytes,
270 unsigned int, flags)
272 int ret;
273 struct fd f;
274 struct address_space *mapping;
275 loff_t endbyte; /* inclusive */
276 umode_t i_mode;
278 ret = -EINVAL;
279 if (flags & ~VALID_FLAGS)
280 goto out;
282 endbyte = offset + nbytes;
284 if ((s64)offset < 0)
285 goto out;
286 if ((s64)endbyte < 0)
287 goto out;
288 if (endbyte < offset)
289 goto out;
291 if (sizeof(pgoff_t) == 4) {
292 if (offset >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
294 * The range starts outside a 32 bit machine's
295 * pagecache addressing capabilities. Let it "succeed"
297 ret = 0;
298 goto out;
300 if (endbyte >= (0x100000000ULL << PAGE_CACHE_SHIFT)) {
302 * Out to EOF
304 nbytes = 0;
308 if (nbytes == 0)
309 endbyte = LLONG_MAX;
310 else
311 endbyte--; /* inclusive */
313 ret = -EBADF;
314 f = fdget(fd);
315 if (!f.file)
316 goto out;
318 i_mode = file_inode(f.file)->i_mode;
319 ret = -ESPIPE;
320 if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
321 !S_ISLNK(i_mode))
322 goto out_put;
324 mapping = f.file->f_mapping;
325 if (!mapping) {
326 ret = -EINVAL;
327 goto out_put;
330 ret = 0;
331 if (flags & SYNC_FILE_RANGE_WAIT_BEFORE) {
332 ret = filemap_fdatawait_range(mapping, offset, endbyte);
333 if (ret < 0)
334 goto out_put;
337 if (flags & SYNC_FILE_RANGE_WRITE) {
338 ret = filemap_fdatawrite_range(mapping, offset, endbyte);
339 if (ret < 0)
340 goto out_put;
343 if (flags & SYNC_FILE_RANGE_WAIT_AFTER)
344 ret = filemap_fdatawait_range(mapping, offset, endbyte);
346 out_put:
347 fdput(f);
348 out:
349 return ret;
352 /* It would be nice if people remember that not all the world's an i386
353 when they introduce new system calls */
354 SYSCALL_DEFINE4(sync_file_range2, int, fd, unsigned int, flags,
355 loff_t, offset, loff_t, nbytes)
357 return sys_sync_file_range(fd, offset, nbytes, flags);