X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=fs%2Fsync.c;h=14eefeb44636bd1e24240ae09fe0dd046ed013fa;hb=ca279cf1065fb689abea1dc7d8c11787729bb185;hp=11e3d1c449018dcf9a95c352746f46d6522c4cb2;hpb=10af8138eb6d09d6a768e43ef1aa9b2f16b8c7be;p=firefly-linux-kernel-4.4.55.git

diff --git a/fs/sync.c b/fs/sync.c
index 11e3d1c44901..14eefeb44636 100644
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -29,16 +29,6 @@
  */
 static int __sync_filesystem(struct super_block *sb, int wait)
 {
-	/*
-	 * This should be safe, as we require bdi backing to actually
-	 * write out data in the first place
-	 */
-	if (sb->s_bdi == &noop_backing_dev_info)
-		return 0;
-
-	if (sb->s_qcop && sb->s_qcop->quota_sync)
-		sb->s_qcop->quota_sync(sb, -1, wait);
-
 	if (wait)
 		sync_inodes_sb(sb);
 	else
@@ -77,29 +67,48 @@ int sync_filesystem(struct super_block *sb)
 }
 EXPORT_SYMBOL_GPL(sync_filesystem);
 
-static void sync_one_sb(struct super_block *sb, void *arg)
+static void sync_inodes_one_sb(struct super_block *sb, void *arg)
 {
 	if (!(sb->s_flags & MS_RDONLY))
-		__sync_filesystem(sb, *(int *)arg);
+		sync_inodes_sb(sb);
 }
-/*
- * Sync all the data for all the filesystems (called by sys_sync() and
- * emergency sync)
- */
-static void sync_filesystems(int wait)
+
+static void sync_fs_one_sb(struct super_block *sb, void *arg)
 {
-	iterate_supers(sync_one_sb, &wait);
+	if (!(sb->s_flags & MS_RDONLY) && sb->s_op->sync_fs)
+		sb->s_op->sync_fs(sb, *(int *)arg);
+}
+
+static void fdatawrite_one_bdev(struct block_device *bdev, void *arg)
+{
+	filemap_fdatawrite(bdev->bd_inode->i_mapping);
+}
+
+static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
+{
+	filemap_fdatawait(bdev->bd_inode->i_mapping);
 }
 
 /*
- * sync everything.  Start out by waking pdflush, because that writes back
- * all queues in parallel.
+ * Sync everything. We start by waking flusher threads so that most of
+ * writeback runs on all devices in parallel. Then we sync all inodes reliably
+ * which effectively also waits for all flusher threads to finish doing
+ * writeback. At this point all data is on disk so metadata should be stable
+ * and we tell filesystems to sync their metadata via ->sync_fs() calls.
+ * Finally, we writeout all block devices because some filesystems (e.g. ext2)
+ * just write metadata (such as inodes or bitmaps) to block device page cache
+ * and do not sync it on their own in ->sync_fs().
  */
 SYSCALL_DEFINE0(sync)
 {
+	int nowait = 0, wait = 1;
+
 	wakeup_flusher_threads(0, WB_REASON_SYNC);
-	sync_filesystems(0);
-	sync_filesystems(1);
+	iterate_supers(sync_inodes_one_sb, NULL);
+	iterate_supers(sync_fs_one_sb, &nowait);
+	iterate_supers(sync_fs_one_sb, &wait);
+	iterate_bdevs(fdatawrite_one_bdev, NULL);
+	iterate_bdevs(fdatawait_one_bdev, NULL);
 	if (unlikely(laptop_mode))
 		laptop_sync_completion();
 	return 0;
@@ -107,12 +116,18 @@ SYSCALL_DEFINE0(sync)
 
 static void do_sync_work(struct work_struct *work)
 {
+	int nowait = 0;
+
 	/*
 	 * Sync twice to reduce the possibility we skipped some inodes / pages
 	 * because they were temporarily locked
 	 */
-	sync_filesystems(0);
-	sync_filesystems(0);
+	iterate_supers(sync_inodes_one_sb, &nowait);
+	iterate_supers(sync_fs_one_sb, &nowait);
+	iterate_bdevs(fdatawrite_one_bdev, NULL);
+	iterate_supers(sync_inodes_one_sb, &nowait);
+	iterate_supers(sync_fs_one_sb, &nowait);
+	iterate_bdevs(fdatawrite_one_bdev, NULL);
 	printk("Emergency Sync complete\n");
 	kfree(work);
 }
@@ -133,21 +148,19 @@ void emergency_sync(void)
  */
 SYSCALL_DEFINE1(syncfs, int, fd)
 {
-	struct file *file;
+	struct fd f = fdget(fd);
 	struct super_block *sb;
 	int ret;
-	int fput_needed;
 
-	file = fget_light(fd, &fput_needed);
-	if (!file)
+	if (!f.file)
 		return -EBADF;
-	sb = file->f_dentry->d_sb;
+	sb = f.file->f_dentry->d_sb;
 
 	down_read(&sb->s_umount);
 	ret = sync_filesystem(sb);
 	up_read(&sb->s_umount);
 
-	fput_light(file, fput_needed);
+	fdput(f);
 	return ret;
 }
 
@@ -186,14 +199,12 @@ EXPORT_SYMBOL(vfs_fsync);
 
 static int do_fsync(unsigned int fd, int datasync)
 {
-	struct file *file;
+	struct fd f = fdget(fd);
 	int ret = -EBADF;
-	int fput_needed;
 
-	file = fget_light(fd, &fput_needed);
-	if (file) {
-		ret = vfs_fsync(file, datasync);
-		fput_light(file, fput_needed);
+	if (f.file) {
+		ret = vfs_fsync(f.file, datasync);
+		fdput(f);
 	}
 	return ret;
 }
@@ -276,10 +287,9 @@ SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
 				unsigned int flags)
 {
 	int ret;
-	struct file *file;
+	struct fd f;
 	struct address_space *mapping;
 	loff_t endbyte;			/* inclusive */
-	int fput_needed;
 	umode_t i_mode;
 
 	ret = -EINVAL;
@@ -318,17 +328,17 @@ SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
 		endbyte--;		/* inclusive */
 
 	ret = -EBADF;
-	file = fget_light(fd, &fput_needed);
-	if (!file)
+	f = fdget(fd);
+	if (!f.file)
 		goto out;
 
-	i_mode = file->f_path.dentry->d_inode->i_mode;
+	i_mode = f.file->f_path.dentry->d_inode->i_mode;
 	ret = -ESPIPE;
 	if (!S_ISREG(i_mode) && !S_ISBLK(i_mode) && !S_ISDIR(i_mode) &&
 			!S_ISLNK(i_mode))
 		goto out_put;
 
-	mapping = file->f_mapping;
+	mapping = f.file->f_mapping;
 	if (!mapping) {
 		ret = -EINVAL;
 		goto out_put;
@@ -351,7 +361,7 @@ SYSCALL_DEFINE(sync_file_range)(int fd, loff_t offset, loff_t nbytes,
 		ret = filemap_fdatawait_range(mapping, offset, endbyte);
 
 out_put:
-	fput_light(file, fput_needed);
+	fdput(f);
 out:
 	return ret;
 }