sync_inodes_sb(sb);
}
-static void writeback_inodes_one_sb(struct super_block *sb, void *arg)
-{
- if (!(sb->s_flags & MS_RDONLY))
- writeback_inodes_sb(sb, WB_REASON_SYNC);
-}
-
static void sync_fs_one_sb(struct super_block *sb, void *arg)
{
if (!(sb->s_flags & MS_RDONLY) && sb->s_op->sync_fs)
sb->s_op->sync_fs(sb, *(int *)arg);
}
-static void flush_one_bdev(struct block_device *bdev, void *arg)
+static void fdatawrite_one_bdev(struct block_device *bdev, void *arg)
{
- __sync_blockdev(bdev, 0);
+ filemap_fdatawrite(bdev->bd_inode->i_mapping);
}
-static void sync_one_bdev(struct block_device *bdev, void *arg)
+static void fdatawait_one_bdev(struct block_device *bdev, void *arg)
{
- sync_blockdev(bdev);
+ 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);
- iterate_supers(writeback_inodes_one_sb, NULL);
- iterate_supers(sync_fs_one_sb, &nowait);
- iterate_bdevs(flush_one_bdev, NULL);
iterate_supers(sync_inodes_one_sb, NULL);
+ iterate_supers(sync_fs_one_sb, &nowait);
iterate_supers(sync_fs_one_sb, &wait);
- iterate_bdevs(sync_one_bdev, NULL);
+ iterate_bdevs(fdatawrite_one_bdev, NULL);
+ iterate_bdevs(fdatawait_one_bdev, NULL);
if (unlikely(laptop_mode))
laptop_sync_completion();
return 0;
*/
iterate_supers(sync_inodes_one_sb, &nowait);
iterate_supers(sync_fs_one_sb, &nowait);
- iterate_bdevs(flush_one_bdev, NULL);
+ iterate_bdevs(fdatawrite_one_bdev, NULL);
iterate_supers(sync_inodes_one_sb, &nowait);
iterate_supers(sync_fs_one_sb, &nowait);
- iterate_bdevs(flush_one_bdev, NULL);
+ iterate_bdevs(fdatawrite_one_bdev, NULL);
printk("Emergency Sync complete\n");
kfree(work);
}