Merge tag 'firewire-updates' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee139...

[linux-block.git] / fs / sync.c

diff --git a/fs/sync.c b/fs/sync.c
index 0b166f26362d216c8f8c8bfefe175401c812d926..eb8722dc556f5b567c40438919c6ef1ddeef084d 100644 (file)
--- a/fs/sync.c
+++ b/fs/sync.c
@@ -73,43 +73,42 @@ static void sync_inodes_one_sb(struct super_block *sb, void *arg)
                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;
@@ -125,10 +124,10 @@ static void do_sync_work(struct work_struct *work)
         */
        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);
 }