1 files changed, 83 insertions, 0 deletions

diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 3f3ff5ee8f9d..c1a7bc923cf6 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -34,6 +34,89 @@
 
 #include <trace/events/ext4.h>
 
+static void dump_completed_IO(struct inode * inode)
+{
+#ifdef  EXT4_DEBUG
+        struct list_head *cur, *before, *after;
+        ext4_io_end_t *io, *io0, *io1;
+        unsigned long flags;
+
+        if (list_empty(&EXT4_I(inode)->i_completed_io_list)){
+                ext4_debug("inode %lu completed_io list is empty\n", inode->i_ino);
+                return;
+        }
+
+        ext4_debug("Dump inode %lu completed_io list \n", inode->i_ino);
+        spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);
+        list_for_each_entry(io, &EXT4_I(inode)->i_completed_io_list, list){
+                cur = &io->list;
+                before = cur->prev;
+                io0 = container_of(before, ext4_io_end_t, list);
+                after = cur->next;
+                io1 = container_of(after, ext4_io_end_t, list);
+
+                ext4_debug("io 0x%p from inode %lu,prev 0x%p,next 0x%p\n",
+                            io, inode->i_ino, io0, io1);
+        }
+        spin_unlock_irqrestore(&EXT4_I(inode)->i_completed_io_lock, flags);
+#endif
+}
+
+/*
+ * This function is called from ext4_sync_file().
+ *
+ * When IO is completed, the work to convert unwritten extents to
+ * written is queued on workqueue but may not get immediately
+ * scheduled. When fsync is called, we need to ensure the
+ * conversion is complete before fsync returns.
+ * The inode keeps track of a list of pending/completed IO that
+ * might needs to do the conversion. This function walks through
+ * the list and convert the related unwritten extents for completed IO
+ * to written.
+ * The function return the number of pending IOs on success.
+ */
+static int flush_completed_IO(struct inode *inode)
+{
+        ext4_io_end_t *io;
+        struct ext4_inode_info *ei = EXT4_I(inode);
+        unsigned long flags;
+        int ret = 0;
+        int ret2 = 0;
+
+        if (list_empty(&ei->i_completed_io_list))
+                return ret;
+
+        dump_completed_IO(inode);
+        spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+        while (!list_empty(&ei->i_completed_io_list)){
+                io = list_entry(ei->i_completed_io_list.next,
+                                ext4_io_end_t, list);
+                /*
+                 * Calling ext4_end_io_nolock() to convert completed
+                 * IO to written.
+                 *
+                 * When ext4_sync_file() is called, run_queue() may already
+                 * about to flush the work corresponding to this io structure.
+                 * It will be upset if it founds the io structure related
+                 * to the work-to-be schedule is freed.
+                 *
+                 * Thus we need to keep the io structure still valid here after
+                 * convertion finished. The io structure has a flag to
+                 * avoid double converting from both fsync and background work
+                 * queue work.
+                 */
+                spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+                ret = ext4_end_io_nolock(io);
+                spin_lock_irqsave(&ei->i_completed_io_lock, flags);
+                if (ret < 0)
+                        ret2 = ret;
+                else
+                        list_del_init(&io->list);
+        }
+        spin_unlock_irqrestore(&ei->i_completed_io_lock, flags);
+        return (ret2 < 0) ? ret2 : 0;
+}
+
 /*
  * If we're not journaling and this is a just-created file, we have to
  * sync our parent directory (if it was freshly created) since