Merge branch 'next' into upstream-merge

[net-next-2.6.git] / fs / ext4 / fsync.c

diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 3f3ff5ee8f9d620b70c4d4f3adf119cde0b343af..c1a7bc923cf6084c84f32b91294ec5feecf8b92c 100644 (file)
--- 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