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-rw-r--r--fs/ext4/fsync.c83
1 files changed, 83 insertions, 0 deletions
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 3f3ff5e..c1a7bc9 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