ext4: Create helper function for EXT4_IO_END_UNWRITTEN and i_aiodio_unwritten

EXT4_IO_END_UNWRITTEN flag set and the increase of i_aiodio_unwritten
should be done simultaneously since ext4_end_io_nolock always clear
the flag and decrease the counter in the same time.

We have found some bugs that the flag is set while leaving
i_aiodio_unwritten unchanged(commit 32c80b32c053d). So this patch just tries
to create a helper function to wrap them to avoid any future bug.
The idea is inspired by Eric.

Cc: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 1 insertions, 4 deletions

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e4b26faac5f..60af5126eb0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2831,10 +2831,7 @@ static void ext4_end_io_buffer_write(struct buffer_head *bh, int uptodate)
          * but being more careful is always safe for the future change.
          */
         inode = io_end->inode;
-        if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
-                io_end->flag |= EXT4_IO_END_UNWRITTEN;
-                atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
-        }
+        ext4_set_io_unwritten_flag(inode, io_end);
 
         /* Add the io_end to per-inode completed io list*/
         spin_lock_irqsave(&EXT4_I(inode)->i_completed_io_lock, flags);