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>

4 files changed, 18 insertions, 20 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 657e82649fa5..604c200216c1 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1275,6 +1275,15 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
                  ino <= le32_to_cpu(EXT4_SB(sb)->s_es->s_inodes_count));
 }
 
+static inline void ext4_set_io_unwritten_flag(struct inode *inode,
+                                              struct ext4_io_end *io_end)
+{
+        if (!(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
+                io_end->flag |= EXT4_IO_END_UNWRITTEN;
+                atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
+        }
+}
+
 /*
  * Inode dynamic state flags
  */
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 36a0f177ecad..a5c8caaaa099 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3472,12 +3472,9 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
                  * that this IO needs to conversion to written when IO is
                  * completed
                  */
-                if (io) {
-                        if (!(io->flag & EXT4_IO_END_UNWRITTEN)) {
-                                io->flag = EXT4_IO_END_UNWRITTEN;
-                                atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
-                        }
-                } else
+                if (io)
+                        ext4_set_io_unwritten_flag(inode, io);
+                else
                         ext4_set_inode_state(inode, EXT4_STATE_DIO_UNWRITTEN);
                 if (ext4_should_dioread_nolock(inode))
                         map->m_flags |= EXT4_MAP_UNINIT;
@@ -4030,12 +4027,9 @@ got_allocated_blocks:
                  * that we need to perform conversion when IO is done.
                  */
                 if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
-                        if (io) {
-                                if (!(io->flag & EXT4_IO_END_UNWRITTEN)) {
-                                        io->flag = EXT4_IO_END_UNWRITTEN;
-                                        atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
-                                }
-                        } else
+                        if (io)
+                                ext4_set_io_unwritten_flag(inode, io);
+                        else
                                 ext4_set_inode_state(inode,
                                                      EXT4_STATE_DIO_UNWRITTEN);
                 }
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index e4b26faac5ff..60af5126eb05 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);
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 9eebf44646f6..7ce1d0b19c94 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -336,10 +336,8 @@ submit_and_retry:
         if ((io_end->num_io_pages >= MAX_IO_PAGES) &&
             (io_end->pages[io_end->num_io_pages-1] != io_page))
                 goto submit_and_retry;
-        if (buffer_uninit(bh) && !(io_end->flag & EXT4_IO_END_UNWRITTEN)) {
-                io_end->flag |= EXT4_IO_END_UNWRITTEN;
-                atomic_inc(&EXT4_I(inode)->i_aiodio_unwritten);
-        }
+        if (buffer_uninit(bh))
+                ext4_set_io_unwritten_flag(inode, io_end);
         io->io_end->size += bh->b_size;
         io->io_next_block++;
         ret = bio_add_page(io->io_bio, bh->b_page, bh->b_size, bh_offset(bh));