ext4: code clean up for dio fallocate handling

(cherry picked from commit 4b70df181611012a3556f017b57dfcef7e1d279f)

The ext4_debug() call in ext4_end_io_dio() should be moved after the
check to make sure that io_end is non-NULL.

The comment above ext4_get_block_dio_write() ("Maximum number of
blocks...") is a duplicate; the original and correct comment is above
the #define DIO_MAX_BLOCKS up above.

Based on review comments from Curt Wohlgemuth.

Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index fcb85d894de65ef74d3e1ef46f0cf3e98f1c5931..d7b3f2a1c41e57b5ceb464ed1b407efa82e33a44 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3440,8 +3440,6 @@ out:
        return ret;
 }
 
-/* Maximum number of blocks we map for direct IO at once. */
-
 static int ext4_get_block_dio_write(struct inode *inode, sector_t iblock,
                   struct buffer_head *bh_result, int create)
 {
@@ -3649,13 +3647,14 @@ static void ext4_end_io_dio(struct kiocb *iocb, loff_t offset,
         ext4_io_end_t *io_end = iocb->private;
        struct workqueue_struct *wq;
 
+       /* if not async direct IO or dio with 0 bytes write, just return */
+       if (!io_end || !size)
+               return;
+
        ext_debug("ext4_end_io_dio(): io_end 0x%p"
                  "for inode %lu, iocb 0x%p, offset %llu, size %llu\n",
                  iocb->private, io_end->inode->i_ino, iocb, offset,
                  size);
-       /* if not async direct IO or dio with 0 bytes write, just return */
-       if (!io_end || !size)
-               return;
 
        /* if not aio dio with unwritten extents, just free io and return */
        if (io_end->flag != DIO_AIO_UNWRITTEN){