linux-kernel - [PATCH 3/3] ext4: pass in DIO_SKIP_DIO_COUNT to do_blockdev_direct

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Date:	Wed, 15 Apr 2015 16:01:38 -0600
From:	Jens Axboe <axboe@...com>
To:	<linux-kernel@...r.kernel.org>, <linux-fsdevel@...r.kernel.org>
CC:	Jens Axboe <axboe@...com>, "Theodore Ts'o" <tytso@....edu>
Subject: [PATCH 3/3] ext4: pass in DIO_SKIP_DIO_COUNT to do_blockdev_direct_IO()

For writes, ext4_ext_direct_IO() already holds the inode i_dio_count
elevated, so we don't need the extra inc/dec that is done in
do_blockdev_direct_IO(). Pass in DIO_SKIP_DIO_COUNT to tell it that.

Cc: Theodore Ts'o <tytso@....edu>
Signed-off-by: Jens Axboe <axboe@...com>
---
 fs/ext4/inode.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 62d4615aa9b0..2605355791a3 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -2977,8 +2977,10 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 	 * conversion. This also disallows race between truncate() and
 	 * overwrite DIO as i_dio_count needs to be incremented under i_mutex.
 	 */
-	if (rw == WRITE)
+	if (rw == WRITE) {
 		inode_dio_inc(inode);
+		dio_flags |= DIO_SKIP_DIO_COUNT;
+	}
 
 	/* If we do a overwrite dio, i_mutex locking can be released */
 	overwrite = *((int *)iocb->private);
@@ -3032,7 +3034,7 @@ static ssize_t ext4_ext_direct_IO(int rw, struct kiocb *iocb,
 		get_block_func = ext4_get_block_write_nolock;
 	} else {
 		get_block_func = ext4_get_block_write;
-		dio_flags = DIO_LOCKING;
+		dio_flags |= DIO_LOCKING;
 	}
 	if (IS_DAX(inode))
 		ret = dax_do_io(rw, iocb, inode, iter, offset, get_block_func,
-- 
1.9.1

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