From ff5462e39ca1d27e530d088c4e38741fd9cddad4 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 8 Feb 2017 14:39:27 -0500 Subject: [PATCH] ext4: fix DAX write locking MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Unlike O_DIRECT DAX is not an optional opt-in feature selected by the application, so we'll have to provide the traditional synchronіzation of overlapping writes as we do for buffered writes. This was broken historically for DAX, but got fixed for ext2 and XFS as part of the iomap conversion. Fix up ext4 as well. Signed-off-by: Christoph Hellwig Signed-off-by: Theodore Ts'o Reviewed-by: Jan Kara --- fs/ext4/file.c | 10 +--------- 1 file changed, 1 insertion(+), 9 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index ff3f6107b0ba..87e11dfe3cde 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -178,7 +178,6 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) { struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; - bool overwrite = false; inode_lock(inode); ret = ext4_write_checks(iocb, from); @@ -191,16 +190,9 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) if (ret) goto out; - if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) { - overwrite = true; - downgrade_write(&inode->i_rwsem); - } ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops); out: - if (!overwrite) - inode_unlock(inode); - else - inode_unlock_shared(inode); + inode_unlock(inode); if (ret > 0) ret = generic_write_sync(iocb, ret); return ret; -- 2.20.1