[PATCH 1/2] ext4: fix DAX write locking
From: Christoph Hellwig <hch@lst.de>
Date: 2017-01-10 15:48:14
Also in:
linux-fsdevel, nvdimm
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
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 <hch@lst.de> --- 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 d663d3d..a1e88aa 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c@@ -175,7 +175,6 @@ 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);
@@ -188,16 +187,9 @@ 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;
--
2.1.4