Re: [PATCH 1/2] ext4: fix DAX write locking
From: Jan Kara <jack@suse.cz>
Date: 2017-01-11 09:01:41
Also in:
linux-fsdevel, nvdimm
On Tue 10-01-17 16:48:07, Christoph Hellwig wrote:
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>
Makes sense. You can add: Reviewed-by: Jan Kara <jack@suse.cz> Ted, can you please pick it up? Thanks! Honza
quoted hunk ↗ jump to hunk
--- 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
-- Jan Kara [off-list ref] SUSE Labs, CR