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authorChristoph Hellwig <hch@lst.de>2017-02-08 14:39:27 -0500
committerTheodore Ts'o <tytso@mit.edu>2017-02-08 14:39:27 -0500
commitff5462e39ca1d27e530d088c4e38741fd9cddad4 (patch)
tree5a1baca148ac859d2f676e2f0bb120e23fef764d
parent783d948544993f55bdacc78b127532e8b6e2fc9f (diff)
downloadlinux-ff5462e39ca1d27e530d088c4e38741fd9cddad4.tar.bz2
ext4: fix DAX write locking
Unlike O_DIRECT DAX is not an optional opt-in feature selected by the application, so we'll have to provide the traditional synchronŃ–zation 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> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/ext4/file.c10
1 files changed, 1 insertions, 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;