fix ITER_PIPE interaction with direct_IO
by making sure we call iov_iter_advance() on original
iov_iter even if direct_IO (done on its copy) has returned 0.
It's a no-op for old iov_iter flavours and does the right thing
(== truncation of the stuff we'd allocated, but not filled) in
ITER_PIPE case. Failures (e.g. -EIO) get caught and dealt with
by cleanup in generic_file_read_iter().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/splice.c b/fs/splice.c
index aa38901..153d4f3 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -315,15 +315,9 @@
*ppos = kiocb.ki_pos;
file_accessed(in);
} else if (ret < 0) {
- if (WARN_ON(to.idx != idx || to.iov_offset)) {
- /*
- * a bogus ->read_iter() has copied something and still
- * returned an error instead of a short read.
- */
- to.idx = idx;
- to.iov_offset = 0;
- iov_iter_advance(&to, 0); /* to free what was emitted */
- }
+ to.idx = idx;
+ to.iov_offset = 0;
+ iov_iter_advance(&to, 0); /* to free what was emitted */
/*
* callers of ->splice_read() expect -EAGAIN on
* "can't put anything in there", rather than -EFAULT.
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 92f16cf..26cf153 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -317,7 +317,7 @@
data = *to;
ret = __blockdev_direct_IO(iocb, inode, target->bt_bdev, &data,
xfs_get_blocks_direct, NULL, NULL, 0);
- if (ret > 0) {
+ if (ret >= 0) {
iocb->ki_pos += ret;
iov_iter_advance(to, ret);
}
diff --git a/mm/filemap.c b/mm/filemap.c
index 8a287df..6b965ef 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1920,7 +1920,7 @@
retval = mapping->a_ops->direct_IO(iocb, &data);
}
- if (retval > 0) {
+ if (retval >= 0) {
iocb->ki_pos += retval;
iov_iter_advance(iter, retval);
}