xfs: introduce xfs_buf_submit[_wait]

There is a lot of cookie-cutter code that looks like:

	if (shutdown)
		handle buffer error
	xfs_buf_iorequest(bp)
	error = xfs_buf_iowait(bp)
	if (error)
		handle buffer error

spread through XFS. There's significant complexity now in
xfs_buf_iorequest() to specifically handle this sort of synchronous
IO pattern, but there's all sorts of nasty surprises in different
error handling code dependent on who owns the buffer references and
the locks.

Pull this pattern into a single helper, where we can hide all the
synchronous IO warts and hence make the error handling for all the
callers much saner. This removes the need for a special extra
reference to protect IO completion processing, as we can now hold a
single reference across dispatch and waiting, simplifying the sync
IO smeantics and error handling.

In doing this, also rename xfs_buf_iorequest to xfs_buf_submit and
make it explicitly handle on asynchronous IO. This forces all users
to be switched specifically to one interface or the other and
removes any ambiguity between how the interfaces are to be used. It
also means that xfs_buf_iowait() goes away.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/xfs/xfs_buf_item.c b/fs/xfs/xfs_buf_item.c
index 4fd41b58e6d2..cbea9099b843 100644
--- a/fs/xfs/xfs_buf_item.c
+++ b/fs/xfs/xfs_buf_item.c
@@ -1081,7 +1081,7 @@ xfs_buf_iodone_callbacks(
 	 * a way to shut the filesystem down if the writes keep failing.
 	 *
 	 * In practice we'll shut the filesystem down soon as non-transient
-	 * erorrs tend to affect the whole device and a failing log write
+	 * errors tend to affect the whole device and a failing log write
 	 * will make us give up.  But we really ought to do better here.
 	 */
 	if (XFS_BUF_ISASYNC(bp)) {
@@ -1094,7 +1094,7 @@ xfs_buf_iodone_callbacks(
 		if (!(bp->b_flags & (XBF_STALE|XBF_WRITE_FAIL))) {
 			bp->b_flags |= XBF_WRITE | XBF_ASYNC |
 				       XBF_DONE | XBF_WRITE_FAIL;
-			xfs_buf_iorequest(bp);
+			xfs_buf_submit(bp);
 		} else {
 			xfs_buf_relse(bp);
 		}