->splice_write() via ->write_iter()

iter_file_splice_write() - a ->splice_write() instance that gathers the
pipe buffers, builds a bio_vec-based iov_iter covering those and feeds
it to ->write_iter().  A bunch of simple cases coverted to that...

[AV: fixed the braino spotted by Cyrill]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 1 insertions, 43 deletions

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 5446e86..b1c489c 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -343,47 +343,6 @@ xfs_file_splice_read(
 }
 
 /*
- * xfs_file_splice_write() does not use xfs_rw_ilock() because
- * generic_file_splice_write() takes the i_mutex itself. This, in theory,
- * couuld cause lock inversions between the aio_write path and the splice path
- * if someone is doing concurrent splice(2) based writes and write(2) based
- * writes to the same inode. The only real way to fix this is to re-implement
- * the generic code here with correct locking orders.
- */
-STATIC ssize_t
-xfs_file_splice_write(
-	struct pipe_inode_info	*pipe,
-	struct file		*outfilp,
-	loff_t			*ppos,
-	size_t			count,
-	unsigned int		flags)
-{
-	struct inode		*inode = outfilp->f_mapping->host;
-	struct xfs_inode	*ip = XFS_I(inode);
-	int			ioflags = 0;
-	ssize_t			ret;
-
-	XFS_STATS_INC(xs_write_calls);
-
-	if (outfilp->f_mode & FMODE_NOCMTIME)
-		ioflags |= IO_INVIS;
-
-	if (XFS_FORCED_SHUTDOWN(ip->i_mount))
-		return -EIO;
-
-	xfs_ilock(ip, XFS_IOLOCK_EXCL);
-
-	trace_xfs_file_splice_write(ip, count, *ppos, ioflags);
-
-	ret = generic_file_splice_write(pipe, outfilp, ppos, count, flags);
-	if (ret > 0)
-		XFS_STATS_ADD(xs_write_bytes, ret);
-
-	xfs_iunlock(ip, XFS_IOLOCK_EXCL);
-	return ret;
-}
-
-/*
  * This routine is called to handle zeroing any space in the last block of the
  * file that is beyond the EOF.  We do this since the size is being increased
  * without writing anything to that block and we don't want to read the
@@ -1442,7 +1401,7 @@ const struct file_operations xfs_file_operations = {
 	.read_iter	= xfs_file_read_iter,
 	.write_iter	= xfs_file_write_iter,
 	.splice_read	= xfs_file_splice_read,
-	.splice_write	= xfs_file_splice_write,
+	.splice_write	= iter_file_splice_write,
 	.unlocked_ioctl	= xfs_file_ioctl,
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= xfs_file_compat_ioctl,
diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 65d8c79..53182f9 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -1060,7 +1060,6 @@ DEFINE_RW_EVENT(xfs_file_read);
 DEFINE_RW_EVENT(xfs_file_buffered_write);
 DEFINE_RW_EVENT(xfs_file_direct_write);
 DEFINE_RW_EVENT(xfs_file_splice_read);
-DEFINE_RW_EVENT(xfs_file_splice_write);
 
 DECLARE_EVENT_CLASS(xfs_page_class,
 	TP_PROTO(struct inode *inode, struct page *page, unsigned long off,