GFS2: Allocate reservation during splice_write

This patch adds a GFS2-specific function for splice_write which
first calls function gfs2_rs_alloc to make sure a reservation
structure has been allocated before attempting to reserve blocks.
Signed-off-by: NBob Peterson <rpeterso@redhat.com>
Acked-by: NSteven Whitehouse <swhiteho@redhat.com>

fs/gfs2/file.c

@@ -1063,6 +1063,22 @@ static int gfs2_flock(struct file *file, int cmd, struct file_lock *fl)
 	}
 }
 
+static ssize_t gfs2_file_splice_write(struct pipe_inode_info *pipe,
+				      struct file *out, loff_t *ppos,
+				      size_t len, unsigned int flags)
+{
+	int error;
+	struct gfs2_inode *ip = GFS2_I(out->f_mapping->host);
+
+	error = gfs2_rs_alloc(ip);
+	if (error)
+		return (ssize_t)error;
+
+	gfs2_size_hint(out, *ppos, len);
+
+	return iter_file_splice_write(pipe, out, ppos, len, flags);
+}
+
 const struct file_operations gfs2_file_fops = {
 	.llseek		= gfs2_llseek,
 	.read		= new_sync_read,
@@ -1077,7 +1093,7 @@ const struct file_operations gfs2_file_fops = {
 	.lock		= gfs2_lock,
 	.flock		= gfs2_flock,
 	.splice_read	= generic_file_splice_read,
-	.splice_write	= iter_file_splice_write,
+	.splice_write	= gfs2_file_splice_write,
 	.setlease	= simple_nosetlease,
 	.fallocate	= gfs2_fallocate,
 };
@@ -1107,7 +1123,7 @@ const struct file_operations gfs2_file_fops_nolock = {
 	.release	= gfs2_release,
 	.fsync		= gfs2_fsync,
 	.splice_read	= generic_file_splice_read,
-	.splice_write	= iter_file_splice_write,
+	.splice_write	= gfs2_file_splice_write,
 	.setlease	= generic_setlease,
 	.fallocate	= gfs2_fallocate,
 };